ABSTRACT
Leishmania infections induce a specific activation of host immunological response, particularly characterized by T cell expansion. Studies indicate the importance of the balance between CD4+ and CD8+ T cells, in which the first ones would have their number reduced during the healing process. Meanwhile, CD25+ T cells have been associated with the suppression of the immune response. Since the immune response has an essential role in both healing and progression of diseases, this study aimed to identify the percentage of CD3+, CD4+, CD8+, CD16+ and CD25+ T cells in the peripheral blood of patients afflicted with American cutaneous leishmaniasis (ACL) - before and after treatment - and healthy controls. Peripheral blood was collected and transferred to cytometry tubes containing monoclonal antibodies specific for cell surface markers CD3, CD4, CD8, CD16 e CD25. The immunophenotypic and morphometric parameters of cells were determined by flow cytometry and the results demonstrated a significant increase in the number of T CD8+ cells after treatment, suggesting a cytotoxic T cell response. An increase in CD25+ T cells in patients with active ACL and after treatment was also observed, suggesting the participation of these cells in the modulation of the exacerbated effector response.