Autoimmune liver diseases

The differential diagnosis of the three disorders that are usually classifi ed as autoimmune liver diseases, namely autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), requires careful exclusion of other causes of chronic liver disease together with t he finding of suggestive patterns of abnormalities of serum biochemical par ameters, immunoglobulin isotypes and 'conventional' non-organ-specific auto antibodies. Anti mitochondrial antibodies (particularly those reacting with epitopes on the E2 components of the pyruvate dehydrogenase and other 2-ox o-acid dehydrogenase complexes), and some sub-specificities of antinuclear antibodies, are virtually pathognomonic of PBC. Anti-liver-kidney microsoma l antibodies reacting with defined epitopes on the cytochrome isoform P4502 D6 are relatively specific for a small sub-group of (so-called 'type 2') AI R However, most of the other serological parameters lack specificity. Addit ionally, within and between each disease group there is wide variability, e ven among patients with comparable severity of liver damage. Thus, in many cases, liver histology and/or cholangiography is still required for definit ive diagnoses or for assessing stage and severity of these disorders. A num ber of autoantibodies that are more directly related to the liver than the 'conventional' autoantibodies are showing promise as possibly more specific diagnostic markers of AIR Commercial tests for some of these are under dev elopment and it is hoped that they will soon become widely available.