Frequency of HLA-DPB1 alleles, including a novel DPB1 sequence, in the Northern Ireland population

HLA-DPB1 allele frequencies in 150 unrelated normal individuals from Northern Ireland were determined using oligonucleotide typing methods. HLA-DPB1^*0401 was the most common allele in the population possessed by 75.3% of subjects, followed by DPB1^*0201 (20.7%). In addition to these alleles, only HLA-DPB1^*0402, -DPB1^*0301, and -DPB1^*0501 were present in subjects at frequencies greater than 10%. The results in this study are in broad agreement with other Caucasoid studies, but there is regional and ethnic variation in HLA-DP allele frequencies. Three DPB1 alleles were found to be in linkage disequilibrium with HLA-DR antigens determined by RFLP, namely, DPB1^*0101 with DRw17 (Dw24 associated) REFLP, DPB1^*0501 with DRw13-Dw19 RFLP, and DPB1^*1901 with DRw13-Dw18 (Dw25 associated) RFLP. One individual revealed a novel DPB1 pattern of probe reactivity, which following DNA sequencing was found to be HLA-DPB1^*2001. To assess the system used and to compare consistency of results between laboratories, 62 cell lines were oligotyped for HLA-DP. The results revealed the system described here to be extremely accurate and showed excellent aggreement of HLA-DP typing results for cell lines between laboratories.