SUCCESSFUL TREATMENT OF CUTANEOUS LEISHMANIASIS USING SYSTEMIC INTERFERON-GAMMA

Background: Interferon-gamma (IFN-gamma) is one decisive cytokine of T -helper type 1 (Th1) cells in experimental leishmaniasis. It activates macrophages to kill intracellular parasites and leads to a decline of less mature macrophages in the infiltrate. Application of IFN-gamma h eals the disease in susceptible mice and has recently been shown to be of benefit in human disease when given locally or in combination with antileishmanial drugs. Objective: We investigated the clinical and hi stological effects of systemic application of IFN-gamma in a case of h uman cutaneous leishmaniasis in which an ulcerating lesion endangered the left upper eyelid of a 4-year-old boy. Results: IFN-gamma (100 mu g/m(2) of body surface per day) was given subcutaneously for a period of 28 days. The well-tolerated treatment resulted in rapid and complet e healing of the lesion without functional impairment. Histological ex amination disclosed the formation of dermal granulomas. Immunohistoche mical characterization of the myelomonocytic cells in the lesion befor e and after treatment revealed a marked decrease of less-mature macrop hages in the infiltrate. This phenomenon equals observations in healin g lesions during naturally occurring resistance in murine leishmaniasi s, Conclusion: Systemic monotherapy with IFN-gamma can be an effective treatment for complicated cases of human cutaneous leishmaniasis with out the side effects sometimes observed with systemic pentavalent anti mony. Its effects on the myelomonocytic infiltrate are similar to the ones observed during the physiological immune response in natural resi stance.