CCL4 and COVID-19: Multiple studies show high levels of proinflammatory cytokines such as IL-1, TNF, IFNs, IL-6, IL-8, IL-18, IL-17α, G-CSF, and GM-CSF, as well as chemokines, such as MCP-1, IP-10, MIP-1α, CXCL10, CCL2, CCL4, CCL14, CCL19, and CCL25 in severe cases of COVID-19 [14,15,16].