High-resolution Sequence-based Typing Research Articles

Frequency of HLA-A*02:01 in the Brazilian population and its impact on uveal melanoma systemic treatment.

Uveal melanoma is a rare malignancy originating from extracutaneous melanocytes on the uveal layer of the eyes. The incidence varies depending on the ethnic and racial global distribution, as uveal melanoma is more frequently diagnosed in non-Hispanic White subjects when compared with Hispanic, Asian, or Black individuals. Despite all the local effective management of uveal melanoma, roughly 50% of the cases will develop distant metastases. For these cases, the historical median overall survival is around 12 months. Recently, tebentafusp became the first therapy to receive Food and Drug Administration approval following a phase 3 trial demonstrating a continued long-term benefit for overall survival among adult HLA-A*02:01-positive patients with previously untreated metastatic uveal melanoma. Since 2021, high-resolution sequence-based HLA typing has been considered the gold standard for determining HLA alleles and haplotypes for the Brazilian Bone Marrow Donor Registry (REDOME) donors. To depict the HLA-A*02:01-positivity in Brazilian individuals, the REDOME database was queried out for the donors included from 2021 to 2023 and tested for HLA in high-resolution platforms. A total of 203, 44 donors were included and the frequency of the HLA-A*02:01 was 21.01%, much lower compared to the frequency in North Americans and Europeans (around 45%). Despite tebentafusp has demonstrated promising results in the treatment of uveal melanoma, the number of patients to benefit from this new approach can strongly vary by ethnic and racial issues. New strategies for the systemic treatment of advanced uveal melanoma have to be developed and tested as this disease still represents an unmet medical need.

High-Resolution HLA Typing of HLA-A, -B, -C, -DRB1, and -DQB1 in Kinh Vietnamese by Using Next-Generation Sequencing.

Human leukocyte antigen (HLA) genotyping displays the particular characteristics of HLA alleles and haplotype frequencies in each population. Although it is considered the current gold standard for HLA typing, high-resolution sequence-based HLA typing is currently unavailable in Kinh Vietnamese populations. In this study, high-resolution sequence-based HLA typing (3-field) was performed using an amplicon-based next-generation sequencing platform to identify the HLA-A, -B, -C, -DRB1, and -DQB1 alleles of 101 unrelated healthy Kinh Vietnamese individuals from southern Vietnam. A total of 28 HLA-A, 41 HLA-B, 21 HLA-C, 26 HLA-DRB1, and 25 HLA-DQB1 alleles were identified. The most frequently occurring HLA alleles were A∗11:01:01, B∗15:02:01, C∗07:02:01, DRB1∗12:02:01, and DQB1∗03:01:01. Haplotype calculation showed that A∗29:01:01∼B∗07:05:01, DRB1∗12:02:01∼DQB1∗3:01:01, A∗29:01:01∼C∗15:05:02∼B∗07:05:01, A∗33:03:01∼B∗58:01:01∼DRB1∗03:01:01, and A∗29:01:01∼C∗15:05:02∼B∗07:05:01∼DRB1∗10:01:01∼DQB1∗05:01:01 were the most common haplotypes in the southern Kinh Vietnamese population. Allele distribution and haplotype analyses demonstrated that the Vietnamese population shares HLA features with South-East Asians but retains unique characteristics. Data from this study will be potentially applicable in medicine and anthropology.

Distribution of HLA-DRB1, DPB1 and DQB1 alleles and haplotypes in Mongolian Minority in China

HLA-DRB1, -DQB1 and -DPB1 allele frequencies and estimated haplotype frequencies from 496 unrelated healthy Mongol subjects who living in Inner Mongolia Autonomous Region of China has been reported. HLA genes were genotyped using high-resolution sequence-based typing method. Chinese-Mongolian belongs to northern group of East Asians, but with its specific HLA-DRB1, DPB1 and DQB1 alleles and haplotypes characteristic.

An Increased Frequency in HLA Class I Alleles and Haplotypes Suggests Genetic Susceptibility to Influenza A (H1N1) 2009 Pandemic: A Case-Control Study.

