Mast cell-derived proteases induce endothelial permeability and vascular damage in severe fever with thrombocytopenia syndrome

It was shown that sever fever with thrombocytopenia syndrome virus (SFTSV) can infect to mast cells. This infection caused the degranulation of mast cells, resulting in the release of vasoactive mediators such as chymase and tryptase. Local activation of mast cells and protease releasing were observed in a SFTSV-susceptible mouse model (treated with anti-IFNAR1 IgG). The chymase and tryptase levels in the acute SFTSV-infected patient's sera were observed to be higher level correlated with fatal outcomes. These proteases were shown to be important as the biomarkers for SFTSV infection disease severity.