Characterization of a novel allelic variant in HLA‐B*40 lineage,HLA‐B*40:298:02, by cloning and sequencing

A novel allelic variant in HLA‐B*40 lineage, HLA‐B*40:298:02, has been identified in an individual of Han ethnicity afflicted with nasopharyngeal carcinoma in Hunan province, southern China. Following polymerase chain reaction–Sanger sequence‐based typing (PCR–SBT), this new variant was further confirmed by two distinct strategies of cloning and sequencing. HLA‐B*40:298:02 differs from HLA‐B*40:298:01 by a single synonymous cytosine substitution at nucleotide position 26 (T→C) in exon 3, which corresponds to codon 99 of the mature HLA‐B mRNA molecule. This new allele has an estimated frequency of 0.0002, in about 2,500 sequence‐based typed subjects from the same population.     

Characterization of a novel HLA‐B*39:01:01‐related allele,HLA‐B*39:130, by cloning and phasing

A novel HLA‐B*39:01:01‐related variant, HLA‐B*39:130, has been identified in a normal individual of Han ethnicity in Hunan province, southern China. Following Sanger polymerase chain reaction–sequence‐based typing (PCR‐SBT), this new allele was further confirmed by cloning, phasing and sequencing. Aligned with HLA‐B*39:01:01, HLA‐B*39:130 has a nonsynonymous thymine substitution at nucleotide position 94 in exon 4, resulting in amino acid change from threonine to isoleucine at codon 214 (ACA→ATA) of the mature HLA‐BmRNA molecule.     

Identification of a new HLA‐G allele,HLA‐G*01:19, by cloning and phasing

A new HLA‐G allelic variant, HLA‐G*01:19, was identified in a southern Chinese Han population by polymerase chain reaction–sequence‐based typing (PCR‐SBT), cloning and phasing. HLA‐G*01:19 differs from HLA‐G*01:04:01 by a nonsynonymous cytosine at position 99 in exon 2, resulting in amino acid change from valine to leucine at codon 34 of the mature HLA‐G molecule.     

A novel HLA‐B*40 allele,B*40:01:40, identified in a Chinese individual

A new allele, officially named B*40:01:40, was detected in a Chinese individual by sequence‐based typing (SBT). The new allele differs from B*40:01:01 by a single nucleotide exchange at position 99 in codon 9, which results in synonymous substitution and seems not to compromise the HLA complex and T‐cell receptor interaction.     

Detection of the rare HLA‐B*40:97 allele in an unrelated Taiwanese bone marrow donor

We detected a rare HLA‐B locus allele, B*40:97, in a Taiwanese unrelated donor in our routine HLA SBT (sequence‐based typing) exercise for a possible hematopoietic stem cell donation. In exons 2, 3 and 4, the sequence of B*40:97 is identical to the sequence of B*40:02:01 except one nucleotide at nucleotide position 760 (C‐>T) in exon 4. The nucleotide variation caused one amino acid alteration at residue 230 (L‐>F). B*40:97 was probably derived from a nucleotide substitution event where C was replaced by T at nucleotide 760 involving B*40:02:01. The HLA‐A, HLA‐B, HLA‐C, HLA‐DRB1 and HLA‐DQB1 haplotype in association with B*40:97 may be deduced as A*26:01‐B*40:97‐C*03:03‐DRB1*11:01‐DQB1*03:03. Our recognition of B*40:97 in Taiwanese helps to fill the void of ethnic information for the allele B*40:97 reported to the IMGT/HLA Database.     

Three new HLA‐C 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 donors for the Saudi Bone Marrow Donor Registry (SBMDR). HLA‐C*14:02:13 differs from HLA‐C*14:02:01 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 nonsynonymous 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 a nonsynonymous C to T substitution at nucleotide position 914 in exon 3, resulting in an amino acid change from arginine to tryptophan at position 156.     

