Antibodies to soluble liver antigen in patients with various liver diseases: A multicentre study

BACKGROUND: Antibodies to soluble liver antigen (anti-SLA) are specific serological markers of autoimmune hepatitis (AIH). The clinical significance and frequency of anti-SLA have never been reported among AIH patients from Italy and Turkey. To retrospectively assess the estimated prevalence, sensitivity, specificity and clinical significance of anti-SLA in AIH and various liver diseases. METHODS: A total of 986 patients who had been tested for serum anti-SLA were included in study. The presence of anti-SLA was detected using recombinant enzyme linked immunosorbent assay and immuno-blot. The general characteristics and outcome of patients were obtained from their medical records. RESULTS: Antibodies to SLA were found in 30 (3%) of 986 patients. Of these, 27 (90%) had AIH and its variants, whereas the remaining three (10%) had primary biliary cirrhosis. The prevalence of anti-SLA was 9% in AIH patients from Italy and 15% in patients from Turkey. The specificity of these antibodies was 99.5%, whereas sensitivity was 11%. The positive predictive and negative predictive values were 90% and 77.5% respectively (95% confidence interval). Biochemical remission was achieved in 90% of anti-SLA positive AIH patients, but relapse after immunosuppressive withdrawal or during maintenance therapy was observed in 53% of the patients. CONCLUSIONS: Seropositivity for anti-SLA occurs at similar frequencies in AIH patients from different geographical regions and ethnic groups. The sensitivity of anti-SLA is low, but it has high specificity for AIH. Additional studies are necessary to prove clinical significance of anti-SLA in AIH.