Antibodies to soluble liver antigen: an additional marker in type 1 auto-immune hepatitis

Background/Aims: Auto-immune hepatitis patients are divided into two well-defined subgroups on the basis of immunoserological markers, i.e. anti-actin cable and/or anti-nuclear antibodies for the auto-immune hepatitis type 1, anti-liver/kidney microsome type 1 and/or anti-liver cytosol type 1 for the autoimmune hepatitis type 2. Controversial antibodies to a soluble liver antigen have been proposed as a diagnostic marker for the putative auto-immune hepatitis type 3. The aim was to investigate the implication of anti-soluble liver antigen antibodies in the diagnosis of auto-immune hepatitis and their ability to define auto-immune hepatitis type 3. Methods: Sera from 483 patients with hepatic and non-hepatic diseases, and 102 sera from blood donors were analyzed by an inhibition capture enzyme-linked immunosorbent assay. Results: Anti-soluble liver antigen antibodies were found in 13 of the 106 (12%) auto-immune hepatitis type 1 patients and 10 of the 49 (20%) cryptogenic hepatitis patients tested. In contrast, they were not detected in auto-immune hepatitis type 2 (n=54), primary sclerosing cholangitis (n=37), primary biliary cirrhosis (n=52), hepatitis C virus infection (n=105), alcoholic hepatitis (n=25), various non-hepatic auto-immune disorders (n=55) and in healthy blood donors (n=102). The clinical and biological features of anti-soluble liver antigen-seropositive patients were similar to those of auto-immune hepatitis type 1 and did not distinguish a subgroup of auto-immune hepatitis. Conclusion: The data support the concept that anti-soluble liver antigen-positive cryptogenic hepatitis is similar to auto-immune hepatitis type 1. Anti-soluble liver antigen antibodies can be considered as an additional and specific auto-immune hepatitis type 1 diagnostic marker.