TMPRSS2 and COVID-19: Due to the suggested potential of A1AT (SERPINA1) to inhibit TMPRSS2-mediated SARS-CoV-2, entry along with its anticoagulatory and anti-inflammatory effects, A1AT therapy is currently undergoing clinical trials for treatment of COVID-19 (ClinicalTrials.gov registration no. NCT04385836, NCT04495101, and NCT04547140).