Objective: To investigate the role of natural killer (NK) cell activity in the development of endometriosis.
Methods: The NK cell activity in peripheral blood (PB) and in peritoneal fluid (PF) of 72 patients with endometriosis was studied by means of MTT-assay and compared with that of infertile women and fertile controls.
Results: The NK cell activity in PB and in PF of patients with endometriosis was lower than that in those of infertile and fertile controls, and decreased as the stage of endometriosis increased. Follow-up of 8 patients with stage II/N endometriosis demonstrated that the NK cell activity in PB had a moderate increase shortly after excision of endometriotic lesions, but decreased again to the preoperative level 6-9 months later.
Conclusions: Patients with endometriosis have a primary defect in their NK cell function, and the defect may be related to the pathogenesis of the disease.