HIV permissiveness in primary CD4+ T cells has been linked to: (i) activation, i. e. proliferating activated CD4+ T lymphocytes are more susceptible to HIV infection compared to resting CD4+ T cells [4–8]; (ii) specific CD4+ T cells subsets, such as effector memory cells [8, 9] or specifically, CCR4+CCR6+ and CXCR3+CCR6+ CD4+ T cells [10]; and (iii) expression of specific HIV dependent/restriction cellular factors that can modulate HIV replication [3]. Here, CD4 is linked to HIV infectious disease.