Background The influenza A H1N1/09 pandemic infected a small number of exposed individuals, which suggests the involvement of genetic factors. There are scarce data available on classical HLA class I association with the influenza A H1N1/09 pandemic. Methods We analyzed the frequency of classical HLA class I alleles and haplotypes in A H1N1/09 influenza in a case-control study including 138 influenza patients (INF-P) and 225 asymptomatic healthy contacts (INF-C) simultaneously recruited. HLA class I typing was performed by high-resolution sequence-based typing method. Results Our analysis revealed higher frequency of C∗07:02:01, B∗39:06:02, C∗03:02:01, B∗44:03:01, B∗51:01:05, and B∗73:01 (p < 0.05; OR = 1.84–9.98) and of two haplotypes—A∗68:01:02-C∗07:02:01 (p = 1.05E − 05; OR = 23.99) and B∗35:01:01-C∗07:02.01 (p = 4.15E − 04, OR = 2.15)—in A H1N1/09 influenza subjects. A∗68:01:01 was exclusively present only in the INF-P group (5/138). A decrease in the frequency of C∗03:03:01, A∗11:01:01, B∗39:01:01, A∗24:02:01, C∗03:04:01, B∗51:01:01, and C∗07:01:01 (p < 0.05; OR = 0.12–0.52) and of haplotypes A∗02:01:01-B∗35:01:01-C∗04:01:01, A∗24:02:01-B∗35:01:01, B∗39:01:01-C∗07:02:01, and B∗40:02:01-C∗03:04:01 (p < 0.05; OR = 0.08–0.22) were observed in INF-P group. Conclusion Selective classical HLA class I allele and haplotype combinations predispose individuals towards susceptibility or protection against the influenza A H1N1/09 pandemic. This work has significant implications for accessing population transmission risk for A H1N1/09 or a similar strain breakout in the future.

The Case for High Resolution Extended 6-Loci HLA Typing for Identifying Related Donors in the Indian Subcontinent

Three-loci low-resolution (LR) or intermediate-resolution HLA typing is generally considered adequate in the related blood and marrow transplantation (BMT) context. However, a single high-resolution (HR) mismatch may have a similar adverse impact on BMT outcome as an LR one. We sought to determine the frequency of mismatches that may go undetected when standard typing (LR or 3-loci HR) is used compared with 6-loci HR typing for related donor compatibility testing, and to assess its impact on relevant BMT outcomes. We analyzed data from a total of 2554 6-loci (HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1) HR sequence-based typing (full typing [FT]) from 754 patients, 1011 siblings, and 789 parents done at DKMS Germany (www.DKMS.de) between January 1, 2014, and June 21, 2016. We also studied 38 cases in which the family had undergone 3-loci HLA typing (standard typing [ST]). Patients were from India (70%), Pakistan (22%), and Sri Lanka (8%). The IMGT/HLA database (www.ebi.ac.uk/ipd/imgt/hla) was used to tease out nonpermissive DPB1 mismatches. HLA disparity–related outcomes, such as rejection and graft-versus-host disease (GVHD) were assessed in a retrospective matched-pair cohort of 50 patients (25 with ST and 25 with FT) who underwent BMT for severe thalassemia from compatible related donors. We found fully matched (either 12/12 HR matches or with a single permissive DPB1 mismatch) related donors for 285 patients (38%). Of these donors, 89% were siblings and 11% were parents. The likelihood of matching on an individual locus on LR but not on HR was found to be 5%. A total of 9 donors (3%; 7 siblings and 2 parents) who would have been considered a full match by HR typing on A, B, and DRB1 alone were not a match by extended 6-loci HR typing. Five of these 9 donors had a mismatch on C or DQB1, and 4 had a nonpermissive DPB1 mismatch. In this group, 5 donors (56%) belonged to a consanguineous family, in 2 donors (22%) there was no reported consanguinity, and in 2 donors (22%) consanguinity was unknown. We identified 18 donors (6%; 13 siblings and 5 parents) who would have been considered a 12/12 match by LR HLA typing alone but were found not to match on extended HR typing. In this group, 11 donors (61%) were from consanguineous families, 3 donors (17%) had no reported consanguinity, and in 4 donors (22%) consanguinity was unknown. Outcome analysis showed that the actuarial proportion of patients with GVHD was 4% in the FT group compared with 16% in the ST group, with log-rank P = .1952. The ST group included 2 patients with grade III-IV acute GVHD and 1 patient each with moderate and severe chronic GVHD, whereas the FT group only 1 patient with grade III acute GVHD. We conclude that even in the context of related donors, the use of LR and/or 3-loci (A, B, and DRB1) HR HLA typing might result in a sizable risk of missing a clinically relevant mismatch, which may have an adverse impact on transplantation outcomes. In the Indian subcontinent, this observation is not limited to putatively compatible parents or consanguineous families; we recommend full 6-loci HR HLA typing even for matched related BMTs.

Novel deletion mutation of HLA-B*40:02 gene in acquired aplastic anemia.

