TRANSFUSION-ASSOCIATED GRAFT-VERSUS-HOST DISEASE AND THE IRRADIATION OF BLOOD COMPONENTS

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare b ut lethal disorder caused when viable donor lymphocytes engraft and pr oliferate in a susceptible transfusion recipient, Patients with immune deficiency disorders, hematologic malignancies and bone marrow transp lants are at risk to TA-GVHD, as are premature newborns and transfusio n recipients who are HLA heterozygous for an HLA-haplotype that is sha red with an HLA homozygous donor. Irradiation of blood components with 2500 cGy will inactivate donor lymphocytes and prevent TA-GVHD. Plate lets and granulocytes are not functionally impaired by this radiation dose, but red cells sustain detectible damage. Red cell units irradiat ed and stored for 42 days have significantly higher supernatant recove ry of chromium-51 labeled cells is sub-optimal. Based on these data, t he maximum permissible storage time for irradiated red cells has been reduced to 28 days.