Hepatitis B virus reactivation after allogeneic bone marrow transplantation in a patient previously immunized against HBV

The presence of antibodies to HBs and HBc antigens indicates previous infec tion with hepatitis B virus but does not necessarily reflect viral clearanc e. Immunosuppression such as that observed in patients with bone marrow tra nsplantation may be responsible for viral reactivation followed by acute ex acerbation after withdrawal of immunosuppressive therapy. We report a case in a patient with natural immunity to hepatitis B who had undergone allogenic bone marrow transplantation with an identical sibling d onor one year before for the chronic myelogenous leukemia in the first chro nic phase. Ganciclovir treatment resulted in control of hepatitis virus B r eplication and in biochemical remission. We suggest that prevention relies on serological evaluation and therapy with active or passive immunisation o r antiviral drugs in case of a rapid decline of anti-HBs Ab titers to undet ectable levels.