Molecular background of RH in Bastiaan, the RH:-31,-34 index case, and two novel RHD alleles

Anti-hr(B) (-RH31) and anti-Hr(B) (-RH34) were found nearly 40 years ago in the serum of a South African woman. The anti-hr(B) was revealed after adsorption with DcE/DcE red blod cells (RCBs). Numerous anti-hr(B), in the absence of anti-Hr(B), have since been identified. We obtained a sample of blood from this index case (Bastiaan) and report the molecular basis of her D+C-E-c+e+/-, V-VS+Hr+hr(S)+hr(B)-Hr(B)- phenotype as well as results of testing her RBCs using currently available regents. We tested a cohort of African Americans to estimate the frequency of the RHCE*ce 48C,733G,1006T allele, and in addition found two novel RHD alleles. Hemagglutination tests and DNA analyses were performed by standard methods. Analyses revealed homozygosity for RHCE*ce 48C,733G,1006T in Bastiaan. RBCs from Bastiaan were strongly agglutinated by three commercial anti-e reagents. Testing RBCs from people homozygous for RHCE*ce 48C,733G,1006T showed that anti-e MS16, MS17, and MS63 were weakly reactive or non reactive, MS21 was strongly reactive, and HIRO38, HIRO41, and HIRO43 were non reactive. Results show that Bastiaan has RHD*DIIIa150C and RHD*DIIIa-CE(4-7)-D. Tests on 605 samples from random African Americans revealed a frequency of 0.036 for RHCE*ce 48C,733G,1006T and revealed two novel alleles: RHD*186T and RHD*DIIIa150C. The Bastiaan phenotype is encoded by RHD*DIIIa150C-RHCE*ce 48C,733G,1006T and RHD*DIIIa-CE(4-7)-D-RHCE*ce 48C,733G,1006T ; thus, this genotype is the gold standard for the hr(B)-Hr(B)-phenotype. The r'(s) complex encodes VS, which explains why most hr(B)-RCBs are VS+.