Abstract
Mutations in hepatitis B virus (HBV) reverse transcriptase (RT) are associated with nucleos(t)ide analogue (NA) resistance during long-term antiviral treatment. However, the characterization of mutations in HBV RT in untreated patients has not yet been well illustrated. The objective of this study was to investigate the characterization and clinical significance of natural variability in HBV RT in treatment-naive patients. HBV RT sequences were analyzed in 427 patients by Sanger sequencing and in 66 patients by next-generation sequencing. Primary or secondary NA resistance (NAr) mutations were not found, except A181T in RT (rtA181T) by Sanger sequencing, but they were detected by next-generation sequencing. Mutations were found in 56 RT amino acid (aa) sites by Sanger sequencing, 36 of which had mutations that could lead to changes in B or T cell epitopes in the RT or S protein. The distribution of mutations was diverse in different sections within the RT region. Multiple mutations showed significant association with HBV DNA, HBsAg, HBeAg, age, and severity of liver fibrosis. Mutations at rt251, rt266, rt274, rt280, rt283, rt284, and rt286 were found most in the advanced liver disease (ALD) group by next-generation sequencing. The present study demonstrates that next-generation sequencing (NGS) was more suitable than Sanger sequencing to monitor NAr mutations at a low rate in the treatment-naive patients, and that mutations in the RT region might be involved in the progression to ALD.
Highlights
Hepatitis B virus (HBV) is the most common cause of acute and chronic liver disease in China
Patients infected by HBV during infancy or early childhood are likely to develop into chronic hepatitis B (CHB) and have an increased risk of progression to liver cirrhosis (LC) and hepatocellular carcinoma (HCC) [1]
The HBV reverse transcriptase (RT) region from rt145 to rt289, covering parts of the A-B interdomain, domain B, B-C interdomain, domain C, C-D interdomain, domain D, D-E interdomain, domain E, and parts of the E-RNA H interdomain, was sequenced by Sanger sequencing in 427 treatment-naive CHB patients, including 57 HBV carriers (HC), 265 chronic hepatitis B (CHB) patients, and 105 patients with advanced liver disease (ALD)
Summary
Hepatitis B virus (HBV) is the most common cause of acute and chronic liver disease in China. It has been reported that patients with spontaneous YMDD mutations had a higher risk of developing HBV-related HCC, suggesting that spontaneous mutations in the RT region were related to the progression of liver disease [14]. Given that the results were obtained by Sanger sequencing with a limited sensitivity, next-generation sequencing could be considered to investigate further the association between the spontaneous mutations and the progression of liver disease. We analyzed the mutations in the RT region by Sanger sequencing and next-generation sequencing, aiming to characterize the natural amino acid substitutions in the RT region and further analyze their potential clinical significance especially associated with the progression of liver disease
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