METEORIN-LIKE PROTEIN (METRNL) AS (BLOOD) BIOMARKER FOR THE DIAGNOSIS OF POLYCYSTIC OVARIAN SYNDROME

Abstract

The present invention relates to a method for assessing whether a subject has Polycystic Ovarian Syndrome (PCOS) or is at risk of developing PCOS, to a method of selecting a patient for therapy of PCOS, to a method for monitoring PCOS progression or for monitoring response to treatment and to a computer-implemented method for assessing a subject with suspected PCOS, by determining the amount or concentration of Meteorin-like protein (METRNL) in a sample of the subject.

Claims

1. A method of assessing whether a subject has Polycystic Ovarian Syndrome (PCOS) or is at risk of developing PCOS, said method comprising: a) determining the amount or concentration of METRNL in a sample of the subject; and b) comparing the determined amount or concentration to a reference.

2. A method of selecting a patient for therapy of PCOS, said method comprising: a) determining the amount or concentration of METRNL in a sample of the subject; and b) comparing the determined amount or concentration to a reference.

3. A method for monitoring PCOS progression in a subject having PCOS or for monitoring response to treatment in a subject having PCOS, said method comprising: a) determining the level of METRNL in a first sample of the subject; b) determining the level of METRNL in a second sample of the subject which has been obtained after the first sample; c) comparing the level of METRNL in the first sample to the level of METRNL in the second sample; and d) monitoring progression in the subject suffering from PCOS or being treated for PCOS, based on the results of step c).

4. The method of claim 1, wherein a decreased amount or concentration of METRNL in the sample of the subject is indicative of the presence of PCOS in the subject.

5. The method of claim 1, wherein the sample is a blood, a serum or a plasma sample.

6. The method of claim 1, wherein PCOS is selected from the group consisting of PCOS of phenotype A, PCOS of phenotype B, PCOS of phenotype C and PCOS of phenotype D according to the Rotterdam scale.

7. The method of claim 1, wherein PCOS of phenotype A is detected.

8. The method of claim 1, wherein PCOS of phenotype B is detected.

9. The method of claim 1, wherein PCOS of phenotype C is detected.

10. The method of claim 1, wherein PCOS of phenotype D is detected.

11. The method of claim 1, wherein PCOS is detected in adolescents or young women.

12. The method of claim 1, wherein the subject suffers from oligo-anovulation, irregular cycles, hyperandrogenism, polycystic ovarian morphology, infertility, diabetes type 2, obesity, and/or psychological distress.

13. (canceled)

14. (canceled)

15. The method of claim 1, wherein the subject is a human.

16. The method of claim 2, wherein the therapy is a drug-based therapy of PCOS or lifestyle changes to control metabolic symptoms.

17. The method of claim 16, wherein the drug-based therapy of PCOS is selected from the group consisting of drugs for regulating periods, drugs for preventing or controlling diabetes, drugs for preventing or controlling high cholesterol, hormones or drugs to increase fertility, hormones to remove excess hair, and drugs to control acne.

18. The method of claim 1, wherein the determination of the amount or concentration of METRNL comprises contacting the sample with an antibody, or antigen-binding fragment thereof, which specifically detects METRNL.

19. The method of claim 18, wherein the determination of the amount or concentration of METRNL comprises performing an immunoassay, and wherein the immunoassay is selected from the group consisting of an enzyme linked immunosorbent assay (ELISA), an enzyme immunoassay (EIA), a radioimmunoassay (RIA), and an immuno assay based on detection of luminescence, fluorescence, chemiluminescence or electrochemiluminescence.

20. The method of claim 1, wherein step a) comprises: i) incubating the sample of the subject with one or more antibodies specifically binding to METRNL, thereby generating a complex between the antibody and METRNL, and ii) quantifying the complex formed in step i), thereby quantifying the amount or concentration of METRNL in the sample of the subject.

21. The method of claim 20, wherein in step i), the sample is incubated with two antibodies specifically binding to METRNL.

22. The method of claim 21, wherein a sandwich will be formed comprising a first antibody to METRNL, METRNL (analyte) and the second antibody to METRNL, wherein the second antibody is detectably labeled.

Description

LIST OF FIGURES

[0040] FIG. 1. ROC curve analysis for Meteorin-like protein. Results obtained using Olink proximity extension technology.

[0041] FIG. 2. Serum Meteorin-like protein in PCOS cases (only phenotype A) versus controls. Results obtained using Olink proximity extension technology.

[0042] FIG. 3. ROC curve analysis for Meteorin-like protein for PCOS cases when all phenotypes were combined (phenotypes A-D). Results obtained by ELISA immunoassay.

[0043] FIG. 4. Serum Meteorin-like protein (pg/mL) of controls versus PCOS cases when all phenotypes were combined (phenotypes A-D). Results obtained using ELISA immunoassays.

[0044] FIG. 5. ROC curves for PCOS phenotypes A-D when compared to controls. Results obtained by ELISA immunoassay.

[0045] FIG. 6. Serum Meteorin-like protein (pg/mL) in healthy controls and in PCOS phenotypes A-D. Results obtained using ELISA immunoassay.

[0046] FIG. 7. ROC curve analysis for Meteorin-like protein for young PCOS cases (age25) when all phenotypes A-D were combined. Results obtained using ELISA immunoassay.

[0047] FIG. 8. Serum Meteorin-like protein concentrations (pg/mL) of young controls versus young PCOS cases (age25) combined phenotypes A-D. The results were obtained using ELISA immunoassay.

[0048] FIG. 9. ROC curves for Meteorin-like protein for young PCOS cases (age25) separated by phenotypes A-D versus young healthy controls (age25). The results were obtained using ELISA immunoassay.

[0049] FIG. 10. Serum Meteorin-like protein concentrations (pg/mL) in young healthy controls (age25) and in PCOS phenotypes A-D (age25). Results obtained by ELISA immunoassay.

[0050] FIG. 11. ROC curve analysis for Meteorin-like protein for PCOS cases when all phenotypes were combined (phenotypes A-D). Results obtained by ELISA immunoassay.

[0051] FIG. 12. Serum Meteorin-like protein concentrations (pg/mL) of controls versus PCOS cases when all phenotypes were combined (phenotypes A-D). Results obtained using ELISA immunoassays.

[0052] FIG. 13. ROC curves for Meteorin-like protein for PCOS phenotypes A-D when compared to controls. Results obtained by ELISA immunoassay.

[0053] FIG. 14. Serum Meteorin-like protein (pg/mL) in healthy controls and in PCOS phenotypes A-D. Results obtained using ELISA immunoassay.

[0054] FIG. 15. ROC curves for Meteorin-like protein for different PCOS age groups (15-20, 20-25, 25-45) when compared to controls. Results obtained by ELISA immunoassay.

[0055] FIG. 16. Serum Meteorin-like protein (pg/mL) in healthy controls and in PCOS age groups (15-20, 20-25, 25-45). Results obtained using ELISA immunoassay.

[0056] FIG. 17. ROC curve analysis for Meteorin-like protein for young PCOS cases (age 15-25) when all phenotypes A-D were combined. Results obtained using ELISA immunoassay.

[0057] FIG. 18. Serum Meteorin-like protein (pg/mL) of young controls versus young PCOS cases (age 15-25) combined phenotypes A-D. The results were obtained using ELISA immunoassay.

[0058] FIG. 19. ROC curves for Meteorin-like protein for young PCOS cases (age 15-25) separated by phenotypes A-D versus young healthy controls (age 15-25). The results were obtained using ELISA immunoassay.

[0059] FIG. 20. Serum Meteorin-like protein concentrations (pg/mL) in young healthy controls (age 15-25) and in PCOS phenotypes A-D (age 15-25). Results obtained by ELISA immunoassay.

DETAILED DESCRIPTION OF THE INVENTION

[0060] The inventors of the present invention have identified Meteorin-like protein (METRNL) as a reliable biomarker for diagnosing PCOS in a subject, for determining if the subject is at risk of developing PCOS, for selecting a patient with PCOS for therapy, or to monitor PCOS progression in a subject having PCOS, or to monitor response to therapy in a subject having PCOS. METRNL can be used either alone or in combination with at least an additional criterion such hyperandrogenism, oligo-anovulation, PCOM or irregular cycles for the diagnosis, risk assessment and/or monitoring response to therapy in a patient. Further, determination of the level of METRNL compared to a control level can be used to monitor response to a treatment and/or to monitor PCOS progression in said subject.

[0061] We show for the first time that METRNL value measured in a sample, preferably a biological fluid sample, which is preferably blood, plasma, serum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or serum, is decreased in women suffering from PCOS compared to controls. Further, we show for the first time that METRNL value measured in a sample, preferably a biological fluid sample, which is preferably blood, plasma, serum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or scrum, is decreased in women suffering from any phenotypes A to D of PCOS. The solution provided by this invention is an immunoassay that detects Meteorin-like protein in a sample, preferably a biological fluid sample, which is preferably blood, plasma, serum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or serum. This immunoassay can be used to diagnose women with PCOS also in combination with other clinical and/or biochemical features such as oligo-anovulation and/or irregular cycles, hyperandrogenism or PCOM. Further, measuring the METRNL value can be used to monitor progression of PCOS in said patients and to monitor response to therapy. We show also that the measurement of METRNL values in a sample, preferably a biological fluid sample, which is preferably blood, plasma, serum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or serum, either alone or in combination with an additional diagnostic criterion as described above, is particularly suitable for the diagnosis of PCOS in adolescents or young women under the age of 25 years, in particular under the age of 20 years, in particular 15 to under the age of 25 years, in particular 15 to under the age of 20 years.

[0062] There is an unmet medical need for an accurate test for the reliable diagnosis of PCOS. Measurements of METRNL in a sample, preferably a biological fluid sample, which is preferably blood, plasma, serum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or serum, have the advantage of a reliable biological fluid-based test that identifies women suffering from PCOS that is currently not possible. Measurements of METRNL in a sample, preferably a biological fluid sample, which is preferably blood, plasma, scrum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or serum, can also be reliably used in adolescent subjects and young women under the age of 25 years, in particular under the age of 20 years, in particular 15 to under the age of 25 years, in particular 15 to under the age of 20 years, for the diagnosis of PCOS. Diagnosis of PCOS in adolescent patients is difficult for the reasons described above and hence, for the first time, we provide an accurate test for the diagnosis of PCOS in the adolescent and young women population. In addition, measurements of METRNL in a sample, preferably a biological fluid sample, which is preferably blood, plasma, serum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or serum, have the advantage to identify if the patient responds to therapy. An additional advantage of measurements of METRNL in a sample, preferably a biological fluid sample, which is preferably blood, plasma, serum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or serum, of a patient is to monitor the progression of PCOS. Furthermore, we enclose a computer-implemented method for assessing a subject suffering from PCOS by measuring METRNL levels in a sample, preferably a biological fluid sample, which is preferably blood, plasma, serum, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid and wherein the biological fluid sample is more preferably blood, plasma or serum, and, optionally, with further criteria such as a value for oligo-anovulation and/or irregular cycles, hyperandrogenism and/or polycystic ovarian morphology or with further biomarkers or hormones, for assessing said subject based on the comparison and/or the calculation of the data described above.

[0063] As described above, patients suffering from PCOS may show two types of characteristics-reproductive or metabolic type. The metabolic type of PCOS include obesity, insulin resistance, metabolic syndrome, pre-diabetes, type-2 diabetes, nonalcoholic fatty liver disease (NAFLD), and cardiovascular factors. The term phenotypical can be used instead of reproductive. The term reproductive (or phenotypical) describes any feature of the phenotype of a female known to be indicative of PCOS. For example, these reproductive characteristics comprise polycystic ovarian morphology (PCOM) and/or clinical hyperandrogenism, such as acne, seborrhea, alopecia, and/or hirsutism. Preferably, these reproductive characteristics comprise polycystic ovarian morphology (PCOM) and/or clinical hyperandrogenism, more preferably acne, seborrhea, alopecia, deepening of voice and/or hirsutism. These reproductive characteristics of clinical hyperandrogenism may be simply diagnosed by asking the female or are apparent after a short physical examination of the female's body. Usually, a reference population does not show any or not more than one of these phenotypical characteristics known to be indicative of PCOS.

