Bone Marrow Donor Registry Research Articles

Two deduced probable HLA-A*24:287-associated HLA haplotypes (A*24:287-B*40-DRB1*15 and A*24:287-B*58-DRB1*03:01) found in Taiwanese unrelated hematopoietic bone marrow stem cell donors-case analysis

ObjectiveHLA-A*24:287 is a low incidence allele in the HLA-A locus. The objective of this study is to report the ethnicity of A*24:287 and its deduced probable human leukocyte antigen (HLA)-associated haplotypes in Taiwanese unrelated bone marrow hematopoietic stem cell donors. Materials and methodsA sequence-based typing method was employed to confirm the low incidence allele A*24:287. 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. ResultsThe DNA sequence of A*24:287 is identical to A*24:02:01:01 in exons 2 and 3, except for residue 617 where C is changed to G (codon 182, ACG->AGG). The nucleotide exchange leads to an amino acid alteration to the protein sequence of A*24:02:01:01 at residue 182 where the threonine of A*24:02:01:01 is changed to the arginine of A*24:287. We deduced the probable HLA haplotypes in association with A*24:287 in Taiwanese to be A*24:287-B*40-DRB1*15 and A*24:287-B*58-DRB1*03:01. ConclusionInformation on the deduced probable HLA haplotypes in association with the low incidence A*24:287 allele that we report here are of value for 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 in unrelated bone marrow donor registries when a patient has this uncommon HLA allele.

HLA-A*33-B*58:45-DRB1*03, a deduced probable human leukocyte antigen haplotype associated with a human leukocyte antigen low-incidence allele B*58:45 in Taiwanese unrelated hematopoietic bone marrow stem cell donors

ObjectiveHLA-B*58:45 is a low-incidence allele in the human leukocyte antigen-B (HLA) locus. The aim of this study is to confirm the ethnicity of B*58:45 and its deduced probable HLA-associated haplotype in Taiwanese unrelated bone marrow hematopoietic stem cell donors. Materials and methodsA total of 40,000 healthy unrelated volunteer bone marrow stem cell donors (aged, 20–45 years) were tested using a sequence-based typing method. We confirmed the low-incidence allele B*58:45 in Taiwanese donors. 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 in both directions with the BigDye Terminator Cycle Sequencing Ready Reaction Kit according to the manufacturer's protocols. ResultsThe DNA sequence of B*58:45 is identical to B*58:01:01 in exon 2 and exon 3 except for residue 595, where G is changed to A (codon 175, GGG→AGG). The nucleotide replacement causes an amino acid change at codon 175 where G (glycine) of B*58:01:01 is replaced by R (arginine). We deduced the probable HLA haplotype associated with B*58:45 in Taiwanese donors to be A*33-B*58:45-DRB1*03. ConclusionInformation on this deduced probable HLA haplotype in association with the low-incidence B*58:45 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-B*40:01:35-associated HLA haplotype (A*24-B*40:01:35-DRB1*11) found in a Taiwanese unrelated hematopoietic bone marrow stem cell donor

ObjectiveHuman leukocyte antigen (HLA)-B*40:01:35 is a low incidence allele in the HLA-B locus. The objective of this study is to report the ethnicity of B*40:01:35 and its deduced probable HLA associated haplotype in a Taiwanese unrelated bone marrow hematopoietic stem cell donor. Materials and methodsA sequence-based typing method was employed to confirm the low incidence allele B*40:01:35. Polymerase chain reaction was performed to amplify exons 2 and 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 using the BigDye Terminator Cycle Sequencing Ready Reaction kit in both directions according to the manufacturer's protocols. ResultsThe DNA sequence of B*40:01:35 is identical to B*40:01:01 in exons 2 and 3, except for residue 324 where C is changed to T (codon 84, TAC→TAT). The nucleotide exchange does not cause amino acid alteration to the protein sequence of B*40:01:01 due to the silent mutation. We deduced the probable HLA haplotype in association with B*40:01:35 in Taiwanese to be A*24-B*40:01:35-DRB1*11. ConclusionInformation on the deduced probable HLA haplotype in association with the low incidence B*40:01:35 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.

