Effect of hydrocortisone on human natural killer activity and its modulation by beta interferon

It is well known that glucocorticoids depress the natural killer (NK) activity of human peripheral blood lymphocytes when used both in vivo and in vitro. Since interferons enhance natural cytotoxicity, potential interaction between β-interferon and hydrocortisone hemisuccinate has been investigated using mononuclear cells of peripheral blood obtained from 17 healthy donors. At the end of in vitro treatment mononuclear cells were tested for NK activity against K562 cells in a 4 h ⁵¹Cr-release assay. The results suggest that β-interferon at the optimal treatment schedule (i.e. before and after exposure to hydrocortisone) is capable of abrogating the hydrocortisone-mediated impairment of NK function. These findings provide valuable suggestions for optimal treatment schedules with β-interferon (i.e. β-interferon treatment before and after exposure of effector cells to hydrocotisone) for overriding the suppressive effects of glucocorticoid therapy on natural immunity.