Association between IL-27 and Tr1 cells in severe form of paracoccidioidomycosis.

Interleukin-27, a cytokine of the IL-12 family, is secreted by antigen-presenting cells such as macrophages and dendritic cells (DCs). Recent studies suggest an anti-inflammatory role for IL-27 by inducing IL-10 producing Tr1 cells capable of inhibiting Th1 and Th17 type responses. Our study aimed to investigate the involvement of IL-27 and Tr1 cells in the immunomodulation of paracoccidioidomycosis (PCM), the most prevalent systemic mycosis in Brazil. The presence of IL-27 was evaluated in serum and biopsies of patients with PCM by ELISA, immunohistochemistry, and immunofluorescence. The presence of Tr1 in peripheral blood was analyzed by flow cytometry. In vitro assays were performed to verify the ability of P. brasiliensis yeast to induce IL-27 production by DCs and macrophages, as well as the polarization of lymphocytes to the Tr1 phenotype. Patients with the acute form and severe chronic form, the most severe and disseminated forms of PCM, presented higher serum concentrations of IL-27 and higher percentage of Tr1 cells compared to patients with mild chronic form. IL-27 was also detected in lesions of patients with PCM and associated with DCs and macrophages. P. brasiliensis Pb18 yeasts were able to induce IL-27 production by both DCs and macrophages. We found that DCs pulsed with Pb18 were able to induce Tr1 lymphocytes in vitro. Our data suggest that IL-27 and Tr1 cells could contribute to the deficient immune response to P. brasiliensis that leads to severe and disseminated forms of the disease.

Platelet-rich plasma lyophilization enables growth factor preservation and functionality when compared with fresh platelet-rich plasma.

AIMS: To compare levels and activity of the growth factors between fresh and lyophilized platelet-rich plasma (PRP). METHODS: Analysis of platelet concentration using fibroblast and human umbilical vein endothelial cell cultures were compared between fresh and lyophilized PRP obtained from peripheral blood. RESULTS: After lyophilization, 54% of platelets were intact whereas the fresh showed no aggregation with agonists (levels under 20%). The concentration of growth factors (VEGF, EGF, TGF-ß and PDGF) in both products were similar. Fresh and lyophilized PRPs induced proliferation in the fibroblasts at 24 h (0.303 vs 0.300, respectively). CONCLUSION: Lyophilized PRP appears to be an alternative to fresh PRP and the results evidenced the role of growth factors as a key element in the activity of this product.

NLRP3 inflammasome is involved in the recognition of Paracoccidioides brasiliensis by human dendritic cells and in the induction of Th17 cells.

OBJECTIVES: To investigate the involvement of NLRP3 in the effector functions of human dendritic cells (DCs) in response to Paracoccidioides brasiliensis yeast cells (Pb) and to evaluate its role in the modulation of the adaptive immune response. METHODS: DCs were differentiated from purified peripheral blood monocytes and analyzed in relation to the participation of TLR-2, dectin-1, and Syk in Pb recognition, as well as, the indirect mechanisms (Reactive Oxygen Species production, endosome acidification, or K+ efflux) involved in NLRP3 inflammasome activation after the stimulus with Pb. Additionally, we analyzed the role of NLRP3 in the activation of T cells. RESULTS: Our results demonstrated that the NLRP3 inflammasome activation and cytokines production by DCs are dependent on ROS generation, endosome acidification, and K+ efflux and involve the Pb recognition by dectin-1 and Syk phosphorylation. Our data also demonstrate that the NLRP3 inflammasome is essential for the activation/expansion of Th1/Th17 cells and its inhibition leads to an increased frequency of Th2 and Treg cells. CONCLUSION: Altogether our data indicated that activation of NLRP3 presents an important role in both the induction of the initial inflammatory response and in the development of the acquired immune response associated with resistance to infection.