CD4 and infection: Studies in PLWH on ART have reported that HIV DNA levels in CD4+ T cells were 2- to 12-fold higher in the duodenum, ileum, right colon and rectum as compared to the peripheral blood, probably due to a higher percentage of CD4+ T cells expressing the HIV coreceptor CCR5, upregulated by lipopolysaccharides of the gut microbiome, with an increased susceptibility to infection [53].