HLA-DPB1 typing with polymerase chain reaction and restriction fragment length polymorphism technique in Danes

We have used the polymerase chain reaction (PCR) in combination with the restriction fragment length polymorphism (RFLP) technique for HLA-DBP1 typing. After PCR amplification of the polymorphic second exon of the HLA-DPB1 locus, the PCR product was digested with seven allele-specific restriction endonucleases: RsaI, FokI, ApaI, SacI, BstUI, EcoNI, and DdeI, and the DNA fragments were separated by electrophoresis in agarose gels. Altogether, 71 individuals were investigated and 16 different HLA-DPB1 types were observed in 26 different heterozygotic combinations, as well as five possible homozygotes. Four heterozygotes could not be unequivocally typed with the PCR-RFLP method. The HLA-DPB1 typing results obtained with the PCR-RFLP method were compared with the typing results obtained with PCR allele-specific oligonucleotides (PCR-ASO) in 50 individuals. The results obtained with the two methods were concordant in 84% of the cases. One of the HLA-DPB1 types was discrepant in six heterozygotes, both HLA-DPB1 types were discrepant in one heterozygote, and in one individual two HLA-DPB1 types were identified with the PCR-RFLP technique while only one HLA-DPB1 type could be demonstrated with the PCR-ASO technique. The frequencies of the HLA-DPB1 genotypes deduced from the results of PCR-RFLP typing were estimated in 71 healthy Danes.