Anti-Saccharomyces cerevisiae as unusual antibodies in autoimmune hepatitis

Autoantibodies are disease markers of autoimmune hepatitis (AIH). Antinuclear antibodies, smooth muscle antibodies, antibodies to liver/kidney microsome type 1, and perinuclear antibodies to neutrophil cytoplasm constitute the ''conventional'' battery of autoantibodies, while an emerging interest to evaluate new autoantibodies as diagnostic or prognostic markers, such as the anti-Saccharomyces cerevisiae antibodies, is detectable (ASCA). This paper focuses mainly on the findings and the potential role of ASCA in AIH. These antibodies are present in 5-6.3% of blood donors and in the gastrointestinal setting, ASCA have been found most often in Crohn's disease and with lower frequency in the course of ulcerative colitis and celiac disease. Furthermore, they have been described, to a lesser extent, in patients with primary sclerosing cholangitis and primary biliary cirrhosis and in AIH. ASCA occur in 20-30% of patients suffering from AIH with a statistically significant increase observed only for IgG ASCA in type 1 AIH. This probably indicates collateral immune reactivities to the primary pathogenic process. The outcome of hepatitis is not influenced by the presence of ASCA. In conclusion, ASCA positivity does not imply that there exists a distinct subgroup of patients with AIH and these autoantibodies are not involved in the pathogenetic mechanism of AIH.