CD4 and cytomegalovirus infection: Numerous studies have shown that CMV specific cellular immunity mediated by cytokine producing CD4+ and cytolytic CD8+ T cells are crucial for the control of CMV infection; TH1 cytokines- IFNγ and TNFα produced by CMV-CD4+ T cells emerge prior to CMV-specific antibodies and cytolytic CD8+ T cells4, 5.