The Spontaneous Mutation Of HBV YMDD Motif And Its Effect On Antiviral Therapy Of Nucleoside Analogues

Despite efficient vaccines, chronic hepatitis B virus (HBV) infection continues to be a major public health problem worldwide. Antiviral agents play a key role in the treatment of chronic hepatitis B (CHB) by inhibiting the replication of the virus or eliminating it, and delaying or preventing progression to cirrhosis, liver failure and hepatocellular carcinoma. Several antiviral nucleoside analogues, including lamivudine (LAM), adefovir dipivoxil (ADV) and entecavir, have been approved for the antiviral therapy against HBV, which mainly target the virus DNA Polymerase and inhibit its reverse transcription activity. Unfortunately, mutation in the YMDD motif of the Polymerase gene frequently occurs after long-term antiviral therapy with LAM and drug-resistance emerges. Moreover, it has been reported that spontaneous YMDD variants existed in patient with CHB who have never received any antiviral treatment, which poses a challenge for the application of antiviral nucleoside analogues in patients with CHB.In this study, we first evaluated three assays for detection of YMDD mutation, and then detected spontaneous YMDD mutation in 183 untreated subjects enrolled into phase III clinical trial of ADV with primer- specific real-time PCR. Factors related to naturelly YMDD mutation and effects of spontaneous YMDD mutation on the antiviral therapy of nucleoside analogues were analyzed.Part I Evaluation of assays for detection of HBV YMDD motif mutation Objective To evaluate assays for detection of HBV YMDD motif mutation and choose optimal assay for further experiment. Methods Three assays, including direct sequencing of PCR products, probe-specific and primer-specific fluorescent real-time PCR, were assessed respectively, based on HBV DNA samples from 105 CHB patients who were resistant to LAM, and human genome DNA samples with positive...