Association of ORAI1 haplotypes with the risk of HLA-B27 positive ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammation of the sacroiliac joints, spine and peripheral joints. The aetiology of ankylosing spondylitis is still unclear. Previous studies have indicated that genetics factors such as human leukocyte antigen HLA-B27 associates to AS susceptibility. We carried out a case-control study to determine whether the genetic polymorphisms of ORAI1 gene, a major component of store-operated calcium channels that involved the regulation of immune system, is a susceptibility factor to AS in a Taiwanese population. We enrolled 361 AS patients fulfilled the modified New York criteria and 379 controls from community. Five tagging single nucleotides polymorphisms (tSNPs) at ORAI1 were selected from the data of Han Chinese population in HapMap project. Clinical statuses of AS were assessed by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), and Bath Ankylosing Spondylitis Global Index (BAS-G). Our results indicated that subjects carrying the minor allele homozygote (CC) of the promoter SNP rs12313273 or TT homozygote of the SNP rs7135617 had an increased risk of HLA-B27 positive AS. The minor allele C of 3′UTR SNP rs712853 exerted a protective effect to HLA-B27 positive AS. Furthermore, the rs12313273/rs7135617 pairwise allele analysis found that C-G (OR 1.69, 95% CI 1.27, 2.25; p = 0.0003) and T-T (OR 1.75, 95% CI 1.36, 2.27; p<0.0001) haplotypes had a significantly association with the risk of HLA-B27-positive AS in comparison with the T-G carriers. This is the first study that indicate haplotypes of ORAI1 (rs12313273 and rs7135617) are associated with the risk of HLA-B27 positive AS.     

Association Study of Polymorphisms rs4552569 and rs17095830 and the Risk of Ankylosing Spondylitis in a Taiwanese Population

Ankylosing spondylitis (AS) is a chronic inflammation of the sacroiliac joints, spine and peripheral joints. However, the development of anklosing spondylitis is unclear. Human leukocyte antigens HLA-B27 and ERAP1 have been widely reported to be associated with AS susceptibility. A recent genome-wide association study (GWAS) showed that two new susceptibility loci between EDIL3 and HAPLN1 at 5q14.3 (rs4552569) and within ANO6 at 12q12 (rs17095830) contribute to the risk of AS in Han Chinese. In this study, we enrolled 475 AS patients and 475 healthy subjects to assess whether these genetic variations contribute to the susceptibility and the severity of AS in the Taiwanese population. The correlation between genetic polymorphisms, AS activity indexes, (namely, BASDAI, BASFI and BAS-G) and AS complications (uveitis and inflammatory bowel disease) were tested using the markers, rs4552569 and rs17095830. Although no association between rs4552569/rs17095830 genetic polymorphisms and AS susceptibility/severity was found, a significant association between rs17095830 and inflammatory bowel disease was observed in a Taiwanese population.     

ERAP1 genetic variations associated with HLA-B27 interaction and disease severity of syndesmophytes formation in Taiwanese ankylosing spondylitis

IntroductionAnkylosing spondylitis (AS) is a familial, heritable disease specified by syndesmophyte formation leading to an ankylosed spine. Endoplasmic reticulum aminopeptidase 1 (ERAP1) genetic variations have been widely proved to be associated with AS in several ethnic populations. The aim of this study was to investigate whether ERAP1 single nucleotide polymorphisms (SNPs) are associated with AS susceptibility and disease severity in Taiwanese.MethodsFour ERAP1 SNPs (rs27037, rs27980, rs27044 and rs30187) were genotyped in 797 Taiwanese AS patients and 1,150 healthy controls. Distributions of genotype and alleles were compared between AS patients and healthy controls, and among AS patients stratified by clinical parameters.ResultsThe SNP rs27037T allele appeared to be a risk factor for AS susceptibility (P = 5.5 × 10^-5, OR 1.30, 95% CI: 1.15 to 1.48; GT+TT vs. GG P = 9.3 × 10^-5, OR 1.49, 95% CI: 1.22 to 1.82). In addition, the coding SNP (cSNP) rs27044G allele (P = 1.5 × 10^-4, OR 1.28, 95% CI: 1.13 to 1.46; CG+GG vs. CC, P = 1.7 × 10^-3, OR 1.44, 95% CI: 1.15 to 1.81) and the cSNP rs30187T allele (P = 1.7 × 10^-3, OR 1.23, 95% CI: 1.08 to 1.40; CT+TT vs. CC P = 6.1 × 10^-3, OR 1.38, 95% CI: 1.10 to 1.74) were predisposing factors for AS. Notably, the rs27044G allele carriers (CG+GG vs. CC, P = 0.015, OR 1.59, 95% CI: 1.33 to 2.30) and rs30187T allele carriers (CT+TT vs. CC, P = 0.011, OR 1.63, 95% CI: 1.12 to 2.38) were susceptible to syndesmophyte formation in AS patients. Furthermore, two cSNPs (rs27044 and rs30187) strongly associated with HLA-B27 positivity in AS patients. Finally, the ERAP1 SNP haplotype TCG (rs27037T/rs27980C/rs27044G) is a major risk factor for AS (adjusted P <0.00001, OR 1.38, 95% CI: 1.12 to 1.58) in Taiwanese.ConclusionsThis study provides the first evidence of ERAP1 SNPs involving syndesmophyte formation. The interactions between ERAP1 SNPs and HLA-B27 play critical roles in pMHC I pathway processing contributing to the pathogenesis of AS in multiple populations.     

