Aim of the study: Host and viral factors can influence the clinical course of chronic hepatitis B virus (HBV) infection. Mutations in pre-S1/S2 gene regions are among the most important viral factors determining the HBV infection outcome. The aim of this study was to investigate the role of pre-S1/S2 mutations in HBV infection outcome.
Material and methods: A total of 52 samples from 26 asymptomatic carriers (ASCs) and 26 liver cirrhosis/hepatocellular carcinoma (LC/HCC) patients were enrolled. The HBV DNA genome was extracted from the sera, and pre-S1/S2 regions of the samples were amplified by nested-polymerase chain reaction, prior to being subjected to sequencing, sequence investigation and phylogenetic analysis.
Results: Certain deletions were detected mostly located at the boundary of the pre-S1 and pre-S2 regions. These deletions were detected more frequently in ASC cases than in LC/HCC patients (p < 0.007). The rate of critical point mutations, including L11Q, N37S and K38R, was significantly higher in the ASC group, whereas the A49V substitution rate was significantly higher in the LC/HCC group (p < 0.05). The phylogenetic analysis indicated that all the sequences belonged to genotype D.
Conclusions: According to the results, point mutations such as L11Q, N37S, K38R and A49V, as well as certain deletions, may be associated with HBV infection outcome, among an HBV genotype D pure population.
Keywords: asymptomatic carrier; cirrhosis; genotype D; hepatitis B virus; hepatocellular carcinoma; pre-S1/S2 variations.