SERPINA1 and diabetes mellitus: Level 3 confirmation. α1-antitrypsin (A1AT) is an inhibitor of the pro-inflammatory protein neutrophil elastase. A1AT is produced in the liver and plasma levels are increased upon inflammatory response (Berger et al., 2018). A1AT deficiency is described to be associated with an increased risk of type 2 diabetes mellitus development (Sandström et al., 2008).