Hepatitis B virus reactivation in HBsAg-negative patients is associated with emergence of viral strains with mutated HBsAg and reverse transcriptase

Background/aims: Virological factors associated with hepatitis B virus reactivation (HBV-R), following chemotherapy for cancer in hepatitis B surface antigen (HBsAg)-negative patients, are not well known. Materials and methods: HBV strains from 16 patients presenting HBV-R following chemotherapy were studied and compared to those obtained from 51 HBV chronically-infected patients. Results: HBsAg variability was significantly increased within the major hydrophilic region, the a determinant and the C-terminal region. Amino acid substitutions were more frequently found in HBV-R patients as compared to controls at 17 and 11 positions within HBsAg and HBV-RT, respectively. This resulted in atypical serological testing in 56% of patients and detection of resistance mutation to nucleoside analogs in 12.5%. Conclusion: HBsAg and HBV-RT mutations are frequently encountered in patients with HBV-R, resulting in atypical serological testing and emergence of HBV strains resistant to nucleos(t)ides analogs.