Discovery of a novel HLA-B*51 variant, B*51:112, in a Taiwanese bone marrow donor and identification of the plausible HLA haplotype in association with B*51:112

HLA-A*29:01-B*07:05-C*15:29*DRB1*10:01-DQB1*05:01, a deduced probable human leukocyte antigen haplotype in association with a human leukocyte antigen-C low-incidence allele C*15:29 in Taiwanese individuals

Objective:

HLA-C*15:29 is a low-frequency allele in the human leukocyte antigen (HLA)-C locus. The aim of this study is to confirm the ethnicity of C*15:29 and to deduce a probable HLA haplotype in association with C*15:29 in Taiwanese population.

Materials and Methods:

A total of 12,534 healthy unrelated Taiwanese individuals were tested for HLA using a sequence-based typing method. The DNA material was subjected to HLA genotyping for the HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1 loci using a commercial polymerase chain reaction–sequencing-based typing kit as per the manufacturer's protocols.

Results:

The DNA sequence of C*15:29 is identical to C*15:02:01:01 in exons 1, 2, 3, 4, 5, and 6 except for residues 420 and 1034 where A and G of C*15:02:01:01 are substituted by C and A in C*15:29, respectively. The nucleotide substitutions introduce two amino acid replacements at residues 116 and 321 where leucine (L) and cysteine (C) of C*15:02:01:01 are replaced by phenylalanine (F) and tyrosine (Y) in C*15:29, respectively. A probable HLA haplotype associated with C*15:29 in Taiwanese was deduced as A*29:01-B*07:05-C*15:29-DRB1*10:01-DQB1*05:01. The frequency of C*15:29 is estimated at about 0.064%.

Conclusion:

Information on the ethnicity and distribution of C*15:29 and its deduced probable HLA haplotype is of value for HLA testing laboratories for reference purposes and can help bone marrow donor registries find compatible donors for patients with this uncommon HLA allele.

Human leukocyte antigen-A*33:03-B*58:01-DRB1*15:140, a deduced probable human leukocyte antigen haplotype in association with a human leukocyte antigen low-incidence allele DRB1*15:140 in Taiwanese individuals: A case analysis

Objective:

Human leukocyte antigen (HLA)-DRB1*15:140 is a low-frequency allele in the HLA-DRB1 locus. The aim of this study is to confirm the ethnicity of DRB1*15:140 and to deduce a probable HLA-DRB1*15:140-associated HLA haplotype in Taiwanese individuals.

Materials and Methods:

A total of 1815 healthy unrelated Taiwanese individuals and 14,562 unrelated mainland Chinese individuals were tested for HLA using a sequence-based typing method. Polymerase chain reaction was performed to amplify exons 2 and 3 of the HLA-A and HLA-B loci and exons 1 and 2 of the HLA-DRB1 locus using group-specific primer sets. The amplicons were sequenced in both directions with the BigDye Terminator Cycle Sequencing Ready Reaction Kit according to the manufacturer's protocols.

Results:

The DNA sequence of HLA-DRB1*15:140 is identical to DRB1*15:02:01:01 in exons 1 and 2, except at residue 91 of DRB1*15:02:01:01 where a G in DRB1*15:02:01:01 is replaced by an A in DRB1*15:140 (codon 2; GAC->AAC). The nucleotide substitution in exon 1 introduces a one amino acid substitution at residue 2 where an aspartic acid (D) in DRB1*15:02:01:01 is replaced by an asparagine (N) in DRB1*15:140. We deduced the probable HLA haplotype associated with DRB1*15:140 in Taiwanese to be HLA-A*33:03-B*58:01-DRB1*15:140.

Conclusion:

Information on the ethnicity and distribution of DRB1*15:140 and its deduced probable HLA haplotype in association with the low-incidence allele is of value for HLA-testing laboratories for reference purposes and can help bone marrow donor registries find compatible donors for patients with this uncommon HLA allele.

Human leukocyte antigen-A*24:02-B*40:247-C*03:04-DRB1*16:02, a deduced probable human leukocyte antigen haplotype associated with a low-incidence human leukocyte antigen allele B*40:247 in Taiwanese individuals: A case analysis

Objective

HLA-B*40:247 is a low incidence allele in the HLA-B locus. The aim of this study is to confirm the ethnicity of B*40:247 and its deduced probable HLA- associated haplotype in Taiwanese individuals.

Materials and Methods

A total of 2,329 unrelated Taiwanese individuals and 66,212 unrelated mainland Chinese individuals were tested for HLA using a sequence-based typing method. We confirmed the low incidence allele B*40:247 in Taiwanese. Polymerase chain reaction was performed to amplify exons 2, 3 and 4 of the HLA-A and HLA-B loci and exon 2 of the HLA-DRB1 locus using group-specific primer sets. The amplicons were sequenced in both directions with the *BigDye Terminator Cycle Sequencing Ready Reaction Kit according to the manufacturer's protocols.

