Characterization of hepatitis B virus (HBV) preS/S gene mutations in blood donors with occult HBV infection in the Baoji area of North China.

BACKGROUND: Occult hepatitis B virus (HBV) infection (OBI) in blood donors was investigated in the Baoji area of North China, and OBI-related viral mutations in donors were characterized.

STUDY DESIGN AND METHODS: In total, 110,843 blood donor samples that were consecutively collected from December 2011 to March 2015 at the Baoji Blood Center were examined. Hepatitis B surface antigen-negative and HBV DNA-positive OBI samples were amplified for sequence analysis of OBI-related mutations in the HBV preS/S region. HBV genomes from 108 adult patients with chronic hepatitis B from North China were used as controls.

RESULTS: OBI was detected in 60 (1:1847) individual blood donors. All OBI samples were negative for hepatitis B e-antigen, and 55 were positive for anti-hepatitis B core antigen. The preS/S genes were successfully sequenced for 43 OBI samples. OBI-related S gene mutations in the major hydrophilic region were detected more frequently in blood donors with OBI than that in controls (51.16 vs. 12.96%; p < 0.01). Specifically, the incidence of five OBI-related major hydrophilic region mutations (sS117T, sT118K, sT131N, sT134Y/L, and sD144E) was significantly higher in blood donors with OBI than in controls. In addition, the coexistence of multiple OBI-related mutations in the major hydrophilic region was detected more frequently in donors than in controls (30.23 vs. 1.85%; p < 0.01), and preS deletions greater than 33 base pairs also were detected more frequently in blood donors with OBI than in controls.

CONCLUSION: OBI in blood donors should be addressed attentively in the Baoji area of North China, and HBV preS/S gene mutations may play an important role in OBI prevalence in the area.