A family infected with hepatitis B and with concurrently circulating HBsAg and heterotypic anti-HBs.

A family is described, of whom all members were found to be infected with the adw2 subtype hepatitis B virus. The mother and both the children were positive for anti-HBs (anti-y). The usual explanation for the co-occurrence of HBsAg and anti-HBs ("two infections hypothesis") was clinically highly unlikely. HLA typing was performed to investigate the possibility that genetically determined host dependent factors are involved. However, no relationship between the simultaneous presence of HBsAg and anti-HBs and a particular haplotype was observed.