Immunoglobulin A in the diagnosis of alcoholic liver disease.

The diagnostic relevance of the serum immunoglobulin A (IgA) concentration and liver deposition of IgA for chronic excessive alcohol consumption was evaluated in 164 patients with biochemical liver abnormalities. A relationship was demonstrated between the amount of daily alcohol consumption and the two IgA parameters and serum gamma-glutamyl transpeptidase. A continuous pattern of IgA deposition along hepatic sinusoids proved to be the best diagnostic feature, combining a specificity of 0.91 with a sensitivity of 0.75. Although serum IgA has a specificity of 0.78, its diagnostic value is restricted by a sensitivity of 0.50, making it not superior to serum gamma-glutamyl transpeptidase. Furthermore, serum IgA proved to be related to liver histopathology. High levels of serum IgA are found in hepatitis and cirrhosis, without significant differences between alcoholic and nonalcoholic patients. However, in the case of mild histopathologic changes in the liver, such as steatosis and fibrosis, significantly higher serum IgA concentrations are found in alcoholic than in nonalcoholic liver disease.