[0064] Meteorin-like protein (METRNL) is a hormone (28 KDa secreted protein) that is induced after exercise and cold exposure in the skeletal muscle and adipose tissue, respectively. Increased expression of METRNL in the circulation or in adipose tissue resulted in browning of the white adipose tissue (WAT). Intraperitoneal injection with Metrnl-Fc protein in mice for 7 days induced significant body weight reduction, increased O2 consumption and glucose tolerance. Metrnl did not show direct effect on the thermogenesis of white adipocytes in vitro, which indicated the involvement of a non-adipose cell type in the induction of beige fat. Metrnl seemed to rather stimulate several immune cell subtypes to enter the adipose tissue and to activate their prothermogenic actions. METRNL-treated mice had increased macrophage and eosinophils numbers in WAT and increased expression of genes that are associated with alternative macrophage activation (Rao R R, Long J Z, White J P, et al. Meteorin-like is a hormone that regulates immune-adipose interactions to increase beige fat thermogenesis. Cell. 2014 Jun. 5; 157(6):1279-1291). METRNL has been associated with innate and possibly acquired immunity. High expression of METRNL was identified in activated monocytes (M2-polarized macrophages), skin and mucosal tissues. In the skin, METRNL is expressed by resting fibroblasts and IFN-treated keratinocytes. Over-expression of METRNL was described in several human skin diseases including psoriasis. METRNL is also up-regulated in synovial membranes of human rheumatoid arthritis (Ushach I, Burkhardt A M, Martinez C, et al. METEORIN-LIKE is a cytokine associated with barrier tissues and alternatively activated macrophages. Clin Immunol. 2015 February; 156(2):119-27). Recently, Baht and colleagues described a role for METRNL in coordinating skeletal muscle repair through macrophage accretion and phenotypical switch. The results suggested that in response to local injury METRNL would be secreted predominantly from macrophages. Furthermore, METRNL promoted an anti-inflammatory function through a STAT3-dependent auto-/paracrine mechanism inducing insulin-like growth factor 1 (IGF-1), which activated muscle progenitors to help myogenesis. Finally, METRNL has been shown to be a critical regulator of muscle regeneration acting directly on immune cells to promote an anti-inflammatory/pro-regenerative environment and myogenesis (Baht G S, Bareja A, Lee D E, et al. Meteorin-like facilitates skeletal muscle repair through a Stat3/IGF-1 mechanism. Nat Metab. 2020 March; 2(3):278-289. Erratum in: Nat Metab. 2020 August; 2(8):794). Interestingly, METRNL has been suggested to act as a neurotrophic factor with therapeutic potential in neural development. METRNL is indeed able to cross the blood brain barrier (BBB) and an increasing blood-brain barrier dysfunction caused increasing cerebrospinal fluid METRNL concentrations (Berghoff M, Hpfinger A, Rajendran R, et al. Evidence of a Muscle-Brain Axis by Quantification of the Neurotrophic Myokine METRNL (Meteorin-Like Protein) in Human Cerebrospinal Fluid and Serum. Journal of Clinical Medicine. 2021; 10(15):3271).

[0065] Serum METRNL levels have been studied in association with type 2 diabetes (T2DM) producing conflicting results (Lee J H, Kang Y E, Kim J M, et al. Serum Meteorin-like protein levels decreased in patients newly diagnosed with type 2 diabetes. Diabetes Res Clin Pract. 2018 January; 135:7-10; Chung H S, Hwang S Y, Choi J H, et al. Implications of circulating Meteorin-like (Metrnl) level in human subjects with type 2 diabetes. Diabetes Res Clin Pract. 2018 February; 136:100-107; Wang K, Li F, et al. Serum Levels of Meteorin-Like (Metrnl) Are Increased in Patients with Newly Diagnosed Type 2 Diabetes Mellitus and Are Associated with Insulin Resistance. Med Sci Monit. 2019 Mar. 31; 25:2337-2343; El-Ashmawy H M, Selim F O, Hosny T A M, Almassry H N. Association of low serum Meteorin like (Metrnl) concentrations with worsening of glucose tolerance, impaired endothelial function and atherosclerosis. Diabetes Res Clin Pract. 2019 April; 150:57-63; Wang C, Pan Y, Song J, et al. Serum Metrnl Level is Correlated with Insulin Resistance, But Not with -Cell Function in Type 2 Diabetics. Med Sci Monit. 2019 Nov. 25; 25:8968-8974; Ferns G A, Fekri K, Shahini Shams Abadi M, et al. A meta-analysis of the relationship between serums metrnl-like protein/subfatin and risk of type 2 diabetes mellitus and coronary artery disease. Arch Physiol Biochem. 2021 May 5:1-7; Lappas M. Maternal obesity and gestational diabetes decrease Metrnl concentrations in cord plasma. J Matern Fetal Neonatal Med. 2021 September; 34(18):2991-2995). Patients with T2DM and coronary artery disease (CAD) showed lower serum levels of METRNL compared to the control group. Additionally, METRNL illustrated a negative correlation with IL-6 and TNF- in both CAD patients and also with BMI, insulin resistance, IL-6 and TNF- in T2DM patients (Dadmanesh M, Aghajani H, Fadaei R, Ghorban K. Lower serum levels of Meteorin-like/Subfatin in patients with coronary artery disease and type 2 diabetes mellitus are negatively associated with insulin resistance and inflammatory cytokines. PLOS One. 2018 Sep. 13; 13(9): e0204180). Furthermore, a case-control study for CAD patients showed significant associations of serum METRNL with the presence and severity of CAD (Liu Z X, Ji H H, Yao M P, et al. Serum Metrnl is associated with the presence and severity of coronary artery disease. J Cell Mol Med. 2019 January; 23(1):271-280). Obese patients undergoing bariatric surgery showed decreased circulating levels of METRLN and improvement in glucose and lipid homeostasis compared to normal-weight controls (Pellitero S, Piquer-Garcia I, Ferrer-Curriu G, et al. Opposite changes in meteorin-like and oncostatin m levels are associated with metabolic improvements after bariatric surgery. Int J Obes (Lond). 2018 April; 42(4):919-922). Recently two studies have investigated circulating levels of METRNL in PCOS patients compared to controls. Fouani et al. study was conducted on a cohort of PCOS-recurrent pregnancy loss (PCOS-RPL, n=60) and infertile PCOS (n=60) patients and 60 healthy controls. Women's age was from 20 to 40 years (average of controls' age: 30.024.60; average of PCOS cases' age: 29.884.22). The authors found lower serum METRNL levels in PCOS patients when compared to controls. Moreover, serum METRNL correlated with BMI, adiponectin, and homocysteine in controls, and inversely correlated with FBG, fasting insulin, and HOMA-IR in PCOS group and subgroups. Besides, it inversely correlated with hs-CRP in control, and PCOS group and subgroups (Fouani F Z, Fadaei R, Moradi N, et al. Circulating levels of Meteorin-like protein in polycystic ovary syndrome: A case-control study. PLOS One. 2020 Apr. 24; 15(4): e0231943). Deniz et al. measured METRNL (subfatin) and asprosin levels in plasma samples from 30 PCOS cases and 30 healthy controls (average of controls' age: 28.222.6; average of PCOS cases' age: 27.143.21). While asprosin levels were significantly higher in women with PCOS compared to healthy controls, METRNL levels were significantly lower compared to controls, in agreement with the results shown by Fouani et al. Both asprosin and METRNL levels showed significant correlation with HOMA-IR in the PCOS subgroup (Deniz R, Yavuzkir S, Ugur K, et al. Subfatin and asprosin, two new metabolic players of polycystic ovary syndrome. J Obstet Gynaecol. 2021 February; 41(2):279-284. doi: 10.1080/01443615.2020.1758926).

[0066] In Inflammatory Bowel Disease (IBD) patients, serum levels of METRNL were decreased and a negative correlation was identified with TNF-, IL-6 and BMI levels (Gholamrezayi A, Mohamadinarab M, Rahbarinejad P, et al. Characterization of the serum levels of Meteorin-like in patients with inflammatory bowel disease and its association with inflammatory cytokines. Lipids Health Dis. 2020 Oct. 30; 19(1):230). In line with other studies on metabolic and inflammatory diseases, in osteoarthritic patients, compared to non-osteoarthritic subjects, serum METRNL was lower while synovial fluid METRNL was higher (Sobieh B H, Kassem D H, Zakaria Z M, El-Mesallamy H O. Potential emerging roles of the novel adipokines adipolin/CTRP12 and meteorin-like/METRNL in obesity-osteoarthritis interplay. Cytokine. 2021 February; 138:155368).

[0067] The first aspect of the present invention relates to a method of assessing whether a subject has PCOS or is at risk of developing PCOS comprising; [0068] (a) Determining the amount or concentration of METRNL in a sample of the subject, and [0069] (b) Comparing the determined amount or concentration to a reference.

[0070] A decreased amount or concentration of METRNL in the sample of the patient is indicative of the presence or the risk or developing PCOS in the patient. In particular, an amount or concentration of METRNL in the sample of the patient is indicative of the presence or the risk of developing PCOS in the patient if the amount or concentration of METRNL in the sample of the patient is higher than the amount or concentration of METRNL in a reference or a reference sample. In particular, METRNL is detectable in higher amounts or concentrations in a biological fluid sample of the patient assessed for the presence or risk of developing PCOS than in the same biological fluid sample of individuals not suffering or being at risk of developing PCOS. In particular an amount or concentration of METRNL decreased by 50% or more, is indicative of the presence or risk of developing PCOS. In particular an amount or concentration of METRNL decreased by 100% or more, is indicative of the presence or risk of developing PCOS. In particular an amount or concentration of METRNL decreased by 150% or more, is indicative of the presence or risk of developing PCOS. In particular an amount or concentration of METRNL decreased by 200% or more, is indicative of the presence or risk of developing PCOS.

[0071] In embodiments, the biological fluid sample is whole blood, serum, plasma, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid preferably the biological fluid sample is serum or whole blood. In embodiments, the sample is an in vitro sample, i.e. it will be analyzed in vitro and not transferred back to the body.

[0072] In particular embodiments, the patient is a laboratory animal, a domestic animal or a primate. In particular embodiments, the patient is a human patient. In particular embodiments, the patient is a female human patient. In particular embodiments, the patient is a female human patient of less than 25 years old. In particular embodiments, the patient is a female human patient of less than 20 years old. In particular embodiments, the patient is a female human patient of 15 to less than 25 years old. In particular embodiments, the patient is a female human patient of 15 to less than 20 years old. In particular embodiments, the patient is a female human patient of less than 25 years old, preferably less than 20 years old, and three years after menarche. In particular embodiments, the patient is a female human patient of less than 20 years old and three years after menarche. In particular embodiments, the patient is a female human patient of 15 to less than 25 years old and three years after menarche. In particular embodiments, the patient is a female human patient of 15 to less than 20 years old and three years after menarche.

[0073] In embodiments, PCOS is assessed from the group consisting of metabolic or phenotypical PCOS. In further embodiments, PCOS is assessed from the group consisting of phenotype A, phenotype B, phenotype C and phenotype D PCOS.

[0074] In embodiments, the first method of the present invention is an in vitro method.

[0075] In embodiments, the amount or concentration of METRNL is determined using antibodies, in particular using monoclonal antibodies. In embodiments, step a) of determining the amount or concentration of METRNL in a sample of the patient comprises performing an immunoassay. In embodiments, the immunoassay is performed either in a direct or indirect format. In embodiments, such immunoassay is selected from the group consisting of enzyme linked immunosorbent assay (ELISA), enzyme immunoassay (EIA), radioimmunoassay (RIA), or immuno assay based on detection of luminescence, fluorescence, chemiluminescence or electrochemiluminescence.

