An atypical case of acquired immunodeficiency syndrome-associated mucocutaneous lesions due toLeishmania braziliensis is described. Many vacuolated macrophages laden with amastigote forms of the parasite were found in the lesions. Leishmanin skin test and serology for leishmaniasis were both negative. The patient was resistant to therapy with conventional drugs (antimonial and amphotericin B). Interestingly, remission of lesions was achieved after an alternative combined therapy of antimonial associated with immunotherapy (whole promastigote antigens). Peripheral blood mononuclear cells were separated and stimulated in vitro with Leishmania antigens to test the lymphoproliferative responses (LPR). Before the combined immunochemotherapy, the LPR to leishmanial antigens was negligible (stimulation index -SI=1.4). After the first course of combined therapy it became positive (SI=4.17). The antigen responding cells were predominantly T-cells (47.5%) most of them with CD8 + phenotype (33%). Very low CD4 + cells (2.2%) percentages were detected. The increased T-cell responsiveness to leishmanial antigens after combined therapy was accompanied by interferon-γ (IFN-γ) production as