EM T-cells exhibit an enhanced capacity to localize within tissues and migrate into non-lymphoid areas in response to infection or inflammation [60,61], suggesting that during acute HIV infection, their migratory potential towards inflammatory sites and the gut remained unaffected, which is in line with the observed stability in CCR6, CCR9, and CXCR3 expression during acute HIV infection. This evidence concerns the gene CCR9 and infection.