[0076] In particular embodiments, step a) of determining the amount or concentration of METRNL in a sample of the patient comprises the steps of: [0077] i) incubating the sample of the patient with one or more antibodies specifically binding to METRNL, thereby generating a complex between the antibody and METRNL, and [0078] ii) quantifying the complex formed in step i), thereby quantifying the amount or concentration of METRNL in the sample of the patient.

[0079] In particular embodiments, in step i) the sample is incubated with two antibodies, specifically binding to METRNL. As obvious to the person skilled in the art, the sample can be contacted with the first and the second antibody in any desired order, e.g. First antibody first and then the second antibody or second antibody first and then the first antibody, or simultaneously, for a time and under conditions sufficient to form a first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex. As the person skilled in the art will readily appreciate it is nothing but routine experimentation to establish the time and conditions that are appropriate or that are sufficient for the formation of a complex either between the specific anti-METRNL antibody and the METRNL antigen/analyte (=anti-METRNL complex) or the formation of the secondary, or sandwich complex comprising the first antibody to METRNL, METRNL (the analyte) and the second anti-METRNL antibody (=first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex).

[0080] The detection of the anti-METRNL antibody/METRNL complex can be performed by any appropriate means. The detection of the first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex can be performed by any appropriate means. The person skilled in the art is absolutely familiar with such means/methods.

[0081] In certain embodiments, a sandwich will be formed comprising a first antibody to METRNL, METRNL (analyte) and the second antibody to METRNL, wherein the second antibody is detectably labeled.

[0082] In one embodiment, a sandwich will be formed comprising a first antibody to METRNL, METRNL (analyte) and the second antibody to METRNL, wherein the second antibody is detectably labeled and wherein the first anti-METRNL antibody is capable of binding to a solid phase or is bound to a solid phase.

[0083] In embodiments, the second antibody is directly or indirectly detectably labeled. In particular embodiments, the second antibody is detectably labeled with a luminescent dye, in particular a chemiluminescent dye or an electrochemiluminescent dye.

[0084] In a second aspect, the present invention relates to a method of selecting a patient for therapy of PCOS, comprising: [0085] (c) Determining the amount or concentration of METRNL in a sample of the subject, and [0086] (d) Comparing the determined amount or concentration to a reference.

[0087] In embodiments, a patient is selected for therapy of PCOS if a decreased amount of METRNL in the sample of the patient is determined. In particular, a patient is selected for therapy of PCOS if the amount of METRNL is higher than the amount of METRNL in a reference or reference sample. In particular, a patient is selected for therapy of PCOS if the amount of METRNL is higher in a biological fluid sample of the patient assessed for therapy of PCOS than in the same biological fluid sample of individuals not suffering or being at risk of developing PCOS or not being selected for therapy of PCOS. In particular a patient is selected for therapy of PCOS if the amount of METRNL is decreased by 50% or more. In particular, a patient is selected for therapy of PCOS if the amount of METRNL is decreased by 100% or more. In particular, a patient is selected for therapy of PCOS if the amount of METRNL is decreased by 150% or more. In particular, a patient is selected for therapy of PCOS if the amount of METRNL is decreased by 200% or more.

[0088] In particular, the patient is selected for a drug-based therapy of PCOS or for lifestyle changes to control metabolic symptoms. In embodiments, drug-based therapy of PCOS is selected from the group consisting of drugs for regulating periods, in particular oral contraceptives or progestin therapy, drugs for preventing or controlling diabetes, in particular type 2 diabetes, drugs for preventing or controlling high cholesterol, hormones or drugs to increase fertility, drugs, hormones or procedures to remove excess hair, drugs or procedure to control acne.

[0089] In embodiments, the biological fluid sample is whole blood, serum, plasma, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid preferably the biological fluid sample is serum or whole blood. In embodiments, the sample is an in vitro sample, i.e. it will be analyzed in vitro and not transferred back to the body.

[0090] In particular embodiments, the patient is a laboratory animal, a domestic animal or a primate. In particular embodiments, the patient is a human patient. In particular embodiments, the patient is a female human patient. In particular embodiments, the patient is a female human patient of less than 25 years old. In particular embodiments, the patient is a female human patient of less than 20 years old. In particular embodiments, the patient is a female human patient of 15 to less than 25 years old. In particular embodiments, the patient is a female human patient of 15 to less than 20 years old. In particular embodiments, the patient is a female human patient of less than 25 years old, preferably less than 20 years old, and three years after menarche. In particular embodiments, the patient is a female human patient of less than 20 years old and three years after menarche. In particular embodiments, the patient is a female human patient of 15 to less than 25 years old and three years after menarche. In particular embodiments, the patient is a female human patient of 15 to less than 20 years old and three years after menarche.

[0091] In embodiments, the second method of the present invention is an in vitro method.

[0092] In embodiments, the amount of METRNL is determined using antibodies, in particular using monoclonal antibodies. In embodiments, step a) of determining the amount of METRNL in a sample of the patient comprises performing an immunoassay. In embodiments, the immunoassay is performed cither in a direct or indirect format. In embodiments, such immunoassay is selected from the group consisting of enzyme linked immunosorbent assay (ELISA), enzyme immunoassay (EIA), radioimmunoassay (RIA), or immuno assay based on detection of luminescence, fluorescence, chemiluminescence or electrochemiluminescence.

[0093] In particular embodiments, step a) of determining the amount of METRNL in a sample of the patient comprises the steps of: [0094] i) incubating the sample of the patient with one or more antibodies specifically binding to METRNL, thereby generating a complex between the antibody and METRNL, and [0095] ii) quantifying the complex formed in step i), thereby quantifying the amount of METRNL in the sample of the patient.

[0096] In particular embodiments, in step i) the sample is incubated with two antibodies, specifically binding to METRNL. As obvious to the person skilled in the art, the sample can be contacted with the first and the second antibody in any desired order, i.g. First antibody first and then the second antibody or second antibody first and then the first antibody, or simultaneously, for a time and under conditions sufficient to form a first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex. As the person skilled in the art will readily appreciate it is nothing but routine experimentation to establish the time and conditions that are appropriate or that are sufficient for the formation of a complex either between the specific anti-METRNL antibody and the METRNL antigen/analyte (=anti-METRNL complex) or the formation of the secondary, or sandwich complex comprising the first antibody to METRNL, METRNL (the analyte) and the second anti-METRNL antibody (=first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex).

[0097] The detection of the anti-METRNL antibody/METRNL complex can be performed by any appropriate means. The detection of the first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex can be performed by any appropriate means. The person skilled in the art is absolutely familiar with such means/methods.

[0098] In certain embodiments, a sandwich will be formed comprising a first antibody to METRNL, METRNL (analyte) and the second antibody to METRNL, wherein the second antibody is detectably labeled.

[0099] In one embodiment, a sandwich will be formed comprising a first antibody to METRNL, METRNL (analyte) and the second antibody to METRNL, wherein the second antibody is detectably labeled and wherein the first anti-METRNL antibody is capable of binding to a solid phase or is bound to a solid phase.

[0100] In embodiments, the second antibody is directly or indirectly detectably labeled. In particular embodiments, the second antibody is detectably labeled with a luminescent dye, in particular a chemiluminescent dye or an electrochemiluminescent dye.

[0101] Further, the present invention relates also to a kit comprising reagents for the diagnosis of PCOS. The reagents of the kit may comprise antibodies or antibody fragments. Preferably, the antibodies or antibody fragments recognize epitopes or antigens of METRNL. The kit may further contain other reagents which recognize other biomarkers. Therefore, the kit may comprise a combination of at least two reagents. The kit may specifically measure the amount or concentration of METRNL and any other biomarker of interest. According to the present invention, a biomarker can also comprise hormones, such as Anti-Mllerian Hormone, AMH. The kit can be used in any diagnostic assay.

[0102] In embodiments, the amount of METRNL is determined using antibodies, in particular using monoclonal antibodies. In embodiments, step a) of determining the amount of METRNL in a sample of the patient comprises performing an immunoassay. In embodiments, the immunoassay is performed either in a direct or indirect format. In embodiments such immunoassays is selected from the group consisting of enzyme linked immunosorbent assay (ELISA), enzyme immunoassay (EIA), radioimmunoassay (RIA), or immuno assays based on detection of luminescence, fluorescence, chemiluminescence or electrochemiluminescence.

[0103] In a third aspect, the present invention relates to a method for monitoring PCOS progression in a subject or for monitoring response to treatment in a subject having PCOS, said method comprising: [0104] (a) determining the level of METRNL in a first sample of the subject, [0105] (b) determining the level of METRNL in a second sample of the subject which has been obtained after the first sample, and [0106] (c) comparing the level of METRNL in the first sample to the level of METRNL in the second sample, and [0107] (d) monitoring progression in the subject suffering from PCOS or being treated for PCOS, based on the results of step c).

[0108] In embodiments, PCOS progression in a subject having PCOS is monitored to determine if the amount or concentration of METRNL is changing over time in a sample of the patient. In particular, PCOS progression is monitored to determine if the amount or concentration of METRNL is increasing, decreasing or not changing over time. In embodiments, PCOS progression is monitored if a decreased amount or concentration of METRNL in the sample of the subject is determined.

[0109] In embodiments, a subject being treated for PCOS is monitored to determine if the amount or concentration of METRNL is changing in a sample of the subject. In particular, a subject being treated for PCOS is monitored to determine if the amount or concentration of METRNL is increasing, decreasing or not changing. In particular, a subject being treated for PCOS is monitored to determine if the amount or concentration of METRNL is increasing, decreasing or not changing due to the therapy applied. In embodiments, a decreasing amount or concentration of METRNL in a subject being treated for PCOS is indicative of the therapy being effective. In embodiments, an unaltered or decreasing amount or concentration of METRNL in a sample of the subject being treated for PCOS is indicative of persisting PCOS. In particular, the treatment for PCOS is ineffective if the amount or concentration of METRNL is decreasing to 50% or more. In particular, the treatment for PCOS is ineffective if the amount or concentration of METRNL is decreasing to 100% or more. In particular, the treatment for PCOS is ineffective if the amount or concentration of METRNL is decreasing to 150% or more. In particular, the treatment for PCOS is ineffective if the amount or concentration of METRNL is decreasing to 200% or more.

[0110] In particular embodiments, therapy is adapted if an unaltered or decreasing amount or concentration of METRNL in a sample of the subject being treated for PCOS is determined.

[0111] In embodiments, the subject is monitored several times at different time points. In embodiments, the subject is monitored several times within a time frame of weeks, months or years. In particular embodiments, a subject is monitored once a month or once a year. In embodiments, a subject suffering from PCOS is monitored once a month or once a year after diagnosis of PCOS. In embodiments, a subject being treated for PCOS is monitored once after therapy. In particular, the subject being treated for PCOS is monitored once a month or once a year to determine the efficacy of treatment.

[0112] In embodiments, therapy of PCOS is selected from the group consisting of drug-based therapy of PCOS and lifestyle changes to control metabolic symptoms. In embodiments, drug-based therapy of PCOS is selected from the group consisting of drugs for regulating periods, in particular oral contraceptives or progestin therapy, drugs for preventing or controlling diabetes, in particular type 2 diabetes, drugs for preventing or controlling high cholesterol, hormones or drugs to increase fertility, drugs, hormones or procedures to remove excess hair, drugs or procedure to control acne.

[0113] In embodiments, the biological fluid sample is whole blood, serum, plasma, capillary blood, interstitial fluid, peritoneal fluid, or menstrual fluid preferably the biological fluid sample is serum or whole blood. In embodiments, the sample is an in vitro sample, i.e. it will be analyzed in vitro and not transferred back to the body.

[0114] In particular embodiments, the patient is a laboratory animal, a domestic animal or a primate. In particular embodiments, the patient is a human patient. In particular embodiments, the patient is a female human patient. In particular embodiments, the patient is a female human patient of less than 25 years old. In particular embodiments, the patient is a female human patient of less than 20 years old. In particular embodiments, the patient is a female human patient of 15 to less than 25 years old. In particular embodiments, the patient is a female human patient of 15 to less than 20 years old. In particular embodiments, the patient is a female human patient of less than 25 years old, in particular of less than 20 years old, and three years after menarche. In particular embodiments, the patient is a female human patient of less than 20 years old and three years after menarche. In particular embodiments, the patient is a female human patient of 15 to less than 25 years old and three years after menarche. In particular embodiments, the patient is a female human patient of 15 to less than 20 years old and three years after menarche.

