HLA-B27 polymorphism in Mumbai, Western India

Human leucocyte antigen (HLA)-B27 encompasses an increasing number of subtypes that show diverse racial/ethnic prevalence in the world. One thousand-one-hundred and seventy unrelated individuals from Mumbai, Maharashtra, Western India were typed for HLA-B27 antigen by serological methods. HLA-B27 positivity was confirmed by polymerase chain reaction using sequence specific primers. High-resolution typing using sequence specific primers for HLA-B27 alleles (B*2701 - B*2721) was carried out in 70 HLA-B27-positive individuals. The frequency of B27 ranged between 1.48 and 9.6% among the caste groups studied. HLA-B27 subtyping identified B*2702 (1.43%), B*2704 (14.29%), B*2705 (70%), B*2707 (12.86%) and B*2718 (1.43%), respectively. The findings illustrate substantial genetic variation and heterogeneity within population groups from India. Extensive subtyping in other Indian caste groups will be necessary to resolve the evolutionary implications of HLA-B27 subtypes and their relationship to disease association in the Indian context.     

Prevalence of HLA-B*27 subtypes in the Tamil population of India with Ankylosing spondylitis and its correlation with clinical features

IntroductionHLA-B*27 is strongly associated with Ankylosing spondylitis (AS). Its subtypes show considerable geographic and ethnic difference. The main aim of this study was to assess the frequency of subtypes of HLA-B*27 in the Indian Tamil AS patients.Methods and materialsAdult AS patients positive for HLA-B*27 were considered for the study. The high-resolution typing to define HLA-B*27 subtypes were done using Invitrogen B kits from One Lambda (SeCore® Sequencing Kits, Thermo Fisher, United States).Results and conclusionPrevalence of subtypes identified were HLA-B*27:04 (52.2%), HLA-B*27:05 (41.6%), HLA-B*27:07 (3.5%) and HLA-B*27:02 (2.7%). All subtypes showed disease predisposition for males. The most common extra articular manifestation seen was enthesitis in HLA-B*27:04 and HLA-B*27:05. Uveitis was mainly associated with HLA-B*27:05 and dactylitis with HLA-B*27:04. A significant peripheral joints involvement for female and axial joint involvement for males was seen in HLA-B*27:04. Our study establishes the prevalence of HLA-B*27 subtypes and the associated clinical phenotypes among the Indian Tamil population. Considering the variability of presentation, organ involvement, and disease course in different subtypes and across ethnicities it is critical to define these associations in the ethnic populations we treat for their appropriate care considering the significant negative health and socioeconomic effects of AS.     

HLA B-27 subtypes in Turkish patients with spondyloarthropathy and healthy controls

The frequency and the distribution of HLA-B27 subtypes in spondylarthropathy (SpA) patients and controls were investigated in a sample Turkish population. B27 subtyping was performed by PCR-SSP method in two groups: 49 unrelated HLA-B27 positive Turkish patients with the diagnosis of SpA according to the European Spondyloarthropathy Study Group Criteria, and 55 HLA-B27 positive healthy controls. The frequency of HLA-B*27 was 2.6% in the Turkish population, and B*2705 was the predominant allele among patients with SpA. The difference was mainly between male patients and male controls The proportion of B*2705 among B27-positive patients and controls was significantly different (P=0.02). Our study supports other reports from different populations which showed that B*2705 and B*2702 were more frequent in Caucasian patients with SpA.     

HLA B27 polymorphism in Western India

We have characterized HLA B27 alleles in a sample population of Maharastra, Western Indians (n = 51), with the aim to investigate the different subtypes present among this population. The study was carried out using polymerase chain reaction with sequence-specific primers (PCR-SSP) and reverse line strip (RLS) techniques. Significant new findings have arisen from this study: B*2704, B*2705, B*2707, B*2708 and B*2714 alleles were found to be present, and two novel B27 alleles, B*2708 and B*2714, were found in this Indian population. In addition, B*2714 was observed in a patient with ankylosing spondylitis. This association has not been previously reported in ethnic groups from India.     

