Panel of Autoimmune Markers for Noninvasive Diagnosis of Minimal-Mild Endometriosis.

Endometriosis, characterized by the presence of endometrial-like tissue at extrauterine sites, is a common, chronic, estrogen-dependent, inflammatory condition associated with pelvic pain, subfertility, dysmenorrhea, and dyspareunia, affecting about 10% of reproductive-age women in any population. The diagnosis of endometriosis is usually delayed on an average by 8 to 11 years leading to significant consequences in terms of disease progression. The current study was aimed to validate enzyme-linked immunosorbent assay based on the epitopes of stomatin-like protein 2, tropomodulin 3 (TMOD3), and tropomyosin 3 (TPM3) for diagnosis of minimal-mild endometriosis (revised American Fertility Society Classification (rAFS) stage I-II) and to compare the performance with the reported markers: cancer antigen (CA) 125, CA19-9, α-enolase, Serine/threonine-protein kinase (PDIK1L), and syntaxin 5. This was a cross-sectional, multicenter study conducted during the year 2012 to 2015. Women with minimal-mild endometriosis (rAFS stage I-II [n = 133]) and healthy controls (n = 104) were screened for 11 novel autoimmune markers and reported markers α-enolase, PDIK1L, syntaxin 5, CA-125, and CA19-9. The sensitivity and diagnostic accuracy of serum antibodies against all the 11 epitopes were higher than that of CA-125, CA19-9, α-enolase, PDIK1L, and syntaxin 5 for diagnosis of rAFS stage I to II endometriosis. The sensitivity of 6 biomarkers (anti-TMOD3b-autoAb, anti-TMOD3c-autoAb, anti-TMOD3d-autoAb, anti-TPM3a-autoAb, anti-TPM3c-autoAb, and anti-TPM3d-autoAb) was higher at the specificity of ≥80% for diagnosis of rAFS stage I to II endometriosis as well as ultrasound-negative endometriosis. Further, logistic regression models of this panel of biomarkers showed increase in sensitivity, specificity, and diagnostic accuracy than individual biomarkers. The panel of 6 autoimmune biomarkers could be useful in setting up of noninvasive diagnostic test for detection of minimal-mild endometriosis.

Identification and validation of novel serum markers for early diagnosis of endometriosis.

BACKGROUND: Non-invasive diagnosis of endometriosis is urgently required to prevent the long delay between the onset of symptoms and diagnosis. A biomarker that possesses both high sensitivity and specificity is greatly required. Here, we describe the use of a proteomic approach to identify potential novel endometrial antigens using sera from endometriosis patients and healthy controls, with evaluation of biomarkers for non-invasive diagnosis of endometriosis. METHODS: A cross-sectional study was conducted to identify specific endometrial antigens using 1D and 2D western blots in women with early endometriosis (n = 17), advanced endometriosis (n = 23) and without endometriosis (n = 30). Five immunoreactive spots were analyzed using matrix-assisted laser desorption/ionization-time-of-flight/mass spectrometry with MASCOT analysis. ELISAs were established for specific epitopes and autoantibody titres were estimated in an independent cohort comprising women with early endometriosis (n = 18), advanced endometriosis (n = 32) and without endometriosis (n = 27) for validation. RESULTS: The 2D western blot analysis resulted in the identification of three endometrial antigens, tropomyosin 3 (TPM3), stomatin-like protein 2 (SLP2) and tropomodulin 3 (TMOD3). Serum levels of antibodies against the epitopes from the immunodominant region of proteins TPM3, SLP2 and TMOD3 were significantly elevated in endometriosis patients when compared with controls. Sensitivity and specificity of serum anti-TPM3a-autoAb (61%, 93%), anti-TPM3c-autoAb (44%, 93%), anti-TPM3d-autoAb (78%, 89%), anti-SLP2a-autoAb (50%, 96%), anti-SLP2c-autoAb (61%, 93%), anti-TMOD3b-autoAb (61%, 96%), serum anti-TMOD3c-autoAb (78%, 93%) and anti-TMOD3d-autoAb (78%, 96%) were better than those of serum CA125 levels (21%, 89%) in the detection of early stages of endometriosis. CONCLUSIONS: Serum anti-TPM3a-autoAb, anti-TPM3c-autoAb, anti-TPM3d-autoAb, anti-SLP2a-autoAb, anti-SLP2c-autoAb, anti-TMOD3b-autoAb, anti-TMOD3c-autoAb and anti-TMOD3d-autoAb could be new markers for the early diagnosis of endometriosis.