Preventing transfusion-associated graft-versus-host disease: state of the art

The transfer of pathogens and the induction of immune responses are deleterious consequences that can result from the transfusion of blood products. Transfusion-associated graft-versus-host disease (TA-GVHD), the most severe immune consequence, occurs when recipient immune responses are incapable of effectively eliminating donor leukocytes, permitting unabated responses of the donor T lymphocytes. Currently, prevention of TA-GVHD is routinely accomplished by exposing blood products to γ-irradiation in order to prevent donor T cell proliferation. Alternative protocols are being developed to meet the challenges associated with the use of γ-irradiation. Use of pathogen reduction protocols, which interfere with nucleic acid replication by modifying nucleic acids, are increasing. Comparison of pathogen reduction protocols with γ-irradiation have found that both protocols are equally effective in preventing T lymphocyte proliferation and GVHD responses when testing in both in vitro and in vivo models. The potential use of pathogen reduction protocols to treat whole blood prior to separation into its components could provide a cost-effective method for preventing TA-GVHD in the future.