A 52-yr-old male with multiple myeloma underwent autologous stem cell transplantation in June 2002. In August 2004, the multiple myeloma had recurred. The patient received allogenic stem cell transplantation in September 2005. Before undergoing transplantation, the presence of HBsAb and the absence of HBsAg were noted. The patient underwent allogenic peripheral blood stem cell transplantation (PBSCT) from a sibling donor who was hepatitis surface antibody (HBsAb) positive and hepatitis surface antigen (HBsAg) negative. Nineteen months after the PBSCT, the liver function tests showed elevation of the aminotransferases. The patient was HBsAg positive and HBsAb negative. The liver biopsy specimen revealed hepatitis. The reactivation of a hepatitis B virus infection, in a hepatitisB immune patient, referred to as reverse seroconversion, is a rare complication of hematopoietic stem cell transplantation. (Korean J Hematol 2008;43:122-125.)

Keywords: Hepatitis B virus, Seroconversion, Multiple myeloma, Stem cell transplantation