PROBLEM: Hormone replacement therapy (HRT) is being increasingly used in postmenopausal women. Sex steroids are known to affect the immune system in several ways, although this is mainly based on clinical observations and experimental studies.
METHOD OF STUDY: We studied the in vivo effects of transdermal estrogens (50 μg 17 β-Estradiol/24 hr) on cytokine production in postmenopausal women. A total of 17 women were randomized to either placebo (n=7) or active estrogen therapy (n=10) for 14 weeks, with addition of oral medoxyprogesterone acetate 10 mg daily during the last 2 weeks in both groups. Secretion of the cytokines IFN-γ, IL-4, IL-10 and IL-6 in blood mononuclear cells was determined, spontaneously and after stimulation with common vaccination antigens and mitogen, using the cell ELISA technique.
RESULTS: IL-6 production after stimulation with purified protein derivate (PPD) decreased in the estrogen treated group (P < 0.01). Mitogen-induced IL-6 production was reduced in the estrogen treated group in contrast to an increase in the placebo group, leading to a significant difference (P < 0.01) between the groups after 12 weeks of treatment. This difference was eliminated after an addition of progestagens for 2 weeks. No significant changes were noted for IFN-γ, IL-4 or IL-10 in relation to estrogen or placebo treatment.
CONCLUSIONS: In the present controlled study, the main in vivo effect of estrogens was a decrease in IL-6 production, indicating a possible beneficial effect of estrogen therapy.