Heterogeneity of alleles encoding high‐ and low‐prevalence red blood cell antigens across Africa: useful data to facilitate transfusion in African patients

Abstract

Summary Ethnic variations in red blood cell (RBC) antigens can be a source of alloimmunization, especially in migrant populations. To improve transfusion safety in continental Africa and countries with African migrants, we performed RBC genotyping to determine allele frequencies coding for high‐ and low‐prevalence antigens. A total of 481 blood samples were collected in ethnic groups from West, Central and East Africa. Molecular typing was performed using a polymerase chain reaction – reverse sequence specific oligonucleotide method. Results demonstrated no DI*1, DI*3, YT*2, SC*2, LW*7, KN*2 alleles in any sample and the CO*2 allele was rare. The frequency of LU*1 was comparable to that of European‐Caucasians (2%) except in Biaka pygmies (8%). The frequency of CROM*−1 was high in Mbuti pygmies (13%). High frequency of KN*7 and KN*6 may reflect selection pressure in the countries investigated. Analysis of Dombrock allele patterns confirmed uneven distribution of the DO*1 and DO*2 alleles with high frequencies of DO*−4 and DO*−5 in all groups. Altogether, findings demonstrated extensive allele‐frequency heterogeneity across Africa and suggested that knowledge of patient ethnicity gives information about the high‐prevalence antigens that may be lacking. These data are medically useful to support transfusion care of African migrants living in countries where the majority of the population is from a different ethnical background.

DO/ART4gene sequencing in sub‐Saharan cohorts and African migrants: useful data describing the diversity and spreading of rare variants

“…Our study confirmed the high frequencies of DO*JO and DO*HY alleles previously observed in people from Africa . DO*JO and DO*HY alleles were present in all of the cohorts tested, except that the DO*HY allele was absent from the South African Bantus and from the D.R.C.…”

“…Given the considerable variability in allele frequencies among African populations previously reported, we found that type DO*B alleles i.e., DO*B , DO*B‐WL , DO*B‐SH , and the other DO*B variants were slightly more common among African ethnic groups than in African migrant populations (mean frequency 0.743 vs. 0.719). In sub‐Saharan cohorts, DO*B allelic diversity seemed higher than in the three migrant populations.…”

“…For CEPH samples, gDNA was amplified using a whole genome amplification kit (WGA) as previously described …”

“…These populations are confronted with a lack of blood screening structures in Africa, while African migrant populations treated in Europe receive RBCs from European donors whose blood groups differ. Nevertheless, except a few reports describing genotyping of the four main Dombrock antigens (Do a , Do b , Hy, Jo a ), the scope of antigen frequency studies has been limited and other variant alleles have not been studied …”

Sequencing of the ART4 gene in sub‐Saharan cohorts reveals ethnic differences and two new DO alleles: DO*B‐Ile5Thr and DO*B‐Trp266Arg

“…S1). For CEPH DNA samples, whole genome amplification was performed and validated as previously described . While the Teke, Tswa, and San samples were used for ART4 sequencing experiments, the Ngala, Biaka, and Mbuti samples were screened for the presence of the DO*B‐SH‐Gln149Lys variant allele.…”