HLA‐A,HLA‐B and HLA‐DRB1 allele and haplotype frequencies of 10 918 Koreans from bone marrow donor registry in Korea

The human leucocyte antigen (HLA) system is the most polymorphic genetic system in humans, and HLA matching is crucial in organ transplantation, especially in hematopoietic stem cell transplantation. We investigated HLA‐A, HLA‐B and HLA‐DRB1 allele and haplotype frequencies at allelic level in 10 918 Koreans from bone marrow donor registry in Korea. Intermediate resolution HLA typing was performed using Luminex technology (Wakunaga, Japan), and additional allelic level typing was performed using PCR–single‐strand conformation polymorphism method and/or sequence‐based typing (Abbott Molecular, USA). Allele and haplotype frequencies were calculated by direct counting and maximum likelihood methods, respectively. A total of 39 HLA‐A, 66 HLA‐B and 47 HLA‐DRB1 alleles were identified. High‐frequency alleles found at a frequency of ≥5% were 6 HLA‐A (A*02:01, *02:06, *11:01, *24:02, *31:01 and *33:03), 6 HLA‐B (B*15:01, *35:01, *44:03, *51:01, 54:01 and *58:01) and 8 HLA‐DRB1 (DRB1*01:01, *04:05, *04:06, *07:01, *08:03, *09:01, *13:02 and *15:01) alleles. At each locus, A*02, B*15 and DRB1*14 generic groups were most diverse at allelic level, consisting of 9, 12 and 11 different alleles, respectively. A total of 366, 197 and 21 different HLA‐A‐B‐DRB1 haplotypes were estimated with frequencies of ≥0.05%, ≥0.1% and ≥0.5%, respectively. The five most common haplotypes with frequencies of ≥2.0% were A*33:03‐B*44:03‐DRB1*13:02 (4.97%), A*33:03‐B*58:01‐DRB1*13:02, A*33:03‐B*44:03‐DRB1*07:01, A*24:02‐B*07:02‐DRB1*01:01 and A*24:02‐B*52:01‐DRB1*15:02. Among 34 serologic HLA‐A‐B‐DR haplotypes with frequencies of ≥0.5%, 17 haplotypes revealed allele‐level diversity and majority of the allelic variation was arising from A2, A26, B61, B62, DR4 and DR14 specificities. Haplotype diversity obtained in this study is the most comprehensive data thus far reported in Koreans, and the information will be useful for unrelated stem cell transplantation as well as for disease association studies.     

Characterization of a new HLA‐A allele,HLA‐A*02:07:08, by cloning and sequencing

In this report, we present a novel HLA‐A*02:07 allele, HLA‐A*02:07:08. HLA‐A*02:07:08 was identified in an individual of Han ethnicity in Hunan province, southern China. Following polymerase chain reaction‐sequence‐based typing (PCR‐SBT), this new allele was further confirmed by cloning and sequencing. HLA‐A*02:07:08 differs from HLA‐A*02:07:01 by a single synonymous C to T substitution at nucleotide position 131 in exon 3.     

Discovery of the novel HLA‐DRB1*09:01:08 allele in a Taiwanese volunteer bone marrow donor and identification of the probable HLA‐A,HLA‐B and HLA‐DRB1 haplotype in association with DRB1*09:01:08

We report here the novel variant of HLA‐DRB1*09:01, DRB1*09:01:08, discovered in a Taiwanese volunteer bone marrow donor by a sequence‐based typing (SBT) method. The DNA sequence of DRB1*09:01:08 is identical to the sequence of DRB1*09:01:02 in exon 2 except a silent mutation at nucleotide position 261(C→T) (GCC→GCT at codon 58). We hypothesize DRB1*09:01:08 was probably derived from DRB1*09:01:02 via a nucleotide point mutation event. The plausible HLA‐A, HLA‐B and HLA‐DRB1 haplotype in association with DRB1*09:01:08 was deduced as A*02:07‐B*46:01‐DRB1*09:01:08.     