HLA A*02 allele and B-associated haplotype diversity in Indians

Human leucocyte antigen (HLA) A2 is the most heterogeneous allele at the HLA A locus, with approximately 56 different subtypes. Substantial heterogeneity in A*02 distribution has been observed in populations worldwide. HLA A2 allele distribution varies (4-25%) in different Indian populations and castes. HLA B40 is the most common allele associated with A2 haplotypes. In this study, molecular A*02 subtyping in Maratha (western Indian--Aryan) and Nadar (south Indian--Dravidian) caste groups using high-resolution polymerase chain reaction/reverse line strip/sequence-specific oligonucleotide hybridisation (PCR-RLS-SSOP) indicates the presence of 10 subtypes (A*02011, A*0203, A*0205, A*0206, A*0207, A*0208, A*0209, A*0211, A*0222 and A*0236) in variable frequencies. Moreover, A*0211-B*4006 was commonly observed among the north Indian Maratha caste and A*02011-B*4006 among the south Indian Nadar caste groups. HLA A*0211 is found frequently in this population and in Asian Indians, and has been reported with low frequencies in many other populations worldwide. A*0222 has been observed among Hispanics, while A*0236 has been observed exclusively among members of the Maratha caste. The findings demonstrate a substantial heterogeneity among the groups studied that may be a consequence of founder effect, racial admixture or selection pressure due to environmental factors.     

HLA-B*27 subtypes in Northern and Northeastern Thais, Karens, and Bamars determined by a high-resolution PCR-SSP technique

Human leukocyte antigens (HLA), class I, are a group of antigens expressed on most nucleated cell surfaces. They transport endogenous peptides to the cell surface for recognition by T-cell receptors. Their functions are involved in immune responses. Many diseases are associated with HLA alleles, especially HLA-B*27 that is strongly associated with ankylosing spondylitis (AS). HLA-B*27 consists of 42 subtypes. Different subtypes of HLA-B*27 were reported in different ethnic groups of AS patients. In this study, a high-resolution polymerase chain reaction–sequence-specific primer technique has been developed to define all the HLA-B*27 subtypes with a total of 29 primer mixtures. Two of the primer mixes were used to detect the HLA-B*27 -specific group, and 27 primer mixes were used to identify 42 subtypes ( B*2701–B*2721 and B*2723–B*27 43). The HLA-B*27 -group-specific primers have been tested in unrelated healthy subjects; 846 Northeastern Thais (NET), 334 Northern Thais (NT), 264 Karens, and 310 Bamars. Sixty-three NET (phenotype frequency, PF = 7.4%), 24 NT (PF = 7.1%), 5 Karens (PF = 1.8%), and 12 Bamars (PF = 3.9%) were positive for HLA-B*27 . Only B*2704 was found in Karens, whereas B*2704 , B*2705/37/39 , B*2706 , and B*2707 were found in NET and NT. In Bamars, B*2704 , B*2705/37/39 , B*2706 , and B*2725 were found. The distribution of HLA-B*27 subtypes was compared with other studies in Asian and Caucasian populations. Significant differences of the distribution of HLA-B*27 subtypes were found in most of the populations. This study established a simple technology for HLA-B*27 subtyping and provided basic information for anthropology and further studies in disease associations.     

少儿强直性脊柱炎与幼儿类风湿性关节炎HLA-B27亚型的鉴别诊断

目的：探讨HLA－B27等位基因亚型与少年强直性脊柱炎和幼年类风湿性关节炎的关联。方法：用PCR－SSP方法对74人HLA－B27等位基因亚型进行研究，其中少年强直性脊柱炎32例，幼年类风湿性关节炎28例，5个家系中患者的父亲或母亲5例，正常对照组9例，并进行关联分析。结果：本组人群的HLA－B27等位基因由HLA－B*2704、*2705、*2702、*2707 4种亚型组成，其中少年强直性脊柱炎患者HLA－B27等位基因亚型频率为B*2704 56.25%、B*2705 40.63%、B*2702 3.13%；幼年类风湿性关节炎HLA－B27等位基因亚型频率为B*2705 60．7％、B*2704 28．57％、B*2702 3．57％及B*2707为7．14％；少年强直性脊柱炎与幼年类风湿性关节炎结果比较，HLA－B*2704基因频率在少年强直性脊柱炎组高于幼年类风湿性关节炎组（RR＝3．21，P＜0．05）。结论：少年强直性脊柱炎与HLA－B*2704等位基因亚型关联。对HLA－B27等位基因亚型的检测可成为少年强直性脊柱炎和幼年类风湿性关节炎鉴别诊断中一个有价值的实验指标。     

HLA-B*15 subtypes in the population of north-eastern Thailand.

