HORMONE REPLACEMENT THERAPY AFFECTS VARIOUS IMMUNE CELL SUBSETS AND NATURAL CYTOTOXICITY

The effects of hormone replacement therapy (HRT) on lymphocytes and gr anulocytes have never been determined in detail. Ten healthy menopausa l women (age 49-51 years; menopause less than 2 years) were treated fo r 6 months by administering transdermal estradiol (100 mu g/day for 21 consecutive days) and oral medroxyprogesterone acetate (10 mg/day fro m day 10 to day 21). Days 22-28 were therapy-free. All subjects were e xamined during the first and the last month of treatment: evaluations were carried out on days 0, 8, 21 and 28. CD4+CD45RO+ cells were found to be significantly reduced on day 8. CD56+ cells and CD8+CD11b+ cell s were decreased on day 21 and recovered basal level on day 28. Natura l killer cell function was transiently increased on day 8 and greatly reduced on day 21. During the first month of therapy, the expression o f Leu8 and CD11b antigens on granulocyte membranes was significantly a ffected by HRT. Taken together, the results indicate that HRT selectiv ely affects various immune cell subsets.