High resolution sequence-based DPB1 typing identified two novel DPB1 alleles,DPB1*9401 and DPB1*9501, from a Kenyan population

Two novel DPB1 alleles, DPB1*9401 and DPB1*9501, were identified from a Kenyan population during sequence-based HLA-DPB1 typing. Molecular cloning and sequencing of multiple clones confirmed that one of the new DPB1 alleles is identical to DPB1*0402 at exon 2 except for a single nucleotide substitution (CGG -->TGG), changing codon 70 from Arg to Trp. The new allele has been named DPB1*9401. This is the first report of polymorphism at codon 70 of HLA-DPB1 alleles. New codon combinations have been identified in another novel DPB1 allele named DPB1*9501. The extensive diversity at DPB1 locus of this East African population is being revealed by high resolution sequence-based DPB1 typing.     

Two new HLA DPB1 alleles identified by sequence-based typing: DPB1*8201 and DPB1*8301

Two new HLA DPB1 alleles were identified by sequence-based typing and are reported. Both alleles differ from DPB1*0402 by a single nucleotide: DPB1*8201 has a difference at position 359 (codon 91) leading to an amino acid change from arg to his, making this position a new polymorphic site; DPB1*8301 has a difference at position 280 (codon 65) changing the amino acid from ile to phe.     

DPB1*7601, a novel DPB1 variant in the Caucasoid population

Abstract: A new DPB1 allele has been identified in a Caucasoid individual, DPB1*7601. The sequence of the complete second exon has been confirmed by cloning and subsequent sequencing. This allele differs by one amino acid, at codon 36, from DPB1*1401, as indicated by SBT and PCR-SSP analysis. The amino-acid motif introduced by the change is shared by DPB1*0401 and some rare alleles. It remains unclear whether the change is due to interallelic microgen conversion or a single point mutation.     

DPB1*8501, a novel DPB1 variant in the US Black population

We describe a new DPB1 allele, DPB1*8501, which was identified by sequencing-based typing (SBT) in the UCLA exchange. DPB1*8501 is similar to DPB1*2701 with a difference at position 272, (G to A). This difference leads to an amino-acid change of codon 91 from arginine (CGC) to histidine (CAC). Until now this position has been considered conserved. This substitution is located at the 3' site of exon 2, and may interfere with typing strategies using primers or probes located in this region.     

DPB1*8601, a previously unrecognized DPB1 variant in the Caucasoid population

A new, previously unrecognized DPB1* allele, DPB1*8601, was found in a Swedish family. The new allele was carried on the common North European haplotype HLA A1-B8-DR3. Both individuals carrying the new allele were initially typed as clear DPB1*4601,*6601 but after family studies and further typing with allele-specific primers it was concluded that a new allele was present together with the common DPB1*0401. The new allele was investigated by direct sequencing of exon 2 in both forward and reverse directions employing intron primers combined with either an allele-specific sense or anti-sense biotinylated primer for bi-directional sequencing. The new allele is identical to DPB1*1701 in the five first variable regions. In the sixth region, however, DPB1*8601 carries the GGPM motif shared by several common alleles such as DPB1*0201 and 0401and 0402.     

Identification of DPB1 Permissive Unrelated Donors Is Highly Likely

HLA-DPB1 permissive matching based on T cell epitope (TCE) groups should be considered when selecting among equally matched HLA-A, -B, -C, -DRB1 unrelated hematopoietic stem cell donors to improve patient survival. Previous studies have defined 3 TCE groups based on functional assays of alloreactivity. Combinations of donor and recipient DPB1 alleles with low immunogenic potential identify permissive donors, who provide no increased risk of mortality compared with DPB1–matched donors. To determine the likelihood of identifying a DPB1 permissive–matched (includes both allele-matched and DPB1-permissive mismatched) unrelated donor for patients with high-resolution matches at 10/10 HLA-A, -B,- C, -DRB1, and -DQB1 in the Be The Match Registry, preliminary search requests from United States' transplant centers for 595 DPB1-typed patients were evaluated for existence of a DPB1 permissive–matched donor, identified either among already typed donors or by prospective DPB1 typing. The baseline DPB1 permissive match rate was 69% and improved to 80% after additional donor DPB1 typing (median, 4 donors per patient). When seeking a 10/10-matched, young (18- to 32-year-old) donor in the registry, the probability of finding a DPB1 permissive–matched donor started lower at 59% and improved to 70% after additional DPB1 testing. Our results show that most patients with a 10/10 match can find a DPB1 permissive–matched donor.     

In a study for acne vulgaris, sequence-based HLA typing showed a novel DPB1 allele, DPB1*2402

In this paper, we characterize the novel human leucocyte antigen (HLA)-DPB1*2402 allele that we found in a patient suffering from acne vulgaris. In comparison to the closest related allele DPB1*0401, HLA-DPB1*2402 has a single nucleotide exchange at position 115 (202), T replaces G. In consequence, codon 39 (68) TAC encodes for tyrosine in the novel allele instead of aspartic acid 39 (68) GAC in DPB1*0401. In November 2008, the DNA samples of a cohort of patients who were afflicted with acne vulgaris were sent to our laboratory for human leucocyte antigen (HLA) high-resolution typing. This happens in course of a study of HLA pattern in respect to the disease. In one of these samples, a male patient of German Caucasoid origin (laboratory code 191849), we showed a novel DPB1 allele.     

Identification of a novel HLA-DPB1 allele, DPB1*9701, by sequence-based typing

This report describes the identification of a novel DPB1 allele, DPB *9701, found in an Italian Caucasian individual. The new allele was detected by human leukocyte antigen sequence-based typing carried out to investigate the role of genetic factors in determining the outcome of hepatitis C virus infection. DPB1*9701 was identical to DPB1*0501 except for a single-nucleotide substitution at codon 43 (GGG --> TGG). This nucleotide change is a non-synonymous mutation and results in the amino acid substitution glycine (G) --> tryptophan (W). The nucleotide sequence has been deposited in GenBank under the accession number AY033075, and denominated DPB1*9701 by the official World Health Organization Nomenclature Committee.