Occult HBV infection in the oncohematological setting.

INTRODUCTION: Occult hepatitis B infection (OBI), a virological condition characterized by a low release of Hepatitis B Virus (HBV) from liver cells and low HBV-DNA levels in serum and/or liver tissue of HBsAg-negative subjects, may reactivate in oncohematological patients undergoing immunosuppression by aggressive chemotherapy or hematopoietic stem cell transplantation. The entity of OBI reactivation varies from an increase in HBV replication without liver damage to an active HBV replication followed by liver cell necrosis, frequently severe and in some cases life threatening. Because of a possible severe outcome associated with OBI reactivation (hepatic failure or death due to the discontinuation of chemotherapy), prophylaxis with anti-HBV nucleot(s)ide analogues is recommended in relation to the foreseeable degree of immunosuppression.

MATERIALS AND METHODS: This review article focuses on the clinical impact of OBI in the oncohematological setting and is addressed to all health care workers having in care oncohematological patients or involved in the treatment of HBV infection and OBI prophylaxis.

CONCLUSION: International guidelines have indicated lamivudine prophylaxis in hematopoietic stem cell transplantation and when high-dose corticosteroids or anti-CD20 or anti-CD52 monoclonal antibodies are used. Entecavir or tenofovir should replace lamivudine for patients with advanced liver diseases for whom reactivation of OBI may be life threatening. When anti-CD20 or anti-CD52 sparing schedules or other non-aggressive chemotherapies are used, monitoring may be indicated, but very early treatment with highly effective antiviral drugs (entecavir or tenofovir) should be administered once a reactivation of OBI has occurred.