Red blood cell transfusion remains a critical therapy for patients with sickle cell disease (SCD). A major problem is the high rate of alloimmunization (antibody formation against transfused red cells) that occurs in patients with SCD. Recent studies performed by Investigators and others demonstrate RH genetic variants in patients and donors is a major risk factor leading to Rh alloimmunization. Anti-D formation in D+ patients occurs frequently, and once identified, providing D- cells for all subsequent transfusions can be challenging. These anti-D antibodies in D+ patients suggest exposure to different or variant D protein on donor cells. Investigators will test whether transfusion of patients with anti-D with RHD genotyped matched red cells is feasible, safe and can decrease D- donor unit demand.