[0115] In embodiments, the second method of the present invention is an in vitro method.

[0116] In embodiments, the amount or concentration of METRNL is determined using antibodies, in particular using monoclonal antibodies. In embodiments, step a) of determining the amount or concentration of METRNL in a sample of the patient comprises performing an immunoassay. In embodiments, the immunoassay is performed either in a direct or indirect format. In embodiments, such immunoassay is selected from the group consisting of enzyme linked immunosorbent assay (ELISA), enzyme immunoassay (EIA), radioimmunoassay (RIA), or immuno assay based on detection of luminescence, fluorescence, chemiluminescence or electrochemiluminescence.

[0117] In particular embodiments, step a) of determining the amount or concentration of METRNL in a sample of the patient comprises the steps of: [0118] i) incubating the sample of the patient with one or more antibodies specifically binding to METRNL, thereby generating a complex between the antibody and METRNL, and [0119] ii) quantifying the complex formed in step i), thereby quantifying the amount or concentration of METRNL in the sample of the patient.

[0120] In particular embodiments, in step i) the sample is incubated with two antibodies, specifically binding to METRNL. As obvious to the person skilled in the art, the sample can be contacted with the first and the second antibody in any desired order, e.g. First antibody first and then the second antibody or second antibody first and then the first antibody, or simultaneously, for a time and under conditions sufficient to form a first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex. As the person skilled in the art will readily appreciate it is nothing but routine experimentation to establish the time and conditions that are appropriate or that are sufficient for the formation of a complex either between the specific anti-METRNL antibody and the METRNL antigen/analyte (=anti-METRNL complex) or the formation of the secondary, or sandwich complex comprising the first antibody to METRNL, METRNL (the analyte) and the second anti-METRNL antibody (=first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex).

[0121] The detection of the anti-METRNL antibody/METRNL complex can be performed by any appropriate means. The detection of the first anti-METRNL antibody/METRNL/second anti-METRNL antibody complex can be performed by any appropriate means. The person skilled in the art is absolutely familiar with such means/methods.

[0122] In certain embodiments, a sandwich will be formed comprising a first antibody to METRNL, METRNL (analyte) and the second antibody to METRNL, wherein the second antibody is detectably labeled.

[0123] In one embodiment, a sandwich will be formed comprising a first antibody to METRNL, METRNL (analyte) and the second antibody to METRNL, wherein the second antibody is detectably labeled and wherein the first anti-METRNL antibody is capable of binding to a solid phase or is bound to a solid phase.

[0124] In embodiments, the second antibody is directly or indirectly detectably labeled. In particular embodiments, the second antibody is detectably labeled with a luminescent dye, in particular a chemiluminescent dye or an electrochemiluminescent dye.

[0125] In a fourth aspect, the present invention relates to a computer-implemented method of assessing a subject with suspected PCOS comprising the steps of: [0126] (a) receiving a value for the amount or concentration of a first biomarker in a sample of the subject, said first biomarker being METRNL, [0127] (b) optionally, receiving a value for the amount or concentration of a second biomarker in a sample of the subject, [0128] (c) optionally, receiving a value for the presence or absence of at least an additional diagnostic criterion selected from the group consisting of oligo-anovulation, hyperandrogenism and polycystic ovarian morphology; [0129] (d) comparing the values for the amounts or concentrations of steps (a)-(b) to references for said biomarkers and the value for the presence or absence of the at least one additional diagnostic criterion, and/or calculating a score for assessing the subject with suspected PCOS based on the amounts or concentrations of the biomarkers and the value; and [0130] (e) assessing said subject based on the comparison and/or the calculation made in step (d).

[0131] In embodiments, the computer-implemented method of assessing a subject with suspected PCOS includes methods which essentially consist of the aforementioned steps or methods which include further steps. Moreover, the method of the present invention, preferably, is an ex vivo and more preferably an in vitro method. Moreover, it may comprise steps in addition to those explicitly mentioned above. For example, further steps may relate to the determination of further markers and/or to sample pre-treatments or evaluation of the results obtained by the method. The method may be carried out manually or assisted by automation.

[0132] The term computer-implemented as used herein means that the method is carried out in an automated fashion on a data processing unit which is, typically, comprised in a computer or similar data processing device. The data processing unit shall receive values for the amount of the biomarkers. Such values can be the amounts, relative amounts or any other calculated value reflecting the amount as described elsewhere herein in detail. Accordingly, it is to be understood that the aforementioned method does not require the determination of amounts for the biomarkers but rather uses values for already predetermined amounts.

[0133] The present invention also, in principle, contemplates a computer program, computer program product or computer readable storage medium having tangibly embedded said computer program, wherein the computer program comprises instructions which, when run on a data processing device or computer, carry out the method of the present invention as specified above. Specifically, the present disclosure further encompasses: [0134] a computer or computer network comprising at least one processor, wherein the processor is adapted to perform the method according to one of the embodiments described in this description, [0135] a computer loadable data structure that is adapted to perform the method according to one of the embodiments described in this description while the data structure is being executed on a computer, [0136] a computer script, wherein the computer program is adapted to perform the method according to one of the embodiments described in this description while the program is being executed on a computer, [0137] a computer program comprising program means for performing the method according to one of the embodiments described in this description while the computer program is being executed on a computer or on a computer network, [0138] a computer program comprising program means according to the preceding embodiment, wherein the program means are stored on a storage medium readable to a computer, [0139] a storage medium, wherein a data structure is stored on the storage medium and wherein the data structure is adapted to perform the method according to one of the embodiments described in this description after having been loaded into a main and/or working storage of a computer or of a computer network, [0140] a computer program product having program code means, wherein the program code means can be stored or are stored on a storage medium, for performing the method according to one of the embodiments described in this description, if the program code means are executed on a computer or on a computer network, [0141] a data stream signal, typically encrypted, comprising a data for parameters as defined herein elsewhere, and [0142] a data stream signal, typically encrypted, comprising the assessment provided by the methods of the present invention.

Definitions

[0143] In the context of the kit of the present invention the term reagent describes a substance or compound added to a sample allowing to display the amount or concentration of a specific component in the sample.

[0144] In the context of the kit of the present invention the term specifically measure means to detect the exact amount or concentration of a clearly defined molecule. For a specific measurement the sample obtained from a female may be incubated with the reagent under conditions appropriate for formation of a binding agent marker-complex. Such conditions need not be specified, since such appropriate incubation conditions are well-known to the skilled artisan.

[0145] In the context of the kit of the present invention the term reagent may describe a protein molecule (such as an antibody), a nucleic acid molecule (such as any form of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA)) or another biochemical, organic or anorganic substance, which may interact with the molecule to be specifically measured in a sample.

[0146] Further, the reagent may be linked to a detectable reporter moiety or label such as an enzyme, dye, radionuclide, luminescent group, fluorescent group or biotin, or the like, such as a fluorescent marker that may be used for immunoassays analysis. Any reporter moiety or label could be used with the reagent of the kit according to the second aspect of the invention so long as the signal of such may be directly related or proportional to the quantity of binding agent remaining on the support after wash. The amount of an optional second binding agent that remains bound to the solid support may then be determined using a method appropriate for the specific detectable reporter moiety or label. For radioactive groups, scintillation counting or autoradiographic methods are generally appropriate. Antibody-enzyme conjugates can be prepared using a variety of coupling techniques (for review see, e.g., Scouten, W. H., Methods in Enzymology 135:30-65, 1987). Spectroscopic methods can be used to detect dyes (including, for example, colorimetric products of enzyme reactions), luminescent groups and fluorescent groups. Biotin can be detected using avidin or streptavidin, coupled to a different reporter group (commonly a radioactive or fluorescent group or an enzyme). Enzyme reporter groups can generally be detected by the addition of substrate (generally for a specific period of time), followed by spectroscopic, spectrophotometric or other analysis of the reaction products. Standards and standard additions can be used to determine the level of antigen in a sample, using techniques well-known to the person skilled in the art.

[0147] The reagent may also be a substance that may additionally be capable of linking to the matrix of a column used for chromatography for purification and/or further analysis (such as mass spectrometry analysis). Moreover, the reagent may be linked to a testing strip.

[0148] Preferably, the reagent is an antibody. Suitable antibodies for measuring the amount or concentration of one of the molecules to be specifically measured in a sample obtained from the female mentioned above are well-known to the person skilled in the art.

[0149] Preferably, the reagent may be used in an electrochemiluminescence-immunoassay, more preferably, the reagent is an antibody that may be used in an electrochemiluminescence-immunoassay.

[0150] Moreover, the kit may comprise more than one reagent, such as two different reagents, three different reagents, four different reagents or more different reagents, preferably two different reagents to interact with one molecule that is specifically measured in a sample. For example, if the molecule that is specifically measured is measured in an electrochemiluminescence-immunoassay, the kit may comprise two different antibodies binding to the same molecule to be measured. Preferably, the two different antibodies binding to the same molecule are not competing for the binding site at the molecule and bind this molecule at different positions. Further, both antibodies may be linked to different detectable reporter moieties or labels.

[0151] The kit may further comprise buffering agents and/or salts to adjust the pH as well as the reaction and measuring conditions. Moreover, the kit may comprise stabilizers, e.g. to support the stability of the reagents and/or hormones during the specific measurement of (i) the amount or concentration of FT or (ii) the amount or concentration of TT and the amount or concentration SHBG; the amount or concentration of AMH; and the amount or concentration of one or more further hormones indicative of PCOS. Suitable buffers, salts and stabilizers are well-known to the person skilled in the art. In addition, sodium azide may be added to all liquid solutions of the kit, such as reagents or buffers.

[0152] The kit may also comprise all equipment necessary to take a blood sample from a female, such as a container for the blood sample, a needle and a device connecting the container and the needle. Preferably, the kit may comprise a syringe.

[0153] In general, a physician or a physician's assistant may take blood from a female. Subsequently, the blood may be sent to a laboratory, where the sample is measured using the kit on a designated analyser, and the data are sent to the physician. However, the kit may also be applied by a physician or by a physician's assistant himself. The kit may be applied during ambulatory, stationary treatment or domiciliary visit of the physician.

[0154] All components of the kit may be packaged separately in individual containers. However, it is also possible that two or more components of the kit may be packaged together in one or more containers.

[0155] The kit may further comprise a label, e.g. comprising instructions on how to use the kit or describing the kit's contents. However, this information may also be provided in any other form, such as on storage media such as a CD-ROM or a USB stick.

[0156] The word comprise, and variations such as comprises and comprising, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0157] As used in this specification and the appended claims, the singular forms a, an, and the include plural referents, unless the content clearly dictates otherwise.

[0158] Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of 150 mg to 600 mg should be interpreted to include not only the explicitly recited values of 150 mg to 600 mg, but to also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 150, 160, 170, 180, 190, 580, 590, 600 mg and sub-ranges such as from 150 to 200, 150 to 250, 250 to 300, 350 to 600, etc. This same principle applies to ranges reciting only one numerical value. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.

[0159] The term about when used in connection with a numerical value is meant to encompass numerical values within a range having a lower limit that is 5% smaller than the indicated numerical value and having an upper limit that is 5% larger than the indicated numerical value.

[0160] The term indicator as used herein, refers to a sign or signal for a condition or is used to monitor a condition. Such a condition refers to the biological status of a cell, tissue or organ or to the health and/or disease status of an individual. An indicator may be the presence or absence of a molecule, including but not limited to peptide, protein, and nucleic acid, or may be a change in the expression level or pattern of such molecule in a cell, or tissue, organ or individual. An indicator may be a sign for the onset, development or presence of a disease in an individual or for the further progression of such disease. An indicator may also be a sign for the risk of developing a disease in an individual.

