SERPINA1 and COVID-19: To validate the result and confirm the inability of AAT to complex free HNE in COVID-19 samples, three of the above specimens (COVID-19, COVID-21 and COVID-25, chosen randomly among all available) were incubated with scalar amounts of exogenous HNE (0.2 mg/mL), submitted to gel electrophoresis and western blot analysis with the anti-HNE and anti-AAT antibodies.