Alpha 1-Antitrypsin is a 52 kDA serine protease inhibitor (serpin) in blood, which protects tissue from enzymes from inflammatory cells, especially elastase. In certain acute phase inflammatory reactions, A1AT is elevated in order to limit the damage caused by activated neutrophil granulocytes and their enzyme elastase. Disorders of A1AT include A1AT deficiency, a hereditary disorder that can lead to severe tissue breakdown during inflammation. This may result in pulmonary emphysema and liver cirrhosis, in severe cases.
Genetic variants of A1AT do occur.