CD4+ T-helper cell subsets also display heterogeneity across COVID-19 disease severity sub-phenotypes, where critical patients report decreased proportion of T-helper 1 (Th1) and T-helper 17 (Th17) lymphocytes, whereas T-helper 2 (Th2) cells’ percentage increased in comparison with less severe individuals (64). This evidence concerns the gene CD4 and COVID-19.