In vitro modulation of activation antigens on human lymphocytes by β-estradiol

PROBLEM: The possible in vitro immunomodulating effect of β-estradiol on phytohemagglutinin-stimulated human lymphocyte cultures was studied. METHOD OF STUDY: Lymphocyte cultures from 12 healthy men and women aged 25-35 years were set up for 12 hr in the presence and in the absence of β-estradiol, and the expression of the activation markers CD25, CD69, and CD71 was examined by flow cytometric analysis with specific fluorescent conjugated antibodies. RESULTS: Although the number of cases is small, in 10 of 12 cases in the presence of β-estradiol in two different concentrations, a significantly decreased expression of CD69 could be observed. A slight decrease could also be observed for the Interleukin-2 receptor expression; however, the difference, in the presence or absence of β-estradiol, was not significant. CONCLUSIONS: The results suggest that in vitro addition of β-estradiol can inhibit, to a certain degree, specific activation markers on phytohemagglutinin-stimulated lymphocytes from young men and women. The present study could not define the role of sex differences because of the small number of samples. A comparison between men and women at various ages in a greater number of cases, as well as studies on activation markers after treatments with estrogens, would be useful.