IL4 and susceptibility to pneumonia measurement: Serum inflammatory factor levels of IL-2, IL-1β, IL-4, IL-6, IL-5, IL-10, IL-8, IL-12P70, IL-17, IFN-α, TNF-α, IFN-γ, and endotoxin in COVID-19 patients showed no significant differences between non-severe and severe pneumonia patients.