SERUM IGA ANTIBODIES TO HUMAN GUT LUMINAL ASPIRATES AND HUMAN LIVER IN ALCOHOLIC LIVER-DISEASE

Background: Elevation of serum IgA is a characteristic feature of alco holic liver disease. It has been proposed that this occurs partly as a n antigenic response to gut-derived proteins or acetaldehyde-modified liver proteins, but the principal antigens responsible remain unknown. Aims The goal of this study was to determine if serum IgA antibodies were present against human gut luminal antigens or liver antigens in a lcoholic liver disease. Patients and Methods: Twenty-nine patients wit h alcoholic liver disease, 10 with primary biliary cirrhosis, 12 with ''other'' liver diseases, 8 alcoholics, and 20 healthy subjects were s tudied. Western blotting was used to examine the reactivity of sera fr om these groups against human small and large bowel aspirates and live r tissue from alcoholic liver disease patients. Results: Serum IgA ant ibodies to a 140 kDa colonic luminal protein were found in 22 (76%) pa tients in the alcoholic liver disease group (p < 0.0001), and 7 (24%) patients had serum IgA antibodies to a 40 kDa colonic luminal protein (p = 0.04). These responses were confined to colonic aspirates and not observed in other disease groups, alcoholics or healthy subjects. The re was no significant serum IgA response to human liver proteins in al coholic liver disease. Conclusions Serum IgA antibodies to a human 140 kDa colonic luminal protein are frequently found in alcoholic liver d isease. This novel antigen may contribute to the increased levels of c irculating IgA in alcoholic liver disease.