Deficient cellular immunity in endometriosis

Cell-mediated autoimmune responses were studied by means of in vivo and in vitro techniques in five rhesus monkeys with spontaneous endometriosis. The results were compared with similar data obtained from five normal rhesus monkeys without endometriosis. The in vivo studies included intrademal injection of autologous antigens prepared from uterine endometrium, ectopic endometrium, or peritoneum, or injection of the mitogen, phytohemagglutinin (PHA). Skin biopsies were obtained at 48 hours and evaluated under the light microscope for perivascular lymphocytic infiltration. The mean number of lymphocytes per high-power field after injection of the autologous endometrial antigen was significantly smaller in animals affected by endometriosis than in the control group. There was no significant difference in lymphocytic response to autologous peritoneal antigens between the groups. Animals of both groups responded readily to PHA with marked perivascular lymphocytic infiltration. Lymphocyte stimulation responses to the same autologous antigens or to PHA were evaluated by means of in vitro assays and micro-methods. Lymphocyte stimulation response to autologous endometrial antigens in the group with endometriosis was significantly less than in the control group. There was no significant difference in response to the peritoneal antigens between the groups, and the response to PHA was marked in all animals of both groups. The results of this study indicate that rhesus monkeys with spontaneous endometriosis have an altered cellular immune response to autologous antigens. Although the animals were immunologically competent, as judged by responses to PHA, both in vivo and in vitro studies indicated a decrease in the cell-mediated immune response to autologous endometrial antigens. These data suggest that endometrial cells translocated from their normal location may implant only in women with specific alteration in cell-mediated immunity. New light is thus shed on the cause of endometriosis.