Alpha 1 Antitrypsin is an acute-phase plasma protein found at 290 mg per 100 ml. It functions as a serine protease inhibitor with targets like elastase，plasmin，collagenase，thrombin，leucocyte proteases，trypsin，chymotrypsin，and plasminogen activator. Clinically，its deficiency is associated with two major diseases: pulmonary emphysema and early onset/juvenile hepatic cirrhosis. It is elevated in inflammatory conditions，malignancies，liver disease and pregnancy and also after surgical trauma and use of oral contraceptives. The simultaneous quantitative determination of alpha-1-PI and ceruloplasmin permits differential diagnosis of liver afflictions. Rise in alpha 1 antitrypsin occurs as an acute phase response to tissue necrosis and inflammation.
