Effects of testosterone, oestradiol and progesterone on immune regulation

Clinical observations on differences in the sexual incidence of diseases associated with defects of immune regulation, and of the occasional beneficial effects of pregnancy on disease course suggest that endocrine mechanisms may be important in the immuno-pathogenesis of these disorders. To investigate this possibility the in vitro effects of testosterone, oestradiol and progesterone on selected aspects of immune regulation were studied in normal adults. We observed the effects of these hormones on a mitogen-induced suppressor T-cell system and a monocyte mediated prostaglandin-producing suppressor cell system. The addition of progesterone but not oestradiol or testosterone to the Concanavalin A (Con A) generation of T lymphocyte suppressor cells produced significantly increased suppressor cell activity (P less than 0.005). Pre-incubation of lymphocytes with testosterone but not oestradiol or progesterone in the absence in the absence of Con A resulted in the generation of modest, but highly significant suppressor cell activity (P less than 0.005) No effect on the prostaglandin-producing suppressor cell activity was observed. These findings suggest that certain endocrine changes may alter immunoregulatory function and account for some of the clinical observations previously noted in diseases associated with defects of immune regulation.