Self-Assessment of Color Categories and Its Relationship with HLA Profiling in Brazilian Bone Marrow Donors

The Brazil Ministry of Health maintains a Registry of Bone Marrow Donors that corresponds to approximately 12% of the Bone Marrow Donors Worldwide registry. This registry contains information on ethnicity (by self-assessment of color) and HLA-A, -B, and -DRB1 type. The self-assessment of color tool has been extensively used for admixed population characterization. In this context, Brazil represents a highly admixed population, resulting from 5 centuries of colonization and interbreeding, mainly, but not exclusively, among Native Americans, Europeans, and Africans. Here we evaluated self-assessed skin color and HLA genetic information from 71,291 bone marrow donors of southern Brazil to verify how likely is the HLA profiling correspondence within and between self-assessed color groups. We found that HLA itself was a better ancestry indicator than was self-assessed color. Therefore, self-assessment of color in highly admixed populations, such as that of Brazil, is not indicative of higher correspondence in the HLA profiles within skin color groups.

Rio Grande do Norte, Brazil, voluntary bone marrow donors registry analysis.

this study aimed to report the allele and haplotype frequencies of volunteer bone marrow donors (VBMD) from the state of Rio Grande do Norte (RN) who were enrolled in the Brazilian Volunteer Bone Marrow Donor Registry (REDOME). the sample comprised 12,973 VBMD who had their allele and haplotype frequencies calculated by Arlequin 3.5.1.2. A multivariate analysis of the data was obtained through a principal component analysis (PCA) and hierarchical cluster analysis (HCA) performed with SPSS 8.0. the most frequent allelic group was HLA-A*02, followed by -DRB1*13, -DRB1*04, -DRB1*07, -B*44, -B*35, -A*24 and -DRB1*01. Of the 2,701 haplotypes observed, the three most frequent were HLA-A*01 B*08 DRB1*03 (1.62%), -A*29 B*44 DRB1*07 (1.56%) and -A*02 B*44 DRB1*04 (1.29%). These haplotypes were in linkage disequilibrium. RN allele and haplotype frequencies were very similar to those in other Brazilian states in which similar studies have been performed. The PCA revealed that RN is highly genetically similar to Caucasian populations, especially those from Iberian countries, which strongly influenced the state's ethnic composition. Africans and Amerindians also influenced the RN population structure, to a lesser extent. the HCA reinforced the conclusion that, despite its highly admixed profile, the RN population is genetically similar to European and European-descended populations. The PCA also showed that RN cities do not contribute to the same extent to REDOME, with less populous cities being underrepresented, indicating the need to enroll more VBMD from these smaller cities to faithfully depict the state's population structure in the database.

HLA‐A, B and DRB1 genetic heterogeneity in Quebec

Recent studies have shown that under specific conditions such as high sample sizes and Hardy-Weinberg equilibrium, bone marrow donor registry data can be used to describe HLA molecular variation across a specific geographic area, thus providing excellent data sets to infer human migrations history. The province of Quebec is known to have experienced a complex history of settlement, characterized by multiple migrations and demographic changes. We thus analysed the data of more than 13000 unrelated individuals acting as volunteer bone marrow donors who were molecularly typed for HLA-A, B and DRB1 polymorphisms in the Héma-Quebec registry. HLA allelic and haplotypic frequencies were estimated and compared among regions. The results indicate that, despite an overall low genetic diversity in Quebec, genetic variation is correlated with geography, compatible with isolation-by-distance across the province. However, some localities also harbour contrasting genetic profiles, that is a highly diversified genetic pool in the two main urban centres (Montréal and Laval) and a more pronounced genetic divergence of two specific regions characterized by a peculiar peopling history (Saguenay-Lac-St-Jean and Gaspésie-Îles-De-La-Madeleine). In agreement with other independent molecular markers, the observations based on HLA data thus account for the main demographic mechanisms that shaped the genetic structure of the present day Quebecer population. In addition, the detailed analysis of the Héma-Quebec registry provides key genetic information on which an efficient bone marrow transplantation recruitment strategy can be settled.

