IL4 and COVID-19: Additionally, we compared the levels of interleukins in severe and nonsevere COVID-19 patients, and the results indicated that the levels of IL-6, IL-8, and IL-10 were elevated in severe COVID-19 patients compared to nonsevere patients, while no significant difference in IL-1β, IL-2, and IL-4 levels between severe and nonsevere COVID-19 patients, implying that IL-6, IL-8, and IL-10 might be related to the disease severity of COVID-19.