CD4 and COVID-19: With this understanding, we focused on eight T cell subsets of the total 17 cell types identified, which include activated CD4+ T, CD8+ TCM, CD8+ TEM, CD4+ TCM, naive CD4+/CD8+ T, NK T, Th1, and Th2, across healthy, COVID-19 positive, and recovered cohorts (Figures 2B–E; Supplementary Figures S1A,B).