High-resolution HLA-A, HLA-B, and HLA-DRB1 haplotype frequencies from the French Bone Marrow Donor Registry

We have estimated human leukocyte antigen (HLA) haplotype frequencies using the maximum likelihood mode, which accommodates typing ambiguities. The results of the frequency distribution of the 7015 haplotypes obtained are presented here. These include a total of 114 HLA-A, 185 HLA-B, and 76 HLA-DRB1 unique alleles at each locus. Across all populations, although the most common individual HLA alleles were HLA-A∗02:01 (29.0%), HLA-B∗07:02 (11.4%), and HLA-DRB1∗07:01 (15.9%), the most frequent haplotype was found to be HLA-A∗01:01∼B∗08:01∼DRB1∗03:01.

Organization and Development of Bone Marrow Donation and Transplantation in Poland.

This paper describes bone marrow donation and transplantation in Poland in terms of its history, current state, and information on the quality control system. Based on data gathered from the informatics systems of the Polish Central Unrelated Potential Bone Marrow Donor and Cord Blood Registry and the Polish transplant registries, as well as World Marrow Donor Association statistics, we performed an overview study to collect and compare numbers on hematopoietic stem cells donations and transplantations in Poland in the years 2010-2014. In the last 5 years, the number of registered potential hematopoietic stem cells donors in Poland increased by more than 4 times, from about 146,000 to over 750,000. During the same period, the number of patients qualified to hematopoietic stem cells transplantation from unrelated donor increased from 557 in 2010 to 817 in 2014. We observed a striking change in the percentage of transplantations performed in Polish centers using material collected from national donors--from 24% to 60%. This shift was also evident in the number of search procedures closed with acceptation of Polish donors--from 27% in 2010 to 58% in 2014. Another consequence of Polish registry growth is the increasing number of donations from Polish donors for international patients. Between 2010 and 2014, the percent of donation for non-national patient increased from 33% to 76%, placing Poland in 6th place in the ranking of the HSC "exporters" worldwide. Growth of transplantation rates involves standardization process, which is a natural way of development for national organizations in the field of HSCT because of its international character.

HLA-F polymorphisms in a Euro-Brazilian population from Southern Brazil.

HLA-F is a non-classical major histocompatibility complex (MHC) gene. It codes class Ib MHC molecules with restricted distribution and less nucleotide variations than MHC class Ia genes. Of the 22 alleles registered on the IMGT database only four alleles encode for proteins that differ in their primary structure. To estimate genotype and allele frequencies, this study targeted on known protein coding regions of the HLA-F gene. Genotyping was performed by Sequence Base Typing (SBT). The sample was composed by 199-unrelated bone marrow donors from the Brazilian Bone Marrow Donor Registry (REDOME), Euro-Brazilians, from Southern Brazil. About 1673 bp were analyzed. The most frequent allele was HLA-F*01:01 (87.19%), followed by HLA-F*01:03 (12.31%), HLA-F*01:02 (0.25%) and HLA-F*01:04 (0.25%). Significant linkage disequilibrium (LD) was verified between HLA-F and HLA classes I and II alleles. This is the first study regarding HLA-F polymorphisms in a Euro-Brazilian population contributing to the Southern Brazilian genetic characterization.

Pauci-immune glomerulonephritis: Does negativity of anti neutrophilic cytoplasmic antibodies (ANCA) matters?

To identify the major challenges faced by bone marrow donor registries in India.HLA typing, using the Sequence specific oligonucliotide probe (SSOP) Luminex-xMap technology, was performed for all 18,000 donors. Haplotype analysis was performed using the Arlequin software.In a cohort of 18,000 donors only 19% patients could find a donor at 10/10 low resolution level. The chances of finding a donor at high resolution 10/10 level is even less. The major challenges faced are lack of awareness, patient's economic status, unavailability of unrelated matched donors, lack of funding for function of registry and high donor dropout rates.As cost is a major challenge, we need to strive to increase donor pool and also take major steps to decrease the donor dropout rates by increasingly motivating potential donors and trying to help them overcome any myth or fear from donating stem cells.

