Aspartate aminotransferase-immunoglobulin complexes in patients with chronic liver disease

To determine the complex of AST and immunoglobulin and to investigate its clinical significance in patients with liver disease.

The complex of AST and immunoglobulin was determined by encounter immunoelectrophoresis and its clinical significance was investigated in 128 patients with liver disease.

AST was bound to immunoglobulin of anti-immunoglobulin A (IgA) class, but any binding to anti-immunoglobulin G and anti-immunoglobulin M classes was not observed. Although the incidence of AST-immunoglobulin complex was 41.8% in chronic hepatitis (CH), the incidences in liver cirrhosis and hepatocellular carcinoma were 62.2 and 90.0%, respectively. In alcoholic liver disease with high level of serum IgA, the incidence of the complex was 66.7%, which was higher than that in CH. The ratio of binding to lambda-chain of IgA was higher than that to kappa-chain of IgA. The serum level of IgA and the ratio of AST/alanine aminotransferase (ALT) were significantly higher in patients with AST-IgA complex than in those without complex.

These results suggest that AST-IgA complex in patients with progressive liver diseases and alcoholic liver injury can lead to elevation of the ratio of AST/ALT.