 Allogeneic hematopoietic stem cell transplantation is widely used for the treatment of hematological malignancies and bone marrow failure diseases. Human cytomegalovirus CMV infection is a major cause of morbidity and mortality for recipients of allogeneic hematopoietic stem cell transplantationHSCT. Approximately half of the recipients would develop CMV infection after transplant. Present treatment recommendation for CMV infection including ganciclovir and foscarnet. However, these medications have many side effects, the most serious is myelosuppression and renal injury, moreover, many patients do not response to these medications. Considering the risk associated with persistent infection and the potential for CMV specific cytotoxic T lymphocyte CMV-CTL to restore immunity, we propose to study the immunologic and virologic effects of donor derived CMV-CTL given to transplant recipients, levels of CMV-CTL and CMV DNA will be measured from CTL recipients. 