[0161] In the context of present invention, the term biomarker refers to a substance within a biological system that is used as an indicator of a biological state of said system. In the art, the term biomarker is sometimes also applied to means for the detection of said endogenous substances (e.g. antibodies, nucleic acid probes etc, imaging systems). In the context of present invention, the term biomarker shall be only applied for the substance, not for the detection means. Thus, biomarkers can be any kind of molecule present in a living organism, such as a nucleic acid (DNA, RNA, miRNA, rRNA etc.), a protein (cell surface receptor, cytosolic protein etc.), a metabolite or hormone (blood sugar, insulin, estrogen, etc.), a molecule characteristic of a certain modification of another molecule (e.g. sugar moieties or phosphoryl residues on proteins, methyl-residues on genomic DNA) or a substance that has been internalized by the organism or a metabolite of such a substance.

[0162] The biomarkers as referred to herein can be detected using methods generally known in the art. Methods of detection generally encompass methods to quantify the level of a biomarker in the sample (quantitative method). It is generally known to the skilled artisan which of the following methods are suitable for qualitative and/or for quantitative detection of a biomarker. Samples can be conveniently assayed for, e.g., proteins using Westerns and immunoassays, like ELISAs, RIAs, fluorescence- and luminescence-based immunoassays and proximity extension assays, which are commercially available. Further suitable methods to detect biomarkers include measuring a physical or chemical property specific for the peptide or polypeptide such as its precise molecular mass or NMR spectrum. Said methods comprise, e.g., biosensors, optical devices coupled to immunoassays, biochips, analytical devices such as mass-spectrometers, NMR-analyzers, or chromatography devices. Further, methods include microplate ELISA-based methods, fully-automated or robotic immunoassays (available for example on Elecsys analyzers), CBA (an enzymatic Cobalt Binding Assay, available for example on Roche-Hitachi analyzers), and latex agglutination assays (available for example on Roche-Hitachi analyzers).

[0163] The term anovulation usually describes the condition when the ovaries do not release any oocyte during a female menstrual cycle at all. The female whose risk of having PCOS is assessed may be determined to suffer from anovulation, if no oocyte is released for the duration of at least one female menstrual cycle, preferably at least three female menstrual cycles, more preferably at least six female menstrual cycles and mostly preferred at least nine female menstrual cycles in one year. Further, the female whose risk of having PCOS is assessed may be determined to suffer from anovulation, if no oocyte is released for the duration of at least 6 months, preferably at least 9 months, more preferably at least 1 year.

[0164] Symptoms of a disease are implication of the disease noticeable by the tissue, organ or organism having such disease and include but are not limited to pain, weakness, tenderness, strain, stiffness, and spasm of the tissue, an organ or an individual. Symptoms typical for PCOS include but are not limited to oligo-anovulation, irregular cycles, hyperandrogenism, polycystic ovarian morphology, infertility, diabetes type 2, overweight and other metabolic conditions, and psychological distress. Signs or signals of a disease include but are not limited to the change or alteration such as the presence, absence, increase or elevation, decrease or decline, of specific indicators such as biomarkers or molecular markers, or the development, presence, or worsening of symptoms. Symptoms of pain include, but are not limited to an unpleasant sensation that may be felt as a persistent or varying burning, throbbing, itching or stinging ache.

[0165] The term disease and disorder are used interchangeably herein, referring to an abnormal condition, especially an abnormal medical condition such as an illness or injury, wherein a tissue, an organ or an individual is not able to efficiently fulfill its function anymore. Typically, but not necessarily, a disease is associated with specific symptoms or signs indicating the presence of such disease. The presence of such symptoms or signs may thus, be indicative for a tissue, an organ or an individual suffering from a disease. An alteration of these symptoms or signs may be indicative for the progression of such a disease. A progression of a disease is typically characterized by an increase or decrease of such symptoms or signs which may indicate a worsening or bettering of the disease. The worsening of a disease is characterized by a decreasing ability of a tissue, organ or organism to fulfill its function efficiently, whereas the bettering of a disease is typically characterized by an increase in the ability of a tissue, an organ or an individual to fulfill its function efficiently. A tissue, an organ or an individual being at risk of developing a disease is in a healthy state but shows potential of a disease emerging. Typically, the risk of developing a disease is associated with early or weak signs or symptoms of such disease. In such case, the onset of the disease may still be prevented by treatment. Examples of a disease include but are not limited to inflammatory diseases, infectious diseases, cutaneous conditions, endocrine diseases, intestinal diseases, neurological disorders, joint diseases, genetic disorders, autoimmune diseases, traumatic diseases, and various types of cancer.

[0166] The terms patient and subject are used interchangeably herein, referring to an animal, preferably a mammal and, more typically to a human. The patient is preferably a human female. There is a need for diagnosis of PCOS.

[0167] The term sample or sample of interest are used interchangeably herein, referring to a part or piece of a tissue, organ or individual, typically being smaller than such tissue, organ or individual, intended to represent the whole of the tissue, organ or individual. Upon analysis a sample provides information about the tissue status or the health or diseased status of an organ or individual. Examples of samples include but are not limited to fluid samples such as blood, serum, plasma, synovial fluid, urine, saliva, and lymphatic fluid, or solid samples such as tissue extracts, cartilage, bone, synovium, and connective tissue. Analysis of a sample may be accomplished on a visual or chemical basis. Visual analysis includes but is not limited to microscopic imaging or radiographic scanning of a tissue, organ or individual allowing for morphological evaluation of a sample. Chemical analysis includes but is not limited to the detection of the presence or absence of specific indicators or alterations in their amount, concentration or level. The sample is an in vitro sample, it will be analyzed in vitro and not transferred back into the body.

[0168] The term amount as used herein encompasses the absolute amount of a biomarker as referred to herein, the relative amount or concentration of the said biomarker as well as any value or parameter which correlates thereto or can be derived therefrom. Such values or parameters comprise intensity signal values from all specific physical or chemical properties obtained from the said peptides by direct measurements, e.g., intensity values in mass spectra or NMR spectra. Moreover, encompassed are all values or parameters which are obtained by indirect measurements specified elsewhere in this description, e.g., response amounts measured from biological read out systems in response to the peptides or intensity signals obtained from specifically bound ligands. It is to be understood that values correlating to the aforementioned amounts or parameters can also be obtained by all standard mathematical operations.

[0169] The term comparing as used herein refers to comparing the amount of the biomarker in the sample from the subject with the reference amount of the biomarker specified elsewhere in this description. It is to be understood that comparing as used herein usually refers to a comparison of corresponding parameters or values, e.g., an absolute amount is compared to an absolute reference amount while a concentration is compared to a reference concentration or an intensity signal obtained from the biomarker in a sample is compared to the same type of intensity signal obtained from a reference sample. The comparison may be carried out manually or computer-assisted. Thus, the comparison may be carried out by a computing device. The value of the measured or detected amount of the biomarker in the sample from the subject and the reference amount can be, e.g., compared to each other and the said comparison can be automatically carried out by a computer program executing an algorithm for the comparison. The computer program carrying out the said evaluation will provide the desired assessment in a suitable output format. For a computer-assisted comparison, the value of the measured amount may be compared to values corresponding to suitable references which are stored in a database by a computer program. The computer program may further evaluate the result of the comparison, i.e. automatically provide the desired assessment in a suitable output format. For a computer-assisted comparison, the value of the measured amount may be compared to values corresponding to suitable references which are stored in a database by a computer program. The computer program may further evaluate the result of the comparison, i.e. automatically provides the desired assessment in a suitable output format.

[0170] The expression comparing the amount or concentration determined to a reference is merely used to further illustrate what is obvious to the skilled artisan anyway. A reference concentration is established in a control sample

[0171] The term reference sample or control sample as used herein, refers to a sample which is analysed in a substantially identical manner as the sample of interest and whose information is compared to that of the sample of interest. A reference sample thereby provides a standard allowing for the evaluation of the information obtained from the sample of interest. A control sample may be derived from a healthy or normal tissue, organ or individual, thereby providing a standard of a healthy status of a tissue, organ or individual. Differences between the status of the normal reference sample and the status of the sample of interest may be indicative of the risk of disease development or the presence or further progression of such disease or disorder. A control sample may be derived from an abnormal or diseased tissue, organ or individual thereby providing a standard of a diseased status of a tissue, organ or individual. Differences between the status of the abnormal reference sample and the status of the sample of interest may be indicative of a lowered risk of disease development or the absence or bettering of such disease or disorder. A reference sample may also be derived from the same tissue, organ, or individual as the sample of interest but has been taken at an earlier time point. Differences between the status of the earlier taken reference sample and the status of the sample of interest may be indicative of the progression of the disease, i.e. a bettering or worsening of the disease over time.

[0172] The control sample may be an internal or an external control sample. An internal control sample is used, i.e. the marker level(s) is (are) assessed in the test sample as well as in one or more other sample(s) taken from the same subject to determine if there are any changes in the level(s) of said marker(s). For an external control sample the presence or amount of a marker in a sample derived from the individual is compared to its presence or amount in an individual known to suffer from, or known to be at risk of, a given condition; or an individual known to be free of a given condition, i.e., normal individual.

[0173] It will be appreciated by the skilled artisan that such external control sample may be obtained from a single individual or may be obtained from a reference population that is age-matched and free of confounding diseases. Typically, samples from 100 well-characterized individuals from the appropriate reference population are used to establish a reference value. However, reference population may also be chosen to consist of 20, 30, 50, 200, 500 or 1000 individuals. Healthy individuals represent a preferred reference population for establishing a control value.

[0174] For example, a marker concentration in a patient sample can be compared to a concentration known to be associated with a specific course of a certain disease. Usually the sample's marker concentration is directly or indirectly correlated with a diagnosis and the marker concentration is e.g. used to determine whether an individual is at risk for a certain disease. Alternatively, the sample's marker concentration can e.g. be compared to a marker concentration known to be associated with a response to therapy in a certain disease, the diagnosis of a certain disease, the assessment of the severity of a certain disease, the guidance for selecting an appropriate drug to a certain disease, in judging the risk of disease progression, or in the follow-up of patients. Depending on the intended diagnostic use an appropriate control sample is chosen and a control or reference value for the marker established therein. As also clear to the skilled artisan, the absolute marker values established in a control sample will be dependent on the assay used.

[0175] The term assessing as used herein refers to assessing whether a patient suffers from PCOS or is at risk of developing PCOS. Accordingly, assessing as used herein includes diagnosing PCOS, predicting the risk for developing PCOS, selecting for therapy of PCOS, monitoring a patient suffering from PCOS or being treated for PCOS, by determining the amount or concentration of METRNL in a sample of the patient, and comparing the determined amount or concentration to a reference.

[0176] As will be understood by those skilled in the art, the assessment made in accordance with the present invention, although preferred to be, may usually not be correct for 100% of the investigated subjects. The term, typically, requires that a statistically significant portion of subjects can be correctly assessed. Whether a portion is statistically significant can be determined without further ado by the person skilled in the art using various well known statistic evaluation tools, e.g., determination of confidence intervals, p-value determination, Student's t-test, Mann-Whitney test, etc., Details may be found in Dowdy and Wearden, Statistics for Research, John Wiley & Sons, New York 1983. Typically envisaged confidence intervals are at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%. The p-values are, typically, 0.2, 0.1, 0.05.

[0177] The terms lowered or decreased level, amount and/or concentration of an indicator refer to the level, amount and/or concentration of such indicator in the sample being reduced in comparison to the reference or reference sample.

[0178] The terms elevated or increased level, amount and/or concentration of an indicator refer to the level, amount and/or concentration of such indicator in the sample being higher in comparison to the reference or reference sample. E.g. a protein that is detectable in higher amounts or concentrations in a fluid sample of one individual suffering from a given disease than in the same fluid sample of individuals not suffering from said disease, has an elevated level.

[0179] The term measurement, measuring or determining preferably comprises a qualitative, a semi-quantitative or a quantitative measurement.

