Concentrations of interferon-gamma-induced protein-10 (IP-10), an antiangiogenic substance, are decreased in peritoneal fluid of women with advanced endometriosis.

To assess whether interferon-gamma-induced protein-10 (IP-10), a chemokine that has antiangiogenic activities, may be involved in the pathogenesis of endometriosis. A total of 120 patients undergoing laparoscopy for pain and/or infertility were recruited, and peritoneal fluid (PF) and bone marrow derived cells in PF were collected. Concentrations of IP-10 in PF were measured with a specific enzyme-linked immunosorbent assay. Expression of IP-10 and IP-10 receptor, CXCR3, in bone marrow derived cells in PF, peritoneum and endometriotic cells was analyzed by reverse transcription-polymerase chain reaction. All of the PF samples examined contained detectable concentrations of IP-10. In women with advanced stages of endometriosis, IP-10 concentrations in PF were significantly lower than those of women in early stages (P = 0.02). The IP-10 concentrations in women with advanced endometriosis also appeared to be lower than those without endometriosis although the difference was statistically marginal (P = 0.06). The expression of both IP-10 and CXCR3 was clearly detected in the bone marrow derived cells in PF, peritoneum and endometriotic stromal cells. Decreased concentrations of IP-10 in PF from women with advanced stages of endometriosis may imply that the peritoneal environment of these women is permissive to the development of the disease by enhancing angiogenesis and/or modulating inflammatory/immunological responses.