Primary biliary cholangitis: the florid duct lesion and AMA
- Lesion
In primary biliary cholangitis the immune system destroys the smallest bile ducts, slowly, mostly in middle-aged women.
What it is
Primary biliary cholangitis is an autoimmune disease in which T cells destroy small intrahepatic (interlobular) bile ducts. It mainly affects middle-aged women, and almost all patients have antimitochondrial antibodies against the E2 subunit of the pyruvate dehydrogenase complex. Duct loss causes chronic cholestasis that can progress to cirrhosis over years. It is often found by a raised alkaline phosphatase before symptoms.
Structure
- Early: dense portal lymphoplasmacytic infiltrate around a damaged interlobular duct, often with an epithelioid granuloma.
- Later: duct loss (ductopenia), ductular reaction, copper-associated protein in periportal hepatocytes.
- End stage: green, finely nodular cirrhotic liver.
Step by step
- Loss of tolerance to a mitochondrial antigen (PDC-E2) expressed by biliary epithelial cells.
- Autoreactive T cells and antibodies target small interlobular ducts.
- Ducts are destroyed; granulomas may form around them (florid duct lesion).
- Bile acids are retained, injuring periportal hepatocytes (cholate stasis).
- Ductular reaction and periportal fibrosis spread.
- Over years septa link portal tracts: biliary cirrhosis.
Markers
- Antimitochondrial antibody (anti-PDC-E2)
- Keratin 7 (shows ducts and ductules)
- Orcein (copper-associated protein)
Test yourself
Think of the answer, then tap the question to see it.
Which autoantibody is characteristic of primary biliary cholangitis?
Antimitochondrial antibody against the E2 subunit of the pyruvate dehydrogenase complex.
What is the florid duct lesion?
Destruction of an interlobular bile duct by dense lymphocytic, often granulomatous, inflammation, the hallmark of PBC.
Which ducts are destroyed in PBC: large or small?
Small intrahepatic interlobular bile ducts; large ducts are spared.
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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: Primary biliary cholangitis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026).
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Representative model, for educational purposes only.