Recognition of a Caucasoid HLA‐B locus allele,B*44:55, in a Taiwanese/Chinese bone marrow stem cell donor

We detected a Caucasoid HLA‐B allele, HLA‐B*44:55, in a potential Taiwanese/Chinese bone marrow hematopoietic stem cell donor during our routine HLA SBT (sequence‐based typing) practice. The sequence of B*44:55 varies with B*44:02:01:01 with one nucleotide in exon 2 at position 97 (T‐>C), while it differs from B*44:03:01 with one nucleotide in exon 2 at position 97 (T‐>C) and three nucleotides in exon 3 at residues 538–540 (CTG‐>GAC). The nucleotide replacements caused one amino acid variation with B*44:02:01:01 at residue 9 (Y‐>H) and two amino acid variations with B*44:03:01 at residue 9 (Y‐>H) and residue 156 (L‐>D). The formation of B*44:55 is probably the result of a nucleotide substitution involving B*44:02:01:01 at position 97 (T‐>C). The Taiwanese/Chinese donor with B*44:55 claims having no kinship with Caucasian. Our speculations on the origin of the Taiwanese/Chinese B*44:55 will be presented.     

A novel HLA‐B*14 allele – B*14:53 – genetics and serology

HLA‐B*14:53 was found in a UK European normal blood donor prior to registration on the Welsh Bone Marrow Donor Registry. It differs from B*14:13 by one base (103G>T) in exon 2 resulting in a substitution of alanine (A) in B*14:13 to serine (S) in B*14:53. Unique among current HLA‐B*14 alleles, B*14:53 and B*14:13 share a motif of 59 bases between positions 361 and 419 in exon 3. This motif is present in numerous HLA‐B alleles the commonest overall being B*08:01, suggesting that both B*14:53 and B*14:13 arose from intralocus gene conversion events with B*08:01. Thus, B*14:53 probably arose from B*14:01:01 (which has TCC at codon 11 (S), while B*14:13 arose from B*14:02:01:01 which has GCC at codon 11 (A). Additionally, the two likely B*14:53‐bearing and B*14:13‐bearing haplotypes are typical of B*14:01:01‐bearing and B*14:02:01:01‐bearing haplotypes, respectively. Serological testing, using 49 antisera with HLA‐B64, or B64, B65 reactivity, showed that the B*14:53 specificity did not react as a B64 (B*14:01) specificity and may appear as a short/weak HLA‐B14. This implies that residues additional to S at position 11 are involved in HLA‐B64 serological identity; for example, the motif 11S 97W 116F is possessed by B*14:01 and many other B*14 products (and B*39:79 plus some HLA‐C products) but not B65 (B*14:02) or the B*14:53 specificity. B*14:53 was found in a random HLA sequence‐based typed population of 32 530 normal subjects indicating a low precision allele frequency of 0.000015 in subjects resident in Wales.     

Genomic sequences of HLA‐A*68:169, HLA‐B*07:298 and HLA‐B*39:129.

Three new HLA class I alleles were described in the Spanish population. HLA‐A*68:169 and ‐B*39:129 show one amino acid replacement at the α1‐domain, compared to A*68:02 (P47 > L47) and ‐B*39:06 (S11 > A11), respectively. HLA‐B*07:298 presents one nucleotide mutation within exon 1, resulting in a new amino acid position ?14, L>Q, which has not been previously described in any HLA protein. Prediction of the B*07:298 signal peptide cleavage did not show significant differences in comparison with that obtained for the rest of HLA‐B genes.     

HLA‐A, ‐B and ‐DRB1 polymorphism in Koreans defined by sequence‐based typing of 4128 cord blood units

Human leucocyte antigen (HLA) alleles and haplotypes differ significantly among different ethnic groups, and high‐resolution typing methods allow for the detection of a wider spectrum of HLA variations. In this study, HLA‐A, ‐B and ‐DRB1 genotypes were analysed in 4128 cord blood units obtained from Korean women using the sequence‐based typing method. A total of 44 HLA‐A, 67 HLA‐B and 48 HLA‐DRB1 most probable alleles were identified. Of these, high‐frequency alleles found at a frequency of ≥5% were 6 HLA‐A (A*02:01, A*02:06, A*11:01, A*24:02, A*31:01, A*33:03), 5 HLA‐B (B*15:01, B*44:03, B*51:01, B*54:01, B*58:01) and 7 HLA‐DRB1 (DRB1*01:01, DRB1*04:05, DRB1*07:01, DRB1*08:03, DRB1*09:01, DRB1*13:02, DRB1*15:01) alleles. At each locus, A*02, B*15 and DRB1*04 generic groups were most diverse at allelic level, consisting of 8, 11 and 10 different alleles, respectively. Two‐ and three‐locus haplotypes estimated by the maximum likelihood method revealed 73 A‐B, 74 B‐DRB1 and 42 A‐B‐DRB1 haplotypes with frequencies of ≥0.3%. A total of 193 A‐B‐DRB1 haplotypes found at a frequency of ≥0.1% were presented, and the six most common haplotypes were A*33:03‐B*44:03‐DRB1*13:02 (4.6%), A*33:03‐B*58:01‐DRB1*13:02 (3.0%), A*24:02‐B*07:02‐DRB1*01:01 (2.7%), A*33:03‐B*44:03‐DRB1*07:01 (2.5%), A*30:01‐B*13:02‐DRB1*07:01 (2.2%) and A*24:02‐B*52:01‐DRB1*15:02 (2.1%). Compared with previous smaller scale studies, this study further delineated the allelic and haplotypic diversity in Koreans including low‐frequency alleles and haplotypes. Information obtained in this study will be useful for the search for unrelated bone marrow donors and for anthropologic and disease association studies.     

