Comprehensive evaluation of two HLA‐B17 monoclonal antibodies for flow cytometry‐based HLA‐B57/B58 screening prior to abacavir prescription

Hypersensitivity reactions to the drug abacavir, used to treat HIV/AIDS patients, is associated with possession of HLA‐B*57:01. We have carefully assessed two commercially available HLA‐B57/B58 murine monoclonal antibodies [0196HA and BIH0243 (One Lambda Inc.)] in a simple flow cytometry‐based assay. The evaluation involved tests on 228 reference and random samples covering 91% of all WHO recognized HLA‐A, B and C specificities. These involved donors with six different HLA‐B*57 alleles and included 19 examples of B*57:01. Both antibodies unambiguously detected B57, but there were small difference in their reactivity against B57‐positive non‐B*57:01 samples. Importantly, there was no reactivity against B57/B58‐negative samples. The possible amino acid motifs involved in the reactivity of these antibodies with B57/B58 were delineated. Thus, HLA‐B57/B58, normally present in <10% of patients, can be easily recognized using these two antibodies and further tested by a DNA‐based typing method to identify B*57:01.     

Human leucocyte antigens class II allele and haplotype association with Type 1 Diabetes in Madeira Island (Portugal)

This study confirms for Madeira Island (Portugal) population the Type 1 Diabetes (T1D) susceptible and protective Human leucocyte antigens (HLA) markers previously reported in other populations and adds some local specificities. Among the strongest T1D HLA associations, stands out, as susceptible, the alleles DRB1*04:05 (OR = 7.3), DQB1*03:02 (OR = 6.1) and DQA1*03:03 (OR = 4.5), as well as the haplotypes DRB1*04:05‐DQA1*03:03‐DQB1*03:02 (OR = 100.9) and DRB1*04:04‐DQA1*03:01‐DQB1*03:02 (OR = 22.1), and DQB1*06:02 (OR = 0.07) and DRB1*15:01‐DQA1*01:02‐DQB1*06:02 (OR = 0.04) as protective. HLA‐DQA1 positive for Arginine at position 52 (Arg52) (OR = 15.2) and HLA‐DQB1 negative for Aspartic acid at the position 57 (Asp57) (OR = 9.0) alleles appear to be important genetic markers for T1D susceptibility, with higher odds ratio values than any single allele and than most of the haplotypes. Genotypes generated by the association of markers Arg52 DQA1 positive and Asp57 DQB1 negative increase T1D susceptibility much more than one would expected by a simple additive effect of those markers separately (OR = 26.9). This study also confirms an increased risk for DRB1*04/DRB1*03 heterozygote genotypes (OR = 16.8) and also a DRB1*04‐DQA1*03:01‐DQB1*03:02 haplotype susceptibility dependent on the DRB1*04 allele (DRB1*04:01, OR = 7.9; DRB1*04:02, OR = 3.2; DRB1*04:04, OR = 22.1).     

Flow Cytometry Analysis with a New FITC-Conjugated Monoclonal Antibody-3E12 for HLA-B*57:01 Rapid Screening in Prevention of Abacavir Hypersensitivity in HIV-1–Infected Patients

Abstract

Background: Rapid screening for the detection of HLA-B*57:01 in the prevention of abacavir hypersensitivity in HIV-1–infected patients is a hallmark for clinical services. Objective: The aim of this work was to analyze the utility of flow cytometry with a new FITC-conjugated B-17 monoclonal antibody (mAb3E12) for HLA-B*57:01 screening in a Spanish cohort of 577 HIV-1+ individuals. Methods: Cryopreserved peripheral blood mononuclear cell samples from HIV-1+ individuals were analyzed by flow cytometry with the mAb 3E12 that recognizes both HLA-B*57 and HLA-B*58 alleles (members of the group specificity, HLA-B17). Patients’ DNA samples had been previously typed for HLA-B*57:01 with PCR-SSO or PCR-SSP and additional DNA sequencing (EPI Study). The results obtained by flow cytometry were compared with the results obtained by the DNA-PCR techniques. Results: By flow cytometry, 46 samples (7.97%) were positive for HLA-B17, 530 (91.86%) were negative, and 1 (0.17%) was undetermined. All samples found negative by flow cytometry were negative for HLA-B*57:01 by DNA-PCR. Of the HLA-B17 positive samples, 31 (67.4%) were positive for HLA-B*57:01, 2 (3.25%) were positive for HLA-B*57:03, 11 (26.1%) were positive for HLA-B*58, and 2 (3.25%) were negative for both HLA-B*57 and HLA–B*58 antigens. The undetermined sample was negative for HLA-B*57 and HLA-B*58 alleles by DNA-PCR. Conclusions: This study shows that flow cytometry with mAb3E12 is a highly sensitive method (no false negatives) to implement prior to DNA-PCR analysis for rapid screening of HLA-B*57:01. Additional confirmation by molecular HLA typing method would be required in less than 10% of the cohort of HIV-1–infected individuals.     

