Danazol suppresses both spontaneous and activated human lymphocyte-mediated cytotoxicity

Danazol is an effective drug in the treatment of endometriosis. Previous reports suggest that it can act by influencing the immune system. Thus, in this study we evaluated whether danazol is able to affect the expression of natural and activated cytotoxicity by human peripheral blood lymphocytes (PBL). A cytotoxicity assay by 51Cr release was performed to determine the effect of danazol on lymphocyte cytotoxic response toward an erythroleukemic cell line (K562). A significant suppression of spontaneous cytotoxicity was observed when lymphocytes were pretreated for 18 h with danazol at the concentration of 5 x 10(-6) M. In addition, danazol could significantly inhibit both IL-2- and INF alpha-activated cytotoxicity at the concentration of 10(-5) M. Following 18 h exposure to danazol, PBL were able to completely recover their spontaneous but not activated cytotoxic potential upon further in vitro incubation (18 h) in absence of the drug. The biological significance of danazol as an inhibitor of immune function under experimentally defined conditions is discussed in relation to its possible role in vivo.