The potential clinical utility of AAT treatment in COVID-19 patients is based on the following considerations: (i) AAT acts as an efficient inhibitor of the host transmembrane protease serine 2 (TMPRSS2) protein receptor (Azouz et al., 2020), which is essential during the initial phase of the SARS-CoV-2 infection. Here, TMPRSS2 is linked to COVID-19.