As expected, the expression of HLA-DR, CD38, and Ki67 on SARS-CoV-2–responding CD4+ T cells was significantly higher in COVID-19 cases compared with non–COVID-19 controls (P = 0.005, P < 0.0001, and P = 0.004, respectively), likely reflecting ongoing viral replication (Figure 3B). This evidence concerns the gene CD4 and COVID-19.