P111 : DISTRIBUTION OF CLASS I AND II HLA HAPLOTYPES IN A MIXED POPULATION FROM SOUTHERN BRAZIL

The aim of this study was evaluate of allele and haplotype frequencies of HLA-A, -B, -DRB1, -DQA1 and -DQB1 in a mixed population from Southern Brazil. Sample donors registered in the National Registry of Bone Marrow Donors (REDOME) were analyzed. Four hundred and seventy-three (67%) subjects were female while 231 (33%) were male. The average age was 33.63 years (SD = 9.37). Genotyping allelic groups of HLA-A , -B-DQA1 and DQB1 was performed by PCR-SSO with Luminex method (One Lambda®, CA, USA) and the HLA-DRB1 alleles was performed by PCR-SSOP HD (High Definition) methodology with Luminex (One Lambda®, CA , USA) in 704 individuals. The distribution of HLA alleles was in Hardy-Weinberg equilibrium. Twenty-two allelic groups were observed for HLA-A locus, the most frequent HLA-A ∗ 02 (27.1%), ∗ 03 (10.7%), ∗ 24 (9.6%), ∗ 01 (9.5%), ∗ 68 (6.3%) and ∗ 11 (5.4%), while for HLA-B locus with 34 allelic groups were the most frequent HLA-B ∗ 35 (12.1 %), ∗ 44 (10.2%), ∗ 51 (8.5%), ∗ 15 (7.5%), ∗ 7 (7.3%) and ∗ 18 (6.5%). The most common DRB1 alleles were: HLA-DRB1 ∗ 07:01 (13.2%), ∗ 03:01 (9.1%), ∗ 11:01 (8.4%), ∗ 15:01 (6.1%) ∗ 1:01 (5.92%) and ∗ 13:01 (5.9%). For the loci HLA-DQA1 and HLA-DQB1: HLA-DQA1 ∗ 01:02 (16.8%), ∗ 05:05 (15.8%) ∗ 02:01 (13.1%), 05:01 (9.8%), ∗ 01:01/04/05 (9.1%); HLA-DQB1 ∗ 03:01 (20.1%), ∗ 05:01 (14.1%), ∗ 02:02 (11.9%), ∗ 02:01 and ∗ 03:02 (9.74%). Four hundred HLA-A/B found possible haplotype, with HLA-A ∗ 02/B ∗ 51 (4.3%), A ∗ 02/B ∗ 15 (2.9%) and A ∗ 01/B ∗ 08 (2.9%) were the most frequent. We observed 2839 HLA-A/B/DRB1 possible haplotypes and the most common were HLA-A ∗ 01/B ∗ 08/DRB1 ∗ 03:01 (2.7%) and A ∗ 29/B ∗ 44/DRB1 ∗ 07:01 (1.9%). For HLA-DRB1/DQA1/DQB1 observed in 1369 possible haplotypes, the most frequent were HLA-DRB1 ∗ 03:01/DQA1 ∗ 05:01/DQB1 ∗ 02:01 (8.4%) and HLA-DRB1 ∗ 11:01/DQA1 ∗ 05:05/DQB1 ∗ 03:01 (5.7%), and the HLA-DQA1 ∗ 05:05/DQB1 ∗ 03:01 (14.9%) and HLA-DQA1 ∗ 02:01/DQB1 ∗ 02:02 (10.9%) were the most frequent. The results obtained for the haplotype extended HLA-A/B/DRB1/DQA1/DQB1 is given below: 15,006 possible haplotypes and HLA-A ∗ 01/B ∗ 08/DRB1 ∗ 03:01/DQA1 ∗ 05:01/DQB1 ∗ 02:01 (2.7%); HLA-A ∗ 29/B ∗ 44/DRB1 ∗ 07:01/DQA1 ∗ 02:01/DQB1 ∗ 02:02 (1.8%), the most frequent haplotypes.

P067: TWO NOVEL ALLELES HLA-A∗02:433 AND HLA-A∗02:434 IDENTIFIED IN SAUDI BONE MARROW DONORS USING SEQUENCE-BASED TYPING

In this report, we present two novel HLA-A alleles: HLA-A ∗ 02:433 and HLA-A ∗ 02:434. These alleles were identified by sequence-based typing method (SBT), in two donors for the Saudi Bone Marrow Donor Registry (SBMDR). Allele A ∗ 02:433 is identical to A ∗ 02:05:01G except for a G to A substitution at nucleotide position 449 in exon 2. This substitution results in glycine to serine substitution at position 83. Whereas, allele A ∗ 02:434 is identical to A ∗ 02:01:01G except for a C to A substitution at nucleotide position 245 in exon 2, which results in phenylalanine to threonine substitution at position 15. The generation of both alleles appears to be the result of nucleotide point mutation involving 02:01:01 and 02:05:01.

