Autoimmune hepatitis: plasma cells, interface injury and types 1 and 2
- Lesion
In autoimmune hepatitis the immune system attacks the person's own liver cells; untreated it often leads to cirrhosis.
What it is
Autoimmune hepatitis is a chronic hepatitis caused by a T-cell attack on hepatocytes, with autoantibodies and raised IgG. It is more common in women, can present at any age, and ranges from abnormal tests to acute liver failure or cirrhosis at diagnosis. The diagnosis combines autoantibodies, high IgG, a compatible biopsy and the exclusion of viral and drug causes. It responds to immunosuppression, so recognizing it matters.
Structure
- Dense portal and interface infiltrate of lymphocytes with many plasma cells in clusters.
- Hepatocyte rosettes: small circles of regenerating hepatocytes around a dilated canaliculus.
- Emperipolesis: lymphocytes or plasma cells inside hepatocyte cytoplasm.
- Confluent perivenular, bridging or panacinar necrosis in severe flares; fibrosis or even burnt-out cirrhosis at first biopsy.
Step by step
- A genetically susceptible person (certain HLA alleles) loses tolerance to liver antigens.
- A trigger is suspected (virus, drug), but the target antigen is usually unknown.
- CD4 helper T cells drive B cells to make autoantibodies and plasma cells gather in portal tracts.
- CD8 cytotoxic T cells kill hepatocytes at the interface.
- Repeated injury causes fibrosis and, without treatment, cirrhosis.
Markers
- ANA
- Anti-smooth muscle (F-actin)
- Anti-LKM-1
- Anti-SLA/LP
- Serum IgG
Clinical notes
- Presentations: asymptomatic raised aminotransferases, acute hepatitis, acute liver failure, or established cirrhosis.
- Overlap features with primary biliary cholangitis or primary sclerosing cholangitis (the latter mostly in children) occur.
Test yourself
Think of the answer, then tap the question to see it.
Which antibodies characterize type 1 autoimmune hepatitis?
Antinuclear antibodies and anti-smooth muscle (anti-actin) antibodies.
Which antibody defines type 2 autoimmune hepatitis and what is its target?
Anti-liver kidney microsome type 1, directed against cytochrome P450 2D6.
What histologic feature most supports autoimmune hepatitis over viral hepatitis?
Clusters of plasma cells in a florid interface hepatitis, with rosettes and emperipolesis.
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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Autoimmune hepatitis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026).
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Representative model, for educational purposes only.