IL23R Gene Confers Susceptibility to Ankylosing Spondylitis Concomitant with Uveitis in a Han Chinese Population

Purpose

The interleukin-23 receptor (IL-23R) has been shown to be associated with ankylosing spondylitis (AS) in many different populations. This study examined whether IL-23R polymorphisms were associated with susceptibility to this disease in a Chinese Han population.

Methods

Three single-nucleotide polymorphisms (SNP), rs7517847, rs11209032, and rs17375018, were genotyped in 291 AS patients and 312 age-, sex-, and ethnically matched healthy controls using a polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) assay.

Results

The genotype and allele frequencies of rs17375018, rs7517847, and rs11209032 were not different between the patients with AS and the healthy controls. On the one hand, stratification analysis indicated that the rs17375018 GG genotype and the G allele were increased in AS patients who were HLA-B27 positive (corrected p = 0.024, odds ratio [OR] 2.35, 95% CI 1.30–4.24; p _c = 0.006, OR 1.98, 95% CI 1.28–3.07, respectively). On the other hand, the analysis according to clinical characteristics showed a significantly increased prevalence of the homozygous rs17375018 GG genotype and the G allele in patients with AS and uveitis compared with the controls (p _c = 0.024 and p _c = 0.024, respectively). In addition, haplotype analysis performed with the SHEsis platform revealed no significant difference concerning the haplotypes between AS patients and healthy controls.

Conclusions

In this study, the results suggested that the rs17375018 of IL23R was positively associated with HLA-B27-positive AS and that the rs17375018 GG of IL-23R was associated with AS concomitant with uveitis. We found no evidence for an association between the other two SNPs of IL-23R and AS.     

Association Study of IL-12B Polymorphisms Susceptibility with Ankylosing Spondylitis in Mainland Han Population

Objective

This study aims to determine whether the genetic polymorphisms of IL-12B gene is a susceptibility factor to Ankylosing spondylitis (AS) in mainland Han Chinese population.

Method

Eight single-nucleotide polymorphisms (SNPs) (rs10045431, rs11167764, rs3212227, rs6556412, rs6556416, rs6871626, rs6887695 and rs7709212) in the IL-12B gene were genotyped by iMLDR Assay technology in 400 patients [96% (384/400) HLA-B27(+)] and 395 geographically and ethnically matched healthy controls in mainland Han Chinese population. The correlation between IL-12B genetic polymorphisms and AS activity index (BASDAI, BASFI) were tested.

Results

The significant difference was found in genotype distribution between AS and healthy controls (χ² = 6.942, P-value = 0.031) of the SNP rs6871626. Furthermore, significant evidence was also detected under the recessive model for minor allele A. The AA genotype carrier had 1.830 fold risk compared with C allele carrier (with CC and AC genotypes) [OR (95% CI) = 1.830 (1.131-2.961), P-value = 0.014]. Nevertheless, the difference was no longer significant after Bonferroni correction. Subset analysis on cases with HLA-B27(+) did find the same results. Three genotypic groups (AA, CC and CA) in rs6871626 site was highly associated with the BASDAI and BASFI (P-value = 0.012 and P-value = 0.023, respectively), after adjustment for effect of age, sex, and disease duration, the P-value was 0.031 and 0.041, respectively. The AA genotype of rs6871626 was also significantly correlated with an increased BASDAI and BASFI compared to the AC and CC genotypes in AS patients.

Conclusion

Our findings suggest that rs6871626 may be associated AS susceptibility and with disease activity (BASDAI, BASFI) in mainland Han Chinese population.     