Results

The DNA sequence of B*40:247 is identical to B*40:01:01 in exons 2, 3 and 4 except for residue 853, where G of B*40:01:01 is changed to A in B*40:247 (codon 261, GTA->ATA). The nucleotide replacement causes a one amino acid change at codon 261 where V (valine) of B*40:01:01 is replaced by I (isoleucine) in B*40:247. We deduced the probable HLA haplotype associated with B*40:247 in Taiwanese to be HLA-A*24:02-B*40:247-C*03:04-DRB1*16:02.

Conclusion

Information on the ethnicity and distribution of B*40:247 and its deduced probable HLA haplotype in association with the low incidence allele is of value for HLA testing laboratories for reference purposes and can help bone marrow donor registries find compatible donors for patients with this uncommon HLA allele.

Deduced probable HLA-C*07:359-associated human leukocyte antigen haplotypes found by case analysis of Taiwanese unrelated bone marrow hematopoietic stem cell donors

Objectives:

HLA-C*07:359 is a low-incidence allele in the human leukocyte antigen (HLA)-C locus. The objective of this study is to report the ethnicity and haplotypes of HLA-C*07:359 that were found during an analysis of Taiwanese unrelated bone marrow hematopoietic stem cell donors.

Materials and methods:

A sequence-based typing method was employed to confirm low-incidence al-leles. Polymerase chain reaction was performed to amplify exon 2 and exon 3 of the HLA-A, HLA-B, and HLA-C loci, as well as exon 2 of the HLA-DRB1 locus, using group-specific primer sets. The amplicons were sequenced in both directions using BigDye Terminator Cycle Sequencing Ready Reaction kits, according to the manufacturer's protocols. The potential unrelated bone marrow stem cell donors investigated here are individuals with Taiwanese ethnicity who are participating in the Tzu Chi Bone Marrow Donor Registry.

Results:

The DNA sequence of C*07:359 is identical to that of C*07:02:01:01 in exons 2, 3, and 4 except at residue 862, where the G of C*07:02:01:01 is substituted by the A of C*07:359. The nucleotide exchange leads to an amino acid replacement at codon 264, where the glutamic acid of C*07:02:01:01 is replaced by the lysine of C*07:359. We deduced a probable HLA-B and HLA-C haplotype that is associated with C*07:359 in Taiwanese, namely B*39-C*07:359.

Conclusion:

Information on the ethnicity of the C*07:359 allele and its deduced probable HLA haplotypes that are associated with the low-incidence C*07:359 allele reported here are of value to HLA testing laboratories for reference purposes. In addition, they can be used by stem cell transplantation donor search coordinators to determine a strategy for finding compatible donors using unrelated bone marrow donor registries when patients carry this uncommon HLA allele.

A deduced probable HLA-DRB1*16:35-associated HLA haplotype (A*11-B*13-DRB1*16:35) found in a case analysis of two Taiwanese unrelated bone marrow hematopoietic stem cell donors

Objective:

HLA-DRB1*16:35 is a low incidence allele in the HLA-DRB1 locus. The objective of this study is to report the ethnicity of DRB1*16:35 and its deduced probable HLA associated haplotype in two Taiwanese unrelated bone marrow hematopoietic stem cell donors and to determine its variation from DRB1*16:02:01 and DRB1*16:01:01.

Materials and Methods:

A sequence-based typing method was employed to confirm the low incidence allele DRB1*16:35. Polymerase chain reaction was performed to amplify exon 2 and exon 3 of the HLA-A and HLA-B loci and exon 2 of the HLA-DRB1 locus using group-specific primer sets. The amplicons were sequenced employing BigDye Terminator Cycle Sequencing Ready Reaction kits in both directions according to the manufacturer's protocols.

Results:

The DNA sequence of DRB1*16:35 is identical to DRB1*16:02:01 in exons 2, except for residue 364 where the C of DRB1*16:02:01 is replaced by the T of DRB1*16:35 (codon 93, CGG->TGG). The nucleotide exchange leads to an amino acid alteration to the protein sequence of DRB1*16:02:01 at residue 93 where the arginine (R) of DRB1*16:02:01 is changed to the tryptophan (W) of DRB1*16:35. We deduced the probable HLA haplotype in association with DRB1*16:35 in Taiwanese to be A*11-B*13- DRB1*16:35.

Conclusion:

Information on the deduced probable HLA haplotype in association with the low incidence DRB1*16:35 allele that we report here is of value for HLA testing laboratories for reference purposes. In addition, it can be used by stem cell transplantation donor search coordinators to determine a strategy for finding compatible donors in unrelated bone marrow donor registries when a patient has this uncommon HLA allele.