CCL2 and COVID-19: Studies have reported that most patients with severe COVID-19 have elevated plasma levels of pro-inflammatory cytokines, interleukin-6 (IL-6), and IL-1β, along with monocyte chemoattractant protein 1 (MCP-1), interferon gamma (IFN-γ)–induced protein 10 (IP-10), and granulocyte colony-stimulating factor (G-CSF) (10).