CXCL9 and COVID-19: From these, several cytokines with antiviral (IFN-α, IFN-β), inflammatory (TNFα, IL-12, IL-22), regulatory (IL-10), chemoattractant (CXCL8, CCL2, CCL4, CCL5, CXCL9, CXCL10), angiogenic (FGF, PDGF, PDGF), and growth factor (G-CSF, FGF, PDGF) properties are constantly upregulated in severe influenza and COVID-19.