Background/aims: Several reports have unequivocally demonstrated that some individuals with antibodies against hepatitis B core antigen as the only serological marker for hepatitis B infection are chronic carriers of the hepatitis B virus. Nevertheless, conflicting data exist about the frequency of this phenomenon; its cause is unknown.
Methods: In a prospective study we tested individuals who were positive for anti-HBc alone for HBV-DNA as well as for coexisting infections with human immunodeficiency virus and hepatitis C virus.
Results: Using polymerase chain reaction with primer pairs from three different regions of the hepatitis B virus genome, we found 54 of 164 individuals (32.9%) with anti-HBc alone to be positive for hepatitis B virus, the majority of them showing very low hepatitis B virus concentrations. 14.3% were human immunodeficiency virus positive; half of them were also hepatitis B virus carriers. Surprisingly, 62 of 153 participants (40.5%) in this study showed antibodies against hepatitis C virus, and about two thirds of the latter were also positive for HCV-RNA. This finding could be confirmed by a retrospective analysis of all people tested for hepatitis B virus markers and anti-HCV in our institution during the 2 years before the prospective study was begun. Again, a high correlation was found between the presence of anti-HCV and anti-HBc alone: 49.2% of individuals with anti-HBc only were anti-HCV positive also, compared to 26.8% of HBsAg carriers and only 10% of individuals showing the serological pattern of past hepatitis B.
Conclusions: Thus our study of individuals positive for anti-HBc alone revealed a high number of carriers of hepatitis B virus and hepatitis C virus among them; furthermore, we found some evidence that hepatitis C virus infection may favour this unusual hepatitis B virus marker pattern.