Plasma Cytokeratin-18 Level As a Novel Biomarker for Liver Fibrosis in Children With Nonalcoholic Fatty Liver Disease

Objectives: Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the obesity epidemic and affects approximately 10% of children in the US. The presence of hepatic fibrosis may be the most important factor in determining the prognosis of NAFLD. Noninvasive methods to identify the presence of fibrosis in children with NAFLD are greatly needed. Hepatocyte apoptosis activates hepatic stellate cells and plays a central role in fibrosis progression in NAFLD. The aim of the present study was to evaluate the use of plasma cytokeratin-18 (CK18) fragment levels, a marker of hepatocyte apoptosis, as a noninvasive biomarker in detecting liver fibrosis in pediatric NAFLD. Methods: Consecutive children with biopsy-proven NAFLD were included and blood samples and anthropometric measurements were collected at the time of the biopsy. NAFLD activity score was calculated (0-8) and fibrosis stage was scored (0-4). We measured plasma CK18 levels using the M30-Apoptosense enzyme-linked immunosorbent assay kit. Results: A total of 201 subjects were enrolled in the study. The mean age was 10.7 +/- 2.5 years, and 37 % were boys. Sixty-eight percent of the patients had any fibrosis, with 56% having F 1, 6% having F2, and 6 % having F3. CK18 levels were found to be significantly higher in subjects with any fibrosis compared with those without fibrosis (304.6 +/- 124.8 vs 210.4 +/- 70.9, P < 0.001). CK18 level revealed good accuracy for prediction of any fibrosis (F1-F3) with AUROC of 0.75. Multivariate logistic regression was performed to assess whether CK18 combination with another clinical factor could improve accuracy of prediction of fibrosis. Together, CK18 with waist circumference percentile generated an area under the receiver operating characteristics curve of 0.842 for prediction of any fibrosis. Conclusions: CK18 is a promising noninvasive biomarker for fibrosis in NAFLD in children. A fibrosis prediction model that includes CK18 and waist circumference percentile should be validated in other populations.