P103 : HIGH RESOLUTION HLA ALLELE FREQUENCIES OF STEM CELL DONORS IN MEXICO. GENETIC DIVERSITY AND ITS RELEVANCE TO IMPROVE UNRELATED DONOR SEARCHES

Aim DNA-based registry typing is commonly done by SSOP and only a few registries employ sequencing at the time of recruitment, allowing to understand allele and haplotype frequencies and evaluating the size and composition of the registry, to assess the likelihood of finding matched donors. We explored the impact of the increasing number of HLA alleles in the genetic diversity of Mexicans, which will in turn impact the possibility of finding a donor for patients with a similar ethnic background. Methods Healthy Mexicans enrolled at the DONORMO-The Mexican Unrelated Bone Marrow Donor Registry, born in different geographic areas of Mexico were HLA typed at the allele level, for A∗, B∗, C∗, DRB1∗, DQB1∗ loci. DNA samples were sequenced in an ABI Prism 310 or in a 3500 sequencer. The SPSS 12 software was used for analysis. For A locus, 127 individuals were typed; 523 for B, 81 for C; 952 were SBT for DRB1 and 3343 for DQB1. Results A total of 273 common and well documented alleles were detected; 91 were unique observations; 40 at A∗ locus; 26 at B∗; 8 at C∗; 14 at DRB1∗ & 3 at DQB1∗. 65 different A∗ alleles are present, of which 32 are A2 different variants: A∗02:01; A2:06; A2:05; (13.4–5.5%) prevail. The prevalent B∗ alleles were 49:01; 35:12; 35:17; 15:15; 14:02; 14:01;39:06; 39:05; 40:05; 40:08; 50:01; 52:01 51:02; 53:01; (>1.5%). Only 10 C∗ alleles are frequent: 04:01, 07:02; 01:02; 03:04; 07:01; 16:01, 03:06; 5:01; 08:01; 08:02; (>2.5%). 16 frequent DRB1∗ alleles are present: 04:07; 08:02; 14:06; 01:02; 04:02; 04:11; 04:04; 19:01; 14:02; 07:01: 03:01; 16:02; 01:03; 04:04; 10:01; 15:03; 15:01, 15:03 (1.8%). Unique observations were found at DQB1∗ for 06:11; 03:08; 02:04. Mediterranean, Amerindian, Spanish, Caucasian, Semitic and African influences are clear. Conclusion The molecular variation shown, and a one-step typing strategy using SBT since donor recruitment, is highly relevant to optimizing donor search algorithms in HSCT, for identification of potential matches, and in understanding the genetic background of this highly heterogeneous country. The data are also very useful for applications that depend on allele prevalence information such as: resolution of ambiguity during HLA typing, research and clinical practice, and the management of the general data, in the face of an ever growing list of recognized allele sequences.

P070 : THREE NEW ALLELES HLA-C∗14:02:13, HLA-C∗15:72, AND HLA-C∗15:74 IN SAUDI BONE MARROW DONORS

Three new HLA-C alleles were identified by sequence-based typing method (SBT) in 1100 participants in the Saudi Bone Marrow Donor Registry (SBMDR). HLA-C ∗ 14:02:13 differs from HLA-C ∗ 14:02:01G by a silent G to A substitution at nucleotide position 400 in exon 2, where lysine at position 66 remains unchanged. HLA-C ∗ 15:72 differs from HLA-C ∗ 15:22 by a non-synonymous C to A substitution at nucleotide position 796 in exon 3, resulting in an amino acid change from phenylalanine to leucine at position 116. HLA-C ∗ 15:74 differs from HLA-C ∗ 15:08 by non-synonymous C to T substitution at nucleotide position 914 in exon 3, resulting in an amino acid change from arginine to tryptophan at position 156.

