AOC3 and COVID-19: In another single-center study, endothelial cell adhesion markers, including vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and vascular adhesion protein-1 (VAP-1), were elevated in 39 COVID-19 patients in comparison to 32 COVID-19 negative controls, and levels of elevation had a correlation to disease severity (104).