Blood donors infected with the hepatitis B virus but persistently lacking antibodies to the hepatitis B core antigen

Background and objectives Antibodies to the core of hepatitis B virus (anti -HBc) are considered to be the best serologically reliable markers of hepat itis B virus (HBV) infection. Through a national epidemiological survey, tw o young and first-time blood donors, originating from HBV-endemic areas, we re identified as HBV carriers with an absence of anti-HBc reactivity. Materials and Methods We followed up these two subjects in order to investi gate the evolution of their HBV serological profiles. Nucleotide sequencing was performed of the entire pre-C/C region of the strains infecting these donors. Results The same serological profile of active viral replication with an ap parent persistent lack of anti-HBc and normal alanine aminotransferase (ALT ) levels was found for both subjects throughout a follow-up of 19 months an d 4 months, respectively. Neither donor was immunocompromised, Nucleotide s equence analysis of the pre-CIC region did not show mutations or deletions in encoded proteins. Conclusion The hypothesis of an in utero HBV infection responsible for an i mmune tolerance to HBV seems to be the most probable explanation for this p articular immunological situation. Such occurrences in the blood donor popu lation are probably rare as less than 0.1% of hepatitis B surface antigen ( HBsAg)-positive donors exhibit such a profile, in our experience. Moreover, this phenomenon does not impose a risk of HBV transmission by blood donati on, as the exclusion of HBV-infected blood donation is based on HBsAg detec tion. However, such a risk might be encountered with the hepatitis C virus (HCV) for which at present only antibodies to HCV are screened.