BLV infection reduces expression of type 1 cytokines from CD4+ T lymphocytes, and cytokine profiles from all peripheral blood mononuclear cell populations, suggesting that both type I and II cytokines are altered with increases in IL10 and IL4, and decreases in IL2, IL12, and IFN-γ [5, 22]. This evidence concerns the gene CD4 and deltaretrovirus infections.