[0180] The term immunoglobulin (Ig) as used herein refers to immunity conferring glycoproteins of the immunoglobulin superfamily. Surface immunoglobulins are attached to the membrane of effector cells by their transmembrane region and encompass molecules such as but not limited to B-cell receptors, T-cell receptors, class I and II major histocompatibility complex (MHC) proteins, beta-2 microglobulin (2M), CD3, CD4 and CDS.

[0181] Typically, the term antibody as used herein refers to secreted immunoglobulins which lack the transmembrane region and can thus, be released into the bloodstream and body cavities. Human antibodies are grouped into different isotypes based on the heavy chain they possess. There are five types of human Ig heavy chains denoted by the Greek letters: a, Y, 8, E, and u. The type of heavy chain present defines the class of antibody, i.e. these chains are found in IgA, IgD, IgE, IgG, and IgM antibodies, respectively, each performing different roles, and directing the appropriate immune response against different types of antigens. Distinct heavy chains differ in size and composition; and may comprise approximately 450 amino acids (Janeway et al. (2001) Immunobiology, Garland Science). IgA is found in mucosal areas, such as the gut, respiratory tract and urogenital tract, as well as in saliva, tears, and breast milk and prevents colonization by pathogens (Underdown & Schiff (1986) Annu. Rev. Immunol. 4:389-417). IgD mainly functions as an antigen receptor on B cells that have not been exposed to antigens and is involved in activating basophils and mast cells to produce antimicrobial factors (Geisberger et al. (2006) Immunology 118:429-437; Chen et al. (2009) Nat. Immunol. 10:889-898). IgE is involved in allergic reactions via its binding to allergens triggering the release of histamine from mast cells and basophils. IgE is also involved in protecting against parasitic worms (Pier et al. (2004) Immunology, Infection, and Immunity, ASM Press). IgG provides the majority of antibody-based immunity against invading pathogens and is the only antibody isotype capable of crossing the placenta to give passive immunity to fetus (Pier et al. (2004) Immunology, Infection, and Immunity, ASM Press). In humans there are four different IgG subclasses (IgG1, 2, 3, and 4), named in order of their abundance in serum with IgG1 being the most abundant (66%), followed by IgG2 (23%), IgG3 (7%) and IgG (4%). The biological profile of the different IgG classes is determined by the structure of the respective hinge region. IgM is expressed on the surface of B cells in a monomeric form and in a secreted pentameric form with very high avidity. IgM is involved in eliminating pathogens in the early stages of B cell mediated (humoral) immunity before sufficient IgG is produced (Geisberger et al. (2006) Immunology 118:429-437). Antibodies are not only found as monomers but are also known to form dimers of two Ig units (e.g. IgA), tetramers of four Ig units (e.g. IgM of teleost fish), or pentamers of five Ig units (e.g. mammalian IgM). Antibodies are typically made of four polypeptide chains comprising two identical heavy chains and identical two light chains which are connected via disulfide bonds and resemble a Y-shaped macro-molecule. Each of the chains comprises a number of immunoglobulin domains out of which some are constant domains and others are variable domains. Immunoglobulin domains consist of a 2-layer sandwich of between 7 and 9 antiparallel -strands arranged in two -sheets. Typically, the heavy chain of an antibody comprises four Ig domains with three of them being constant (CH domains: CHI. CH2. CH3) domains and one of the being a variable domain (V H). The light chain typically comprises one constant Ig domain (CL) and one variable Ig domain (V L). Exemplified, the human IgG heavy chain is composed of four Ig domains linked from N- to C-terminus in the order VwCH1-CH2-CH3 (also referred to as VwCy1-Cy2-Cy3), whereas the human IgG light chain is composed of two immunoglobulin domains linked from N- to C-terminus in the order VL-CL, being either of the kappa or lambda type (VK-CK or VA.-CA.). Exemplified, the constant chain of human IgG comprises 447 amino acids. Throughout the present specification and claims, the numbering of the amino acid positions in an immunoglobulin are that of the EU index as in Kabat, E. A., Wu, T. T., Perry, H. M., Gottesman, K. S., and Foeller, C., (1991) Sequences of proteins of immunological interest, 5.sup.th ed. U.S. Department of Health and Human Service, National Institutes of Health, Bethesda, MD. The EU index as in Kabat refers to the residue numbering of the human IgG lEU antibody. Accordingly, CH domains in the context of IgG are as follows: CHI refers to amino acid positions 118-220 according to the EU index as in Kabat; CH2 refers to amino acid positions 237-340 according to the EU index as in Kabat; and CH3 refers to amino acid positions 341-44 7 according to the EU index as in Kabat.

[0182] The terms full-length antibody, intact antibody, and whole antibody are used herein interchangeably to refer to an antibody in its substantially intact form, not antibody fragments as defined below. The terms particularly refer to an antibody with heavy chains that contain an Fc region.

[0183] Papain digestion of antibodies produces two identical antigen binding fragments, called Fab fragments (also referred to as Fab portion or Fab region) each with a single antigen binding site, and a residual Fe fragment (also referred to as Fe portion or Fe region) whose name reflects its ability to crystallize readily. The crystal structure of the human IgG Fe region has been determined (Deisenhofer (1981) Biochemistry 20:2361-2370). In IgG, IgA and IgD isotypes, the Fc region is composed of two identical protein fragments, derived from the CH2 and CH3 domains of the antibody's two heavy chains; in IgM and IgE isotypes, the Fe regions contain three heavy chain constant domains (CH2-4) in each polypeptide chain. In addition, smaller immunoglobulin molecules exist naturally or have been constructed artificially. The term Fab fragment refers to a Fab fragment additionally comprise the hinge region of an Ig molecule whilst F(ab) 2 fragments are understood to comprise two Fab fragments being cither chemically linked or connected via a disulfide bond. Whilst single domain antibodies (sdAb) (Desmyter et al. (1996) Nat. Structure Biol. 3:803-811) and Nanobodies only comprise a single VH domain, single chain Fv (scFv) fragments comprise the heavy chain variable domain joined via a short linker peptide to the light chain variable domain (Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85, 5879-5883). Divalent single-chain variable fragments (di-scFvs) can be engineered by linking two scFvs (scFvA-scFvB). This can be done by producing a single peptide chain with two VH and two VL regions, yielding tandem scFvs (VHA-VLA-VHB-VLB). Another possibility is the creation of scFvs with linkers that are too short for the two variable regions to fold together, forcing scFvs to dimerize. Usually linkers with a length of 5 residues are used to generate these dimers. This type is known as diabodies. Still shorter linkers (one or two amino acids) between a V H and V L domain lead to the formation of monospecific trimers, so-called triabodies or tribadies. Bispecific diabodies are formed by expressing to chains with the arrangement VHA-VLB and VHB-VLA or VLA-VHB and VLB-VHA, respectively. Singlechain diabodies (scDb) comprise a VHA-VLB and a VHB-VLA fragment which are linked by a linker peptide (P) of 12-20 amino acids, preferably 14 amino acids, (VHA-VLB-P-VHB-VLA). Bispecific T-cell engagers (BiTEs) are fusion proteins consisting of two scFvs of different antibodies wherein one of the scFvs binds to T cells via the CD3 receptor, and the other to a tumor cell via a tumor specific molecule (Kufer et al. (2004) Trends Biotechnol. 22:238-244). Dual affinity retargeting molecules (DART molecules) are diabodies additionally stabilized through a C-terminal disulfide bridge.

[0184] Accordingly, the term antibody fragments refers to a portion of an intact antibody, preferably comprising the antigen-binding region thereof. Antibody fragments include but are not limited to Fab, Fab, F(ab).sub.2, Fv fragments; diabodies; sdAb, nanobodies, scFv, di-scFvs, tandem scFvs, triabodies, diabodies, scDb, BiTEs, and DARTs.

[0185] The term binding affinity generally refers to the strength of the sum total of noncovalent interactions between a single binding site of a molecule (e.g., an antibody) and its binding partner (e.g., an antigen). Unless indicated otherwise, as used herein, binding affinity refers to intrinsic binding affinity which reflects a 1:1 interaction between members of a binding pair (e.g., antibody and antigen). The affinity of a molecule X for its partner Y can generally be represented by the dissociation constant (Kd). Affinity can be measured by common methods known in the art, including but not limited to surface plasmon resonance based assay (such as the BIAcore assay as described in PCT Application Publication No. WO2005/012359); enzyme-linked immunoabsorbent assay (ELISA); and competition assays (e.g. RIA's). Low-affinity antibodies generally bind antigen slowly and tend to dissociate readily, whereas high-affinity antibodies generally bind antigen faster and tend to remain bound longer. A variety of methods of measuring binding affinity are known in the art, any of which can be used for purposes of the present invention.

[0186] Sandwich immunoassays are broadly used in the detection of an analyte of interest. In such assay the analyte is sandwiched in between a first antibody and a second antibody. Typically, a sandwich assay requires that capture and detection antibody bind to different, non-overlapping epitopes on an analyte of interest. By appropriate means such sandwich complex is measured and the analyte thereby quantified. In a typical sandwich-type assay, a first antibody bound to the solid phase or capable of binding thereto and a detectably-labeled second antibody each bind to the analyte at different and non-overlapping epitopes. The first analyte-specific binding agent (e.g. an antibody) is either covalently or passively bound to a solid surface. The solid surface is typically glass or a polymer, the most commonly used polymers being cellulose, polyacrylamide, nylon, polystyrene, polyvinyl chloride, or polypropylene. The solid supports may be in the form of tubes, beads, discs of microplates, or any other surface suitable for conducting an immunoassay. The binding processes are well-known in the art and generally consist of cross-linking covalently binding or physically adsorbing, the polymer-antibody complex is washed in preparation for the test sample. An aliquot of the sample to be tested is then added to the solid phase complex and incubated for a period of time sufficient (e.g. 2-40 minutes or overnight if more convenient) and under suitable conditions (e.g., from room temperature to 40 C. such as between 25 C. and 37 C. inclusive) to allow for binding between the first or capture antibody and the corresponding antigen. Following the incubation period, the solid phase, comprising the first or capture antibody and bound thereto the antigen can be washed, and incubated with a secondary or labeled antibody binding to another epitope on the antigen. The second antibody is linked to a reporter molecule which is used to indicate the binding of the second antibody to the complex of first antibody and the antigen of interest.

[0187] An extremely versatile alternative sandwich assay format includes the use of a solid phase coated with the first partner of a binding pair, e.g. paramagnetic streptavidin-coated microparticles. Such microparticles are mixed and incubated with an analyte-specific binding agent bound to the second partner of the binding pair (e.g. a biotinylated antibody), a sample suspected of comprising or comprising the analyte, wherein said second partner of the binding pair is bound to said analyte-specific binding agent, and a second analyte-specific binding agent which is detectably labeled. As obvious to the skilled person these components are incubated under appropriate conditions and for a period of time sufficient for binding the labeled antibody via the analyte, the analyte-specific binding agent (bound to) the second partner of the binding pair and the first partner of the binding pair to the solid phase microparticles. As appropriate such assay may include one or more washing step(s).

[0188] The term detectably labeled encompasses labels that can be directly or indirectly detected.

[0189] Directly detectable labels either provide a detectable signal or they interact with a second label to modify the detectable signal provided by the first or second label, e.g. to give FRET (fluorescence resonance energy transfer). Labels such as fluorescent dyes and luminescent (including chemiluminescent and electrochemiluminescent) dyes (Briggs et al Synthesis of Functionalised Fluorescent Dyes and Their Coupling to Amines and Amino Acids, J. Chem. Soc., Perkin-Trans. 1 (1997) 1051-1058) provide a detectable signal and are generally applicable for labeling. In one embodiment detectably labeled refers to a label providing or inducible to provide a detectable signal, i.e. to a fluorescent label, to a luminescent label (e.g. a chemiluminescent label or an electrochemiluminescent label), a radioactive label or a metal-chelate based label, respectively.

[0190] Numerous labels (also referred to as dyes) are available which can be generally grouped into the following categories, all of them together and each of them representing embodiments according the present disclosure: [0191] (a) Fluorescent dyes

[0192] Fluorescent dyes are e.g. described by Briggs et al Synthesis of Functionalized Fluorescent Dyes and Their Coupling to Amines and Amino Acids, J. Chem. Soc., Perkin-Trans. 1 (1997) 1051-1058).