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.     

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.     

HLA‐A, ‐B and ‐DRB1 allele and haplotype frequencies of 8333 Chinese Han from the Zhejiang province,China

The distribution of human leucocyte antigen (HLA) allele and haplotype is varied among different ethnic populations. In this study, HLA‐A, ‐B and ‐DRB1 allele and haplotype frequencies were determined in 8333 volunteer bone marrow donors of Zhejiang Han population using the polymerase chain reaction sequence‐based typing. A total of 52 HLA‐A, 96 HLA‐B and 61 HLA‐DRB1 alleles were found. Of these, the top three frequent alleles in HLA‐A, HLA‐B and HLA‐DRB1 loci, respectively, were A*11:01 (24.53%), A*24:02 (17.35%), A*02:01 (11.58%); B*40:01 (15.67%), B*46:01 (11.87%), B*58:01 (9.05%); DRB1*09:01 (17.54%),DRB1*12:02 (9.64%) and DRB1*08:03 (8.65%). A total of 171 A‐B‐DRB1 haplotypes with a frequency of >0.1% were presented and the five most common haplotypes were A*33:03‐B*58:01‐ DRB1*03:01, A*02:07‐B*46:01‐DRB1*09:01, A*30:01‐B*13:02‐DRB1*07:01, A*33:03‐B*58:01‐RB1*13:02 and A*11:01‐B*15:02‐DRB1*12:02. The information will be useful for selecting unrelated bone marrow donors and for anthropology studies and pharmacogenomics analysis.     

The involvement of the HLA‐DQB1 alleles in the risk and the severity of Iranian coeliac disease patients

Coeliac disease (CD) is a highly prevalent autoimmune disorder that is triggered by the ingestion of wheat gluten and related proteins in genetically susceptible individuals. The CD is associated with human leucocyte antigen (HLA) genes particularly with HLA‐DQ alleles encoding HLA‐DQ2 and DQ8 proteins. To define risk and severity alleles for CD, a total of 120 definite CD patients and 100 healthy controls were genotyped for HLA‐DQB1 gene. HLA‐DQB1 genotyping was performed in all patients and controls using PCR‐SSP technique, and to evaluate the clinical relevance of testing for HLA‐DQB1 and determining absolute risk of disease, prevalence‐corrected positive predictive value and prevalence‐corrected negative predictive value (PcPPV and PcNPV) were calculated. Our results for a first time show that DQB1*02:00 and DQB1*03:02 alleles and DQB1*02:01/03:02 genotype very significantly associated with increased risk of patients with CD, and DQB1*03:01,4 allele provides protection against CD in Iranian patients. Furthermore, the PcPPV for DQB*02:01 and 03:02 alleles in CD were 0.014 and 0.012, respectively, and the highest absolute risk presented by DQB*0201/0302 genotype (PcPPV = 0.079) and 98% of patients with CD carried DQB1*02:01/x or DQB1*03:02/x genotype. The results also clearly demonstrated that the DQB1*02:01 allele significantly associated with severity of CD, while DQB1*03:02 allele associated with mild form of CD. These results suggest that clinically suspected individuals for CD and first‐degree relatives of patients with CD to be screened for HLA‐DQB*0201 and DQB*0302 alleles for possible early diagnosis and treatments.     

