CD4+ CTLs have been reported in humans with chronic viral infections includingvaccinia, BK virus, and Dengue, among others [9, 11, 13–17].VZV-specific in vitro derived CD4+ T-cell clones have alsobeen shown to exhibit cytolytic activity against VZV-infected B cells [18, 19].Furthermore, CD4+ CTL responses correlate with clinical outcomes of viralinfections, suggesting a significant role in adaptive cellular antiviral immunity[20–22]. Here, CD4 is linked to dengue disease.