CCL2 and acute respiratory distress syndrome: Several clinical studies on mortality in COVID-19 have outlined that non-survivor patients typically had elevated serum levels of pro-inflammatory cytokines (IL-2, IL-7, IL-10, G-CSF, IP-10/CXCL10, MCP-1/CCL2, MIP-1a/CCL3 and TNF- α), together with ferritin, C reactive protein and lactate dehydrogenase, which peaked before the development of ARDS [57,58].