Frequent presence of HBV in the sera of HBsAg-negative, anti-HBc-positive blood donors

BACKGROUND: Recent studies have revealed that HBV may not be cleared even after the disappearance of serum HBsAg. The purpose of this study was to investigate whether the replication of HBV persists in HBsAg-negative blood donors who lack apparent liver disease. STUDY DESIGN AND METHODS: Serum HBV was examined by using PCR coupled with Southern blotting in 50 blood donors who were identified to be HBsAg negative but anti-HBc positive. RESULTS: HBV DNA was detected in the sera from 19 (38%) of 50 donors. In 11 of the 19, HBV existed exclusively as immune complexes, while HBV presumably did not exist as immune complexes in the remaining eight. The levels of HBV DNA were similar to those in patients who had recovered from acute HBV. Some nucleotide substitutions, which did not confer amino acid changes in the major epitope of HBsAg, were found in the preS-S regions. CONCLUSION: The replication of HBV is ongoing in a substantial proportion of healthy blood donors who have anti-HBc. Blood from such donors may contain very low levels of HBV free of immune complex formation and should be excluded for transfusion. The fact that such blood donors apparently lacked liver disease suggests no pathogenicity of such "occult" HBV.