Primary biliary cholangitis (PBC) is characterized by a specific autoantibody highly sensitive and specific for the diagnosis. This antibody targets:
- A Anti-smooth muscle antibody (ASMA) against filamentous actin
- B Anti-liver-kidney microsomal antibody type 1 (anti-LKM1) against CYP2D6
- C Anti-mitochondrial antibody (AMA) against the E2 subunit of pyruvate dehydrogenase complex (PDC-E2) ✓
- D Antinuclear antibody (ANA) sp100 and gp210 pattern
Correct answer: C. Anti-mitochondrial antibody (AMA) against the E2 subunit of pyruvate dehydrogenase complex (PDC-E2)
Explanation
Anti-mitochondrial antibody (AMA), particularly against PDC-E2 (pyruvate dehydrogenase complex E2 subunit), is present in >95% of PBC patients and is highly specific (>99%). It is the diagnostic autoantibody for PBC. ASMA is the hallmark of autoimmune hepatitis type 1. Anti-LKM1 against CYP2D6 defines AIH type 2. ANA with sp100/gp210 pattern can also be seen in AMA-negative PBC but is not the primary marker.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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