NS1 induces the secretion of granule-stored mediators but not newly synthesized IL-1β. Platelets from healthy donors were stimulated with NS1 (0, 0.5, 5, or 50 μg/mL) for 1.5 or 3 hours. Concentrations of the chemokines PF4/CXCL4 (A) and RANTES/CCL5 (B), and the cytokines MIF (C) and IL-1β (D) were quantified in platelet supernatants by enzyme-linked immunosorbent assay. Platelets stimulated with DENV2 (MOI = 1) for 3 hours were used as the positive control for IL-1β secretion. Bars represent mean ± standard error of the mean of 5 independent experiments. *P < .05 compared with unstimulated platelets at the same time frame.