Study on the polymorphisms of HLA‐ABCDQB1DRB1 alleles and haplotypes in Hubei Han population of China

The present study aimed to analyse the frequencies of human leukocyte antigen HLA‐ABCDQB1 and HLA‐DRB1 alleles and haplotypes in a subset of 3,732 Han population from Hubei of China. All samples were typed in the HLA‐ABCDQB1 and HLA‐DRB1 loci using the sequence‐based typing method; subsequently, the HLA polymorphisms were analysed. A total of 47 HLA‐A, 89 HLA‐B, 43 HLA‐C, 49 HLA‐DRB1 and 24 HLA‐DQB1 alleles were identified in the Hubei Han population. The top three most frequent alleles in the HLA‐ABCDQB1 and HLA‐DRB1 were A*11:01 (0.2617), A*24:02 (0.1590), A*02:07 (0.1281); B*46:01 (0.1502), B*40:01 (0.1409) and B*58:01 (0.0616); C*01:02 (0.2023), C*07:02 (0.1691) and C*03:04 (0.1175); and DQB1*03:01 (0.2000), DQB1*03:03 (0.1900), DQB1*06:01 (0.1187); DRB1*09:01 (0.1790), DRB1*15:01 (0.1062) and DRB1*12:02 (0.0841), respectively. Meanwhile, the three most frequent two‐loci haplotypes were A*02:07‐C*01:02 (0.0929), B*46:01‐C*01:02 (0.1366) and DQB1*03:03‐DRB1*09:01 (0.1766). The three most frequent three‐loci haplotypes were A*02:07‐B*46:01‐C*01:02 (0.0883), B*46:01‐DQB1*03:03‐DRB1*09:01 (0.0808) and C*01:02‐DQB1*03:03‐DRB1*09:01 (0.0837). The three most frequent four‐loci haplotypes were A*02:07‐B*46:01‐C*01:02‐DQB1*03:03 (0.0494), B*46:01‐DRB1*09:01‐C*01:02‐DQB1*03:03 (0.0729) and A*02:07‐B*46:01‐DQB1*03:03‐DRB1*09:01 (0.0501). The most frequent five‐loci haplotype was A*02:07‐B*46:01‐C*01:02‐DQB1*03:03‐DRB1*09:01 (0.0487). Heat maps and multiple correspondence analysis based on the frequencies of HLA specificity indicated that the Hubei Han population might be described into Southern Chinese populations. Our results lay a certain foundation for future population studies, disease association studies and donor recruitment strategies.     

The distributions of HLA‐A,HLA‐B,HLA‐C,HLA‐DRB1 and HLA‐DQB1 allele and haplotype at high‐resolution level in Zhejiang Han population of China

The distributions of HLA allele and haplotype are variable in different ethnic populations and the data for some populations have been published. However, the data on HLA‐C and HLA‐DQB1 loci and the haplotype of HLA‐A, HLA‐B, HLA‐C, HLA‐DRB1 and HLA‐DQB1 loci at a high‐resolution level are limited in Zhejiang Han population, China. In this study, the frequencies of the HLA‐A, HLA‐B, HLA‐C, HLA‐DRB1 and HLA‐DQB1 loci and haplotypes were analysed among 3,548 volunteers from the Zhejiang Han population using polymerase chain reaction sequencing‐based typing method. Totals of 51 HLA‐A, 97 HLA‐B, 45 HLA‐C, 53 HLA‐DRB1 and 27 HLA‐DQB1 alleles were observed. The top three frequent alleles of HLA‐A, HLA‐B, HLA‐C, HLA‐DRB1 and HLA‐DQB1 loci were A*11:01 (23.83%), A*24:02 (17.16%), A*02:01 (11.36%); B*40:01 (14.08%), B*46:01 (12.20%), B*58:01 (8.50%); C*07:02 (18.25%), C*01:02:01G (18.15%), C*03:04 (9.88%); DRB1*09:01 (17.52%), DRB1*12:02 (10.57%), DRB1*15:01 (9.70%); DQB1*03:01 (22.63%), DQB1*03:03 (18.26%) and DQB1*06:01 (10.88%), respectively. A total of 141 HLA‐A‐C‐B‐DRB1‐DQB1 haplotypes with a frequency of ≥0.1% were found and the haplotypes with frequency greater than 3% were A*02:07‐C*01:02:01G‐B*46:01‐DRB1*09:01‐DQB1*03:03 (4.20%), A*33:03‐C*03:02‐B*58:01‐DRB1*03:01‐DQB1*02:01 (4.15%), A*30:01‐C*06:02‐B*13:02‐DRB1*07:01‐DQB1*02:02 (3.20%). The likelihood ratios test for the linkage disequilibrium of two loci haplotypes was revealed that the majority of the pairwise associations were statistically significant. The data presented in this study will be useful for searching unrelated HLA‐matched donor, planning donor registry and for anthropology studies in China.     

