IL6 and COVID-19: Patients with severe COVID-19 have been shown to have increased levels of cytokines such as interleukins IL-6, IL-7, IL-8, IL-9, IL-10, IL-1β, IL-1RA, fibroblast growth factor, platelet-derived growth factor, tumor necrosis factor-alpha (TNF-α), granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant protein, and vascular endothelial growth factor (8, 9, 51, 52).