NOVEL HEPATITIS-B VARIANTS IN SIBLING CARRIERS POSITIVE FOR ANTIBODY TO HEPATITIS-B SURFACE-ANTIGEN

We analyzed the pre-S and S genes of hepatitis B virus (HBV) obtained from a pair of siblings, who tested positive for antibody to hepatitis B surface antigen, and identified novel HBV variants. While Patient 1 tested positive for hepatitis B surface antigen (HBsAg) by radioimmun oassay, Patient 2 tested negative for the same antigen. Two different mutants were obtained from Patient 1. The first strain showed three am ino acid mutations in the S region at positions 130 (G --> N), 138 (C --> S) and 145 (G --> R). Another strain had mutations at 133 (M --> T ) and 134 (F --> I). Although one strain obtained from Patient 2 had a mutation at 145 (G --> K), the second strain showed no mutation in th e S region. The different genetic and serological states found in thes e patients suggest that further diagnostic and vaccine strategies shou ld be considered in eliminating HBV infection.