IL13 and COVID-19: Thus, our goal was to analyze tissue expression of interleukins 4, 13, (IL-4, IL-13), transforming growth factor-beta (TGF-β), and the number of M2 macrophages (Sphingosine-1) in patients who died by COVID-19, comparing with cases of severe pneumopathy caused by H1N1pdm09, and a control group without lung injury.