Levels of complement components iC3b, C3c, C4, and SC5b-9 in peritoneal fluid and serum of infertile women with endometriosis

ObjectiveTo assess whether complement components iC3b, C3c, C4, and SC5b-9 may be involved in the pathogenesis of endometriosis.DesignProspective, experimental trial.SettingMedical university.Patient(s)112 women infertile women undergoing laparoscopy.Intervention(s)Venipuncture and laparoscopic peritoneal fluid collection.Main Outcome Measure(s)Peritoneal fluid and serum iC3b, C3c, C4, and SC5b-9 levels were measured by the enzyme-linked immunosorbent assay (ELISA) method.Result(s)Higher levels of C3c, C4, and SC5b-9 complement components were found in the serum compared with the peritoneal fluid, but the levels of iC3b were higher in the peritoneal fluid. We observed higher concentrations of C3c, C4, and SC5b-9 in the peritoneal fluid and serum of women with endometriosis compared with healthy women. However, the levels of iC3b in both peritoneal fluid and serum were statistically significantly lower than in the control group.Conclusion(s)The impairment of the mechanisms involved in the regulation of activation of complement system may be an important factor in the pathogenesis of endometriosis and endometriosis-associated infertility.