A 45-year-old woman with primary biliary cholangitis has a liver biopsy showing granulomatous destruction of interlobular bile ducts with a dense lymphocytic infiltrate. The serological marker most specific for this condition is:
- A Anti-mitochondrial antibody (AMA), specifically against pyruvate dehydrogenase complex E2 ✓
- B Anti-smooth muscle antibody (ASMA)
- C Anti-liver-kidney microsomal antibody (anti-LKM1)
- D Anti-neutrophil cytoplasmic antibody (p-ANCA)
Correct answer: A. Anti-mitochondrial antibody (AMA), specifically against pyruvate dehydrogenase complex E2
Explanation
Primary biliary cholangitis (PBC) is defined by anti-mitochondrial antibodies (AMA) in >95% of cases, specifically targeting the E2 component of pyruvate dehydrogenase complex on the inner mitochondrial membrane. The histological hallmark is florid duct lesion — granulomatous inflammation destroying interlobular bile ducts. ASMA is seen in autoimmune hepatitis type 1; anti-LKM1 in AIH type 2; p-ANCA in primary sclerosing cholangitis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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