CCL2 and COVID-19: We found that severe COVID-19 patients displayed, as extensively already reported [50,62,63], high level of circulating inflammatory cytokines, including IL-6, TNF-α, IL-1β and chemokines such as CXCL-10, CCL-2 and CXCL-8 contributing to the diffuse inflammatory status and the so-called cytokine storm.