To elucidate the potential role of preexisting DENV immune responses on ZIKV infectivity, a total of 40 convalescent human serum samples from 20 DENV-1 and 20 DENV-3 infected individuals were included in this study, with approximately equal distributions of gender and primary/secondary infection status as determined by the anti-DENV IgM/IgG responses (Table 1). The gene discussed is CD40LG; the disease is infection.