Deficient antiendometrium lymphocyte-mediated cytotoxicity in patients with endometriosis

OBJECTIVE: To study the possible role of the immune system in the pathogenesis of endometriosis. DESIGN: A cytotoxicity assay by 51Cr release was performed to determine the lymphocyte cytotoxic response toward endometrial targets and an erytroleukemic cell line (K562). SETTING: The assays were performed in an academic research environment. PATIENTS, PARTICIPANTS: Twenty-five control women and 25 patients with endometriosis were selected on the basis of laparoscopic examination. INTERVENTIONS: The lymphocyte cytotoxic activity was evaluated separately on endometrial stromal and epithelial cells after 4 hours' incubation. MAIN OUTCOME MEASURE: The study was designed to determine, in controls and endometriosis patients, the lymphocyte-mediated cytotoxicity toward stromal and epithelial cells of endometrium. RESULTS: The lymphocyte response in the presence of stromal cell antigens was significantly lower (P less than 0.02) in disease-affected women when compared with that obtained in controls (2.89 +/- 0.87 and 7.64 +/- 1.66, respectively). In contrast, when the same assay was performed on K562 cells, no difference was observed between endometriosis patients and controls. CONCLUSIONS: These data suggest that an altered immune recognition might be one of the pathogenic mechanisms of endometriosis. Moreover, they indicate that this is not a general phenomenon but is specific for the endometrial target.