Acute Hepatitis B in a Patient with Antibodies to Hepatitis B Surface Antigen Who Was Receiving Rituximab

Abstract
CD20 antigen is expressed on most B lymphocytes. Therefore, humanized monoclonal antibodies to CD20, especially rituximab, specifically kill lymphomatous and normal B lymphocytes by means of cytotoxicity and apoptosis.1 Few infections have been reported in recipients of rituximab. A lethal reactivation of hepatitis B virus (HBV) infection occurred in a patient who was treated with cyclophosphamide, doxorubicin, vincristine, and prednisone and rituximab.1 We describe a patient who had antibodies to hepatitis B surface antigen (anti-HBs) but not hepatitis B surface antigen (HBsAg) before rituximab therapy and in whom anti-HBs disappeared and hepatitis B developed.