SERPINA1 and COVID-19: In conclusion, based on our data we can hypothesize that a supplemental therapy with exogenous AAT, that has been suggested in COVID-19 patients, might be unsuccessful due to the following reasons: AAT might be inactivated by the highly inflammatory microenvironment either by binding to NETs or by oxidation and, on the other side, HNE might be inaccessible due to interaction with other proteins.