Background/Aims: Chronic hepatitis B virus (HBV) infection still poses major threat to global health. Oligoadenylate synthetase‐Ribonuclease L (OAS‐RNase‐L) antiviral pathway is one of interferon‐induced antiviral effectors. The relationship between RNase‐L and HBV has never been investigated and we aim to examine the serum RNase‐L levels in patients with different stage of chronic HBV infection.MethodsThe patients were enrolled from 1985 to 2000, who had been HBsAg‐positive for longer than 6 months, at the National Taiwan University Hospital. A total of 426 subjects with chronic HBV infection were included in this study, including 135 inactive carriers, 148 cirrhosis and 143 HCC cases.ResultsThe RNase‐L levels increase as the disease severity increases. Higher RNase‐L levels was associated with higher HBV viral load, and the HBV‐RNase‐L relationship was replaced by the disease severity status when adding disease status into the model. Compared to inactive carriers, the risk of liver cirrhosis was 60‐fold (OR=60.8, 95% CI=3.49 – 1061) with the highest quintile of RNase‐L levels, after the adjustment of HBVDNA. The dose‐response trend was statistically significant with quintiles and one increment of RNase‐L level in relation to liver cirrhosis. Similar results were found when compared HCC to inactive carriers, while no association when compared between liver cirrhosis and HCC.ConclusionsA positive relationship between serum RNase‐L and HBV viral titers or advanced disease status is uncovered in this study. Further investigation in this area may provide more details of innate immune response for HBV and opportunity for novel therapeutic strategy.This article is protected by copyright. All rights reserved.