title: Dynamics of hepatitis B virus quasispecies in association with nucleos(t)ide analogue treatment determined by ultra-deep sequencing.
abstract: OBJECTIVE
  Although the advent of ultra-deep sequencing technology allows for the analysis of heretofore-undetectable minor viral mutants, a limited amount of information is currently available regarding the clinical implications of hepatitis B virus (HBV) genomic heterogeneity.
  
  
  METHODS
  To characterize the HBV genetic heterogeneity in association with anti-viral therapy, we performed ultra-deep sequencing of full-genome HBV in the liver and serum of 19 patients with chronic viral infection, including 14 therapy-naïve and 5 nucleos(t)ide analogue(NA)-treated cases.
  
  
  RESULTS
  Most genomic changes observed in viral variants were single base substitutions and were widely distributed throughout the HBV genome. Four of eight (50%) chronic therapy-naïve HBeAg-negative patients showed a relatively low prevalence of the G1896A pre-core (pre-C) mutant in the liver tissues, suggesting that other mutations were involved in their HBeAg seroconversion. Interestingly, liver tissues in 4 of 5 (80%) of the chronic NA-treated anti-HBe-positive cases had extremely low levels of the G1896A pre-C mutant (0.0%, 0.0%, 0.1%, and 1.1%), suggesting the high sensitivity of the G1896A pre-C mutant to NA. Moreover, various abundances of clones resistant to NA were common in both the liver and serum of treatment-naïve patients, and the proportion of M204VI mutants resistant to lamivudine and entecavir expanded in response to entecavir treatment in the serum of 35.7% (5/14) of patients, suggesting the putative risk of developing drug resistance to NA.
  
  
  CONCLUSIONS
  Our findings illustrate the strong advantage of deep sequencing on viral genome as a tool for dissecting the pathophysiology of HBV infection.
authors.affiliation: Department of Gastroenterology and Hepatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Nishijima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Marusawa
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Ueda
authors.forename: Ken
authors.initials: K
authors.lastname: Takahashi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nasu
authors.forename: Yukio
authors.initials: Y
authors.lastname: Osaki
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Kou
authors.forename: Shujiro
authors.initials: S
authors.lastname: Yazumi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Soken
authors.initials: S
authors.lastname: Tsuchiya
authors.forename: Kazuharu
authors.initials: K
authors.lastname: Shimizu
authors.forename: Shinji
authors.initials: S
authors.lastname: Uemoto
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Chiba
mesh_terms: D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000627:therapeutic use; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D016679:Genome, Viral / Q000235:genetics; D006147:Guanine / Q000031:analogs & derivatives / Q000627:therapeutic use; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology*; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use; D008099:Liver / Q000737:chemistry; D008297:Male; D008875:Middle Aged
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D019259:Lamivudine; C413685:entecavir; D006147:Guanine