What is the hallmark lab finding of primary biliary cholangitis (PBC)?

Updated: Nov 08, 2017
  • Author: Nikolaos T Pyrsopoulos, MD, PhD, MBA, FACP, AGAF; Chief Editor: BS Anand, MD  more...
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Answer

The hallmark of this disease is the presence of antimitochondrial antibodies (AMAs) in the sera. Note the following:

  • AMAs can be found in 90-95% of patients with primary biliary cholangitis, and they have a specificity of 98% for this disease.

  • These antibodies target different components, mainly enzymes, in the mitochondria.

  • The presence of anti-M2, anti-M4, anti-M8, and anti-M9 has been associated with the severity of primary biliary cholangitis. Patients with profile A (ie, only anti-M9) or profile B (ie, anti-M9 and/or anti-M2–positive by enzyme-linked immunosorbent assay [ELISA]) have a better disease course than patients with profile C (ie, anti-M2, anti-M4, and/or anti-M8–positive by ELISA) and profile D (ie, anti-M2, anti-M4, and/or anti-M8–positive by ELISA and complement-fixation test).

  • Antinuclear antibodies (ANAs) can be identified in 20-50% of patients with primary biliary cholangitis

  • Some patients have clinical, biochemical, and histologic features of primary biliary cholangitis, but their sera are negative for AMA. The diagnosis of autoimmune cholangitis has been used for these patients, but whether these patients represent the AMA-negative primary biliary cholangitis group is a matter of debate. In terms of autoimmune markers, their profile is compatible with this type of autoimmune hepatitis (ie, high-titer ANA and/or SMA).

  • The natural history and associated autoimmune conditions in AMA-positive and AMA-negative primary biliary cholangitis appear to be identical. A careful review of the liver biochemical pattern reveals cholestasis (ie, ALP and GGTP are elevated), and the liver biopsy findings are compatible with bile duct injury, ductopenia, cholestasis, and granulomas. [8]


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