Proteomic analysis of peritoneal fluid in fertile and infertile women with endometriosis.

Objective: To evaluate the peritoneal fluid (PF) proteome of fertile and infertile women with endometriosis.

Study Design: PF samples were collected at laparoscopy from 26 fertile women and 26 infertile ones. Samples were subjected to 2-dimensional gel electrophoresis and compared by computerized analysis. Protein spots were identified by liquid chromatography tandem mass spectrometry.

Results: One isoform of immunoglobulin light chain spot was more frequently present in PF of infertile women than infertile patients. Nine protein spots had significantly higher expression in PF of infertile patients than infertile controls. They were 2 isoforms of serotransferrin, 1 isoform of complement C3, serum amyloid P-component, alpha-1-antitrypsin and clusterin; 3 protein spots remain unidentified. No protein spots had significantly lower expression in PF of infertile women with endometriosis than in PF of fertile controls. Complement C3 had higher PF levels in the luteal than in the follicular phase of the menstrual cycle in both infertile and fertile patients.

Conclusion: Among women with endometriosis, those with infertility have aberrant expression of several PF proteins; most of these molecules are involved in the immune response.