IL2 and infection: Hatch and colleagues (2011) have shown stimulation with DENV-4 antigen significantly increases IL-2 production in DENV-3, indicating heterotypic infection increases IL-2; our observation is similar and can be attributed to heterotypic infection. Kurane and colleagues (1991) have shown elevated IL-2 in Thai children; similar results were observed in DF of DENV-1 than DENV-2 (Figure 7B) and control (Figure S2).