Haptoglobin concentration in peritoneal fluid of women with endometriosis

ABSTRACT: Objective: To determine the concentration of haptoglobin (Hp) in peritoneal fluid (PF) of women with and without endometriosis and its correlation with the phase of the menstrual cycle. The expression of Hpβe (determined by two-dimensional polyacrylamide gel electrophoresis) was correlated to total PF Hp concentration. Materials and methods: PF samples were obtained from 240 women with or without endometriosis. PF Hp concentration was measured by a sandwich enzyme-linked immunosorbent assay. Hpβe expression in PF was estimated by two-dimensional polyacrylamide gel electrophoresis. Results: PF Hp concentration was similar in women with and without endometriosis; it was significantly higher during the luteal phase of the menstrual cycle than in the follicular phase in control subjects, but not in women with endometriosis. There was a positive correlation between serum progesterone level and PF Hp concentration in control subjects during the luteal phase of the menstrual cycle. There was a mild positive correlation between PF Hp concentration and Hpβe expression in controls but not in wom- en with endometriosis. PF Hp concentration was not correlated with the ASRM stage of endometriosis and the type of endometriotic lesions. Conclusions: Women with and without endometriosis have similar PF Hp concentration. There is a mild positive correlation between PF Hp concentration and Hpβe expression in control subjects but not in women with endometriosis. Future investigations should aim to produce antibodies against specific epitopes of Hpβe that might allow its measurement by ELISA.