Transplant immunology
-
Almost all identified acute and/or severe immunological reactions towards blood transfusions, reported by surveillance systems such as SHOT (Severe Hazards of Transfusion) in the UK are mediated by allo-antibodies. In contrast, the clinical effects of transfusion-induced cellular immunity are virtually unknown. Although alterations in lymphocyte responses and natural killer cell functions after blood transfusion has been reported in many publications, the relevance of these in vitro assays for in vivo immunity are lacking. ⋯ Since the UK and France introduced a transfusion vigilance system, severe immunological side-effects such as haemolytic reactions, TRALI (acute lung injury), PTP (post-transfusion purpura) and graft vs. host disease are registrated in these countries and their incidence can be estimated based on the national number of transfusions. However, every blood transfusion interferes with the immune system of the recipient. The available evidence of harm from immune responses not leading to severe transfusion reactions will be discussed.