Macrophage activation factors and cytokines in peritoneal fluid from patients with endometriosis

Endometriosis is often associated with infertility, which might be a consequence of intraperitoneal macrophage activation and various immunological events related to it. To determine what triggers macrophage activation and what immunologic conditions occur in the peritoneal cavity of a patient with endometriosis, we measured the amounts of phospholipase A2, cholesterol fractions (HDL, LDL, and VLDL), interleukins (IL)-1 and 6, granulocyte-macrophage-colony stimulating factor (GM-CSF), and phosphatidylserine in peritoneal fluid. Peritoneal-fluid samples were collected during laparoscopy or laparotomy from 14 patients with endometriosis and from 11 patients with other diseases (5 with myoma uteri, 5 with benign ovarian cysts and 1 with a double uterus) as controls. With regard to phospholipase A2, there were no significant differences between the endometriosis group and the control group. LDL was significantly lower in the endometriosis group than in the control (p < 0.05). The levels of IL-1 and GM-CSF were similar in both groups; IL-6, however, was higher in 7 endometriosis patients with associated infertility than in the 9 non-endometriosis fertile patients. These findings suggest that inflammatory tissues are not related to the activation of intraperitoneal macrophages in endometriosis patients. Cholesterol fractions (HDL or LDL) might participate in macrophage activation in these patients, but this remains to be clarified. The high IL-6 levels observed in infertile endometriosis suggest that some immunological events that prevent patients from becoming pregnant take place in women with endometriosis-associated infertility.