Likewise, analysis from Liu et al. (40) demonstrated significant decreases in the counts of T cells, especially CD8+ T cells, as well as increases in IL-6, IL-10, IL-2, and IFN-γ levels in the peripheral blood in the severe COVID-19 cases (n = 13) compared to those in the mild cases (n = 27), suggesting that disease severity is associated with significant lymphopenia and hyperinflammation. This evidence concerns the gene CD8A and COVID-19.