[0193] Fluorescent labels or fluorophores include rare earth chelates (europium chelates), fluorescein type labels including FITC, 5-carboxyfluorescein, 6-carboxy fluorescein; rhodamine type labels including TAMRA; dansyl; Lissamine; cyanines; phycoerythrins; Texas Red; and analogs thereof. The fluorescent labels can be conjugated to an aldehyde group comprised in target molecule using the techniques disclosed herein. Fluorescent dyes and fluorescent label reagents include those which are commercially available from Invitrogen/Molecular Probes (Eugene, Oregon, USA) and Pierce Biotechnology, Inc. (Rockford, Ill.). [0194] (b) Luminescent dyes

[0195] Luminescent dyes or labels can be further subcategorized into chemiluminescent and electrochemiluminescent dyes.

[0196] The different classes of chemiluminogenic labels include luminol, acridinium compounds, coelenterazine and analogues, dioxetanes, systems based on peroxyoxalic acid and their derivatives. For immunodiagnostic procedures predominantly acridinium based labels are used (a detailed overview is given in Dodeigne C. et al., Talanta 51 (2000) 415-439).

[0197] The labels of major relevance used as electrochemiluminescent labels are the Ruthenium- and the Iridium-based electrochemiluminescent complexes, respectively. Electrochemiluminescense (ECL) proved to be very useful in analytical applications as a highly sensitive and selective method. It combines analytical advantages of chemiluminescent analysis (absence of background optical signal) with ease of reaction control by applying electrode potential. In general Ruthenium complexes, especially [Ru (Bpy)3]2+ (which releases a photon at 620 nm) regenerating with TPA (Tripropylamine) in liquid phase or liquid solid interface are used as ECL-labels.

[0198] Electrochemiluminescent (ECL) assays provide a sensitive and precise measurement of the presence and concentration of an analyte of interest. Such techniques use labels or other reactants that can be induced to luminesce when electrochemically oxidized or reduced in an appropriate chemical environment. Such electrochemiluminescence is triggered by a voltage imposed on a working electrode at a particular time and in a particular manner. The light produced by the label is measured and indicates the presence or quantity of the analyte. For a fuller description of such ECL techniques, reference is made to U.S. Pat. Nos. 5,221,605, 5,591,581, 5,597,910, PCT published application WO90/05296, PCT published application WO92/14139, PCT published application WO90/05301, PCT published application WO96/24690, PCT published application US95/03190, PCT application US97/16942, PCT published application US96/06763, PCT published application WO95/08644, PCT published application WO96/06946, PCT published application WO96/33411, PCT published application WO87/06706, PCT published application WO96/39534, PCT published application WO96/41175, PCT published application WO96/40978, PCT/US97/03653 and U.S. patent application Ser. No. 08/437,348 (U.S. Pat. No. 5,679,519). Reference is also made to a 1994 review of the analytical applications of ECL by Knight, et al. (Analyst, 1994, 119:879-890) and the references cited therein. In one embodiment the method according to the present description is practiced using an electrochemiluminescent label.

[0199] Recently also Iridium-based ECL-labels have been described (WO2012107419). [0200] (c) Radioactive labels make use of radioisotopes (radionuclides), such as 3H, 11C, 14C, 18F, 32P, 35S, 64Cu, 68Gn, 86Y, 89Zr, 99TC, 111 In, 123I, 124I, 125I, 131I, 133Xe, 177Lu, 211At, or 131Bi. [0201] (d) Metal-chelate complexes suitable as labels for imaging and therapeutic purposes are well-known in the art (US 2010/0111861; U.S. Pat. Nos. 5,342,606; 5,428,155; 5,316,757; 5,480,990; 5,462,725; 5,428,139; 5,385,893; 5,739,294; 5,750,660; 5,834,461; Hnatowich et al, J. Immunol. Methods 65 (1983) 147-157; Meares et al, Anal. Biochem. 142 (1984) 68-78; Mirzadeh et al, Bioconjugate Chem. 1 (1990) 59-65; Meares et al, J. Cancer (1990), Suppl. 10:21-26; Izard et al, Bioconjugate Chem. 3 (1992) 346-350; Nikula et al, Nucl. Med. Biol. 22 (1995) 387-90; Camera et al, Nucl. Med. Biol. 20 (1993) 955-62; Kukis et al, J. Nucl. Med. 39 (1998) 2105-2110; Verel et al., J. Nucl. Med. 44 (2003) 1663-1670; Camera et al, J. Nucl. Med. 21 (1994) 640-646; Ruegg et al, Cancer Res. 50 (1990) 4221-4226; Verel et al, J. Nucl. Med. 44 (2003) 1663-1670; Lee et al, Cancer Res. 61 (2001) 4474-4482; Mitchell, et al, J. Nucl. Med. 44 (2003) 1105-1112; Kobayashi et al Bioconjugate Chem. 10 (1999) 103-111; Miederer et al, J. Nucl. Med. 45 (2004) 129-137; DeNardo et al, Clinical Cancer Research 4 (1998) 2483-90; Blend et al, Cancer Biotherapy & Radiopharmaceuticals 18 (2003) 355-363; Nikula et al J. Nucl. Med. 40 (1999) 166-76; Kobayashi et al, J. Nucl. Med. 39 (1998) 829-36; Mardirossian et al, Nucl. Med. Biol. 20 (1993) 65-74; Roselli et al, Cancer Biotherapy & Radiopharmaceuticals, 14 (1999) 209-20).

EXAMPLES

[0202] The invention will be merely illustrated by the following Examples. The said Examples shall, whatsoever, not be construed in a manner limiting the scope of the invention.

Example 1: Diagnostic Performance of Biomarker METRNL in Women with PCOS (Phenotype A) and Controls Determined by the Proximity Extension Assay (PEA) Technology Developed at Olink

[0203] As part of the measurements, 88 serum samples from human females were analyzed. The case group comprised 51 samples from patients diagnosed with PCOS (Phenotype A) according to the Rotterdam criteria. The control group included 37 samples from healthy women without PCOS. The concentration of the analytes was determined using the Proximity Extension Assay (PEA) technology developed at Olink. Briefly, a matched pair of antibodies, coupled to unique, partially complementary oligonucleotides, addresses each biomarker. Quantification is then performed by quantitative real-time PCR.

[0204] After sample dilution according to the manufacturer's protocol for each of the selected panels, the Olink protocol consists of three core steps: 1. Incubation, 2. Extension and amplification, 3. Detection. One l of each sample was mixed with 3 l of incubation mix in a 96 well plate. The incubation mix, additionally to the 92 antibody pairs, labeled with DNA oligonucleotides, contains also internal controls designed to monitor the three main steps of the Olink protocol (2 incubation controls, 1 extension control and 1 detection control). As external controls, 3 positive (inter-plate control) and 3 negative controls were included in the plate as well as 2 sample controls (pooled plasma samples). Samples were incubated overnight at +4 C. During this step the antibody pairs bind to the respective protein in the samples. When the incubation was complete, 96 l of Extension mix were added to the samples. The plate was placed in a thermal cycler for hybridization and extension was performed by a DNA polymerase (50 C. 20 min, 95 C. 5 min (95 C. 30 s, 54 C. 1 min, 60 C. 1 min)17, 10 C. hold). The DNA barcode was amplified by PCR. Finally, the amount of each DNA barcode was quantified by microfluidic qPCR. A 96.96 Dynamic Array Integrated Fluidic Circuit (IFC) was used according to the manufacturer's instructions. Seven point two l of Detection mix were added to 2.8 l of each sample, of these, 5 l were transferred into the primed 96.96 Dynamic Array IFC left inlets. Five l of primer solution were transferred into the primed 96.96 Dynamic Array IFC right inlets. Chip was loaded in the Fluidigm IFC Controller HX according to the manufacturer's instructions. The Olink Protein Expression 9696 Program was ran in the Fluidigm Biomark Reader according to the manufacturer's instructions (50 C. 120 s, 70 C. 1800 s, 25 C. 600 s, 95 C. 300 s (95 C. 15 s, 60 C. 60 s)35; with the following settings: application-Gene Expression; passive Reference-ROX; assay-Single probe; probes-FAM-MGB). The Ct values obtained from the qPCR were transformed into arbitrary unit called Normalized Protein expression (NPX, a relative quantification unit on log 2 scale) using the following equations:

Extension Control:

[00001]${\mathrm{Ct}}_{\mathrm{Analyte}}-{\mathrm{Ct}}_{\mathrm{Extension}\mathrm{Control}}={\mathrm{dCt}}_{\mathrm{Analyte}}$

Inter-Plate Control:

[00002]${\mathrm{dCt}}_{\mathrm{Analyte}}-{\mathrm{dCt}}_{\mathrm{Inter}-\mathrm{plate}\mathrm{Control}}={\mathrm{ddCt}}_{\mathrm{Analyte}}$

Adjustment Against a Correction Factor:

[00003]$\mathrm{Correction}\mathrm{factor}-{\mathrm{ddCt}}_{\mathrm{Analyte}}={\mathrm{NPX}}_{\mathrm{Analyte}}$

[0205] Quality control and normalization was achieved using the Olink NPX Manager software.

[0206] Receiver Operating Characteristic (ROC) curves were generated (FIG. 1). The model performance is determined by looking at the area under the curve (AUC). The best possible AUC is 1 while the lowest possible is 0.5. The ROC curve analysis illustrated an AUC of 0.972 (95% CI 0.944-1.0, FIG. 1), showing that METRNL has high diagnostic accuracy for PCOS. The diagnostic performance of METRNL to distinguish between women with PCOS with the full blown phenotype A (cases) and healthy control subjects using ROC analysis is shown in Table 1 describing the AUC of the ROC curve analysis and the associated 95% confidence interval. The results were obtained using Olink proximity extension technology.

TABLE-US-00001 TABLE 1 AUC (area under 95% CI (confidence N (sample Sample Marker the curve) interval) size) type METRNL 0.972 0.944-1 88 serum

[0207] The data obtained by the Olink PEA technology were used to generate box and whisker plots for healthy controls and PCOS cases. The boxes include the median (middle quartile), the interquartile range (which represents the middle 50% of scores for the group), the upper quartile (75% of scores fall below the upper quartile) and the lower quartile (25% of scores fall below the lower quartile). The whiskers represent values that are 1.5 times the interquartile ranges. Serum METRNL concentrations are decreased in women with PCOS when compared to healthy controls (FIG. 2).

Example 2: Diagnostic Performance of Biomarker METRNL in Women with PCOS (Phenotypes A, B, C and D) and Controls Determined by ELISA Technology

[0208] Performance validation has been performed in a sample collective of 85 cases (serum samples from women with PCOS) and 46 controls (scrum samples from healthy women).

[0209] The concentration of the analyte was determined by ELISA (enzyme-linked immunosorbent assay). The case group is composed of patients diagnosed with PCOS (26 phenotype A, 19 phenotype B, 20 phenotype C and 20 phenotype D) according to the Rotterdam criteria. The control group includes healthy women without PCOS.

[0210] The concentration of METRNL in human scrum was determined using the Human METRNL ELISA kit from R&D Systems (catalog number: DY7867-05). The kit is a solid-phase sandwich Enzyme-Linked Immunosorbent Assay (ELISA) designed to detect and quantify the level of human METRNL in cell culture supernatants, plasma, and serum.

