CCL2 and COVID-19: The high serum levels of pro-inflammatory biomarkers, including TNF-α, Interleukin 2 (IL-2), IL-7, IL-10, granulocyte colony-stimulating factor (G-CSF), C–X–C motif chemokine ligand 10 (CXCL10), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory proteins-1α (MIP-1α) were all detected in hospitalized COVID-19 patients.