Cell membrane polymorphisms coded for in the HLA-D/DR region. I. Relation between D and DR.

The relation of HLA-D and -DR determinants was studied in Dutch Caucasoids. The recognition of subgroups of DR4, DR5, and DR7, and the specificities LB12 and LB13 are described. Phenotype and gene frequencies and a Hardy--Weinberg analysis of DR and local (LB) B-cell groups are given. Excellent correlation between D and DR typing was obtained when HTCs were studied by selected B-cell antisera. When the same sera were used to type a panel of D typed cells, the correlation was decreased (with the exception of DR3 and Dw3). In the case of discrepancies the DR specificity, but not the corresponding D specificity, always could be found and not the other way around. The data fit best the assumption that HLA-D and -DR are carried by the same molecule, although they might be different determinants on this molecule. A number of possible explanations for the observed discrepancies has been given.