CD4⁺ CD25⁺ FOXP3⁺ regulatory T cells in peripheral blood and peritoneal fluid of patients with endometriosis

STUDY QUESTION: Is endometriosis associated with changes in CD4⁺ CD25⁺ FOXP3⁺ regulatory T cells (Treg cells)? SUMMARY ANSWER: Endometriosis is associated with disturbed compartmentalization of CD25(high) FOXP3⁺ Treg cells. WHAT IS KNOWN ALREADY: Endometriosis is associated with an abrogated immune response and displays some features of an autoimmune disorder. Treg cells play a part in the development of autoimmune reactions; however, their role in pathogenesis of endometriosis is still poorly recognized. STUDY DESIGN, SIZE AND DURATION: Case-control study comparing 17 women with laparoscopically and histopathologically confirmed ovarian endometriosis with 15 control women without visible endometriosis foci, pelvic inflammation or related pathology who were subjected to laparoscopic surgery between 2010 and 2011. PARTICIPANTS/MATERIALS, SETTING AND METHODS: Peripheral blood and peritoneal fluid were collected during laparoscopy and T cell subpopulations were analysed by flow cytometry using specific monoclonal antibodies recognizing CD4⁺, CD25⁺ and FOXP3⁺ markers. MAIN RESULTS: The percentage of CD25(high) FOXP3⁺ Treg cells was significantly decreased in the peripheral blood of women with ovarian endometriosis compared with control women. On the other hand, the proportion of these cells was significantly increased in the peritoneal fluid of women with endometriosis. LIMITATIONS, REASONS FOR CAUTION: The present study is limited to patients with ovarian endometrioma and further investigations are needed, including patients with lower grade of endometriosis. WIDER IMPLICATIONS OF THE FINDINGS: The present results suggest that Treg cells may play a part in immunopathogenesis of endometriosis being responsible for abrogated local cellular immune responses and facilitation and development of autoimmune reactions. Treg cells may be thus a potential target in the treatment of endometriosis. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by 1M15/N/2011 and NK1W grants from the I Faculty of Medicine, Warsaw Medical University. None of the authors has any competing interests to declare.