IL6 and COVID-19: High serum TNF-α and IL-1β levels in patients with COVID-19 may downregulate the Kruppel-like factor 2 (KLF2) expression in human endothelial cells, and subsequently induce monocyte adhesion, leading to endodermatitis characterized by endothelial dysfunction and hypercoagulability, and lymphocytic monocyte infiltration in patients with COVID-19.122 IL-6 trans-signaling mediates the plasminogen activator inhibitor-1 (PAI-1) releasing from vascular endothelial cells in CRS.