The antibodies raised in primary dengue infection can circulate in the blood for years or even decades, providing protection from the same serotype of dengue infection, but cause cross-enhancement of secondary heterotypic dengue infections, in which subneutralizing antibodies enhance heterotypic dengue virus infection (89–92), and alter immune response shifting type 1 T helper (Th1) response to Th2 response with dominant IL-10 in patients with DHF (89, 92, 94). The gene discussed is IL10; the disease is Dengue hemorrhagic fever.