CCL2 and COVID-19: Consistent with previous reports36,37, patients with severe disease (WHO score 5–7) or those who subsequently died from COVID-19 (WHO score 8) had greater concentrations of proinflammatory cytokines and chemokines, including IL-6, IL-8, TNF-α, IL-15, IL-16, and MCP-1, than hospitalized patients with moderate disease (WHO score 3–4) (p < 0.05 in each case, Fig. 1d–i).