[0211] The capture antibody was diluted to the working concentration in PBS without carrier protein. A 96-well microplate was incubated with 100 L per well of the diluted Capture Antibody. The plate was scaled and incubated overnight at room temperature. The plate was washed 3 times with 400 L of Wash Buffer per well each time. After the last wash the Wash Buffer was completely removed, the plate was blocked by adding 300 L of Regent Diluent to each well and incubated at room temperature for a minimum of 1 hour. The plate was washed 3 times with 400 L of Wash Buffer per well each time and was made ready to use. Samples were measured in 4-fold dilution. After bringing all reagents to room temperature, 100 L of each sample and standard were added. Samples and standards were measured in duplicates. During 2 hours incubation at room temperature, any METRNL present was bound to the immobilized capture antibody on the microtiter plate. During the washing steps (3400 L), unbound substances were removed from the plate before 100 L of the anti-METRNL Detection Antibody diluted in Reagent Diluent was added to the wells. Following 2 hours incubation and another washing step (3400 L) to remove any unbound detection antibody, 100 L of the prepared Streptavidin-HRP solution was added to the plate. Followed a 20 minutes incubation at room temperature and the washing steps (3400 L) avoiding direct exposure to the light. After the last wash, 100 L of Substrate Solution was added to the plate. The plate was incubated for 20 minutes at room temperature avoiding direct light exposure. During the incubation the substrate turned blue. The color developed in proportion to the amount of METRNL bound in the initial step. Color development was stopped by addition of 50 L of Stop Solution, the color of the solution in the well changed from blue to yellow and color intensity was measured with a plate reader at 450 nm for detection and 540 or 570 nm for background subtraction. This subtraction is correcting for optical imperfections in the plate. For generation of calibration curves, lyophilized, recombinant METRNL delivered with the kit was reconstituted and diluted in Reagent Diluent. The calibration range of the assay is 15.6 pg/mL to 1000 pg/mL. A seven point standard curve was obtained using 2-fold serial dilutions of the recombinant METRNL in the Reagent Diluent. The calibration curves were fitted using a four parameter logistic (4-PL, Newton/Raphson) curve-fit.

[0212] Receiver Operating Characteristic (ROC) curves were generated (FIG. 3). The model performance is determined by looking at the area under the curve (AUC). The best possible AUC is 1 while the lowest possible is 0.5. The ROC curve analysis for METRNL for PCOS cases when all phenotypes were combined (phenotypes A-D) illustrated an AUC of 0.94 (95% CI 0.89-0.99), confirming the high diagnostic accuracy of METRNL for PCOS (FIG. 3). The diagnostic performance of METRNL to distinguish between women with PCOS (cases, PCOS phenotypes A-D) and healthy control subjects using ROC analysis is shown in Table 2 describing the AUC of the ROC curve analysis and the associated 95% confidence interval. The results were obtained using ELISA immunoassay.

TABLE-US-00002 TABLE 2 AUC (area under 95% CI (confidence N (sample Sample Marker the curve) interval) size) type METRNL 0.94 (0.89-0.99) 131 serum

[0213] The data obtained by ELISA immunoassay were used to generate box and whisker plots for control and PCOS cases when all phenotypes were combined (phenotypes A-D). Serum METRNL concentrations (pg/mL) are decreased in women with PCOS when compared to healthy controls (FIG. 4).

[0214] Table 3 shows the diagnostic performance of METRNL to distinguish between women with PCOS when separated by the different phenotypes A, B, C and D versus healthy control subjects. The results were obtained using ELISA immunoassay. AUC for each phenotype is reported in the table.

TABLE-US-00003 TABLE 3 N Pheno- Pheno- Pheno- Pheno- (sample Sample Marker type A type B type C type D size) type METRNL 0.9 0.93 0.99 0.95 131 serum

[0215] ROC curve analysis for METRNL for PCOS cases separated by the different phenotypes versus healthy controls showed an AUC of 0.9 (95% CI 0.78-1), 0.93 (95% CI 0.84-1), 0.99 (95% CI 0.97-1) and 0.95 (95% CI 0.86-1), respectively for the phenotypes from A to D (FIG. 5). The results confirm the high diagnostic accuracy of METRNL for PCOS. Serum METRNL concentrations (pg/mL) in all the different PCOS phenotypes (Phenotype A-D) showed decreased levels compared to healthy controls (FIG. 6, results obtained using ELISA immunoassay).

[0216] Table 4 shows the diagnostic performance of METRNL in young women (age25), to distinguish young women with PCOS from young healthy control subjects when all phenotypes were combined (phenotypes A-D). The results were obtained using ELISA assays.

TABLE-US-00004 TABLE 4 AUC (area under 95% CI (confidence N (sample Sample Marker the curve) interval) size) type METRNL 0.93 (0.83-1.00) 30 serum

[0217] The ROC curve analysis for METRNL for young PCOS cases (age25) when all phenotypes were combined (phenotypes A-D) illustrated an AUC of 0.93, confirming high diagnostic accuracy, for women that are 25 or younger, in discriminating PCOS cases from controls (95% CI 0.83-1.00, FIG. 7). When only young women were included in the analysis (age25) PCOS cases (all phenotypes A-D combined) showed decreased serum METRNL concentrations (pg/mL) compared to young controls (age25, FIG. 8).

[0218] The diagnostic performance of METRNL to distinguish between young women with PCOS (age25) when separated by the different phenotypes A, B, C and D versus young healthy control subjects (age25) has been evaluated and results are reported in table 5 (AUC for PCOS phenotypes versus controls). The results were obtained using ELISA immunoassay.

TABLE-US-00005 TABLE 5 N Pheno- Pheno- Pheno- Pheno- (sample Sample Marker type A type B type C type D size) type METRNL 0.93 0.67 1.00 1.00 30 serum

[0219] The ROC curve analysis for METRNL for young PCOS cases (age25, phenotypes A-D) illustrated an AUC of 0.93 (95% CI 0.78-1), 0.67 (95% CI 0.01-1), 1.00 (95% CI 1-1), 1.00 (95% CI 1-1) for each phenotype respectively, confirming high diagnostic accuracy of METRNL for PCOS, in the subgroup of women of age 25 or younger (FIG. 9). METRNL concentrations were decreased in all the different PCOS phenotypes (Phenotype A-D, age25) when compared to METRNL concentrations in young healthy controls (age25, FIG. 10).

Example 3: Diagnostic Performance of Biomarker METRNL in Women with PCOS (Phenotypes A, B, C and D) and Controls Determined by ELISA Technology, in Different Age Groups

[0220] Performance validation has been performed in an additional sample collective of 240 cases (serum samples from women with PCOS) and 48 controls (serum samples from healthy women).

[0221] The concentration of the analyte was determined by ELISA (enzyme-linked immunosorbent assay). The case group is composed of patients diagnosed with PCOS (155 phenotype A, 5 phenotype B, 8 phenotype C and 72 phenotype D) according to the Rotterdam criteria, belonging to three different age groups: 15-20 (n=70), 20-25 (n=99), 25-40 (n=71). The control group includes healthy women without PCOS.

[0222] The concentration of METRNL in human serum was determined using the Human METRNL ELISA kit from R&D Systems (catalog number: DY7867-05) as described in example 2.

[0223] Receiver Operating Characteristic (ROC) curves were generated (FIG. 11). The model performance is determined by looking at the area under the curve (AUC). The ROC curve analysis for METRNL for PCOS cases when all phenotypes were combined (phenotypes A-D) illustrated an AUC of 0.91 (95% CI 0.88-0.95), confirming the high diagnostic accuracy of METRNL for PCOS (FIG. 11).

[0224] The diagnostic performance of METRNL to distinguish between women with PCOS (cases, PCOS phenotypes A-D) and healthy control subjects using ROC analysis is shown in Table 6 describing the AUC of the ROC curve analysis and the associated 95% confidence interval. The results were obtained using ELISA immunoassay.

TABLE-US-00006 TABLE 6 AUC (area under 95% CI (confidence N (sample Sample Marker the curve) interval) size) type METRNL 0.91 (0.88-0.95) 288 serum

[0225] The data obtained by ELISA immunoassay were used to generate box and whisker plots for control and PCOS cases when all phenotypes were combined (phenotypes A-D). Serum METRNL concentrations (pg/mL) are decreased in women with PCOS when compared to healthy controls (FIG. 12).

[0226] Table 7 shows the diagnostic performance of METRNL to distinguish between women with PCOS when separated by the different phenotypes A, B, C and D versus healthy control subjects. The results were obtained using ELISA immunoassay. AUC for each phenotype is reported in the table.

TABLE-US-00007 TABLE 7 N Pheno- Pheno- Pheno- Pheno- (sample Sample Marker type A type B type C type D size) type METRNL 0.91 1.00 1.00 0.90 288 serum

[0227] ROC curve analysis for METRNL for PCOS cases separated by the different phenotypes versus healthy controls showed an AUC of 0.91 (95% CI 0.87-0.95), 1.00 (95% CI 1.00-1.00), 1.00 (95% CI 1.00-1.00) and 0.90 (95% CI 0.84-0.97), respectively for the phenotypes from A to D (FIG. 13). The results confirm the high diagnostic accuracy of METRNL for PCOS.

[0228] Serum METRNL concentrations (pg/mL) in all the different PCOS phenotypes (Phenotype A-D) showed decreased levels compared to healthy controls (FIG. 14, results obtained using ELISA immunoassay).

[0229] Table 8 shows the diagnostic performance of METRNL in different age groups (15age<20, 20age<25, 25age<40), to distinguish women with PCOS from healthy control subjects when all phenotypes were combined (phenotypes A-D). The results were obtained using ELISA assays.

TABLE-US-00008 TABLE 8 15 20 25 N (sample Sample Marker age < 20 age < 25 age < 40 size) type METRNL 0.88 0.91 0.96 288 serum

[0230] ROC curve analysis for METRNL for PCOS cases separated by the different age groups versus healthy controls showed an AUC of 0.88 (95% CI 0.80-0.95), 0.91 (95% CI 0.86-0.96) and 0.96 (95% CI 0.91-1.00), respectively for the age groups 15-20, 20-25, 25-40 (FIG. 15). The results confirm the high diagnostic accuracy of METRNL for PCOS in all the different age groups.

[0231] Decreased serum METRNL concentrations (pg/mL) in women with PCOS compared to controls were confirmed in all the different age groups (FIG. 16).

[0232] Considering the lack of reliable biomarkers for diagnosing PCOS especially in young women (age<25), a separate analysis was performed for the age group 15 and <25.

[0233] Table 9 shows the diagnostic performance of METRNL in young women (15age <25), to distinguish young women with PCOS from young healthy control subjects when all phenotypes were combined (phenotypes A-D). The results were obtained using ELISA assays.

TABLE-US-00009 TABLE 9 AUC (area under 95% CI (confidence N (sample Sample Marker the curve) interval) size) type METRNL 0.90 (0.85-0.94) 192 serum

[0234] The ROC curve analysis for METRNL for young PCOS cases (15age<25) when all phenotypes were combined (phenotypes A-D) illustrated an AUC of 0.90, confirming high diagnostic accuracy for 15-25 year old women, in discriminating PCOS cases from controls (95% CI 0.85-0.94, FIG. 17). When only young women were included in the analysis (15age<25) PCOS cases (all phenotypes A-D combined) showed decreased serum METRNL concentrations (pg/mL) compared to young controls (15age<25, FIG. 18).

[0235] The diagnostic performance of METRNL to distinguish between young women with PCOS (15age<25) when separated by the different phenotypes A, B, C and D versus young healthy control subjects (15age<25) has been evaluated and results are reported in table 10 (AUC for PCOS phenotypes versus controls). The results were obtained using ELISA immunoassay.

TABLE-US-00010 TABLE 10 N Pheno- Pheno- Pheno- Pheno- (sample Sample Marker type A type B type C type D size) type METRNL 0.89 1.00 1.00 0.89 192 serum

[0236] The ROC curve analysis for METRNL for young PCOS cases (15age<25, phenotypes A-D) illustrated an AUC of 0.89 (95% CI 0.83-0.95), 1.00 (95% CI 1.00-1.00), 1.00 (95% CI 1.00-1.00), 0.89 (95% CI 0.81-0.97) for each phenotype respectively, confirming high diagnostic accuracy of METRNL for PCOS, in the subgroup of women of age 15-25 (FIG. 19). METRNL concentrations were decreased in all the different PCOS phenotypes (Phenotype A-D, 15age<25), when compared to METRNL concentrations in young healthy controls (15age<25, FIG. 20).