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.     

Allelic and haplotype diversity of HLA‐A,HLA‐B and HLA‐DRB1 gene at high resolution in the Nanning Han population

The distribution of human leucocyte antigen (HLA) allele and haplotype varied among different ethnic populations. In this study, we investigated the allele and haplotype frequencies of HLA‐A, HLA‐B and HLA‐DRB1 loci in the Nanning Han population who live in Guangxi province of China. We identified 26 HLA‐A, 56 HLA‐B and 31 HLA‐DRB1 alleles in 562 Nanning individuals of Han ethnic group by sequence‐based typing method. Of these, the three most common alleles in HLA‐A, HLA‐B and HLA‐DRB1 loci, respectively, were A*11:01 (32.12%), A*02:07 (12.54%), A*24:02 (12.01%); B*46:01 (14.41%), B*15:02 (13.61%), B*40:01 (11.48%); DRB1*15:01 (14.15%), DRB1*16:02 (11.57%) and DRB1*12:02 (10.14%). With the exception of HLA‐DRB1, the p values of the HLA‐A and HLA‐B loci showed that the HLA allelic distribution in this population was in accordance with Hardy–Weinberg expectation (p > 0.05). A total of 173 HLA~A‐B~DRB1 haplotype with a frequency of >0.1% were presented and the three most common haplotype were HLA‐A*33:03~B*58:01~DRB1*03:01 (6.12%), HLA‐A*11:01~B*15:02~DRB1*12:02 (3.39%) and HLA‐A*11:01~B*15:02~DRB1*15:01 (3.22%). The phylogenetic tree and the principal component analysis suggested that Nanning Han population had a relative close genetic relationship with Chinese Zhuang population and a relative distant genetic relationship with Northern Han Chinese. The information will be useful for anthropological studies, for HLA matching in transplantation and disease association studies in the Chinese population.     

Molecular modelling of HLA‐B*35:132

Here we describe the molecular modelling of the new variant HLA‐B*35:132. This allele shows one mismatch with B*35:01:01:01 in exon 3 at position 575 where a T is substituted by a C, which implies an amino acidic change from Leucine to Proline. This seems not to alter the molecular structure and not to compromise the HLA complex and T‐cell receptor interaction.     

HLA‐B*38:55Q: a new alternatively expressed allele identified in a three‐generation Italian family

The new allelic variant HLA‐B*38:55Q differs from the closest related B*38:01:01 by one nucleotide substitution at position 373 in exon 3 (TGC>CGC). This results in a difference of one amino acid at residue 101 of the HLA‐B heavy chain, from a neutral‐polar Cys to a basic‐polar Arg, thus impairing disulphide bridge formation in the alpha‐2 domain. This alteration of the secondary structure probably affects the maturation of the heavy chain and the level of surface expression, making the HLA‐B*38:55Q undetectable by standard serological typing.     