Interaction between HLA-B60 and HLA-B27 as a Better Predictor of Ankylosing Spondylitis in a Taiwanese Population

Objective

Ankylosing spondylitis (AS) is a form of chronic inflammatory spondyloarthritis (SpA) that causes pain and stiffness in spines or joints. Human leukocyte antigen B27 (HLA-B27) and B60 (HLA-B60) have been reported as major genetic risk factors of AS. In addition, rs13202464, located on major histocompatibility complex (MHC) region, showed high sensitivity (98.7%) and specificity (98.0%) for HLA-B27.

Design

The aim of our study is to test whether the interaction between HLA-B60 and HLA-B27 (rs13202464) can serve as a better predictor of AS. We have genotyped HLA-B60 and rs13202464 among 471 patients with AS and 557 healthy subjects. Combined risk factors were investigated to test the biological interaction.

Results

Our results indicated that the relative risk (RR) for HLA-B27+/HLA-B60− was 152 (95% CI 91 to 255) and it increased to 201 (95% CI 85 to 475) in HLA-B27+/HLA-B60+ patients (with HLA-B27−/HLA-B60− as reference). Combinational analysis of two risk factors (HLA-B27+/HLA-B60+) showed a relative excess risk due to interaction (RERI) of 46.79 (95% CI: -117.58 to 211.16), attributable proportion (AP) of 0.23 (95% CI: -0.41 to 0.88) and a synergy index (S) of 1.31 (95% CI: 0.56 to 3.04).

Conclusion

In conclusion, genetic interaction analysis revealed that the interaction between HLA-B60 and HLA-B27 is a better marker for the risk of AS susceptibility in a Taiwanese population.     

Association of IL1R polymorphism with HLA-B27 positive in Iranian patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is one of the most common causes of inflammatory arthritis, with an estimated prevalence of 0.1-0.9%. Genetic factors have been strongly implicated in its aetiology, and heritability as assessed by twin studies has been estimated to be >90%. HLA- B27 is almost essential for inheritance of AS; it is not merely sufficient for explaining the pattern of familial recurrence of the disease. This study's purpose is to investigate the association of ankylosing spondylitis with single-nucleotide polymorphisms (SNPs) in the IL-1 family: IL-1a (-889C/T) rs1800587, IL-1b (-511C/T) rs16944, IL-1b (+3962C/T) rs1143634, IL-1R (Pst-1 1970C/T) rs2234650 and IL-1RA (Mspa-1 11100C/T) rs315952. 99 unrelated Iranian AS patients and 217 healthy control subjects were selected. Cytokine typing was performed by the polymerase chain reaction with sequence-specific primers assay. The allele and genotype frequencies of the polymorphisms were determined: The IL1α rs1800587, IL1β rs16944 and IL1β rs1143634 were not significantly associated with AS. Genotype frequencies at IL1R rs2234650 differed between cases and controls (χ(2)=8.85; p=0.01); the IL1R rs2234650 C/T and T/T genotypes were less common in AS patients than controls. The IL1R rs2234650 C/T genotype was inversely associated with AS comparing with the IL1R rs2234650 C/C genotype (OR=0.48; p=0.005). IL1R rs2234650 C/T genotype was less common in patients than controls (OR=0.37; p=0.02).Furthermore IL1R rs2234650 T allele was strongly associated with HLA-B2702 patients rather than HLA-B2705 but was not associated with HLA-B27 negative patients (OR=0.33; p=0.01). Polymorphisms of IL1α rs1800587, IL1β rs16944 and IL1β rs1143634 were not significantly associated with ankylosing spondylitis but inversely in this study IL1R rs2234650 was significantly associated and carriage of T allele in IL1R rs2234650 seems to be protective, while carriage of C allele result in two fold higher risk of developing AS.     

人白细胞抗原HLA-B27在强直性脊柱炎中的临床意义

目的:探讨人白细胞抗原HLA-B27在强直性脊柱炎(AS)中的临床意义,及联合检测HLA-B27、C反应蛋白(CRP)和红细胞沉降率(ESR)的意义。方法:对18例AS患者、24例腰背痛患者和21健康体检者的血液标本进行HLA-B27、CRP、ESR检测,并比较其HLA-B27阳性率。结果:与健康对照组比较,AS组的3项指标均高于对照组(P0.05),且AS组HLA-B27阳性率均高于另外2组(P0.05)。结论:HLA-B27在强直性脊柱炎诊断中具有重要意义,与其具有高度疾病相关性,联合检测HLA-B27及CRP比联合检测HLA-B27及ESR更有利于疾病诊断。     

Prevalence of HLA-B27 in the New Zealand population: effect of age and ethnicity

Introduction

HLA-B27 genotyping is commonly used to support a diagnosis of ankylosing spondylitis (AS). A recent study has suggested that HLA-B27 may adversely affect longevity. The objectives of this study were to determine, for the first time, the prevalence of HLA-B27 in the New Zealand population, and to test whether HLA-B27 prevalence declines with age.

