CD8A and cytomegalovirus infection: This subpopulation displays enhanced natural cytotoxicity activity and cytokine secretion, and it was proposed that the frequency of CD56+CD8+ T cells could be affected by cytomegalovirus infection and aging.28, 29 With this phenotypic characterization, we provided information about how CD8+ cells from TB patients could be NKG2D downregulated as an evasion system, probably by favoring Mtb infection.