CCL2 and COVID-19: Indicative cytokines in severely ill COVID-19 patients are characterized by boosted expression of IL-6, TNF-α, IL-17 macrophage inflammatory proteins 1-α (MIP-1α), MCP3, GM-CSF, IL-2, and IP-10, in addition to the elevated chemokines (IP-10, CCL2/MCP1, CXCL1, CXCL5) (58, 66).