Patients with sickle cell disease (SCD) often require chronic red blood cell exchanges. The American Society for Hematology recommends matching for ABO, Rh (C, E, C/c, E/e) and K antigens for patients with SCD. Nevertheless, many of these patients develop alloantibodies, necessitating hundreds or even thousands of Rh-negative RBC units over their lifetimes. Anti-D alloantibodies may develop in D+ patients…