SERPINA1 and alpha 1-antitrypsin deficiency: A recent clinical trial determined that nebulization of ATT in patients with severe AATD and frequent exacerbations of COPD may have changed the pattern of episodes [199], it also found that when modifications to the use of the nebulizer were required, which led to the rate of safety events in the AAT-treated group decreasing to that of the placebo group.