Amplification and sequence analysis of the precore and core region of the HBV genome from sera of Spanish patients with HBV2-like infections.

Hepatitis B virus (HBV) infections are occasionally associated with unusual serological profiles which may be attributed to the lack of immune responsiveness of the patients or to variants of the virus. The term HBV2 was introduced to describe potential variants of HBV which do not elicit a detectable immune response to the nucleocapsid (anti-HBc) in apparently immune-competent patients. The entire nucleotide sequences of the nucleocapsid genes of viruses from two Spanish patients with HBV2-like infections are reported here. In-frame deletions and other mutations in these sequences may account, at least in part, for the unusual serological profiles of the patients. Antibody responses to viral proteins containing deletions may not be detected by commercially available assays.