Detection of YMDD mutant using a novel sensitive method in chronic liver disease type B patients before and during lamivudine treatment.
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.
Article: Rate of YMDD motif mutants in lamivudine-untreated Iranian patients with chronic hepatitis B virus infection.[show abstract] [hide abstract]
ABSTRACT: Lamivudine is used for the treatment of chronic hepatitis B patients. Recent studies show that the YMDD motif mutants (resistant hepatitis B virus) occur as natural genome variability in lamivudine-untreated chronic hepatitis B patients. In this study we aimed to determine the rate of YMDD motif mutants in lamivudine-untreated chronic hepatitis B patients in Iran. A total of 77 chronic hepatitis B patients who had not been treated with lamivudine were included in the study. Serum samples from patients were tested by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for detection of YMDD motif mutants. All patients were also tested for liver enzymes, anti-HCV, HBeAg, and anti-HBe. Of the 77 patients enrolled in the study, 73% were male and 27% were female. Mean ALT and AST levels were 124.4+/-73.4 and 103.1+/-81 IU/l, respectively. HBeAg was positive in 40% and anti-HBe in 60% of the patients. Anti-HCV was negative in all of them. YMDD motif mutants were not detected in any of the patients despite the liver enzyme levels and the presence of HBeAg or anti-HBe. Although the natural occurrence of YMDD motif mutants in lamivudine-untreated patients with chronic hepatitis B has been reported, these mutants were not detected in Iranian lamivudine-untreated chronic hepatitis B patients.International Journal of Infectious Diseases 06/2008; 12(3):252-5. · 1.94 Impact Factor
Article: How to diagnose and treat hepatitis B virus antiviral drug resistance in the liver transplant setting.[show abstract] [hide abstract]
ABSTRACT: 1. Hepatitis B virus variants with antiviral drug-resistant mutations and/or hepatitis B immune globulin-resistant mutations are the main cause of hepatitis B virus reinfections post-liver transplant. 2. Early diagnosis of antiviral drug resistance and prompt initiation of rescue therapy are important in preventing hepatitis flares and hepatic decompensation. 3. Virologic breakthrough is the first indication of antiviral drug resistance. 4. Genotypic resistance testing should be performed when possible to avoid unnecessary modification of treatment in patients who do not have confirmed antiviral drug resistance and to permit appropriate selection of rescue therapy in those who have confirmed antiviral drug resistance. 5. Choice of rescue therapy requires knowledge of the past history of hepatitis B virus treatments and virologic response to those treatments, patterns of mutations detected at the time of virologic breakthrough, and in vitro cross-resistance data. 6. Occurrence of antiviral drug resistance can be reduced by the use of the most potent nucleos(t)ide analogue(s) with the highest genetic barrier to resistance, emphasis of medication compliance, and close monitoring of virologic response.Liver Transplantation 10/2008; 14 Suppl 2:S8-S14. · 3.39 Impact Factor
Article: Evaluation of peptide nucleic acid array for the detection of hepatitis B virus mutations associated with antiviral resistance.[show abstract] [hide abstract]
ABSTRACT: A major problem of long-term antiviral therapy in chronic hepatitis B patients is the emergence of hepatitis B virus (HBV) mutations associated with drug resistance. Recently, a new array using peptide nucleic acids (PNAs), which are synthetic nucleic acid analogues, was developed for the detection of HBV mutations at six different codon positions associated with lamivudine (LAM) and adefovir (ADV) resistance. We compared the PNA array with direct sequencing and reverse hybridization (INNO-LiPA) in 73 samples obtained from chronic hepatitis B patients. The PNA array detected mutations associated with LAM and/or ADV resistance in 60 (82.2%) of the 73 samples. The overall concordance rate of PNA array and INNO-LiPA compared with direct sequencing was 99.5% and 98.2%, respectively. The rate of complete concordance between PNA array and INNO-LiPA was 92.7%. The PNA array assay results were comparable with INNO-LiPA for detection of HBV mutations associated with antiviral resistance.Archives of Virology 05/2011; 156(9):1517-24. · 2.11 Impact Factor