The HLA-B*15 group is the most polymorphic HLA-B allele and so has several subtypes. These subtypes have not been defined in the population of north-eastern Thailand (NET). In a previous study, using polymerase chain reaction-sequence-specific primers (PCR-SSP), subtypes were categorized into four groups, namely: group I: HLA-B*15 (01, 04-07, 12, 14, 19, 20, 24, 25, 26N, 27, 32, 33, 34 and 35); group II: HLA-B*15 (02, 08, 11, 15, 28 and 30); group III: HLA-B*1503/4802; group IV: HLA-B*1521. Groups I and II occurred frequently (allele frequency = 8.0 and 2.5%), and thus we optimized the polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) method to identify HLA-B*15 subtypes of groups I and II. Eighty samples of DNA carrying HLA-B*15 from 300 healthy unrelated individuals were tested. B*1502 (52.5%) and B*1525 (13.8%) were the most common subtypes found in NET. They also showed strong linkage disequilibrium with HLA-Cw and heterogeneity of HLA-A, DR, DQ haplotypes. Although limited conclusions can be drawn from this study because of the small number of DNA references used, the baseline data will be useful in the selection of common HLA-B*15 alleles when subtyping for unrelated donor transplantations.     

Frequency of HLA-B27 subtypes in a Danish population and in Danish patients with ankylosing spondylitis

Polymerase chain reaction in combination with sequence-specific oligonucleotide probes were used to analyze nine HLA-B27 subtypes among 51 healthy I HLA-B27 positive Danish blood donors and 30 Danish HLA-B27 positive patients with ankylosing spondylitis (AS). In the group of healthy Danes we found two subtypes, B*2705 (90.2%) and B*2702 (9.8%), however, among the AS patients only the B*2705 subtype was detected. We did not find a significant evidence for associations between AS and a particular HLA-B27 subtype in a Danish population.     

New alleles of HLA-B35 in South India.

Serological pattern analysis of HLA B35 alleles from south India revealed the existence of polymorphism in the HLA-B35 alleles. HLA-B typing was carried out on 42 HLA-B35 individuals from south India using 210 antisera of AHS#4, XII workshop: all these cells were those characterized in III AOH and XI IHW. Of the 42 cells analysed for HLA-B35 sub-types by PCR-SSOP technique, 3 alleles predominated; HLA-B*3503 followed by B*3501/5 and B*3501/5/8. These were correlated to serological patterns of the cells typed in XI and XII workshops. The analysis identified some sera which did not identify HLA-B*3503 and B*3501/5. The serological patterns of HLA-B*3501/5/8 and B*3503 were clearly assignable in Iyer caste group by sera WEG 107 & HA3 109 sera of XI IHWC but not in many south Indian samples. A systematic analysis of B*35 in various Indian caste groups is warranted.     

HLA-B27 polymorphism in patients with juvenile and adult-onset ankylosing spondylitis in Southern China

Abstract
Distribution of B27 subtypes in juvenile and adult-onset ankylosing spondylitis (JAS and AAS) in Southern China was studied. A total of 505 patients belonged to Han population were included (145 JAS and 360 AAS patients), and 1368 healthy individuals were included as controls. Human leukocyte antigen (HLA)-B27 typing was performed by Luminex liquid array combining polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) and/or serological method. HLA-B27 subtyping was performed by polymerase chain reaction-sequence specific primer (PCR-SSP). The sequence-based typing was performed for the B*2715 samples to verify the PCR-SSP results. HLA-B27 was presented in 453 of 505 patients (89.7%), compared with 74 of 1368 controls (5.41%). B*2704 subtype in AS group was significantly higher than controls and B*2705 subtype significantly lower. B*2715 and B*2702 were found in 1.32% and 0.66% of the B27-positive patients but none in controls, and there was no significant difference between either of them and controls. B27-positive patients were 134 (92.4%) in JAS group and 319 (88.6%) in AAS group. There was no significant difference for B27 subtypes distribution between JAS (B*2704, 05, 15) and AAS (B*2704, 05, 15, 02) groups. The frequency of B*2715 in two groups was 3 (2.24%) and 3 (0.94%), respectively. The onset age of three JAS patients carrying B*2715 was 5, 9 and 13 years old, respectively. Our results suggested that B*2704 was the predominant subtype in AS patients in Southern China. B*2715 was observed in AS group only and slightly more in JAS than in AAS, and the patients carrying this allele tended to have early onset, B*2715 may be disease-association subtype.     

