Leishmania-reactive CD4 and CD8 T cells associated with cure of human cutaneous leishmaniasis. Infect. Immun

Fourteen patients suffering from American cutaneous leishmaniasis were studied. Assays of the lymphocyte proliferative response induced in vitro by Leishmania braziliensis antigens were performed. After 5 days in culture, L. braziliensis-stimulated blast T cells were harvested for CD4+ and CD8+ phenotype analysis. When results before and at the end of therapy were compared, leishmaniasis patients showed an increase in the percentage of CD8+ blast T cells and a decline in the proportion of CD4+ blast T cells in cultures. The levels of gamma interferon in T-cell culture supernatants showed a tendency to increase when the patients were cured. These results show a pattern of higher proportions of Leishmania-reactive CD8+ T cells and lower proportions of Leishmania-reactive CD4+ T cells after cure. Human American cutaneous leishmaniasis (CL) is caused in Rio de Janeiro, Brazil, by the protozoan parasite Leishmania braziliensis, the only species of Leishmania that has been found parasitizing humans and dogs in the region (30). Transmission occurs by inoculation of the parasite at the site where the infected Phlebotominae bites the human host, producing in general a single skin ulcer. The majority of human infections are characterized by a mild form of the disease, without metastatic lesions, with healing often occurring spontaneously or after therapy. A minority of patients fail to recover and instead develop a severe, chronic form of the disease, with secondary metastatic lesions on the mucous membranes of the mouth and nose. These lesions, which are resistant to therapy, result in severe destruction of the face