CCL4 and COVID-19: Our analysis revealed the significant upregulation of genes expressing IFN-γ, CXCL10, IL-33, Granzyme-B, and PD-L1 in moderate COVID-19 patients only and IL-8, IL-1Ra, IFN-α, CCL4, TNF, CCL3, and IL-1ß was in moderate and severe COVID-19 patients; in comparison, to healthy donors or asymptomatic patients (Figure 2A).