HLA-B and HLA-C alleles and haplotypes in the Dravidian tribal populations of southern India

The Dravidians are believed to be the earliest inhabitants of India. Their subsequent migration and admixture with invading racial groups has been of scientific interest for population geneticists. In the present study, seven highly endogamous and extremely isolated colonies of Dravidian tribal populations (n = 105) from Kerala in South India were analysed and compared with random non-tribal Dravidian (RND) samples (n = 78) of southern India using the polymerase chain reaction with sequence-specific primer method for HLA-B and HLA-C typing. The tribal group comprises Adiya, Kanikkar, Kattunaikka, Kuruma, Kurichiya, Malapandaram and Paniya, while the RND group includes Malayalam-speaking individuals from various non-tribal castes of Kerala selected randomly. Some of the most frequent HLA-B alleles in the RND population were similar to the North Indian population and included B*07, B*61 (B*40), B*44, B*51, B*35 and B*52. Although B*61 was the most frequent allele in our total study population, the frequency fluctuated in individual populations. HLA-Cw*14 was one of the most frequent alleles while HLA-Cw*17 was totally absent in all populations studied. The haplotype B*61-Cw*14 was present in all the study groups except in Kurichiya, and the haplotype B*51-Cw*14 was only absent in Kattunaikka. Phylogenetic tree and correspondence analysis indicate that all the Dravidian tribal communities group together as a separate cluster, while the RND group of individuals from South India lie close to the North Indian population. This suggests that the RND population of South India might have a crypto-Dravidian origin, while the smaller Dravidian tribal communities have a distinct Dravidian origin.     

Association of an extended haplotype of HLA class I alleles and their flanking microsatellites with spondyloarthropathies in South Indian patients

Spondyloarthropathy (SpA) is a complex autoimmune disease known to have an association with the HLA system. The aims of the present study were to compare the suballelic association of HLA-B27 and other HLA class I genes with microsatellite markers spanning the HLA class I region in the South Indian population of Kerala. The five microsatellites were C1_2_A (D6S2793), C1_2_5 (D6S2811), C1_4_1 (D6S2927), MIB (D6S2810), and STR-MICA. HLA typing was performed in 67 SpA patients and 77 ethnically matched healthy controls by polymerase chain reaction using sequence-specific primers, whereas fluorescence-labeled microsatellites were analyzed using GeneScan analysis. There was a significant association of HLA-B27 and Cw*02 with SpA, whereas B*44 had a negative association with the disease. Only two HLA-B27 subtypes, B*2704 and B*2705, were observed in the South Indian population. We were able to successfully predict the major B27 subtype B*2705 based on the C1_2_5 microsatellite. A significant association of different alleles of all the microsatellite markers with SpA was observed. An extended six-locus haplotype, B*2705-Cw*02-STR-MICA(A4)-C1_4_1 (213 bp)-C1_2_5 (178 bp)-MIB (340 bp), was significantly associated with SpA.     

