MPO and COVID-19: Among the mechanisms studied, the formation of neutrophil extracellular traps (NETs) (aggregates of extracellular DNA, histones, neutrophil elastase, myeloperoxidase, and other molecules such as tissue factor) (111) are thought to play a prominent role in COVID-19 pathogenesis, mediated in part through target-organ microvascular occlusion (111) and associated immunothrombosis (111, 117) (Figure 1I).