Despite prevalence of clonal evolution in patients with aplastic anemia (AA), somatic mutation of human leukocyte antigen (HLA) gene is rarely reported. Herein, we reported a case of acquired AA (aAA) harboring a new four-base-pair deletion mutation within exon 4 of HLA-B*40:02 leading to frameshift and premature stop codon. The HLA-B*40:02 mutant allele was detected in the patient's peripheral blood sample not in patient's buccal epithelial cells. The patient received allogenic hematopoietic stem cell transplantation (HSCT) from HLA-matched sibling donor. On day 30 after HSCT, the mutant HLA allele was not detected by high-resolution sequence-based HLA typing. Serial chimerism analyses showed mixed chimeric status indicative of coexisting donor and recipient hematopoietic cells. Our data could provide additional support in view of pathophysiology of aAA that somatic mutation of HLA-B*40:02 allele is one of the possible origin of clonal escape to evade immune attack in patient with aAA.

Allele and Haplotype Frequencies of Human Leukocyte Antigen-A, -B, -C, -DRB1, and -DQB1 From Sequence-Based DNA Typing Data in Koreans.

BackgroundData on allele frequencies (AFs) and haplotype frequencies (HFs) of HLA-C and -DQB1 are limited in Koreans. We investigated AFs and HFs of HLA-A, -B, -C, -DRB1, and -DQB1 in Koreans by high-resolution sequence-based typing (SBT).MethodsHematopoietic stem cells were obtained from 613 healthy, unrelated donors to analyze HLA-A, -B, -C, -DRB1, and -DQB1 genotypes by using AlleleSEQR HLA-A, -B, -C, -DRB1, and -DQB1 SBT kits (Abbott Molecular, USA), respectively. Alleles belonging to HLA-C*07:01/07:06 group were further discriminated by using PCR-sequence specific primer analysis. AFs and HFs were calculated by direct counting and maximum likelihood method, respectively.ResultsIn all, 24 HLA-A, 46 HLA-B, 24 HLA-C, 29 HLA-DRB1, and 15 HLA-DQB1 alleles were identified. AFs and HFs of HLA-A, -B, and -DRB1 were similar to those reported previously. For the HLA-C locus, C*01:02 was the most common allele, followed by C*03:03, C*03:04, C*14:02, C*03:02, and C*07:02 (AF ≥7%). AFs of C*07:01 and C*07:06 were 0.16% and 3.18%, respectively. For the HLA-DQB1 locus, DQB1*03:01 was the most common allele, followed by DQB1*03:03, *03:02, *06:01, *05:01, *04:01, and *06:02 (AF ≥7%). AFs of DQB1*02:01 and DQB1*02:02 were 2.12% and 6.69%, respectively. HFs of A*33:03-C*07:06 and C*07:06-B*44:03 were 3.09% and 3.10%, respectively, while those of DRB1*07:01-DQB1*02:02 and DRB1*03:01-DQB1*02:01 were 6.61% and 2.04%, respectively.ConclusionsThis study reported AFs and HFs of HLA, including HLA-C and -DQB1, in Koreans by using high-resolution SBT. These data can be used to resolve ambiguous results of HLA typing for organ and hematopoietic stem cell transplantations.

Promiscuous T-cell responses to drugs and drug-haptens

Promiscuous T-cell responses to drugs and drug-haptens

The KIR3DS1*0130105 allele identified using high‐resolution sequence‐based typing

KIR3DS1*0130105 allele differs from KIR3DS1*0130101 with a single mutation at position 6739G>T of intron 5.

A novel HLA-B allele,HLA-B*44:184, identified by super high-resolution single-molecule sequence-based typing in a Japanese individual

The novel allele HLA-B*44:184 differs from HLA-B*44:77 by three non-synonymous amino acid exchanges, T94I, L95I and S97R.

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Aim When doing search for matched unrelated donor (MUD) in the international bone marrow donor registries, it is recommended to start the search with HLA class I and II high resolution typing of the patient. However, performing high resolution typing specially for HLA class I; is not available in many laboratories in contrast to HLA class II high resolution, due to cost of equipment, reagent and technical expertise and TAT. The Aim of this study was to determine the correlation between the results of HLA class I typing obtained by One Lambda rSSO Lab Type method (suggested allele level typing) and high resolution HLA sequence based typing (SBT). Methods A total of 50 samples previously SBT typed specimen were also typed by rSSO Lab Type (One Lambda, Inc.). The correlation was made of the ability of the rSSO Lab Type low resolution typing suggested first or second allele choice in each locus to predict the correct HLA allele. Results See [ Table 1 ]. Conclusions When we obtain the potential matched donors list for the search that was performed with low resolution HLA class I and high resolution HLA class II typing of the patient, in our hand we found the Lab Type rSSO method to be fast and reliable for screening (inclusion/exclusion) of possible match donor. Once a potential matched donor is identified based on the alleles identified by the Lab Type rSSO. An actual high resolution SBT typing would have been ready for confirmation of the matching level.

