From the Journals

Serum keratin 18 promising as AAH biomarker

Outperforms MELD, ABIC


 

FROM CLINICAL GASTROENTEROLOGY AND HEPATOLOGY

Serum keratin 18, an epithelial protein released from dying hepatocytes, identifies patients with severe acute alcoholic hepatitis (AAH) at high risk for death, according to an investigation of 173 subjects.

Standard biomarker scores – Model for End-stage Liver Disease (MELD), age, serum bilirubin, International Normalized Ratio, and serum creatinine (ABIC), as well as others – predict prognosis and severity of alcoholic liver disease, but they don’t reflect “the magnitude of cell death nor the form of cell death (apoptosis/necrosis), which may be important in distinguishing various forms of liver injury” and guiding therapy, explained investigators led by Vatsalya Vatsalya, MD, of the division of gastroenterology, hepatology, and nutrition at the University of Louisville (Ky.).

It’s important, for instance, to identify people with alcoholic cirrhosis but not active hepatitis, as they “would likely not benefit from anti-inflammatory agents such as steroids or [interleukin]-1 receptor antagonists, but would incur their side effects.” For those and other reasons, “new biomarkers are needed for diagnosing AAH, assessing the degree of hepatocyte death, and predicting mortality,” they said (Clin Gastroenterol Hepatol. 2019 Dec 4. doi: 10.1016/j.cgh.2019.11.050).

Keratin 18 – both the cleaved form (K18M30) and the uncleaved protein (K18M65) – have been suggested before as a marker for AAH, so the investigators took a closer look.

They analyzed serum from 57 people with severe AAH (MELD score above 20), 27 people with moderate AAH (MELD score 12-19), 34 with nonalcoholic steatohepatitis, 17 healthy controls, and 38 people with alcohol use disorder and either mild or no liver injury.

Overall, 51.9% of moderate AAH cases and 38.9% of severe cases had K18M65 levels between 641 and 2,000 IU/L; 25.9% of moderate and 61.1% of severe cases had K18M65 levels greater than 2,000 IU/L. All severe cases had levels above 641 IU/L. Serum levels of K18 also identified patients who died within 90 days with greater accuracy than did MELD, ABIC, and other scores, the investigators said.

The K18M65:ALT [alanine aminotransferase] ratio distinguished AAH from nonalcoholic steatohepatitis with a sensitivity of 0.971 and specificity of 0.829. Findings were similar for the K18M30:ALT ratio.

Levels of K18M65 and K18M30 increased significantly as liver disease worsened, as did the degree of necrosis as indicated by the K18M65:K18M30 ratio. Meanwhile, although k18 levels correlated with MELD scores, levels of ALT, aspartate aminotransferase (AST), and the ratio of AST:ALT did not.

“There is a stronger association between serum level of keratin 18 and amount of hepatocyte death and liver disease severity than for other biomarkers,” the team concluded.

Patients were in their mid 40s, on average, and there were more men than women.

The National Institutes of Health supported the work, and the investigators had no disclosures.

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