IL6 and COVID-19: In addition, pro-inflammatory cytokines (such as IL-1β, IL-6, C-reactive protein or TNF-α), proangiogenic factors (such as vascular endothelial growth factor, VEGF), vascular adhesion molecules (intercellular adhesion molecule-1, ICAM-1) and many others have been found to participate in pathogenesis of severe COVID-19,4,57,58 but were not analyzed in the current study.