HLA B27 polymorphism in Western India

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

INTRODUCTION

HLA-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 MATERIALS

Adult 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 CONCLUSION

Prevalence 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.

Interethnic Variations and Clinical Features of Spondyloarthropathies in a Middle Eastern Country

Objectives

The study aimed to demonstrate the interethnic differences and clinical features of Spondyloarthropathy(SpA) patients in a diverse Middle Eastern Country.

Methods

A retrospective review of medical records to collect the required data was conducted for SpA patients at two study institutions in the United Arab Emirates.

Results

Of 141 SpA patients found, 88 AS(Ankylosing Spondylitis) patients and 53 'other SpA' patients were identified. Males constituted 81% of AS and 55% of 'other SpA' patients. Patients with AS and 'other SpA' had a mean age of symptom onset of 28 and 34 years, respectively.49% and 40% of AS and 'other SpA' patients had a history of Anti-TNF therapy usage. Enthesitis and Uveitis were noted in 16% and 18% of AS patients whilst 53% and 11% in 'other SpA' patients, respectively.Caucasian, Indian Subcontinent and Arabs constituted 93% of our cohort. Mean age of onset of symptoms in the Indian Subcontinent 'other SpA' group was much greater than the other two ethnicities. Duration of symptoms to diagnosis was 3.5 and 4 years in AS and other SpA patients' respectively. HLA-B27 positivity was found in 53%, 80% and 93% of Arab, Indian Subcontinent and Caucasian AS patients, respectively, whilst seen in 50%, 25% and 33% of the same respective ethnicties in 'other SpA' patients.

Conclusion

This study on 141 patients is the largest to analyse inter-ethnic variations in SpA patients in the region. Our cohort shows a short delay in diagnosis with a relatively higher Anti-TNF usage.

HLA-B27 testing: A journey from flow cytometry to molecular subtyping

BACKGROUND

Determination of HLA-B27 status plays an important role as adjuvant in suspected cases for diagnosis of Ankylosing Spondilytis (AS). Objectives of this study were to evaluate (i) flow cytometry method in comparison with DNA microarray for HLA-B27 typing and (ii) EUROArray HLA-B27 Direct assay for HLA-B27 allele detection along with discrimination of AS/non-AS subtypes in Indian population.

METHODS

A total of 7543 patients with a presumptive clinical diagnosis of AS were referred for screening of HLA-B27. All samples were initially tested by flow cytometry, and based on its findings, 1560 samples were analyzed for the presence of HLA-B27 allele by microarray technology. A subset of samples (n = 200) were further tested by DNA sequencing for identification of HLA-B27 subtypes.

RESULTS

Screening of HLA-B27 by flow cytometry reported 1551 positive (20.56%) and 5556 negative (73.65%) cases. Remaining 436 (5.78%) samples were identified within equivocal zone. Of cases (n = 1560) analyzed by microarray method, 1333 (85.44%) and 227 (14.55%) were detected microarray positive and negative, respectively. DNA sequencing identified HLA-B*27:07 as the predominant subtype among cases showing ex2 positivity by microarray method. Of 200 cases, 20 cases (14 of HLA-B*07 and 6 of HLA-B*37) of HLA-B27 cross-reactive subtypes were also identified.

CONCLUSION

We recommend DNA typing as a complementary tool along with flow cytometry to accomplish successful HLA-B27 phenotype determination. This is the first study among Indian population to evaluate efficacy of EUROArray to detect B27 allele and its potential to indicate the presence of nondisease-associated alleles in Indian population.

Glioma Indian scenario: Is there a human leucocyte antigen association?

Background:

The central nervous system tumors are a rare neoplasm with little knowledge with Human Leukocyte Antigen (HLA) involvement. Primary brain tumors are cancers that originate in brain classified according to their appearance under a microscope as low grade (grade I and II) with diffuse astrocytomas, pliocytic astrocytomas, oligodendrogliomas, gangliogliomas, and mixed gliomas as common subtypes and high grade (grade III and IV).

Materials and Methods:

HLA associations in common glioma are reported from other parts of the world. The normal cancer treatment is surgery, followed by radiotherapy, and chemotherapy; nowadays immunotherapy is advised. HLA distribution in a Glioma patient was done based on serology and molecular techniques. The immune response gene studies have implicated the HLA allele association in most of the common diseases from India. Considerable variations are noted in HLA association with cancers; hence, we have summarized the HLA involvement in Glioma with respect to the literature.

Results:

HLA A*030101, A*310102, B*350101, B*4406, Cw*040101, Cw*070101, DRB1*070101, and DRB1*1001.

Conclusion:

Ethnic diversity and HLA polymorphism precipitate differential immune response genes involved in variable disease manifestations. Therefore, caste-specific HLA allelic specificity needs to be identified, which may help in early identification of the associated HLA allele and establishing clinical practices among glioma patients.

