IMMUNOLOGICAL PATTERNS ASSOCIATED WITH CURE IN HUMAN AMERICAN CUTANEOUS LEISHMANIASIS

Patients with American cutaneous leishmaniasis were studied before the rapy (active lesion) and at the end of therapy (cured patients). Assay s of lymphocyte proliferative responses of peripheral blood mononuclea r cells induced in vitro by Leishmania braziliensis promastigote antig ens (Lb) were performed. Antigen-stimulated cells were harvested for C D4 and CD8 phenotype analysis and the levels of gamma interferon (IFN- gamma) and interleukin 4 (IL-4) produced were also determined in the c ulture supernatants. Two different patterns of Lb-induced T cell respo nses were observed: a) predominance of responding CD4(+) cells and mix ed type 1 and type 2 cytokine production (IFN-gamma and IL-4) during t he active disease, and b) similar proportions of responding CD4(+) and CD8(+) cells, and type 1 cytokine production (presence of IFN-gamma a nd very low IL-4) at the end of therapy (healed lesions). This last pa ttern is probably associated with a beneficial T cell response.