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 women 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 reproductive age (control group). Intervention(s): Continuous usage of E₂ valerate 2 mg/d and medroxyprogesterone acetate 5 mg/d in postmenopausal women in the study group. Main Outcome Measure(s): Immunophenotyping with flow cytometry, cytokine production with and without mitogen stimulation of the peripheral mononuclear cells, and a natural killer (NK) cell cytotoxicity test against K562 target cells by the ⁵¹Cr-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-γ production, and the T-cell subpopulation were significantly decreased, and the subpopulations of CD3⁺CD25⁺ and CD3⁺HLA-DR⁺ were increased in the study group before HRT when compared 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. Copyright (C) 2000 American Society for Reproductive Medicine.