Analysis of memory T cells in the human paracoccidioidomycosis before and during chemotherapy treatment.

Memory T cell populations in patients with paracoccidioidomycosis (PCM) were analyzed before and after chemotherapy treatment. Peripheral blood mononuclear cells (PBMC) collected from patients infected by Paracoccidioides brasiliensis or from non-infected individuals were stimulated in vitro with either membrane and extra-cellular antigens (MEXO) or yeast cell antigen preparation (PbAg) of P. brasiliensis. An increase in the level of CD4(+) memory T cells was determined in PBMC from PCM patients before (NT) and after treatment (TR) and in those with PCM relapsed (RE) compared to that from non-infected controls (NINF). The CD8(+) memory T cells were increased in PBMC from RE patients stimulated with MEXO, but not in NT or TR. The distribution of memory B cells did not differ between NT and TR patients, while a significant elevation was determined in RE patients and higher antibody levels were also detected. The cytokine analysis showed low production of IFN-gamma by cells from RE patients compared with NT or TR patients. In contrast, high production of IL-4 was detected in NT and RE patients, and moderate levels were produced by RE patients. These results suggest that IFN-gamma production may participate in the maintenance of immunological memory in the acquired protection against P. brasiliensis infection and this data can contribute to future development of successful treatment of PCM to avoid relapsing.