PF4 and dengue disease: As shown in Fig. 6, platelets isolated in the acute phase from dengue-infected patients, but not platelets from HIV plus dengue-coinfected patients, released higher levels of PF4/CXCL4 and RANTES/CCL5 when incubated ex vivo compared to platelets from the same patients collected and examined at the recovery (Fig. 6A and B).