HLA-B27 subtypes in the spondarthropathies

The spondartliropathy (Sp)-associated HLA-B27 antigen includes al least seven subtypes. B*2701–07, of which 01, 02, 05 and 07 occur in Caucasians. This study examined the B27 subtype distribution in British patients with Sp. The 133 HLA-B27⁺ subjecis comprised 94 European Caucasian Sp (58 ankylosing spondylitis (AS), 22 reactive arlhrilis (ReA: 11 sexually acquired (SARA). 11 enteric (EReA)). eight undifferentiated Sp (USp). and six pauciarticular juvenile-onset chronic arthritis (pJCA)) patients, antl 34 healthy Caucasian controls, together with four Asian Indian and one Chinese. ³⁵S-labelled B27 was immunoprecipitated with anti-B27 MoAbs. and subtyped according to isoelectric point (pi) following isoelectric focussing. The use of B27 MoAb permitted subtype assignment without full class 1 HLA lyping. The vast majority (95%) were B*27O5 (Caucasian controls 31/34; AS 55/58; ReA 21/22; USp 8/8. and pJCA 6/6; Indian control 1/1 and AS 2/3: Chinese pJCA I/I), and the remainder B*2702. No B*270l or 07 subjects were identified. AS occurs in both B*2702 and 05 subjects, and we extend this observation to small numbers of ReA and of Indian AS subjects. This implicates molecular features shared between B27 subtypes, rather than subtype-determining regions of the antigen, in Sp palhogenesis.     

Diversity of human leukocyte antigen-B27 alleles in Han population of Hunan province, southern China

This study was to investigate the frequency of HLA-B27 and its subtypes in the Han population of Hunan province, southern China. One hundred and sixty-nine healthy unrelated donors were tested for HLA-B27 by polymerase chain reaction-sequence-specific primer (PCR-SSP). One hundred and twenty-eight B27-positive spondyloarthropathy patients and 18 B27-positive healthy controls were subtyped using the high-resolution PCR-SSP. The phenotype frequency of human leukocyte antigen (HLA)-B27 was found to be 2.36% in healthy population. Five B27 alleles were identified: B*2704, B*2705, B*2706, B*2707, and B*2724. No significant difference was found in the distribution of HLA-B27 subtypes between the patients and controls studied. Notably, B*2724 was observed in a juvenile patient with ankylosing spondylitis. This subtype has not been previously reported in Chinese ankylosing spondylitis (AS) patients and other ethnic groups.     

HLA and tumour necrosis factor (TNF) polymorphisms in ocular Behçet's disease

The role of HLA-B*51 and other major histocompatibility complex (MHC) genes in Beh?et's disease (BD) remains unknown. We have performed HLA and tumour necrosis factor (TNF) polymorphism analysis in BD and evaluated their contribution to ocular disease. In this study, 102 patients and 115 controls of Middle Eastern descent were investigated by HLA and B*51 subtyping using novel primers, and by LT alpha NCo 1 and TNF 308 promoter polymorphism analysis. The frequency of the HLA-B*51 family of alleles was raised in patients compared to controls (66% vs. 15%, Pc=2.5x10(-12), OR=10.9). The odds ratio (OR) of this group of alleles for subgroups of patients was as follows: non-ocular patients 7.8, all ocular patients 12.6, blind patients >22. HLA-B*51 subtyping detected B*5101, 07, 08 and 09 alleles, with a similar frequency among patients and controls. HLA-Cw*1602 was associated with B*5108, but was not an independent risk factor for disease. The LT alpha (TNFB*2) allele was associated with HLA-B*51 among patients and the frequency of this allele was significantly higher among completely blind patients compared to both non-ocular patients (P=0.048, OR >3.6) and to healthy controls (P=0.022, OR >4.3). The rare TNF-2 polymorphism at the TNF -308 promoter position was associated with HLA-B*50 (not B*51), and was not associated with BD. Thus, in this population the HLA*B51 family of alleles is a strong risk factor for BD, and in particular the development of ocular disease. HLA-B*51 subtyping did not define new markers for BD. A primary role for TNF gne polymorphisms in BD was not identified, but co-expression of the TNFB*2 allele with HLA-B*51 may contribute to severity of ocular disease.     

HLA-B27 polymorphism in the Malays

The frequency of HLA-B27 and its subtypes was determined in 878 Malay subjects. Thirty-five of the subjects typed for HLA-A, -B and -DR were found to be positive for HLA-B27. The frequency of this allele in the Malay population was found to be 3.99%. The subtypes observed and their frequencies are: HLA-B*2704 (19.4%), HLA-B*2705 (5.6%), HLA-B*2706 (72.2%) and HLA-B*2707 (2.8%).     

