IL4 and COVID-19: The meta-analysis by Chinese authors demonstrated the strong association between elevated circulating cytokines and COVID-19 severity and mortality; they revealed that circulating levels of IL-2R, IL-10, IL-1β, IL-4, IL-8, IL-17, TNF-α, and particularly IL-6, were elevated in severe and nonsurviving COVID-19 patients when compared with mild patients [224].