Interferon‐Gamma (IFN‐γ) and Interleukin‐6 (IL‐6) in Peritoneal Fluid and Macrophage‐Conditioned Media of Women With Endometriosis

PROBLEM: The presence of the various cytokines in human peritoneal fluid has been incompletely evaluated. Changes in cytokine levels may be related to activation of peritoneal macrophages, development of endometriosis, and infertility. This study assesses peritoneal fluid levels of interferon gamma (IFN-gamma) and interleukin-6 (IL-6), and peritoneal macrophage production of IL-6, in women with and without endometriosis. METHOD: Peritoneal fluid was obtained from 62 women at the time of diagnostic or operative laparoscopic surgery for benign gynecologic disease. Peritoneal macrophages were isolated, cultured for 24 h, and the culture media collected. IFN-gamma and IL-6 levels in peritoneal fluid samples and macrophage conditioned media were determined by commercial ELISA. RESULTS: IL-6 was significantly higher in the macrophage conditioned media of women with endometriosis as compared with controls. IL-6 levels were fourfold higher in early stage endometriosis (P < 0.05) and eightfold higher in advanced endometriosis. There were no significant differences between groups in the peritoneal fluid levels of IL-6 or IFN-gamma. CONCLUSIONS: Peritoneal macrophage IL-6 secretion is increased in women with endometriosis, and appears to correlate with disease stage. IFN-gamma does not appear to be responsible for the activation of macrophages in women with endometriosis.