HLA-B27 subtypes determination in patients with ankylosing spondylitis from Zulia,Venezuela

To perform an investigation regarding the distribution of the human leukocyte antigen (HLA)-B27 subtypes in the Zulian population with ankylosing spondylitis (AS), 48 unrelated Mestizos, HLA-B27 positive by serology, were studied using the polymerase chain reaction-specific sequence oligonucleotides probe (PCR-SSOP) and specific sequence primers (SSP) to analyze the polymorphism in exons 2 and 3 of the HLA-B27 gene. Only two of eight HLA-B27 subtypes studied (B*2701-B*2708) were found. The distribution of these alleles in the population of patients was: B*2705, 68.8%, and B*2702, 31.2%. B*2705 subtype showed significant association with patients being male. In the healthy controls, the most common subtype was B*2708. These results were compared with frequencies reported in other Mestizo and Spanish populations and showed significant differences, such as a high frequency of B*2702. Such results show that HLA*B2705 and HLA*B2702 are the subtypes most frequently associated with AS in our Mestizo population and suggest a possible protector role for HLA*B2708, which was found only in the healthy population.     

Lack of carboxyl–terminal tyrosine distinguishes the B2706–bound peptide repertoire from those of B2704 and other HLA–B27 subtypes associated with ankylosing spondylitis

B*2704 and B*2706 are two closely related HLA-B27 subtypes, which differ from the common B*2705 by the Asp>Ser77, Val>Glu152, and Ala>Gly211 amino acid changes. In addition, B*2706 differs from B*2704 by the His>Asp114 and Asp>Tyrl 16 changes. In spite of their similarity B*2704, but not B*2706, was associated to ankylosing spondylitis in a same population. We have carried out pool sequence analyses of the peptides naturally bound to each of these subtypes, and of several individual peptide ligands. B*2704 and B*2706 shared with B*2705, among other features, their selectivity for Arg² and their allowance for some aliphatic and aromatic C-terminal residues in their bound peptides. The main features that distinguished both subtypes from B*2705 were: 1) their failure to present peptides with C-terminal basic residues, and 2) their allowance for both polar and nonpolar residues at peptide position 3. A major difference between B*2704 and B*2706 was that C-terminal Tyr was prominent among the peptides bound to B*2704, but was not detected among those from B*2706. The use of Tyr as a C-terminal anchor motif is the only functional feature shared by the disease-associated B*2705, B*2702, and B*2704 subtypes that is absent in B*2706. This suggests that the ability of HLA-B27 to present peptides with C-terminal Tyr might be critical for its association to spondyloarthropathy,     

Comparative analysis of the association of HLA-B*51 suballeles with Behçet's disease in patients of German and Turkish origin

The distribution of the different HLA-B*51 suballeles among patients with Beh?et's disease (BD) of German (n=33) and Turkish (n=92) origin in comparison to their presence in the respective ethnically matched healthy control groups (German: n=325, Turkish: n=93) was studied. HLA-B*51x was significantly increased in both patient groups in comparison to the controls (Germans: 58% vs. 12%, OR 9.76, P<0.001; Turkish: 75% vs. 25%, OR 9.13, P<0.001). Molecular subtyping of B*51x revealed HLA-B*51011 and B*5108 as the predominant suballeles in both patient groups and controls although with a slightly increased frequency of HLA-B*5108 in the diseased individuals. HLA-B*5105 was the only further HLA-B*51x subtype detected in one Turkish patient heterozygous also for HLA-B*5101. HLA-B*5107 although present in a Turkish as well as German control was absent in the patient groups. There was also a tendency towards a higher degree of homozygosity for HLA-B*51x in both patient groups versus the matched controls (Germans: 10% in patients vs. 2,5% in controls; Turkish: 27% in patients vs. 13% in controls). Our study further supports previous hypothesis of an association of BD with B51 suballeles which share amino-acid residues at positions 63 and 67 as well as at positions 77-83 for specific peptide binding and natural killer (NK)-cell interactions. This applies to HLA-B*5101 and B*5108, but not to HLA-B*5107 different at position 67, which could be negatively associated with BD.