The association of HLA-B*27 subtypes with ankylosing spondylitis in Wuhan population of China

The aim of this study was to investigate the association of the B27 subtypes with ankylosing spondylitis (AS) in the Wuhan population of China. We selected 317 HLA-B27-positive individuals (145 controls and 172 patients with ankylosing spondylitis). The B27 subtypes were characterized using a PCR-SSP method. Six B27 subtypes were determined: B*2702, 03, 04, 05, 06 and B*13. HLA-B*2704 and HLA-B*2705 were the two high frequency genotypes in controls and patients. Compared with the controls, the AS patients had high frequency of B*2704 (patients 69.2% vs. controls 53.8%) and low frequency of B*2705 (patients 23.8% vs. controls 33.1%). B*2703 was detected in 10 (5.8%) patients and in 13 (8.9%) controls. B*2702, 06 and B*2713 were relatively rare. Our results show that the allele conferring risk to AS in the Wuhan population of China was B*2704 and B*2705. B*2704 is strongly associated with AS.

Demography and clinical course of ulcerative colitis in a multiracial Asian population: a nationwide study from Malaysia

OBJECTIVE

To establish the clinical course of ulcerative colitis (UC) in the Malaysian population, comparing the three major ethnic groups: Malay, Chinese and Indian.

METHODS

Patients who were diagnosed with UC from seven major medical referral centers in Malaysia were recruited. Their baseline characteristics, and the extent of the disease, its clinical course and complications were recorded.

RESULTS

A total of 118 patients was included. The extent of disease was as follows: proctitis alone in 22 (18.6%), sigmoid colon in 23 (19.5%), descending colon in 16 (13.6%), transverse colon in 11 (9.3%), ascending colon and pancolitis 46 (39%). Most patients had chronic intermittent disease. Extra-intestinal complications were seen in 27 (22.9%) patients and fulminant colitis was seen in four (3.4%). None developed colorectal cancer. The overall cumulative colectomy rates at 1, 5 and 10 years were 3.4% (CI: 0.9-8.5), 5.9% (CI: 1.9-13.2) and 15.6% (CI: 6.5-29.4), respectively. There was a higher prevalence of extra-intestinal manifestations and a trend towards more extensive disease among Indian patients. However, no significant differences were seen in the age of onset, the severity of disease (fulminant colitis, refractory disease) and the colectomy rate.

CONCLUSION

As in developed countries, most of our patients have a remitting and relapsing pattern of disease but the clinical course appears to be milder, with lower rates of colectomies. There are differences in clinical presentation among the three major ethnic groups, with Indians having a higher prevalence of extra-intestinal manifestations and a trend towards more extensive disease.

Molecular diversity of HLA-A, -B and -C alleles in a North Indian population as determined by PCR-SSOP

We have used molecular methods to determine the frequencies of human leukocyte antigen (HLA)-A, -B and -C alleles in normal, healthy, unrelated individuals from North India using polymerase chain reaction and hybridization with sequence-specific oligonucleotide probes as there is no comprehensive report showing molecular diversity of all the class-I alleles present in North Indians. A*0101, A*0206, A*0301, A*1101, A*6801, A*2401 and A*3101 were the most prevalent alleles of the A locus with 91.11% of the samples showing heterozygosity. At the HLA-B locus a total of 47 B locus alleles were observed and the only allele found with an allele frequency of 15% was B*5801. Other frequent B-locus alleles observed were B*5101, B*3503 and B*4006 with relatively less frequent alleles like B*5201, B*3501, B*0702, B*4403, B*5701, B*1801 and B*5501. Of the samples studied 92.31% were heterozygous for B-locus alleles. Cw*0602 and Cw*0401 were the most frequent C-locus alleles. Other frequent C-locus alleles were Cw*0102, Cw*0302, Cw*0701, Cw*0702, Cw*1202, Cw*1203, Cw*1502 and Cw*1503. HLA alleles common in Africans like B*5801, A*68012, B*5301, B*44032, B*4006 and Cw*1701 were observed in the North Indians besides oriental alleles like B*1301, B*1502 and B*4001 confirming that the genetic make-up of North Indians is Caucasoid with elements of Mongoloid and Negrito races. Some new/rare alleles like B*1802, described as a new allele from Thailand and B*8101, described earlier in a Bubi population were also observed although with low frequencies, showing the diversity of HLA class-I alleles present in the North Indians.

