MPO and COVID-19: Indeed, immunostaining for MPO, citH3, CD66b, and CD15 unambiguously demonstrates an abundant presence of NETs and NET-generating neutrophils at sites of alveolar damage (e.g., Figure 1(a); Figures 2(c) and 2(g); and Figures 3(b), 3(i), and 3(n)) and intravascular clotting (Figures 1(h), 1(i), and 1(k); Figures 2(c), 2(e), and 2(f); and Figures 3(c), 3(j), and 3(k)) in COVID-19 lungs.