Expanding diversity at the HLA-B locus: 28 novel HLA-B alleles

Increased HLA class I and II diversity as 72 novel alleles are identified in volunteers for the National Marrow Donor Program Registry in 2010

Seventy-two novel human leukocyte antigen (HLA) class I and class II alleles are described from volunteers for the 'Be The Match Registry®': 17 HLA-A alleles, 12 HLA-C alleles, 31 HLA-B alleles and 12 HLA-DRB1 alleles. Forty-six (≈ 64%) of the 72 novel alleles are single-nucleotide substitution variants when compared with their most homologous allele. Five of these single-nucleotide variants are silent substitutions and one creates a non-expressed allele (B*44:108N). The remaining novel alleles differ from their most similar allele by two to five nucleotide substitutions. One of the novel HLA-C alleles (C*07:150Q) is of questionable expression due to an insertion of 21 nucleotides starting at codon 143 that adds seven amino acids to exon 3. An inter-locus gene conversion may have created the novel allele HLA-A*23:31 that shares its codon differences with HLA-B*07:28. Some of the new alleles encode novel codons and unique amino acid changes at polymorphic positions in the HLA-A (codons 116 and 150), HLA-C (codon 114), HLA-B (codons 11, 21, 35, 42, 48, 73, 98 and 170) and HLA-DRB1 (codon 29) loci.

Four-locus high-resolution HLA typing in a sample of Mexican Americans

Mexicans are the most common minority population of the United States. From a sample of 553 bone marrow donor registrants of self-described Mexican ancestry, human leukocyte antigen (HLA) loci A, C, B and DRB1 were typed by high resolution sequence based typing (SBT) methods. A total of 47, 34, 76 and 46 distinct alleles at A, C, B and DRB1 respectively were identified, including 3 new alleles. The four-locus haplotype frequency distribution was extremely skewed with only 53.9% of 1106 chromosomes present with more than one estimated copy. Haplotypes of Native American origin were identified. These data form an initial basis for determining the requirements for an adequate donor pool for stem cell transplantation in this population.

Description of novel class I alleles encountered during routine registry typing in 2007

Twenty-six novel human leukocyte antigen (HLA) class I alleles are described: 3 HLA-A alleles, 19 HLA-B alleles and 4 HLA-C alleles. Only one of the novel alleles (HLA-B*0753) was found in multiple individuals and likely is not uncommon in the population. Nineteen (approximately 70%) of the 26 novel alleles are single nucleotide substitution variants when compared with their most homologous allele. Four of these single nucleotide variants are silent substitutions, and one creates a null allele. The remaining novel alleles differ from their most similar allele by two to six nucleotide substitutions. Some of the new alleles encode novel codons and unique amino acid changes at polymorphic positions in the HLA-B lows (codons 30, 67 and 72), while HLA-Cw*0347 encodes an amino acid change at a position not previously reported to be polymorphic for this locus.

Characterization of 104 novel alleles at the HLA-A, -B, and -DRB1 loci from National Marrow Donor Program volunteer donors

One hundred and four novel human leukocyte antigen (HLA) alleles are described from volunteer donors of the National Marrow Donor Program: 37 HLA-A alleles, 37 HLA-B alleles, and 30 HLA-DRB1 alleles. Seventeen ( approximately 16%) of the novel alleles were found in multiple individuals and likely are relatively common in the population. Seventy-two ( approximately 69%) of the 104 novel alleles are single nucleotide substitution variants when compared with their most homologous allele. Nine of these single nucleotide variants are silent substitutions and three create null alleles. The remaining novel alleles differ from their most similar allele by two to seven nucleotide substitutions. Some of the novel alleles encode amino acid changes at positions not previously reported to be polymorphic, such as codons 6 and 11 in HLA-A alleles and codons 5, 105, and 141 in HLA-B alleles. Interestingly, one of the novel HLA-DRB1 alleles (*1471) has a change that is not the typical glycine/valine dimorphism at codon 86, which plays a key role in peptide binding to DR molecules. This is only the second DRB1 allele described that encodes an amino acid other than glycine or valine at this position.

Characterization of new HLA-B and -DRB1 alleles from Singapore

Six novel alleles, three human leukocyte antigen (HLA)-B and three HLA-DRB1 alleles, are described. Five of the variants are single nucleotide substitutions from their most homologous allele, of which three result in amino acid changes (B*3572, *9509 and DRB1*1157) and two are silent substitutions (B*370103 and DRB1*150204). DRB1*0462 differs by three nucleotide substitutions that alter two amino acids.