The grey edges of autoimmune hepatitis

Evolving knowledge on autoimmune hepatitis (AH) since the 1950s has highlighted its challenge to nosology. Descriptive diagnostic criteria have been provided recently from three sources: (i) the IASL revision of the 1976 Fogarty manual; (ii) the World Congress of Gastroenterology Terminology Working Party; (iii) the International Autoimmune Hepatitis Group (Brighton Report). Problems with definition of AH relate to (i) stage of disease, whether very early or very late, when markers are less evident; (ii) distinction between an ‘autoimmune state’ with minimal disease (‘chronic persistent hepatitis’) and progressive autoimmune hepatitis; (iii) overlaps and/or coexistences among autoimmune diseases affecting the liver or other tissues; (iv) possible subtypes, whether based on serological reactions or HLA $\text{DR3}\text{DR4}$ phenotypes. The particular problem presented by cases of HCV-associated chronic hepatitis with LKM autoantibodies is unresolved, but such cases are best placed in a virological category. There is a call for standardisation of testing and uniformity in expression of results for autoantibodies relevant to AH. The diagnostic utility of antibody to asialoglycoprotein receptor is promising despite difficulty in production, and insufficient sensitivity and specificity of current assays. Meanwhile the serological diagnosis of AH is necessarily based on carefully titrated reactivity by immunofluorescence for antibodies to nuclei or actin (Type 1), or liver-kidney microsomes (Type 2).