Allosensitization in patients receiving multiple blood transfusions.

Extended antigen (C, E, K) matching decreased the incidence of alloantibody (alloAB) and autoantibody (autoAB) formation, in addition to eliminating transfusion reactions in the multiply transfused sickle cell disease patients. AlloAB formation possibly transforms the immune system into a hyperactive state leading to further and earlier alloAB and autoAB formation. However, additional CEK matching results in marked overuse of Rh-negative packed red blood cell (pRBC) units, 30 minutes' extra time of a skilled technologist, and 153 dollars extra CEK reagent cost per unit to find CEK-matched pRBCs for every transfusion for these multiply transfused patients.