After infection with SARS‐CoV‐2, a significant reduction of peripheral blood CD4+ and CD8+ T cells (a condition known as lymphopenia) results in moderate to severe COVID‐19 patients, which is correlated with disease severity and mortality (G. Chen, Wu, et al., 2020; Diao et al., 2020; Liu, Li, et al., 2020; Tan et al., 2020). This evidence concerns the gene CD4 and COVID-19.