The deduced probable human leukocyte antigen haplotype associated with human leukocyte antigen low incidence allele B∗40:36 (A∗02-B∗40:36-DRB1∗12) in Taiwanese unrelated hematopoietic bone marrow stem cell donors

ObjectiveHuman leukocyte antigen (HLA)-B∗40:36 is a low incidence allele in the HLA-B locus. This study reports the ethnicity of B∗40:36 and the deduced probable HLA haplotype associated with HLA-B∗40:36 in Taiwanese unrelated bone marrow hematopoietic stem cell donors. Materials and methodsA sequence-based typing method was employed to confirm that the low incidence allele was present. Polymerase chain reaction was performed to amplify exons 2 and 3 in the HLA-A and HLA-B loci and exon 2 in the HLA-DRB1 locus using group-specific primer sets. The amplicons were sequenced using the BigDye Terminator Cycle Sequencing Ready Reaction Kit in both directions. ResultsThe DNA sequence of B∗40:36 is identical to B∗40:01:01 in exons 2 and 3, except for a one nucleotide substitution at residue 419 (A→T), which results in a one amino acid replacement at position 116 (Y→F; tyrosine→phenylalanine). We deduced the probable HLA haplotype in an association with B∗40:36 in Taiwanese to be A∗02-B∗40:36-DRB1∗12. ConclusionInformation on the deduced probable HLA haplotype in an association with the low incidence B∗40:36 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 the likelihood of finding compatible donors in unrelated bone marrow donor registries when a patient has this uncommon HLA allele.

Challenges faced by bone marrow registries in India

AimTo identify the major challenges faced by bone marrow donor registries in India. Materials and methodsHLA typing, using the Sequence specific oligonucliotide probe (SSOP) Luminex-xMap technology, was performed for all 18,000 donors. Haplotype analysis was performed using the Arlequin software. ResultsIn a cohort of 18,000 donors only 19% patients could find a donor at 10/10 low resolution level. The chances of finding a donor at high resolution 10/10 level is even less. The major challenges faced are lack of awareness, patient's economic status, unavailability of unrelated matched donors, lack of funding for function of registry and high donor dropout rates. ConclusionAs cost is a major challenge, we need to strive to increase donor pool and also take major steps to decrease the donor dropout rates by increasingly motivating potential donors and trying to help them overcome any myth or fear from donating stem cells.

Two novel alleles HLA-A*02:433 and HLA-A*02:434 identified in Saudi bone marrow donors using sequence-based typing.

In this report, we present two novel HLA-A alleles: HLA-A*02:433 and HLA-A*02:434. These alleles were identified by sequence-based typing method (SBT), in two donors for the Saudi Bone Marrow Donor Registry (SBMDR). Allele A*02:433 is identical to A*02:05:01G except for a G to A substitution at nucleotide position 449 in exon 2. This substitution results in glycine to serine substitution at position 83. Whereas, allele A*02:434 is identical to A*02:01:01G except for a C to A substitution at nucleotide position 245 in exon 2, which results in phenylalanine to threonine substitution at position 15. The generation of both alleles appears to be the result of nucleotide point mutation involving 02:01:01 and 02:05:01.

Recognition of the three deduced probable HLA haplotypes that are associated with HLA-C∗16:04:01 (A∗33:03-B∗44:02-C∗16:04:01-DRB1∗11:04:01 and A∗24-B∗44:02-C∗16:04:01-DRB1∗11:04) and HLA-B∗15:109 (A∗11-B∗15:109-DRB1∗04) in Taiwanese unrelated hematopoietic stem cell donors

ObjectiveHLA-C∗16:04:01 and HLA-B∗15:109 are two uncommon alleles at the HLA-C locus and HLA-B locus, respectively. The objective of this study is to report the deduced probable human leukocyte antigen (HLA) haplotypes associated with HLA-C∗16:04:01 and HLA-B∗15:109 among Taiwanese unrelated bone marrow hematopoietic stem cell donors. Materials and methodsA sequence-based typing method was employed to confirm the two low incidence alleles observed. Polymerase chain reaction was performed to amplify exons 2 and 3 of the HLA-A, and HLA-B loci with group-specific primer sets. Amplicons were sequenced using a BigDye Terminator Cycle Sequencing Ready Reaction Kit in both directions according to the manufacturer's protocols. ResultsThe DNA sequence of C∗16:04:01 is identical to that of C∗16:01:01 in exons 2 and 3, except for two nucleotide substitutions at residues 538 (C->T) and 539 (A->G), which results in a single amino acid replacement at position 156 (glutamine->tryptophan). We deduced two probable HLA haplotypes that are found in association with C∗16:04:01 as A∗33:03-B∗44:02-C∗16:04:01-DRB1∗11:04 and A∗24-B∗44:02-C∗16:04:01-DRB1∗11:04. The DNA sequence of B∗15:109 is identical to B∗15:27:01 in exons 2 and 3 except for one nucleotide substitution at residue 200 (C->T), which results in a single amino acid replacement at position 43 (proline->leucine). A probable HLA haplotype associated with B∗15:109 was deduced to be A∗11-B∗15:109-DRB1∗04. ConclusionInformation on the deduced HLA haplotypes that are found in association with the rare C∗16:04:01 and B∗15:109 alleles that we report here is useful for reference purposes at HLA testing laboratories and will help stem cell transplantation donor search coordinators when they are determining the likelihood of finding a compatible donor for patients bearing these two uncommon HLA alleles from unrelated bone marrow donor registries.

