Caracterização imunofenotípica de linfócitos T em pacientes com leishmaniose visceral

Abstract

Visceral Leishmaniasis (VL) is a disease caused by the protozoan of the genus Leishmania, if misdiagnosed or not treated early can lead to death. The establishment of the VL clinical form is closely associated with the immune response triggered in the host. Adaptive immunity and modulation of the T cell profile is crucial for the development of an efficient immune response against the parasite. The quality of the response of CD4 and CD8 T cells is based on their capacity of effective response and memory and it is mainly related to the production of three cytokines: IFN-γ, IL-2 and TNF-α. The aim of the present study was to evaluate the functionality of T cells involved in suppressing the immune response of patients with VL and in restoring that response during and after treatment. Peripheral blood mononuclear cells from patients with VL and healthy controls were cultured and stimulated in vitro with Soluble Leishmania Antigen (SLA) for 18 hours and marked with surface antibodies: CD3, CD4, CD8, CCR7 and CD45RA and intracellular antibodies: IFN-γ, TNF-α, IL-2. The samples were acquired using the BD FACS Canto II flow cytometer and analyzed using the Flowjo® program. From this analysis, we observed some populations of functional CD4 and CD8 T cells during treatment. IL-2 and TNF-α producing CD4 T cells were evident at the beginning of treatment, while IFN-γ and TNF-α producing CD4 T cells were observed throughout the treatment. Multifunctional CD4 T cells producing IL-2, TNF-α and IFN-γ were observed at the end of treatment. IL2 and TNF-α-producing TCD8 cells were evident 21 days after treatment and IL-2 and IFN-γ-producing cells 30 days after treatment. Multifunctional CD8 T cells that express IL-2, TNF-α and IFN-γ were evident 60 and 90 days after treatment. These results show the participation of functional T cells during the treatment of patients with VL, which suggests that the clinical improvement of patients may be related to the participation of these cells.