title: High-resolution HLA typing for the DRB3/4/5 genes by sequence-based typing.
abstract: The high degree of polymorphism of the HLA genes at the nucleotide sequence level has proven sequence-based typing a major typing strategy. For DRB1 the allelic variability is predominantly present in the second exon and by DNA sequencing of exon 2 all hitherto known DRB1 alleles can be detected. For the associated genes DRB3, DRB4 and DRB5 the situation is slightly different. Allelic differences are not limited to exon 2 and the sequence of exon 3 and sometimes exon 4 is needed for complete subtyping. Oligonucleotides to amplify the exons needed for subtyping of DRB3, DRB4 and DRB5 were designed. Gene-specific products were generated to make simultaneous detection of alleles in heterozygous combinations possible. In this way 238 individuals were fully typed for their DRB3, 4 and 5 subtypes. Additional samples were typed for only one of the genes. All samples had been previously typed by PCR-SSP. Concordant typing results were obtained for all individuals tested. The DRB3 alleles typed for included *0101, *0201, *0202 and *0301, for DRB4 they were *01011, *0102 and *0103 and for DRB5 *0101, *0102, *0103, *0105, *0201, *0202 and *0203. All alleles were easily detected by the protocol described except for DRB5*0201. Sequencing of exon 3 and 4 of the DRB5*0201 allele showed this allele to be a sequencing error and the sequences obtained were identical to the exon 2, 3 and 4 sequences of DRB5*0202. Two new alleles were identified in the samples studied, DRB4*0105 and DRB3*0207. Sequence based typing has been recognized as a valuable tool for HLA typing of DRB1, DQB1 and DPB1 since several years. It is shown to be a superior typing method as well in the detection of the different DRB3, 4 and 5 subtypes.
authors.affiliation: Tissue Typing Laboratory, University Hospital, Maastricht, The Netherlands.
authors.forename: C E
authors.initials: CE
authors.lastname: Voorter
authors.forename: D
authors.initials: D
authors.lastname: de Bruyn-Geraets
authors.forename: E M
authors.initials: EM
authors.lastname: van den Berg-Loonen
mesh_terms: D000483:Alleles; D001483:Base Sequence; D006684:HLA-DR Antigens / Q000235:genetics*; D059826:HLA-DRB3 Chains; D059845:HLA-DRB4 Chains; D059847:HLA-DRB5 Chains; D006650:Histocompatibility Testing / Q000379:methods*; D006801:Humans; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D006684:HLA-DR Antigens; D059826:HLA-DRB3 Chains; D059845:HLA-DRB4 Chains; D059847:HLA-DRB5 Chains