On the other hand, serum levels of cytokines in COVID-19 ICU patients showed a significant increase in the production of GM-CSF, IFN-α, IL-2, IL-4, and IL-6 and a significant decrease in the levels of IFN-γ, IL-5, IL-12, IL-17A, and TNF-α. This evidence concerns the gene IL4 and COVID-19.