Serologic hallmark in PBC

Q: Which of the following is the serologic hallmark of Primary Biliary Cirrhosis (PBC)? - select one

A) Antinuclear antibodies (ANA)

B) Antimitochondrial antibodies (AMA)

Answer: B

Expected lab findings in PBC are elevated alkaline phosphatase, mild elevations in the aminotransferases, and bilirubin levels. Hyperlipidemia and iron deficiency anemia are also common.

AMA is considered the serologic hallmark of PBC, which is rarely missing. In such cases, it is called AMA-negative PBC. Interestingly, many patients with positive AMA will eventually go on to develop features of PBC! AMA also predicts rapid progression and a poorer prognosis.

Although ANA is also common but not considered a hallmark as it is generally positive in many other etiologies. Other antibodies that may be present are anticentromere, anti-SSA/Ro, and anti-dsDNA antibodies.

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References:

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2. Chascsa DM, Lindor KD. Antimitochondrial Antibody-Negative Primary Biliary Cholangitis: Is It Really the Same Disease? Clin Liver Dis. 2018 Aug;22(3):589-601. doi: 10.1016/j.cld.2018.03.009. PMID: 30259855.

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