CCL4 and COVID-19: While the levels of IP-10, IL-15 and IL-18 were exclusively increased in SOTRs with COVID-19, Non-SOT patients with COVID-19 showed solely higher levels of IFN-β, IL-2, IL-10, GM-CSF and low levels of Eotaxin, MCP-1, MIP-1β, IL-4, IL-5.