Effect of glucocorticoids and interferon-γ on the oxidative responses of monocytes from leprosy patients and normal donors

Leprosy patients suffering from erythema nodosum leprosum are frequently treated with glucocorticosteroids. The role glucocorticosteroids and interferon-gamma (IFN-γ) play in regulating the interaction of phagocytic cells with Mycobacterium leprae was examined. Monocytes from leprosy patients receiving prednisone therapy responded to lower concentrations of IFN-γ in vitro with enhanced superoxide anion release when challenged with M. leprae or M. bovis BCG than did monocytes from healthy subjects and other leprosy patients. Although the number of patients was small and the population heterogeneous, the data suggested that prednisone could alter IFN-γ efficacy and led to the examination of the effect of glucocorticosteroids on IFN-γ activation of monocytes. IFN-γ treatment following in vitro dexamethasone pretreatment of monocytes from healthy subjects resulted in a greater enhancement of superoxide anion generation than that observed with IFN-γ treatment alone. These findings are important considerations in evaluating patient immune function because IFN-γ is being used in a number of clinical trials with leprosy patients.