Identification of a novel DPB1* allele (DPB1*6901) and the occurrence of HLA haplotypes that extend to DPB1.

The sequence of a novel DPB1 allele, DPB1*6901, observed in a Caucasian bone marrow donor phenotype HLA A2; Cw*0501,*1601; B*4402, *4403; DRB1*0401; *07; DQB1*02; *0301; DPB1*0401; *6901, is described. The sequence is consistent with that previously described for DPB1*0601 with the exception of codon 69. The sequence at this codon is consistent with that previously observed only in the DPB1*1101 and *1501 alleles. It is suggested that DPB1*6901 may have arisen as a result of a recombination event occurring between codons 58 and 64 between DPB1*0601 and DPB1*1101. The sequence of DPB1*1501 from codon 64 is not consistent with DPB1*6901. A linkage disequilibria analysis that examined 212 potential bone marrow recipients in which HLA-A to DQ haplotypes had been established by family studies showed linkage disequilibrium between HLA-B, DRB1 and DPB1 in some haplotypes and not others.