PRF1 and dengue disease: Previous studies also indicated that CD4+ EMRA cells could demonstrate cytotoxic features and express the chemokine receptor CX3CR1 in the setting of Dengue virus infection (Weiskopf et al., 2015), which are associated with cytotoxic lymphocytes with cytoplasmic granules containing perforin and granzymes (Nishimura et al., 2002).