Immunogenetics of three novel HLA‐Class II alleles: DRB1*03:112, DQB1*03:02:16 and DQB1*03:139

Three novel HLA‐Class II alleles, DRB1*03:112, DQB1*03:02:16 and DQB1*03:139, are described with predicted bearing haplotypes of A*02:01, B*40:01, C*03:04, DRB1*03:112, DQB1*02:01; A*23:01, B*15:01, C*03:03, DRB1*04:01, DQB1*03:02:16 and A*01:01, B*44:02, C*05:01/03, DRB1*04:01, DQB1*03:139. Serological tests showed that the DRB1*03:112 and DQB1*03:139 specificities failed to react as expected with some well‐documented monoclonal antibodies. Subsequent examination of published HLA‐Class II epitopes and inspection of amino acid motifs suggested that epitopes exist that include the positions of their single substitutions (F31C between DRB1*03:01:01:01 and DRB1*03:112, and R48P between DQB1*03:01:01:01 and DQB1*03:139 specificities). This suggests that the reactivity of the monoclonal antibodies used was dependent on these epitopes and that their loss from these rare allele products resulted in their aberrant serology. The new alleles were found after the sequence‐based typing of 32 530 random UK European routine blood donors suggesting that each has a maximum carriage frequency of 0.0031% in the blood donor population resident in Wales.     

New genetic predictors for abacavir tolerance in HLA-B*57:01 positive individuals

Abacavir hypersensitivity syndrome (ABC HSS) is strongly associated with carriage of human leukocyte antigen (HLA)-B*57:01, which has a 100% negative predictive value for the development of ABC HSS. However, 45% of individuals who carry HLA-B*57:01 can tolerate ABC. We investigated immune and non-immune related genes in ABC HSS (n = 95) and ABC tolerant (n = 43) HLA-B*57:01 + patients to determine other factors required for the development of ABC HSS. Assignment of phenotype showed that ABC HSS subjects were significantly less likely than tolerants to carry only ERAP1 hypoactive trimming allotypes (p = 0.02). An altered self-peptide repertoire model by which abacavir activates T cells is in keeping with observation that endoplasmic reticulum aminopeptidase 1 (ERAP1) allotypes that favour efficient peptide trimming are more common in ABC HSS patients compared to patients who tolerate ABC. Independently, non-specific immune activation via soluble cluster of differentiation antigen 14 (sCD14) may also influence susceptibility to ABC HSS.     

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.     

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.     

The genetic contribution of HLA‐DRB5*01:01 to systemic lupus erythematosus in Thailand

Human leucocyte antigen (HLA) study in patients with systemic lupus erythematosus (SLE) has been investigated in various countries, but the results are still inconclusive. This study was performed to investigate the association between HLA‐DR and SLE in patients in northern Thailand. HLA‐DR subtyping was performed in 70 patients with SLE and 99 normal healthy controls living in northern Thailand using the INNO‐LiPA HLA‐DR Decoder kit (Innogenetics) and MICRO SSP HLA DNA Typing kit (One Lambda) for reconfirmation. The allele frequency (AF) of DRB5*01:01 in SLE was significantly higher than in the controls [25.7% vs. 14.6%, P = 0.012, Pc = 0.048, OR = 2.02 (95%CI = 1.17–3.48)]. The AF of DRB1*15:01 and DRB1*16:02 showed a nonsignificant tendency to be higher in SLE (10.7% vs. 8.1%, and 17.9% vs. 11.1%). Interestingly, the DRB5*01:01 allele linked to DRB1*16:02 in 47.2% of SLE and 37.9% of controls, and the prevalence of the DRB1*16:02‐DRB5*01:01 haplotype was higher in the patients with SLE [12.1% vs. 5.6%, P = 0.044, OR = 2.35 (95%CI = 1.06–5.19)]. The DRB1*16:02 linked to DRB5*02:02 and *02:03 in 18.2% and 31.8% of controls, respectively, and linked to DRB5*02:03 in 32.0% of SLE patients. The frequency of DRB1*03:01 and *15:02 alleles was not increased in Thai SLE. There was no significant association between DRB5*01:01 and any auto‐antibodies or clinical manifestations of SLE. DRB5*01:01 is associated with Thai SLE, and the association is stronger than that of DRB1*15:01. The genetic contribution of DRB5*01:01 is due partially to the linkage disequilibrium between DRB1*16:02 and DRB5*01:01 in the northern Thai population.     

