Yee MEM, et al. - This study strived to explore the red blood cell minor antigen mismatches during chronic transfusion therapy, for sickle cell anemia. Higher incidence of alloimmunization was found among those with prior RBC antibodies. Hence, past immunologic responders appeared to be at greater risk for future alloimmunization. In such cases, an advantage could be gained via more extensive antigen matching beyond C/c, E/e, K, Fy, and Jk.