Prevalence of RHD*DOLand RHCE*ce(818T)in two populations

The alleles RHCE*ceBI (RHCE*ce 48C, 712G, 818T, 1132G)and RHCE*ceSM (RHCE*ce 48C, 712G, 818T)encode the low-prevalence Rh antigen STEM. These alleles frequently travel in ciswith RHD*DOL.To estimate the frequency of these alleles, we tested a total of more than 700 samples in two populations. Blood samples were obtained from patients with sickle cell disease and from blood donors of African descent. DNA extractions and analyses were performed by standard methods. In the United States, none of 70 patient samples had the RHCE*818nucleotide change. Two of 220 donors (frequency of 0.009) were heterozygous for RHCE*818C/T (RHCE*ceBI).One of these samples had RHD/RHD*DOLand the other had RHD/RHD*DOL-2.In these 290 samples, no other RHD*DOLalleles were found. In Brazil, 1 of 244 patients with sickle cell disease (frequency of 0.004) and 1 of 171 donors (frequency of 0.006) were heterozygous for RHCE*818C/T (RHCE*ceBI).Testing of more than 500 additional samples from people of African descent, selected because they had a diverse range of common and variant RHCEalleles, did not reveal a sample with RHD*DOLor RHD/RHD*DOL-2in the absence of RHCE*ce(818T).Although the numbers are small, our study shows that in the United States, the frequency of RHCE*818Tis 0.007 (2 in 290 samples) and in Brazil it is 0.004 (2 in 515 samples). The four RHCE*818Talleles were RHCE*ceBI.Immunohematology2011;27:66–67.