CD4 and viral infectious disease: Memory T-cells subsets were reported to increase in both CKD and controls, as reported by one study, while mono- and polyfunctional CD4+ and CD8+ T cells was lower in HD and CKD, respectively, compared to controls, highlighting the importance of cellular responses to achieve protection against viral infections and supporting the hypothesis that CD8+ T cells could play an important role in SARS-CoV-2 protection (63).