Polymorphisms within the HLA-DRw6 haplotype. I. Restriction fragment length variation and its correlation with serology.

The Dw6/DRw6 complex, one of the MHC class II specificities that can be defined by cellular techniques and by serology, probably has one or more immunoregulatory functions. To obtain information on the molecular structure of the DRw6 region, we studied several DRw6 homozygous cell lines, of which three were of consanguineous origin. DNA-DNA hybridization comprised the use of seven restriction enzymes in combination with three DR beta cDNA probes. The obtained results were compared with similar analyses of an HLA homozygous cell panel, expressing DR1-w8 specificities. This comparison indicated that in DRw6 homozygous individuals the coding potential for DR beta chains resembles closely that of all other DR specificities, thus identifying DRw6 as a regular DR region. In addition, we found a restriction fragment length pattern unique for DRw6, indicating the possibility to type for DRw6 by DNA-DNA hybridization. Comparisons within the DRw6 cell panel revealed the occurrence of several HLA class II DNA subtypes. These subdivisions partly correlated with serologically obtained reaction patterns. No correlation, however, could be observed between the different DNA subtypes and cellular reaction patterns as obtained by MLC and T cell cytotoxicity.