HLA-DR beta gene DNA polymorphisms revealed by Taq I correlate with HLA-DR specificities

Human genomic DNA digested with restriction endonuclease Taq I was hybridized with cDNA probes for DR beta and DQ beta, for correlation of restriction fragment length polymorphisms with HLA-DR specificities. DR beta Taq I RFLPs were distinctive for DR serological types 1 to w9, with the exception of DR3 and w6, and were markedly consistent within DR specificity. Some common variants in RFLPs did emerge within serological type; DR3, e.g., was associated with two different fragment patterns, one of which occurred on the A1.B8.DR3 haplotype and was linked with a DR alpha Bgl II variant, and the other on the B18.DR3 haplotype. In the Pacific specimens examined, RFLPs were, with few exceptions, similar to those seen in Caucasoids sharing the same DR specificity. This study indicates that genomic hybridization is a useful adjunct to serological and cellular class II typing and should be particularly informative in identifying new HLA-DR alleles in populations serologically less well-defined than Caucasoids.