Effect of estrogen replacement therapy on natural killer cell activity in postmenopausal women

Abstract Objective : To evaluate the impact of menopause and estradiol substitution on natural killer cell activity. Methods : Natural killer cell activity and antibody-dependent cellular cytotoxicity were measured in peripheral blood of 53 postmenopausal and 20 premenopausal women in an interval of 3 weeks. Postmenopausal patients were randomly assigned to receive either estradiol valerate (2 mg daily) orally ( n = 18), estradiol (50 μg/24 h) transcutaneously ( n = 18) or no substitution ( n = 17), and the testing was repeated 3 weeks later. Results : Natural killer cell activity but not antibody-dependent cellular cytotoxicity was significantly ( P P P P > 0.1), whereas antibody-dependent cellular cytotoxicity showed no changes. The addition of 0.1 to 10 ng/ml estradiol to peripheral blood mononuclear cells of untreated postmenopausal women in vitro had no influence upon natural killer cell activity. Conclusion : Postmenopausal women receiving no estrogen replacement exhibited an increased natural killer cell activity which decreased during estrogen substitution.