mRNA expression of Foxp3 and RORc transcription factors and of IL-10 and IL-17A cytokines in ovarian endometrioma of women with endometriosis.

Introduction. In endometriosis (E), the implant of regurgitating endometrial cells outside the uterus triggers an immune response. Our previous work showed the upregulation of Th1- in early and Th2-cytokines in severe stages of E. The cytokines drive the differentiation program of CD4+T cells toward Th1, Th2 and Th17 effector cells and toward regulatory cells (Tregs). Transcription factor Foxp3 is induced by TGF-beta together with IL-2 and retinoic acid and characterizes Tregs. These cells suppress immune response and maintain peripheral tolerance by IL-10. Transcription factor RORc, induced by TGF-beta together with IL-6, IL-21 and IL-23, drives differentiation of Th17 cells, which produce IL17-A, IL17-F and IL-22 and favour inflammation and autoimmunity. The eutopic endometrium of healthy women behaves like an immune regulatory tissue: Th17 are few and Tregs are recruited to, infiltrate and increase in the proliferative phase of cycle to exert immune suppressive effects required to embryo implant. Aim of this work is to verify the presence of Foxp3+ or RORc+ cells and IL-10 or IL-17A producing cells by evaluating gene expression at mRNA production in ovarian endometrioma (OE) from women with E and ovarian functional cysts (OFC) from women without E. Materials and Methods. We collected OE from 50 women with E and OFC from 10 women without E as controls (C), during laparoscopy. Total RNA was isolated from tissues for reverse-PCR real time analysis of Foxp3, RORc, IL-10, IL-17A and beta-actin as endogenous control. PCR Real Time was performed by means of ready-to-use assays (Assays on demand, Applied Biosystems) on both targets and endogenous control. Results and Conclusions. Our results showed Foxp3 mRNA presence in 52% of OE with levels almost overlapping to C. RORc- and IL-17A-mRNAs were present and slightly upregulated respect to C in 61% and 68% of samples, respectively. Indeed, IL-10 mRNA was present and strongly overexpressed (3.0-fold higher than C) in 100% of OE. We hypothesize that, in the positive samples, RORc and IL-17A presence may represent a hallmark of inflammation linked to the endometriosis stage. All of OE samples were IL-10 mRNA positive, but only half of them comprised Foxp3+ cells. IL-10 production by many Foxp3- cell types may account for this discrepancy. Anyway, IL-10 overproduction may exert suppressive effects on the phagocytic and cytotoxic activity of infiltrated immune cells and so promote the endometriotic cell escape, survival and growth.