Seronegative Spondyloarthropathy – Studies from the Asia Pacific Region

Recent therapeutic advances, in particular the use of anti-tumour necrosis factor (anti-TNF) agents, have revived interest in the seronegative spondyloarthropathies (SpA), a group of arthritides characterised by axial skeletal involvement and the absence of rheumatoid factor. The purpose of this article is to review the studies that have been done in the Asia Pacific region, as a broad understanding of the scope and severity of this group of diseases would enable rheumatologists and physicians in this part of the world to better manage their patients. The majority of genetic studies have focused on the associations of HLA-B27 with ankylosing spondylitis (AS) and SpA, while a few studies examined the associations of the CARD, IL-1, LMP2, TAP and TGF with AS. There are a handful of studies on the immunological responses to bacteria and cytokine levels in AS. The onset and clinical features of SpA have been reported from most countries in the region, but no data on patient outcomes, using current measurement tools such as the Bath Ankylosing Spondylitis Disease Activity index (BASDAI), is available. Validation of these instruments of measurement as well as classification criteria in different ethnic populations is necessary where no prior data exist. Future studies will likely be focused on better clinical characterisation of patient cohorts, particularly with regard to the use of currently used measurement tools for disease activity and spinal function and mobility, and the identification of the need for biologic therapy in each country. Key words: ESSG criteria, Genetics, Immunological and clinical features

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.

B*2707 differs in peptide specificity from B*2705 and B*2704 as much as from HLA-B27 subtypes not associated to spondyloarthritis

HLA-B*2707 is associated with ankylosing spondylitis in most populations. Like the non-associated allotypes B*2706 and B*2709, it lacks Asp116 and shows preference for peptides with nonpolar C-terminal residues. The relationships between the peptide specificity of B*2707 and those of the disease-associated B*2705 and the non-associated subtypes were analyzed by determining the overlap between the corresponding peptide repertoires, the sequence of shared and differential ligands, and by comparing allospecific T cell epitopes with peptide sharing. The B*2707-bound repertoire was as different from that of B*2705 as from those of B*2706, B*2709, or the two latter subtypes from each other. Differences between B*2707 and B*2705 were based on their C-terminal residue specificity and a subtle modulation at other positions. Differential usage of secondary anchor residues explained the disparity between the B*2707-, B*2706-, and B*2709-bound repertoires. Similar differences in residue usage were found between B*2707 and both B*2704 and B*2706, as expected from the high peptide overlap between the two latter subtypes. T cell cross-reaction paralleled peptide sharing, suggesting that many shared ligands conserve their alloantigenic features on distinct subtypes. Our results indicate that association of HLA-B27 subtypes with ankylosing spondylitis does not correlate with higher peptide sharing among disease-associated subtypes or with obvious peptide motifs.

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 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.

HLA-B27 polymorphism in Turkish patients with ankylosing spondylitis

The aim of this study was to determine the distribution of human leukocyte antigen (HLA)-B27 subtypes in serologically HLA-B27-positive ankylosing spondylitis (AS) patients and healthy controls from the Turkish population and to compare this with other reports from other populations. We subtyped HLA-B27 in 38 HLA-B27-positive Turkish patients with AS and 47 HLA-B27-positive healthy controls without AS by polymerase chain reaction with specific sequence primers (PCR-SSP). The results demonstrated that: B*2705 was the predominant subtype among both of the patients (71.1%) and controls (68.0%). B*2702 was observed in 26.3% and 32.0% of the patients and controls, respectively. B*2708 subtype was found in 2.6% of the patients but not among the control group. When the distribution of B27 subtypes in Turkish populations was compared with that in other populations, similar frequencies with the Caucasian-Europe groups were noted. However, this should be interpreted carefully because of the small number of individuals in our study.

HLA and disease

Association of HLA and diseases is well known. Several population studies are available suggesting evidence of association of HLAs in more than 40 diseases. HLA found across various populations vary widely. Some of the reasons attributed for such variation are occurrence of social stratification based on geography, language and religion, consequences of founder effect, racial admixture or selection pressure due to environmental factors. Hence certain HLA alleles that are predominantly associated with disease susceptibility or resistance in one population may or may not show any association in other populations for the same disease. Despite of these limitations, HLA associations are widely studied across the populations worldwide and are found to be important in prediction of disease susceptibility, resistance and of evolutionary maintenance of genetic diversity. This review consolidates the HLA data on some prominent autoimmune and infectious diseases among various ethnic groups and attempts to pinpoint differences in Indian and other population.

Human leukocyte antigen allele associations in type-1 autoimmune hepatitis patients from western India

BACKGROUND AND AIMS

The immunogenetic basis of autoimmune diseases has become more and more evident. We have analyzed the human leukocyte antigen (HLA) associations with type-1 autoimmune hepatitis (AIH) among patients from western India.

METHODS

In 20 patients and 120 healthy controls, polymerase chain reaction amplified with sequence specific primers and hybridized with oligoprobes was carried out to elucidate the HLA A, B, C and DRB1 allele associations.

