CD9 and dengue disease: First, we detected CD41, the platelet specific marker and exosomal markers CD63 and CD9 in the platelet fractions - pellet, microvesicles and exosomes isolated from platelet rich plasma (PRP) of healthy subjects and dengue patients suggesting that platelets and platelet derived exosomes (PLT-EXOs) express exosome specific proteins (Figure 3A).