Human leucocyte antigen but not KIR alleles and haplotypes associated with chronic HCV infection in a Chinese Han population

The host immune system plays a key role in the elimination of infected cells which depend on killer‐cell immunoglobulin‐like receptors (KIR), human leucocyte antigen (HLA) class I molecules and their combinations. To evaluate the roles of HLAclass I, KIR genes and their combination in Chronic hepatitis C virus (HCV) infection (CHC), a total of 301 CHCs and 239 controls in a Chinese Han population were included for HLA and KIR genotyping using next‐generation sequencing and multiplex PCR sequence‐specific priming, respectively. The allele frequency of HLA‐C*08:01 was significantly higher in the CHCs than that of the controls (0.088 vs. 0.040, OR = 2.332, 95%CI: 1.361–3.996, p = 0.022), while the frequencies of B*13:01 (0.032 vs. 0.084, OR = 0.357, 95%CI: 0.204–0.625, p = 0.009) and C*08:04 (0.008 vs. 0.038, OR = 0.214, 95%CI: 0.079–0.581, p = 0.022) were significantly lower in the CHCs. The frequencies of haplotype A*11:01‐C*08:01 were higher in the CHCs (0.058 vs. 0.019, OR = 3.096, 95%CI: 1.486–6.452, p = 0.026), while haplotype B*13:01‐C*03:04 were lower in the CHCs compared to the controls (0.028 vs. 0.071, OR = 0.377, 95%CI: 0.207–0.685, p = 0.012). No association of CHC with KIR genes, genotypes, or haplotypes, as well as HLA/KIR combinations was observed. Our results indicated that HLA‐C*08:01 was a risk factor for CHC, while HLA‐C*08:04 and HLA‐B*13:01 were protective factors against CHC. Haplotypes HLA‐A*11:01‐C*08:01 could increase susceptibility to CHC, while HLA‐B*13:01‐C*03:04 could be protective against CHC in the Chinese Han population.     

Characterization of HLA‐F polymorphism in four distinct populations in Mainland China

Currently, there is a lack of information on polymorphism of human leucocyte antigen‐F (HLA‐F) gene in ethnically diverse human populations. In this study, HLA‐F allelic typing was performed for 690 individuals representing two southern Chinese Han populations (Hunan Han and Guangdong Han) and two northern Chinese populations (Inner Mongolia Han and Inner Mongolia Mongol), using polymerase chain reaction‐sequence‐specific priming (PCR‐SSP) and PCR‐sequencing methods. Our results showed that (i) HLA‐F*01 : 01 predominated in each population with a frequency >0.94 and HLA‐F*01 : 03 was relatively more common in the two northern Chinese populations with a frequency of approximately 0.05; (ii) both geographical and ethnical factors are related to HLA‐F allelic distribution, as evidenced by the significant difference in HLA‐F allelic distribution between the Hunan Han population and the two northern Chinese populations; (iii) significant linkage disequilibrium (LD) was observed for haplotype HLA‐A*03‐F*01 : 03 in three populations. In most cases, this haplotype extended to HLA‐E*01 : 03; and (iv) Ewens–Watterson homozygosity statistic at the HLA‐F locus did not depart significantly from expectation in each of the four populations. Our data revealed a low level of HLA‐F allelic variation in Chinese populations, suggesting that HLA‐F gene may have existed before some of the HLA‐A polymorphism and have been evolving under neutrality.     