Methods

117 Caucasian controls, 111 New Zealand Māori controls, and 176 AS patients were directly genotyped for HLA-B27 using PCR-SSP. These participants and a further 1103 Caucasian controls were genotyped for the HLA-B27 tagging single nucleotide polymorphisms (SNPs) rs4349859 and rs116488202. All AS patients testing positive for HLA-B27 of New Zealand Māori ancestry underwent high resolution typing to determine sub-allele status.

Results

HLA-B27 prevalence was 9.2% in New Zealand Caucasian controls and 6.5% in Māori controls. No decline in HLA-B27 prevalence with age was detected in Caucasian controls (p = 0.92). Concordance between HLA-B27 and SNP genotypes was 98.7-99.3% in Caucasians and 76.9-86% in Māori. Of the 14 AS patients of Māori ancestry, 1 was negative for HLA-B27, 10 were positive for HLAB*2705, and 3 positive for HLAB*2704. All cases of genotype discordance were explained by the presence of HLAB*2704.

Conclusions

HLA-B27 prevalence in New Zealand Caucasians is consistent with that of Northern European populations and did not decline with increasing age. In Māori with AS who were HLA-B27 positive, 76.9% were positive for HLA-B*2705, suggesting that genetic susceptibility to AS in Māori is primarily due to admixture with Caucasians.     

MMP-2, TNF-α and NLRP1 polymorphisms in Chinese patients with ankylosing spondylitis and rheumatoid arthritis

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are autoimmune, inflammatory diseases with substantial genetic contributions. Matrix metalloproteinase (MMP)-2, tumor necrosis factor (TNF)-α and NLR family pyrin domain-containing 1 (NLRP1) play important roles in the immune response. We studied the MMP-2 rs243865 C/T, TNF-α rs1800629 A/G, NLRP1 rs878329 C/G and NLRP1 rs6502867 C/T polymorphisms in a Chinese cohort of 520 patients with RA, 100 with AS and 520 controls. Genotyping was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Using the MMP-2 rs243865 CC homozygote genotype as the reference group, the CT and TT/CT genotypes were associated with significantly reduced risks of AS. However, logistic regression analyses revealed that the MMP-2 rs243865 C/T polymorphism was not associated with risk of RA. TNF-α rs1800629 A/G, NLRP1 rs878329 C/G and NLRP1 rs6502867 C/T polymorphisms were not associated with risk of RA or AS. These findings suggest that the MMP-2 rs243865 C/T polymorphism is associated with AS development.     

Determination of IL-23 receptor gene polymorphism in Iranian patients with ankylosing spondylitis

Introduction

The result of recent genome-wide association studies revealed that, in addition to HLA-B27, a few non-HLA genes are associated with susceptibility to ankylosing spondylitis (AS) in Caucasian populations. According to these studies, IL-23R is one of the genes that is associated with AS. In this study, we evaluated five important single nucleotide polymorphisms (SNPs) of the IL-23R gene which confers susceptibility to AS, and its effects on the severity of the disease in HLA-B27 positive and negative patients and several subtypes of HLA-B27.

Materials and methods

The study population consisted of 294 AS patients and 352 age-, sex-, and ethnicity-matched healthy controls. All patients were examined by rheumatologists, and met modified,NewYork criteria for the disease. Five SNPs (rs1004819, rs11209032, rs1495965, rs11465804, and rs1004819) of the IL-23R gene were genotyped using the Real-Time PCR TaqMan genotyping method.

Results

We found that only rs1004819 has a significant association with AS, and that the remaining four SNP alleles are not associated with AS. Also, there was no association between these five polymorphisms and BASDAI, BASFI, and BASMI indices. Two haplotypes, ACGAT and ACGAG, were found to be associated with the heritability of AS. In addition, two significant, protective diplotypes (D8, \(\frac{{GCGAG}}{{GTGGG}}\); and D9, \(\frac{{ACGAG}}{{GCGAG}}\)) were discovered.

