Alpha-1-antitrypsin: an ignored protein in understanding liver disease.

alpha 1AT should no longer be ignored by hepatologists with regard to its role in protecting the liver from injury. This protective role needs further definition with regard to protease inhibition, immunologic control, and functional inactivation. Severe deficiency of alpha 1AT clearly predisposes to definable types of liver disease not only in infants and children, but at the other end of the spectrum in elderly adults. It is unfortunate that the pathophysiology of human and animal alpha 1AT related liver injury is not as readily apparent as in pulmonology conditions. However, it is time to digest the tremendous progress that has evolved in that field in relating alpha 1AT to emphysema. Cirrhosis of the liver should be studied in relationship to the pathophysiology demonstrated by our colleagues to be important in "cirrhosis of the lung." The diagnosis of alpha 1AT deficiency and the course of the associated liver disease have been reviewed and updated. Prevention and cure have been demonstrated to be possible but neither method has universal applicability. In contrast, other potential therapeutic endeavors, although not presently proved to be efficacious, with time and research will provide methodologies for the treatment of this disorder as well as insight into mechanisms of general liver injury not previously appreciated.