SERPING1 and COVID-19: Although the complement classical pathway regulator SERPING1 (also known as C1 inhibitor, C1‐INH, with serine protease activity) is upregulated in NPA, SERPING1 is downregulated in the COVID‐19 lung, suggesting excess activity of the classical complement pathway and potential additional impact on clotting propensity in the COVID‐19 lung.72