Cytokeratin-18 and hyaluronic acid levels predict liver fibrosis in children with non-alcoholic fatty liver disease.

OBJECTIVES There is a need to replace liver biopsy with non-invasive markers that predict the degree of liver fibrosis in fatty liver disease related to obesity. Therefore, we studied four potential serum markers of liver fibrosis and compared them with histopathological findings in liver biopsy in children with non-alcoholic fatty liver disease (NAFLD). METHODS We determined fasting serum level of hyaluronic acid (HA), laminin, YKL-40 and cytokeratin-18 M30 in 52 children (age range 4-19, mean 12 years, 80 % of them were overweight or obese) with biopsy-verified NAFLD. Viral hepatitis, autoimmune and metabolic liver diseases (Wilson's disease, alpha-1-antitrypsin deficiency, cystic fibrosis) were excluded. Fibrosis stage was assessed in a blinded fashion by one pathologist according to Kleiner. Receiver operating characteristics (ROC) analysis was used to calculate the power of the assays to detect liver fibrosis (AccuROC, Canada). RESULTS Liver fibrosis was diagnosed in 19 children (37 %). The levels of HA and CK18M30 were significantly higher in children with fibrosis compared to children without fibrosis (p=0.04 and 0.05 respectively). The ability of serum HA (cut-off 19.1 ng/ml, Se=84 %, Sp=55 %, PPV=52 %, NPV=86 %) and CK18M30 (cut-off 210 u/l, Se=79 %, Sp=60 %, PPV=56 %, NPV=82 %) to differentiate children with fibrosis from those without fibrosis was significant (AUC=0.672 and 0.666, respectively). The combination of both markers was superior (AUC=0.73, p=0.002). Laminin and YKL-40 levels did not allow a useful prediction. CONCLUSIONS Cytokeratin-18 and hyaluronic acid are suitable serum markers predicting liver fibrosis in children with NAFLD. Studying these markers may identify patients at risk of disease progression.