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

Abstract

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.

Serum KL-6 Level is Elevated in Chronic Hepatitis C Patients with Combination Therapy of Pegylated Interferon and Ribavirin

“…However, serum levels of KL-6 are sometimes elevated in patients with certain malignancies such as adenocarcinoma of the lung, breast, pancreas and HCC (21,22). In the present study, none of the patients had malignancies for two years after the initiation of follow-up.…”

Serum biomarkers in idiopathic pulmonary fibrosis

“…However, in a later report increased levels of KL-6 were mainly associated with the development of hepatocellular carcinoma in HCV patients [76]. In addition, KL-6 concentrations can be increased in patients with other malignancies, such as adenocarcinoma of the lung, breast or pancreas [76][77]. This may be a confounding factor in the investigations into KL-6 as a biomarker for prognosis of IPF, as IPF itself is associated with an increased incidence of lung cancer, raising the question whether the correlation between increased levels of KL-6 and a worse prognosis of IPF patients is partly due to an increase in lung cancer [78][79][80].…”

“…Arase et al reported increased levels of KL-6 one year before clinical onset of IPF in HCV patients [75]. However, in a later report increased levels of KL-6 were mainly associated with the development of hepatocellular carcinoma in HCV patients [76]. In addition, KL-6 concentrations can be increased in patients with other malignancies, such as adenocarcinoma of the lung, breast or pancreas [76][77].…”

Chronic hepatitis C virus infection: Prevalence of extrahepatic manifestations and association with cryoglobulinemia in Bulgarian patients

“…The prevalence of idiopathic pulmonary fibrosis in anti-HCV positive patients was 9.4% [71] . HCV patients with mixed cryoglobulinemia have been found to have asymptomatic interstitial lung fibrosis diagnosed by chest X-ray and highresolution computed tomography [15] .…”