We demonstrated endothelial activation by the detection of IL-6, IL-8, and TNFα as previously described.3,10 This activation of the endothelial system not only contributes to bleeding, which is common in DF and DHF,11 but also involved in liver damage, leading to hepatitis complicating dengue.12 Our results were consistent with previous studies in respect to higher viremia in DHF,31 and we observed more bleeding and symptoms of systemic illness in DHF, reflecting the degree of severity when compared with DF. Here, IL6 is linked to Dengue hemorrhagic fever.