The HLA-D system: at least two loci and four distinct phenotypic traits per haplotype. Introduction to component typing in families and population by primed lymphocyte typing.
Using a number of intrafamilial PLTs raised against identical HLA haplotypes it has been possible to construct a model in an informative family defining the HLA-D region as a genetic system. This system consists of at least two regions separated by a recombination between HLA-D and GLO. In relation to the site of recombination, a minimum of one centromeric and three telomeric components can be identified per haplotype. - Fourteen PLTs raised and defined within the family were subsequently tested in a Caucasian population (n = 84) and in 13 unrelated, complete families. - It is concluded that the hypothetical model proposed for the HLA-D regions as a genetic system of linked loci, coding at the cell surface for associated but distinct components (at least four per haplotype), allows for typing of the components of the HLA-D system of any given haplotype. Serological typing of HLA-D components should, in the near future, provide a more convenient way of establishing component phenotypes than the present use of primed lymphocyte typing reagents. Among the components isolated, some have a high association with the classic alleles defined either by homozygous typing cells or DR serology. Others form the basis of cross-reactivity but their presence does not interfere with standard typing. Others, however, seem by their mere presence to be responsible for false assignments. - The concept of HLA-D as a genetic system clarifies many of the inconsistencies observed with a one-locus system.
D002874:Chromosome Mapping; D005190:Family; D005260:Female; D006238:Haploidy; D000949:Histocompatibility Antigens Class II; D006650:Histocompatibility Testing; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D010641:Phenotype; D011153:Population
D000949:Histocompatibility Antigens Class II