Evaluation of sequence‐specific priming and real‐time polymerase chain reaction assays for detecting HLA‐B*51 alleles confirmed by sequence‐based typing

The human leukocyte antigen (HLA)-B*51 genotype is one of the well-known genetic factors associated with the development of Behcet's disease. We evaluated three sequence-specific priming (SSP) assays and one real-time PCR assay for detecting HLA-B*51 alleles using 93 whole blood samples, which were genotyped by high-resolution sequence-based typing (SBT). All HLA-B*51 alleles determined by SBT were detected by the four evaluated assays, and the results for all HLA-B alleles other than HLA-B*51 were negative on all assays. Thus, all HLA-B51 tests showed 100% sensitivity and 100% specificity for detecting HLA-B*51 alleles. The three SSP assays and the real-time PCR test for HLA-B*51 genotyping are simple, but reliable for detecting HLA-B*51 alleles in clinical laboratories.

Molecular characterization of swine leukocyte antigen gene diversity in purebred Pietrain pigs

The porcine major histocompatibility complex (MHC) harbors the highly polymorphic swine leukocyte antigen (SLA) class I and II gene clusters encoding glycoproteins that present antigenic peptides to T cells in the adaptive immune response. In Austria, the majority of commercial pigs are F 2 descendants of F 1 Large White/Landrace hybrids paired with Pietrain boars. Therefore, the repertoire of SLA alleles and haplotypes present in Pietrain pigs has an important influence on that of their descendants. In this study, we characterized the SLA class I ( SLA-1 , SLA-2 , SLA-3 ) and class II ( SLA-DRB1 , SLA-DQB1 , SLA-DQA ) genes of 27 purebred Pietrain pigs using a combination of the high-resolution sequence-based typing (SBT) method and a low-resolution (Lr) PCR-based method using allele-group, sequence-specific primers (PCR-SSP). A total of 15 class I and 13 class II haplotypes were identified in the studied cohort. The most common SLA class I haplotype Lr-43.0 ( SLA-1 *11XX- SLA-3 *04XX- SLA-2 *04XX) was identified in 11 animals with a frequency of 20%. For SLA class II, the most prevalent haplotype, Lr-0.14 [ SLA-DRB1 *0901- SLA-DQB1 *0801- SLA-DQA *03XX], was found in 14 animals with a frequency of 26%. Two class II haplotypes, tentatively designated as Lr-Pie-0.1 [ SLA-DRB1 *01XX/be01/ha04- SLA-DQB1 *05XX- SLA - DQA*blank] and Lr-Pie-0.2 [ SLA-DRB1 *06XX- SLA-DQB1 *03XX- SLA-DQA *03XX], appeared to be novel and have never been reported so far in other pig populations. We showed that SLA genotyping using PCR-SSP-based assays represents a rapid and cost-effective way to study SLA diversity in outbred commercial pigs and may facilitate the development of more effective vaccines or identification of disease-resistant pigs in the context of SLA antigens to improve overall swine health.

B*13:50, a novel HLA‐B*13 allele, identified by sequence‐based typing

We report a novel HLA-B*13 allele, B*13:50, found using high-resolution sequence-based typing in a Chinese donor. B*13:50 differs from B*13:01:01 by a single-nucleotide substitution (A→T) at position 482, in exon 3.

