Article

Detection of YMDD mutant using a novel sensitive method in chronic liver disease type B patients before and during lamivudine treatment.

Third Department of Internal Medicine, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Japan.
Journal of Hepatology (impact factor: 9.26). 09/2002; 37(2):259-65. pp.259-65
Source: PubMed

ABSTRACT The emergence of lamivudine-resistant hepatitis B virus (HBV) was reported in patients with prolonged lamivudine administration. There was no report of the existence of tyrosine-methionine-aspartate-aspartate (YMDD) mutant in non-lamivudine treated chronic hepatitis B patients. In the present study, we developed a sensitive assay and applied it to the detection of YMDD mutant.
We developed peptide nucleic acid (PNA) mediated polymerase chain reaction clamping for detecting mutations in a YMDD motif of the hepatitis B virus DNA polymerase gene. We studied YMDD mutants in a patient with HBV DNA breakthrough longitudinally and in non-lamivudine treated patients (36 patients).
We could detect as little as 0.01-0.001% of mutant viruses coexisting in 10(5)-10(9) copies of wild-type viruses using this assay. YMDD mutant was detected 7 months before clinical breakthrough, which was 6 months earlier than using the conventional restriction fragment length polymorphism assay. YMDD mutants were also detected in four of 18 anti-HBe antibody positive untreated chronic hepatitis type B: YMDD+tyrosine-valine-aspartate-aspartate (YVDD) in two patients and YMDD+tyrosine-isoleucine-aspartate-aspartate (YIDD) in two patients, however, none in HBe antigen positive patients.
We developed a highly sensitive assay for detecting YMDD mutants. This is an effective procedure for monitoring patients during or before lamivudine treatment and can provide more insights into the therapeutic strategies for chronic hepatitis B patients.

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Keywords

18 anti-HBe antibody positive untreated chronic hepatitis type B
 
36 patients
 
chronic hepatitis B patients
 
conventional restriction fragment length polymorphism assay
 
detecting YMDD mutants
 
effective procedure
 
HBe antigen positive patients
 
HBV DNA breakthrough longitudinally
 
hepatitis B virus DNA polymerase gene
 
lamivudine treatment
 
lamivudine-resistant hepatitis B virus
 
monitoring patients
 
mutant viruses coexisting
 
peptide nucleic acid
 
polymerase chain reaction clamping
 
sensitive assay
 
therapeutic strategies
 
wild-type viruses
 
YMDD motif
 
YMDD+tyrosine-valine-aspartate-aspartate