Relationship between the YMDD mutants of HBV and serum HBV DNA level

Objective To investigate the relationship between lamivudine -resistant (YMDD) mutants of hepatitis B virus (HBV) and serum HBV DNA level. Methods Seventy-eight patients were enrolled in the study, prescribed with lamivudine tablet at the oral dose of 100mg once a day and followed-up for two years. During the treatment, the liver function was tested by Olympus AU640 automatic biochemical analyzer, the HBV-markers were detected by ELISA, serum HBV DNA level was measured with PCR and HBV YMDD mutants were detected using mismatched PCR-restriction fragment length polymorphism (PCR-RFLP) every three months. Results HBV DNA level was significantly higher in patients with YMDD mutants during lamivudine therapy than those without YMDD mutants. Conclusion The higher the patients’serum HBV DNA level is, the easier and earlier the YMDD mutant comes into being if lamivudine is administered. The prolonged lamivudine therapy would increase the incidence of HBV YMDD variation.