In the present study we observed an association of IFN-γ with disease severity. Indeed, increased IFN-γ concentrations have been detected in dengue patients in a variety of studies [29, [44] [45] [46] [47] . DHF induced by Dengue-3 was associated with higher viremia early in illness and earlier peak plasma IFN-γ levels; maximum plasma viremia levels correlated with the degree of plasma leakage and thrombocytopenia [45] . However, in a previous study from our group we failed to observe association of IFN-γ with disease severity [44] , probably due to the small number of severe patients analyzed or to the Dengue-1 incidence.