The r′ gene is overrepresented in hr^B-negative individuals

A screening program was implemented to identify hr^B– donors. D– C+, D–C–, and D+C– samples from African-American donors were typed with multiple examples of anti-hr^B and anti-hr^B-like, and one example each of anti-V and anti-VS. Of 75 D–C+ donors, 4 (5%) typed as hr^B–, and 14 others had weak or variable expression of hr^B. Of these 18 individuals, 15 were V–VS+, and 3 were V+VS+. No hr^B– sample was found in 90 C– donors, 26 of whom were V+VS+, and 1 was V–VS+. A review of our records of 44 hr^B– patients and donors studied earlier revealed that at least 12, and possibly as many as 30, carried r′ or r′^s. All hr^B– donors found in our screening program had D–C+VS+ RBCs, indicating an overrepresentation of r′. Our record review also showed that the presence of r′ and r′^s more often results in hr^B– RBCs, and that the most effective way to screen for hr^B– donors is to type African Americans who have D–C+ RBCs. Immunohematology 1995;11:74–77.