Recognition of the deduced probable HLA haplotypes associated with HLA low incidence alleles B∗13:50 (A∗11:02-B∗13:50-DRB1∗07:01) and B∗51:39 (A∗02-B∗51:39-DRB1∗15; and A∗11-B∗51:39-DRB1∗15) in Taiwanese unrelated hematopoietic stem cell donors

ObjectivesHLA-B∗13:50 and -B∗51:39 are two low incidence alleles in the HLA-B locus. The objective of this study is to report the deduced probable human leukocyte antigen (HLA) haplotypes in association with HLA-B∗13:50 and -B∗51:39 in Taiwanese unrelated bone marrow hematopoietic stem cell donors. Materials and MethodsA sequence-based typing method was used to confirm the two low incidence alleles observed. Polymerase chain reaction was performed to amplify exons 2 and 3 in the HLA-A and HLA-B loci and exon 2 in the HLA-DRB1 locus with group-specific primer sets. Amplicons were sequenced using the BigDye Terminator Cycle Sequencing Ready Reaction Kit in both directions according to the manufacturer's protocols. ResultsThe DNA sequence of B∗13:50 is identical to B∗13:01:01 in exons 2 and 3, except for a one nucleotide substitution at residue 482 (A→T), which results in a one amino acid replacement at position 137 (aspartic acid→valine). We deduced the probable HLA haplotype in association with B∗13:50 in Taiwanese as A∗11:02-B∗13:50-DRB1∗07:01. The DNA sequence of B∗51:39 is identical to B∗51:01:03 in exons 2 and 3 except for two nucleotide exchanges at residue 226 (A→G) and residue 228 (A→G), which result in a one amino acid substitution at position 52 (isoleucine→valine).The probable HLA haplotypes associated with B∗51:39 in Taiwanese may be deduced as A∗02-B∗51:39-DRB1∗15 and A∗11-B∗51:39-DRB1∗15. ConclusionInformation on the deduced HLA haplotypes in association with the low incidence B∗13:50 and B∗51:39 alleles that we report here is valuable for HLA testing laboratories for reference purposes and for stem cell transplantation donor search coordinators, to determine the likelihood of finding compatible donors in unrelated bone marrow donor registries for patients carrying these two uncommon HLA alleles.

HLA-A, HLA-B and HLA-DRB1 allele and haplotype diversity among volunteer bone marrow donors from Croatia.

The determination of human leucocyte antigen (HLA)-A, HLA-B and HLA-DRB1 alleles in the routine procedure of a volunteer hematopoietic stem cell (HSC) donor's registration in the Croatian Bone Marrow Donor Registry (CBMDR) is performed to enhance the odds of finding a suitable HLA compatible donor for patients in need of a HSC transplantation worldwide. However, besides its original purpose, it also provides valuable information about the HLA polymorphism among Croats. The aim of the present study was to analyse the HLA allele and haplotype frequencies in a sample of 4000 donors from CBMDR. The distribution of HLA-A, HLA-B and HLA-DRB1 alleles did not demonstrate significant differences from the data reported for other European populations. The higher frequency of B*40:02 allele in comparison with B*40:01 and DRB1*11:04 in comparison with DRB1*11:01 is interesting because it represents a difference in comparison with the Western and Northern European populations which are a main source of donors for Croatian patients. The haplotype frequencies show a greater variation and difference in comparison with data from other registries and populations; however, due to a lack of high-resolution haplotype data, comparison was possible only with a very limited number of other populations.