Lack of interferon sensitivity-determining region in the genome of hepatitis B virus genotype Ba

Abstract

Background/aims: In chronic hepatitis B, both host and viral factors may predict the response to interferon (IFN) treatment. Whether IFN sensitivity-determining regions exist within the hepatitis B virus (HBV) genomic background remains largely unknown. We therefore performed full-length viral genomic comparison between HBVs obtained from IFN responders and non-responders. Methods: We enrolled 18 HBV genotype Ba patients who had received 24-week IFN 5 MU three times weekly and were followed monthly for 12 months post-treatment. There were 10 responders and eight non-responders. Pre-treatment full-length viral nucleotide consensus sequence was obtained. In six non-responders and four responders, post-treatment viral nucleotide sequence was further compared with their corresponding pre-treatment specimens. In addition, the average number of nucleotide substitutions of the HBV quasispecies was compared between three responders and three non-responders. Results: HBV nucleotide consensus sequence was identical between responders and non-responders. We found 0-15 (mean 7.7) nucleotide substitutions in the post-treatment HBV genome in the six non-responders and 0-14 (mean 3.8) nucleotide substitutions in the four responders, respectively. Genetic complexity of HBV quasispecies was comparable between responders and non-responders. Conclusions: Our results suggest that an IFN sensitivity-determining region might not exist within the genome of HBV genotype Ba. Host factors and virus-host interactions may be more important in determining the response to IFN treatment.