title: Detection of YMDD motif mutations in some lamivudine-untreated asymptomatic hepatitis B virus carriers.
abstract: OBJECTIVE
  It is well documented that long-term lamivudine treatment induces emergence of lamivudine-resistant hepatitis B virus (HBV), namely, YMDD motif mutation in some patients chronically infected with HBV. We previously reported that there were no YMDD mutant viruses in patients with chronic hepatitis B who were not treated with lamivudine. In this series, we examined mutations in the YMDD motif gene in asymptomatic carriers who maintained normal ALT values for 1 year or more.
  
  
  METHODS
  Serum samples obtained from 18 patients chronically infected with HBV who consulted our university were used. None of these patients had any experience of using antiviral agents. For detection of mutant viruses, a kit developed in our laboratory was used.
  
  
  RESULTS
  Mutations were detected in five of 18 samples: YMDD+YIDD in three samples and YMDD+YVDD+YIDD in two samples. All of these five samples were positive for anit-HBe. In five samples in which mutations were observed, sequencing was carried out following subcloning.
  
  
  CONCLUSIONS
  The present study demonstrates that YMDD mutant viruses are present in lamivudine-untreated asymptomatic hepatitis B virus carriers as well.
authors.affiliation: Medical Business Department, Sumitomo Metal Industry Ltd., Ibaraki, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Ide
authors.forename: M
authors.initials: M
authors.lastname: Sata
mesh_terms: D000328:Adult; D000368:Aged; D020816:Amino Acid Motifs; D002353:Carrier State; D005260:Female; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*
chemical_list: D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine