YKL-40 and hyaluronic acid (HA) as noninvasive markers of liver fibrosis in kidney transplant patients with HCV chronic infection

Objective. Hepatitis C is highly prevalent among kidney transplant (KT) recipients. In this population, the natural history of hepatitis C virus (HCV) infection and its proper management remains controversial. The invasiveness of the procedure and the interpretation variability of liver biopsy limit its use in these patients. We sought to evaluate the performance of YKL-40 and HA as markers of liver fibrosis in KT patients with HCV infection. Material and methods. This cross-sectional study included HCV infected KT individuals. Univariate analysis was used to identify variables associated with significant fibrosis (METAVIR ≥ F2). The diagnostic values of the YKL-40 and HA were compared using receiver operating characteristic (ROC) curves. Results. Eighty-five patients were included (60% males, mean age 44.9 ± 9.4 years). Significant fibrosis was observed in 14 patients (17%). When compared to F0/F1 individuals, patients with significant fibrosis were older, showed a higher time since transplantation, and higher prevalence of diabetes. No difference was observed in YKL-40 levels between the groups. Significantly higher levels of HA were noted in METAVIR ≥ F2 subjects (108 vs. 37 ng/ml, p = 0.002). The AUROCs of YKL-40 and HA for predicting significant fibrosis were 0.615 and 0.765, respectively (p = 0.144). Levels of YKL-40 ≤ 105 ng/ml and of HA ≤ 27 ng/ml showed a NPV of 36% and 96%, respectively. YKL-40 ≥ 418 ng/ml and HA ≥ 120 ng/ml exhibited a PPV of 31% and 39%, respectively. Conclusions. Increased serum levels of HA but not of YKL-40 were associated with more advanced stages of liver fibrosis in KT HCV-infected patients.