A simple, practical model for reducing alloimmunization in patients with sickle cell disease.

Patients with sickle cell disease (SCD) form immune alloantibodies more frequently than other transfused populations because red cells (RBCs) from white donors (with a higher incidence of certain Rh, Duffy, Kell, and Kidd blood group antigens) are transfused to black patients often lacking these antigens. We propose a model to reduce alloimmunization in patients with SCD by providing them with blood from only black random donors. Rationale is shown by examining calculations based on the phenotype E-, C-, Fy(a-), K-, and Jk(b-). There is a 7% probability that this phenotype belongs to a white donor, while there is a 93% probability that this phenotype belongs to a black donor. The probability of selecting blood from a black donor identical with the above phenotype for black recipients from an all black population and from a typical urban blood inventory population (90% white, 10% black) is 1/4 and 1/33, respectively. Therefore, an 8-fold greater chance of selecting antigen non-identical blood occurs if blood is obtained from a typical urban donor population as compared to a black population. Based on these calculations, alloimmunization can be reduced prospectively in patients with SCD by meeting their transfusion requirements with blood selected from random black blood donors.