RESULTS

The study revealed that A*0222 (20% vs 1.66%; P = 0.0001), A*3201 (15% vs 0.83%; P = 0.0004), A*680102 (30% vs 6.66%; P = 0.001), B*35 (40% vs 11.66%; P = 0.001), B*5501 (10% vs 0.83%; P = 0.008), Cw*0102 (15% vs 1.66%; P = 0.002) and Cw*070101 (50% vs 11.66%; P = 2.5E-05) were significantly increased among the A, B and C alleles of AIH patients. Among the HLA DRB1 alleles, DRB1*0301 (20% vs 6.19%; P = 0.03), DRB1*1301 (15% vs 2.65%; P = 0.01), DRB1*14 (30% vs 11.5%; P = 0.02) and DRB1*1501 (40% vs 22.12%; P = 0.08) were increased in AIH patients when compared with the controls.

CONCLUSIONS

The present study indicates that the HLA susceptibility to type 1 AIH in the different populations studied is complex.

Polymorphism of HLA-B27 in Taiwanese Chinese

Heterogeneity of HLA-B27 is represented by a family of 24 closely related alleles/subtypes. Frequency and disease association of these alleles with spondyloarthropathies differ among ethnic groups. Accurate investigation of frequencies of alleles is often hindered by the size and demographic region of sample tested. With an ever-increasing number of B27 alleles being discovered, it is becoming imperative to establish disease association of each individual alleles and its biological importance. In a large number of normal healthy Taiwanese Chinese individuals (75,777) tested nationally, over a period of five years, in a single immunogenetics centre, we found additional B27 subtypes not revealed in a previous Taiwanese Chinese population study. The subtypes found in Taiwanese Chinese and the frequencies of each of the subtypes are reported.

Genetic analysis of Indian HIV-1 nef: subtyping, variability and implications

HIV-1 subtype C is predominant in India and globally. In the present study, we analyze HIV-1 subtype C regulatory protein Nef sequences from five recent Indian seroconverters and five long-term survivors (LTSs) for variability at crucial functional domains. Sequence analysis suggested the possibility of using regulatory gene sequences for viral subtyping and evolutionary studies apart from structural genes. In the phylogenetic tree, Indian nef sequences segregated away from other reported subtype C sequences, forming an Indian subclade within subtype C. Our studies also suggested no evidence for the association of truncated Nef with slow progression of disease, as all LTSs had intact Nef. We could identify some variations in juxtapositions to crucial functional domains, especially in seroconverter sequences, when comparing them with others. In phylogenetic analysis, specifically for the base-pair regions 411-428 and 478-525, our seroconverter sequences segregated away from those reported earlier in the literature, indicating specific evolutionary changes in these conserved regions of nef in currently circulating viruses. But the dN/dS ratio for our samples was less than one on comparing them with reported subtype C and representative sequences of different clades, strongly emphasizing the necessity of sequence conservation at different disease stages and even across clades. HLA-I binding epitope predictions for common Indian HLAs indicated that specific mutations in seroconverter Nef may alter the intensity of epitope binding, which may alter the outcome of the immune response. Hence these data would be useful in designing Nef epitopes to be included in multi-epitope HIV-1 vaccine for the Indian population and would also be of immense help in HIV-1 evolutionary studies.

HLA diversity among Nadars, a primitive Dravidian caste of South India

South India is one of the oldest geophysical regions mainly occupied by Dravidian language-speaking people. Here a random panel of 61 unrelated Nadar healthy individual from Tamil Nadu State were analyzed and compared with other populations of India and the world. HLA-A, B and C alleles frequencies and their haplotype frequencies were determined by high-resolution typing of genomic DNA. The analysis revealed that the Nadar caste of South India have several characters shared with East Asian populations consistent with the demographic history of South India, as well as specific features including several unique alleles such as A*03011, A*31011, B*15011, B*3501, B*51011, Cw*02022. In addition, haplotypes such as A*31011-Cw*02022-B*3501, A*03011-Cw*04011-B*4406 and A*2402101-Cw*04011-B*51011 are of high frequency in both these populations but are rare or absent in other populations of India and the world. The study suggests that a comparatively lesser degree of genetic admixture occurred between the South Indian and North Indian racial groups than that between South Indian and East Asian groups.

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%).

Novel HLA B*2714 and B*2708 allele associations in seronegative spondarthritis patients and haemophilia patients with chronic synovitis in India

HLA B27 association with seronegative spondarthritis (SSA) has been recognized for over a decade and its association with chronic synovitis in Haemophilia patients has been recently reported. We characterized the HLA B27 subtypes in a cohort of 98 B27 positive individuals with SSA (n = 45), haemophilia with chronic synovitis (n = 21) and normal controls (n = 32), using polymerase chain reaction-based sequence specific primers (PCR-SSP) and reverse line strip (RLS) techniques. The results revealed a significant association for a novel allele B*2714 in SSA along with the previously reported B*2705 allele. We also found a significant association between haemophilia patients with chronic synovitis from India and a hitherto unidentified allele, B*2708.