Association of leptin with inflammatory cytokines and lymphocyte subpopulations in peritoneal fluid of patients with endometriosis

Introduction: Endometriosis is a common, complex and chronic disease related to ectopic implantation and growth of endometrial tissue that may manifest by pelvic inflammatory reactions, chronic pelvic pain and subfertility. Endometriosis may be associated with increased peritoneal fluid leptin levels. Leptin is known to exert immunomodulatory effects; however, an association between leptin and inflammatory reactions in endometriosis has not been documented. Therefore, the aim of this study was to investigate a relationship between leptin concentrations in peritoneal fluid and the levels of peritoneal fluid inflammatory cytokines and mononuclear leukocyte subpopulations. Materials and methods: Peritoneal fluid was aspirated by laparoscopy from 46 women in whom endometriosis had been confirmed by clinical and histopathological examinations and from 10 control women qualified for ART in whom pelvic pathology has been excluded. Concentrations of leptin and inflammatory cytokines (IL-1 beta, IL-6, IFN-gamma and TNF) in peritoneal fluid were evaluated by specific ELISAs. Percentage of peritoneal leukocyte subpopulations (CD3(+), CD4(+), CD8(+) and CD14(+)) was analyzed by FACS using specific monoclonal antibodies. Results: Leptin concentrations in peritoneal fluid correlated negatively with concentrations of IL-1 beta and IFN-gamma (r(s) = -0.38,p = 0.01 and r(s) = -0.31, p = 0.03, respectively) and correlated positively with the percentage of CD3(+) pan-T cells (r(s) = 0.69, p = 0.009) and CD4(+) T helper cells (r(s) = 0.74, p = 0.036). Conclusions: Increased leptin levels in peritoneal fluid from endometriosis patients may affect local inflammatory/immune reactions, especially infiltration of CD4(+) T helper cells. Thus, leptin may play an important role in the immunopathogenesis of endometriosis. (C) 2008 Elsevier Ireland Ltd. All rights reserved.