SERPINA1 and alpha 1-antitrypsin deficiency: Current guidelines recommend AAT augmentation therapy in patients with severe AATD (ZZ or Null genotypes) with airflow obstruction [37–39], with additional criteria to select the treatment candidates, including smoking cessation, FEV1 ≤ 65% and AAT serum levels ≤ 11 μM [38, 40].