Transfusion-associated graft-versus-host disease and its prevention

Transfusion-associated graft-versus-host disease is a rare but usually fatal complication of transfusion of cellular blood components, caused by multiorgan engraftment and proliferation of donor T lymphocytes. The classical features of skin rash, diarrhoea and hepatitis, along with striking bone-marrow failure, are seen 1–2 weeks after transfusion. Although early reports described the condition only in immunusuppressed individuals, sharing of an HLA haplotype between donor and an immunocompetent recipient can also result in transfusion-associated graft-versus-host disease. The condition is entirely preventable by gamma irradiation of cellular blood components to 25 Gy, although this results in some reduction of red-cell viability and increased loss of red-cell potassium. The major indications for irradiated blood components include bone marrow/stem cell auto- or allografting, Hodgkinʹs disease, intrauterine transfusions, and transfusions from relatives or HLA-selected platelet donors.