Hematological Support in Patients Undergoing Allogenetic Bone Marrow Transplantation

Abstract

Bone marrow transplantation (BMT) is not possible without the substitution of blood cell components [1]. Cytostatic conditioning and total body irradiation (TBI) as the usual preparative regimen for BMT induces severe bone marrow aplasia lasting at least 2–4 weeks until marrow function takes place, as well as profound humoral and cellular immunosuppression. Under these circumstances transfusion of blood cells can be associated with several hazards. Clinical consequences of HLA-sensitization due to leukocyte contamination in random donor blood products include febrile transfusion reactions, random donor platelet transfusion refractoriness, and poor granulocyte increments after granulocyte transfusions. Because of possible sensitization for non-MHC-antigens, transfusions from close relatives should be strictly avoided prior to transplantation. Use of single random donors for platelet substitution [2] and leukocyte depletion of red blood cell (RBC) and platelet (PLI) concentrates [1] are important in patients when BMT is attempted. For patients with severe aplastic anemia, blood transfusion therapy should be restricted as much as possible since the survival of untransfused patients is significantly better [3]. In the post-transplantation period there is hardly a risk of alloimmunization owing to the profound immunosuppression. Major risks after BMT, however, include transmission of viral disease (Epstein-Barr virus, cytomegalovirus, and recently HIV), since these viruses can be latently present in the circulating leukocytes [4, 5, 6, 7]. Viral reactivation occurs as a consequence of the severe immunodeficiency state. These risks increase greatly when granulocyte transfusions are administered. Selection of seronegative blood donors, use of frozen RBC units, leukocyte depletion of RBC and PLT concentrates, and use of the marrow donor for PLT substitution are effective in reducing some of these hazards.