Autoimmune hepatitis (AIH) is a chronic inflammatory disease in which the immune system attacks the liver. Three findings define it: circulating autoantibodies, a raised serum immunoglobulin G (hypergammaglobulinaemia), and interface hepatitis on liver biopsy — inflammation at the boundary between the portal tract and the liver lobule, where hepatocytes meet the portal connective tissue. No single finding is specific to AIH, and some patients lack one or more of them, so the diagnosis is built from the combination together with the exclusion of the chronic liver diseases that look the same.
Choose a route through the topic
The topic follows one thread: the immune system loses tolerance to the liver’s own antigens, immune attack injures hepatocytes, and that injury leaves traces the clinician can find in the patient, the blood and the biopsy. The notes below follow that thread in order, and each can also be read alone.
Why it happens and who gets it
- Pathophysiology of Autoimmune Hepatitis: how tolerance to hepatocyte self-antigens is lost, how CD8+ T cells and the cells around them destroy hepatocytes, and how that injury becomes fibrosis.
- Epidemiology of Autoimmune Hepatitis: how common AIH is, how that varies between regions, and which groups it affects.
What the patient and the tests show
- Clinical Manifestations of Autoimmune Hepatitis: the symptoms, physical findings and laboratory changes, from fatigue and hepatomegaly to the selective rise in IgG.
- Autoantibodies in Autoimmune Hepatitis: the conventional and less common antibodies, what each marks, and what a positive result does and does not prove.
- Liver Histology in Autoimmune Hepatitis: the biopsy features, from interface hepatitis to plasma cells, rosettes and emperipolesis.
How the disease varies
- Clinical Patterns of Autoimmune Hepatitis: the ways it can present, from asymptomatic disease through acute severe and fulminant hepatitis to the overlap syndromes.
- Serological Types of Autoimmune Hepatitis: the type 1 and type 2 classification, the patients each describes, and why the distinction changes follow-up.
Putting the pieces together
- Diagnosis and Treatment of Autoimmune Hepatitis: the diagnostic criteria and the diseases that must be excluded, the scoring systems, and the treatment and its endpoints.