Hormone replacement therapy reverses the decrease in natural killer cytotoxicity but does not reverse the decreases in the T-cell subpopulation or interferon-gamma production in postmenopausal women

Objective: To investigate the immunologic deviations of postmenopausal wome n before and after hormone replacement therapy (HRT). Design: Prospective study. Setting: University teaching hospital. Patient(s): Seventeen postmenopausal women (study group) and 17 women of re productive age (control group). Intervention(s): Continuous usage of E-2 valerate 2 mg/d and medroxyprogest erone acetate 5 mg/d in postmenopausal women in the study group. Main Outcome Measure(s): Immunophenotyping with flow cytometry, cytokine pr oduction with and without mitogen stimulation of the peripheral mononuclear cells, and a natural killer (NK) cell cytotoxicity test against K562 targe t cells by the Cr-51-release assay were performed in the control group and in the study group before, 1 month after, and 6 months after HRT. Result(s): NK cytotoxicity, interferon-gamma production, and the T-cell sub population were significantly decreased, and the subpopulations of CD3(+)CD 25(+) and CD3(+)HLA-DR+ were increased in the study group before HRT when c ompared with those in the control group. After HRT was given for 6 months, however, the NK cytotoxicity increased significantly in the postmenopausal women to a value similar to that of the control group. Conclusion(s): Women after menopause are prone to impaired immune responses . Nevertheless, some of the impairment can be restored after HRT. (C) 2000 by American Society for Reproductive Medicine.