CD4 and COVID-19: In GSE152641, we found that healthy controls had a higher immune infiltrating level of naïve B cells, activated NK cells, resting memory CD4+ T cells, naïve CD4+ T cells, and CD8+ T cells compared to those in COVID-19 patients, while higher proportions of M0 macrophages, neutrophils, plasma cells, and γ-delta T cells were found in COVID-19 patients than those in healthy controls (Figure 2A).