Usefulness of the Serum KL-6 Assay in Patients with Hepatitis C Virus.

Objective: The aim of this study is to evaluate the serum level of KL-6 in hepatitis C virus (HCV)-positive patients with chronic liver disease. Methods and Results: Subjects consisted of 502 HCV-positive patients. The serum samples of these patients stored at –80°C were measured by enzyme-linked immunosorbent assay for KL-6 at the same time. The cutoff point of the serum KL-6 level was defined as 500 U/ml. The serum KL-6 level of the 502 patients ranged between 71 and 2,295 (median, 223) U/ml. Thirty-two of the 502 (6.4%) patients showed an elevated KL-6 level of >500 U/ml. Three of the 32 (9.4%) patients with elevated KL-6 level >500 U/ml had idiopathic pulmonary fibrosis. Multivariate analysis showed that patients achieved elevated KL-6 when: (1) they had hepatocellular carcinoma (HCC; p = 0.0007), and (2) age was >60 years (p = 0.0085). The HCC rate was 37.5% (12/32) in the patients with elevated KL-6 and 8.3% (39/470) in the patients with normal KL-6 group. The median (range) age was 70 (56–77) years in the patients with elevated KL-6 group and 60 (12–92) years in the patients with normal KL-6. Conclusion: The patients with HCC aged >60 years had significantly elevated serum levels of KL-6. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]