Minor Blood Group Antigen Disparities in Sickle Cell Disease Population

Red blood cell (RBCs) transfusion is the mainstay of treatment for sickle cell disease (SCD) patients and indications continue to expand. Differences in geographic origin between blood donors and sickle recipients has been posited as a cause of the high rate of alloantibodies in patients with sickle cell disease (Vichinsky et al. NEJM 1990; 322: 1617–21). Alloimmunization is one of the major limiting factors of obtaining compatible blood for transfusion and exchange transfusion compromising the management of patients with SCD. Mismatch in minor antigen distribution has been attributed as one of the main reasons for significantly high rate of alloantibodies in SCD patients. Here we describe the minor blood group antigen lacking in SCD patients and comparing with frequencies in white and black populations.

Patients with diagnoses of SCD, confirmed by standard hemoglobin electrophoresis, who had at least one type and cross match done from 1995 through 2011 were included in this study. All patients are evaluated for K, C, E, S, Fya, Fyb, Jka and Jkb antigens in addition to ABO and RhD system before transfusion. Results were routinely recorded in the electronic database of the Georgia Comprehensive Sickle Cell Program at Grady Health System to improve patient transfusion management. The frequency of antigens was compared to published prevalence of antigens in Whites and African American population.

A total of 594 patients were identified with SCD who have been tested for antigens during this period, of these, 310 (52%) females and 284 (48%) males. Average age of the patients is 27 (range 3–84). Most common antigen lacking in SCD patients is from Kell blood group K (98%). About 9% of white population is positive for K. Frequency of E+ is 30% in white population and 2% in blacks while 83% of SCD patients lack E antigen. Overall antigen distribution and comparison included in Table 1.

Mismatch of antigen expression in white population (mainly donors) especially for K, E, C and Fya; may explain why these are common antibodies detected in SCD patients Anti E (42.3%), Anti C (30.2%), Anti K (28.1%) and Anti Fya (18.3%) (Rosse et al, Blood, Vol 76, No 7). Given these antigen frequency differences, efforts should be made to increase blood donation in the African American population and at least limited phenotypic matching continues to be justified.

No relevant conflicts of interest to declare.