However, previous studies have certified that coronavirus could cause an irregular T cell response by stimulating T cell apoptosis (Zhou et al., 2014), and substantial clinical studies have also demonstrated a reduction in and functional exhaustion of T cells (especially CD4+ and CD8+ T cells) based on data from 522 patients with laboratory-confirmed COVID-19 (Diao et al., 2020a). The gene discussed is CD4; the disease is COVID-19.