Conclusion

This study supported our previous findings regarding the differences between the genetic patterns of AS in Iranian patients compared with those in other parts of the world.

     

Association between cytokines and methylation of SOCS-1 in serum of patients with ankylosing spondylitis

In this study, we aim to determine the relationship between methylation level of an inflammatory-related gene, SOCS-1 in serum samples of patients with ankylosing spondylitis (AS) and their degree of inflammation as well as serum cytokine level. Quantitative real time methylation specific PCR was performed to examine the promoter methylation of SOCS-1 in serum samples of 43 HLA-B27+ AS patients and 6 B27+ healthy controls. Degree of inflammation was accessed by spondylopathy, sacroiliitis as well as acute phase reactant, erythrocyte sedimentation rate and C-reactive protein (CRP). Serum IL-6 and TNF-α level was determined by ELISA assay. SOCS-1 methylation can only be found in serums samples from patients but not normal control. Methylation of SOCS-1 significantly associated with severity of patient’s spondylopathy (P < 0.005), sacroiliitis (P < 0.005) and acute phase reactant CRP (P = 0.0278). AS patients also exhibited higher serum IL-6 (P < 0.001) and TNF-α level (P < 0.001). Importantly, patients with high serum IL-6 or TNF-α level demonstrated a significantly higher SOCS-1 methylation (P < 0.001). In conclusion, this proof-of-principle study suggested that methylation of SOCS-1 can be detected in serum of HLA-B27+ AS patients but not in B27+ controls. The pathogenic potential of SOCS-1 methylation in AS deserves further investigation.     

Analysis of PPARGC1B,RUNX3 and TBKBP1 Polymorphisms in Chinese Han Patients with Ankylosing Spondylitis: A Case-Control Study

Background

Susceptibility to and severity of ankylosing spondylitis (AS) are largely genetically determined. PPARGC1B, RUNX3 and TBKBP1 have recently been found to be associated with AS in patients of western European descent. Our purpose is to examine the influence of PPARGC1B, RUNX3 and TBKBP1 polymorphisms on the susceptibility to and the severity of ankylosing spondylitis in Chinese ethnic majority Han population.

Methods

Blood samples are drawn from 396 AS patients and 404 unrelated healthy controls. All the patients and the controls are Han Chinese and the patients are HLA-B27 positive. The AS patients are classified based on the severity of the disease. Twelve tag single nucleotide polymorphisms (tagSNPs) in PPARGC1B, RUNX3 and TBKBP1 are selected and genotyped. Frequencies of different genotypes and alleles are analyzed among the different severity AS patients and the controls.

Results

After Bonferroni correction, the rs7379457 SNP in PPARGC1B shows significant difference when comparing all AS patients to controls (p = 0.005). This SNP also shows significant difference when comparing normal AS patients to controls (p = 0.002). The rs1395621 SNP in RUNX3 shows significant difference when comparing severe AS patients to controls (p = 0.007). The rs9438876 SNP in RUNX3 shows significant difference when comparing normal AS patients to controls (p = 0.007). The rs8070463 SNP in TBKBP1 shows significant difference in genotype distribution when comparing severe AS patients to controls (p = 0.003).

Conclusions

The rs7379457 SNP in PPARGC1B is related to susceptibility to AS in Chinese Han population. The rs7379457 SNP in PPARGC1B, the rs1395621 and rs9438876 SNPs in RUNX3, and the rs8070463 SNP in TBKBP1 are related to the severity of AS in Chinese Han population.     

Association between Polymorphism of the Vitamin D Metabolism Gene CYP27B1 and HLA-B27-Associated Uveitis. Is a State of Relative Immunodeficiency Pathogenic in HLA B27-Positive Uveitis?

Objective

Polymorphisms of the vitamin D metabolism gene CYP27B1 showed associations with multiple autoimmune diseases. The aim of this study was to investigate a possible association between the rs703842 A>G polymorphism of the CYP27B1 gene and HLA-B27-associated uveitis.

Design

One hundred fifty-nine patients with HLA-B27-associated uveitis, 138 HLA-B27-negative controls and 100 HLA-B27-positive controls were recruited for this retrospective case-control study. Main outcome parameters were genotype distribution and allelic frequencies determined by polymerase chain reaction.

Results

Carriers of the rs703842G allele were found significantly more often in patients with HLA-B27-associated uveitis than in HLA-B27-positive controls (p = 0.03). Between patients and HLA-B27-negative controls no significant difference in the genotype distribution of the rs703842 A>G polymorphism was found (p = 0.97).

