In PWHs and NHPs that progress to AIDS, effector memory CD4+ T-cells are preferentially depleted [135], with a massive depletion of activated memory CD4+ T-cells in the lamina propria of the gut [18,32,34,35,36] and, to a lesser extent, in the peripheral blood and lymph nodes (LNs) [35,36,142]. Here, CD4 is linked to AIDS.