IL6 and COVID-19: Among the inflammatory mediators released by immune cells, the cytokines IFN-α, IFN-γ, IL-1β, IL-6, IL-12, IL-18, IL-33, TNF-α and TGF-β are highlighted, and altered levels are associated with different clinical features of COVID-19 (Huang et al., 2021a; Chang et al., 2021).