Characterization of the B*5002‐Cw*0602‐DRB1*0406‐DQB1*0402 Haplotype: impact on the unrelated‐bone marrow donor search strategy

Abstract

Improvements in HLA-typing by DNA-based methods now allow accurate genotyping of unrelated bone marrow (UBM) donors and recipients and also definition of haplotypes. In this regard, B*5002 has been predicted in linkage disequilibrium with Cw*0602, DRB1*0406 and DQB1*0402 based on the frequency of allele coexistence. Here, we confirm this assumption by HLA genotyping of four informative families and three unrelated individuals. In the four families, the extended haplotype HLA-B*5002, -Cw*0602, -DRB1*0406, DQB1*0402 can be definitely assigned by the mode of heritance. Furthermore, this association of alleles was also found in the three B*5002 unrelated individuals. Knowledge of the frequent linkage disequilibrium of these rare alleles can improve UBM donor search strategies.

Common genomic HLA haplotypes contributing to successful donor search in unrelated hematopoietic transplantation

“…23,24 However, these results have limitations in predicting the chance of finding matched-unrelated HSC donors because most haplotypes occur with different frequencies from those predicted by random distribution of their alleles. [25][26][27][28] There are very few data on genomic haplotype frequencies (frequent vs rare or unique). Furthermore, in most studies, haplotype segregation is based on a probability calculation and not by family studies.…”