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.     

HLA-DPA1*/DPB1* en asociación con leucemias linfoides agudas y leucemias mieloides crónicas en mestizos venezolanos

More is now known of the involvement of HLA-DP region in the pathogenesis of the leukemias through several previousstudies showing interference of these molecules in modulating the immune response to pathogens. For evaluation of HLA alleles and haplotypes DPA1*/DPB1* (28 alleles HLA DPA1* and 123 of HLA- DPB1*) Olerup SSP ™PCR (Genovision) was used in 48 patients with ALL, 48 CML, and 48 Venezuelan twins as controls. For HLA/leukemias, a relative risk (RR) > 3 was considered to be a positive association and negative with an RR < 3, with a p corrected P<.05. ALL patients confirmed positive associations with DPA1*0105 allele, and negative with DPA1*010301-010302. In addition, they were positively associated with DPA1*0106 and *0107, with DPA1*020101-020106 being negatively associated with ALL. DPA1*0105, *0108 and *0109 were negatively associated with CML. The observed frequencies of HLA-DPB1* 01:01, 02:01, 03:01, 04:01 and 4:02 alleles in Venezuelan, which twins were between 7 and 16%, were higher than those of leukemic patients. Negative associations of DPB1*2:01, *3:01 and LLA were confined. No positive associations were observed with ALL. Non-confirmed positive associations were observed between DPB1*99:01 and CML. Haplotypes HLA-DPA1*01:03-DPB1*4:01, *2:01, *99:01 were strongly positively associated with CML. DPA1*1:09-DPB1*2:01, *4:01 were negatively associated with the CML. DPA1*1:03-DPB1*4:02; DPA1*01:09-DPB1*2:01, *4:01 and DPA1*02:01-DPB1*04:02 were negatively associated with ALL. The DPB1* single region does not appear to be associated with leukemia in the Venezuelan population. The strong association with several haplotypes DPA*1/DPB1* and LMC suggests massive differences between the pathogenesis of both diseases.     

The influence of the HLA-DRB, HLA-DQB and polymorphic positions of the HLA-DRβ1 and HLA-DQβ1 molecules on risk of Iranian type 1 diabetes mellitus patients

Type 1 Diabetes mellitus (T1D) is an autoimmune and multifactorial disease. HLA-DRB1 and DQB1 loci have the strongest association with T1D. This study aimed at investigating (i) susceptibility or protection of alleles, genotypes and haplotypes of HLA-DRB1 and DQB1 loci; and (ii) highly polymorphic amino acid residues of HLA-DRβ1 and DQβ1 in 105 Iranian T1D patients and 100 controls. The results indicated that DRB1*04:01, 03:01, DQB1*03:02, 02:01 alleles, DRB1*03:01/04:01, 03:01/13:03, DQB1*02:01/03:02 genotypes, DRB1*04:01-DQB1*03:02, DRB1*03:01-DQB1*02:01, DRB1*07:01-DQB1*03:03 haplotypes had positive association with T1D. In contrast, HLA-DRB1*15:01, 13:01, DQB1*03:01, 06:01 alleles, DRB1*11:01/15:01, DQB1*03:01/06:01, 03:01/05:01 genotypes and DRB1*15:01-DQB1*06:01, DRB1*11:01-DQB1*03:01 haplotypes had negative association with T1D. Analysis of amino acid sequence of HLA-DRβ1 and DQβ1 revealed that DRβ1(Lys71+) and DQβ1(Asp57-) were significantly more frequent in patients than in controls and had a positive effect in the development of T1D. Haplotype analysis demonstrated that HLA-DRB1(Lys71+) allele provided major susceptibility for T1D, and DQβ1(Asp57-) had an additive effect. We designed an allele-specific primer to develop an easy, quick and cost-benefit method to detect the DRβ1(Lys71+) . This method can identify all 114 DRB1 alleles encoding DRβ1(Lys71+) by three PCR reactions. The PcPPV and PcNPV were also calculated to determine the impact of HLA genotype testing at amino acid positions. It showed that the DRβ1(Lys71+/+) genotype carrier had 1% absolute risk of developing T1D.