Abstract
DNAs extracted from peripheral blood leukocytes of 24 individuals, selected for their HLA-DR types, -DR2, -DR5, and -DRw6, were analyzed with four restriction enzymes, BamHI, EcoRV, HindIII, and Taq I, using the Southern technique. This panel includes 16 individuals with homozygous typing cells and 8 heterozygous individuals who carry rare Dw subtypes or unusual DR-DQ associations. Eighty-five polymorphic fragments were detected and assigned to the DR or DQ gene families according to their hybridization signals. Thirty-eight fragments (DR or DQ) were found to correlate with single DR or Dw specificities or rare associations such as DRw14-DQw3. Forty-two fragments correlated with the association of immunologically defined specificities. In total, these 85 fragments constituted 44 different patterns, each comprising 1-9 fragments. For each homozygous typing cell a combination of patterns was observed. Fourteen different combinations of 10-20 patterns were found among the 16 individuals with homozygous typing cells, showing that Dw18, Dw19, Dw9, and Dw5 are heterogeneous at the genomic level whereas only the Dw2 individuals tested here are identical.