SERPINA1 and pulmonary emphysema: Low concentrations of A1AT (<100 mg/ml) lead to A1AT deficiency in humans with liver and lung diseases, including liver cirrhosis, pulmonary emphysema, bronchiectasis, asthma, and cryptogenic fibrosing alveolitis (Fregonese & Stolk, 2008; Mahadeva, Stewart, Bilton, & Lomas, 1998).