Two novel alleles HLA‐DRB1*11:150 and HLA‐DRB1*14:145 identified in Saudi individuals

Two new HLA‐ DRB1 alleles were identified by sequence‐based typing method (SBT) in 1100 participants in the Saudi Stem Cell Donor Registry. HLA‐DRB1*11:150 differs from HLA‐DRB1*11:01:01G by a single C to A substitution at nucleotide position 5580 in exon 2, resulting in an amino acid change from alanine to glutamic acid at position 74. HLA‐DRB1*14:145 differs from HLA‐DRB1*14:04 by a C to G substitution at nucleotide position 5511 in exon 2, resulting in an amino acid change from threonine to arginine at position 51.     

MICA,MICB Polymorphisms and Linkage Disequilibrium with HLA‐B in a Chinese Mongolian Population

In this study, polymorphisms of major histocompatibility complex class I chain‐related genes A and B (MICA and MICB) and human leucocyte antigen (HLA)‐B gene were investigated for 158 unrelated Chinese Mongolian subjects recruited from central Inner Mongolia Autonomous Region, northern China, by polymerase chain reaction–sequence‐based typing (PCR‐SBT) and cloning. Collectively, 79 alleles, including 20 MICA, 12 MICB and 47 HLA‐B alleles, were identified. MICA*008:01 (21.2%), MICB*005:02 (48.1%) and HLA‐B*51:01 (7.91%) were the most common alleles. Significant global linkage disequilibrium (LD) was detected between HLA‐B and MICA, HLA‐B and MICB, and MICA and MICB loci (all P < 0.000001). The most frequent haplotypes were HLA‐B*51:01‐MICA*009:01 (7.28%), HLA‐B*58:01‐MICB*008 (6.96%), MICA*010‐MICB*005:02 (13.92%) and HLA‐B*58:01‐MICA*002:01‐MICB*008 (6.96%). HLA‐B‐MICA haplotypes such as HLA‐B*50:01‐MICA*009:02 were associated with single MICB allele. Some HLA‐B‐MICA haplotypes were associated with multiple MICB alleles, including HLA‐B*51:01‐MICA*009:01. One novel MICB allele, MICB*031, was identified, which has possibly arisen from MICB*002:01 through single mutation event. We also confirmed the existence of a recently recognized MICA allele, MICA*073, whose ethnic origin has not been previously described. Genotype distributions at MICA, MICB and HLA‐B were consistent with a neutrality model. Our results provide new insight into MIC genetic polymorphisms in Chinese ethnic groups. Findings shown here are important from an anthropologic perspective and will inform future studies of the potential role of MIC genes in allogeneic organ transplantation and HLA‐linked disease association in populations of related ancestry.     

A novel HLA-B*40 sequence--B*40:92

A new allele, HLA‐B*40:92, was identified in a north‐western European subject during polymerase chain reaction using sequence‐specific priming (PCR‐SSP)‐based typing of haematopoietic stem cell (HSC) donors. B*40:92 differs from B*40:01:01 by six nucleotides at positions 559, 560, 603, 605, 610 and 618 in exon 3 which represents a substitution motif of at least 60 nucleotides. This motif, which occurs in numerous HLA alleles including the relatively high frequency B*15 and B*35 allele families, encode four amino acid changes at positions 163 (glutamic acid > leucine), 177 (aspartic acid > glutamic acid), 178 (lysine > threonine), 180 (glutamic acid > glutamine) and a silent substitution, conserved alanine, at codon 182. Thus, it is likely that HLA‐B*40:92 occurred following a gene conversion‐like or interallelic recombination event involving B*40:01:01 and probably a B*15 or more likely a B*35 family allele. HLA‐B*40:92 was found on a haplotype with HLA‐A*02:01, B*40:92, C*03:04, DRB1*13:02, DRB3*03:01, DQA1*01:02, DQB1*06:04, DPA1*02:02, DPB1*05:01. Tests on 69 selected B40 and B35 antisera and Lambda Monoclonal Trays? show that B*40:92 encodes a ‘short’ B40/B60 serological specificity which displays some HLA‐B35 reactivity. The HLA‐B40 and HLA‐B35 motifs (possible epitopes) responsible for this serological reactivity were identified. This single example of HLA‐ B*40:92 was found in 56,823 consecutive HLA PCR‐SSP typed HSC donors indicating a carriage frequency of 0.00176% (allele frequency 0.00001) in blood donors resident in Wales. An Epstein‐Barr virus transformed B‐cell line from the HLA‐B*40:92 donor is available.