C5AR1 and COVID-19: Findings from mouse models, cellular systems, and samples from patients with SARS-CoV-2-induced COVID-19 have shown massive generation of C5a, CCL chemokines (e.g., CCL2, CCL3, and CCL5), CXCL chemokines (e.g., CXCL9 and CXCL10), and growth factors, i.e., TGFβ, GCSF, GMCSF, VEGF, FGF, and PDGF (Table 1 and Table 2).