HLA-A*3101 and Carbamazepine-Induced Hypersensitivity Reactions in Europeans

Carbamazepine causes various forms of hypersensitivity reactions, ranging from maculopapular exanthema to severe blistering reactions. The HLA-B*1502 allele has been shown to be strongly correlated with carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS-TEN) in the Han Chinese and other Asian populations but not in European populations. We performed a genomewide association study of samples obtained from 22 subjects with carbamazepine-induced hypersensitivity syndrome, 43 subjects with carbamazepine-induced maculopapular exanthema, and 3987 control subjects, all of European descent. We tested for an association between disease and HLA alleles through proxy single-nucleotide polymorphisms and imputation, confirming associations by high-resolution sequence-based HLA typing. We replicated the associations in samples from 145 subjects with carbamazepine-induced hypersensitivity reactions. The HLA-A*3101 allele, which has a prevalence of 2 to 5% in Northern European populations, was significantly associated with the hypersensitivity syndrome (P=3.5×10(-8)). An independent genomewide association study of samples from subjects with maculopapular exanthema also showed an association with the HLA-A*3101 allele (P=1.1×10(-6)). Follow-up genotyping confirmed the variant as a risk factor for the hypersensitivity syndrome (odds ratio, 12.41; 95% confidence interval [CI], 1.27 to 121.03), maculopapular exanthema (odds ratio, 8.33; 95% CI, 3.59 to 19.36), and SJS-TEN (odds ratio, 25.93; 95% CI, 4.93 to 116.18). The presence of the HLA-A*3101 allele was associated with carbamazepine-induced hypersensitivity reactions among subjects of Northern European ancestry. The presence of the allele increased the risk from 5.0% to 26.0%, whereas its absence reduced the risk from 5.0% to 3.8%. (Funded by the U.K. Department of Health and others.).

A novel HLA-B*35 variant, HLA-B* 35:02:03, identified by sequence-based typing in a bone marrow donor

We report the identification of the novel allele human leukocyte antigen-B*35:02:03 that was found during confirmatory high-resolution sequence-based typing of a bone marrow donor. The B*35:02:03 allele has one nucleotide change from B*35:02:01 at position 318 in exon 2 which does not result in an amino acid change (codon 82: CGC --> CGG).

HLA DR-DQ combination associated with the increased risk of developing human HCV positive non-Hodgkin's lymphoma is related to the type II mixed cryoglobulinemia

This investigation was focused on the contribution of individual human leukocyte antigen (HLA)-DR and -DQ alleles to the human hepatitis C virus (HCV)(+) non-Hodgkin's lymphoma (NHL), with and without mixed cryoglobulinemia (MC), to study whether individual HLA class II alleles are expressed preferentially or equally in human HCV-specific NHL. For this purpose, peripheral blood mononuclear cells were obtained from two groups of patients with HCV(+) NHL and with or without MC (70 and 71 cases, respectively), and from 4575 blood donors. Eighty-three subjects with HCV infection only, and 118 patients with MC, only without lymphoma, were added as additional control groups. Individual HLA-DR and -DQ alleles were determined using high-resolution sequence-based typing and then data were collected by considering the HLA-DRB1 and DQB1 supertypes on the basis of common structural and functional features, proposed by in silico Bioinformatic studies. From the data, it is evidenced that the DR5-DQ3 HLA combination was strongly associated with the HCV (+) MC (+) NHL group of patients compared with bone marrow donor population (P<or= 0.001, RR = 2.498), while the contribution of DR1-DQ1 was higher in HCV (+) NHL without MC (P<or= 0.001, RR = 2.519). Thus, cryoglobulinemia clinical manifestation was found to be correlated with the preferential use of HLA DR-DQ combination in HCV-associated NHL. These data provide new insight into HCV-associated lymphoproliferative pathogenesis.

A novel HLA‐Cw*07 variant, HLA‐Cw*0760, identified by sequence‐based typing in a bone marrow donor

We report the identification of the novel allele HLA-Cw*0760 that was found during confirmatory high-resolution sequence-based typing of a bone marrow donor. The Cw*0760 allele has two nucleotide changes from Cw*070101 at positions 341 and 343 in exon 2, resulting in two amino acid changes from Asp to Ala (codon 90: GAC-->GCC) and Gly to Arg (codon 91: GGG-->AGG).

Identification of a new HLA‐DRB1*14 variant, HLA‐DRB1*1478, in a Korean individual

We report the identification of novel allele HLA-DRB1*1478 that was found during routine high-resolution sequence-based typing of the cord blood unit in Korean population. The DRB1*1478 allele shows two nucleotide differences from DRB1*1463 in exon 2 at nucleotide position 344 (G-->T) and 345 (T-->G), resulting in an amino acid change, Gly86Val.

Identification of a new HLA‐B*40 allele, HLA‐B*4081, in a Chinese individual

A novel human leukocyte antigen (HLA)-B*40 allele, officially named B*4081, was identified during routine high-resolution sequence-based typing in a Chinese potential hematopoietic stem cell transplantation donor. The HLA-B*4081 allele shows one nucleotide difference from B*400101 in exon 2 at nucleotide position 124 where G-->C (codon 18 GGG-->CGG) resulting in a coding change, 18Gly is changed to Arg, this is a unique nucleotide change among the HLA class I alleles, suggesting a point mutation mechanism.