Genaro LM, de Oliveira Coser L, da Silva Justo Junior A, et al. - Focusing on the involvement of IL-27 (interleukin-27) and Tr1 cells in the immunomodulation of paracoccidioidomycosis (PCM), which is the most common systemic mycosis in Brazil, researchers undertook this investigation. Using serum samples and biopsies of patients with PCM, they assessed the presence of IL-27 by performing ELISA, immunohistochemistry, and immunofluorescence. Using flow cytometry, they assessed the presence of Tr1 in peripheral blood. They found higher serum levels of IL-27 and higher percentage of Tr1 cells in patients with the acute form and severe chronic form vs in those with mild chronic form. The ability of P. brasiliensis Pb18 yeasts to provoke IL-27 generation by both dendritic cells (DCs) and macrophages was also shown. They also noted that DCs pulsed with Pb18 were capable of inducing Tr1 lymphocytes in vitro. The contribution of IL-27 and Tr1 cells to the deficient immune response to P. brasiliensis was suggested, resulting in severe and disseminated forms of the disease.