Conclusions

Our data suggest that the rs703842 A>G polymorphism may play a role in HLA-B27-associated uveitis.     

Potential role of aromatase over estrogen receptor gene polymorphisms in migraine susceptibility: a case control study from North India

Background

The present study was undertaken to find out the role of estrogen pathway related gene polymorphisms in susceptibility to migraine in Northern Indian population. Aromatase, CYP19A1 (rs10046 and rs4646); estrogen receptors, ESR1 (rs2234693, rs1801132, rs2228480 and rs9340799) and ESR2 (rs1271572 and rs1256049) polymorphisms were selected for the present study.

Methodology/Principal Findings

The patients were recruited in two cohorts – primary (207) and replicative (127) along with 200 healthy controls and genotyped for various polymorphisms. Logistic regression analysis was applied for statistical analyses. The results were validated in the replicative cohort and pooled by meta analysis using Fisher''s and Mantel-Haenszel test. Furthermore, Benjamini – Hochberg false discovery rate test was used to correct for multiple comparisons. CYP19A1 rs10046 and CYP19A1 rs4646 polymorphisms were found to confer risk and protective effect, respectively. Out of four ESR1 polymorphisms, only rs2234693 variant allele was significantly associated in migraine with aura. No significant associations were observed for ESR2 polymorphisms. Significant haplotypes were identified for CYP19A1 and ESR1 polymorphisms. Gene- gene interactions of genotypes as well as haplotypes were observed for CYP19A1- ESR1 showing both risk and protective combinations.

Conclusion

We strongly suggest CYP19A1 polymorphisms to be the major contributing factors in migraine susceptibility instead of genetic variants of estrogen receptors.     

Induction of HLA-B27 heavy chain homodimer formation after activation in dendritic cells

Introduction

Ankylosing spondylitis (AS) is a severe, chronic inflammatory arthritis, with a strong association to the human major histocompatibilty complex (MHC) class I allele human leucocyte antigen (HLA) B27. Disulfide-linked HLA-B27 heavy-chain homodimers have been implicated as novel structures involved in the aetiology of AS. We have studied the formation of HLA-B27 heavy-chain homodimers in human dendritic cells, which are key antigen-presenting cells and regulators of mammalian immune responses.

Method

Both an in vitro dendritic-like cell line and monocyte-derived dendritic cells from peripheral blood were studied. The KG-1 dendritic-like cell line was transfected with HLA-B27 cDNA constructs, and the cellular distribution, intracellular assembly and ability of HLA-B27 to form heavy-chain homodimers was compared with human monocyte-derived dendritic cells after stimulation with bacterial lipopolysaccharide (LPS).

Results

Immature KG-1 cells expressing HLA-B27 display an intracellular source of MHC class I heavy-chain homodimers partially overlapping with the Golgi bodies, but not the endoplasmic reticulum, which is lost at cell maturation with phorbyl-12-myristate-13-acetate (PMA) and ionomycin. Significantly, the formation of HLA-B27 homodimers in transfected KG-1 cells is induced by maturation, with a transient induction also seen in LPS-stimulated human monocyte-derived dendritic cells expressing HLA-B27. The weak association of wildtype HLA-B*2705 with the transporter associated with antigen processing could also be enhanced by mutation of residues at position 114 and 116 in the peptide-binding groove to those present in the HLA-B*2706 allele.

Conclusion

We have demonstrated that HLA-B27 heavy-chain homodimer formation can be induced by dendritic cell activation, implying that these novel structures may not be displayed to the immune system at all times. Our data suggests that the behaviour of HLA-B27 on dendritic cells may be important in the study of inflammatory arthritis.     

ETS1 variants confer susceptibility to ankylosing spondylitis in Han Chinese

Introduction

ETS1 is a negative regulator of the Th17 differentiation gene and plays a central role in the pathogenesis of autoimmune diseases. We aimed to investigate whether polymorphisms in ETS1 confer susceptibility to ankylosing spondylitis (AS) in Han Chinese.

Methods

We selected seven single nucleotide polymorphisms (SNPs) within ETS1 based on HapMap data and previous genome-wide association study. Genotyping involved the TaqMan method in 1,015 patients with AS and 1,132 healthy controls from Shandong Province, and 352 AS patients and 400 healthy controls from Ningxia, a northwest region in China. Gene expression was determined by real-time PCR.

Results

The SNP rs1128334 was strongly associated with AS (odds ratio 1.204, 95% confidence interval 1.06-1.37; P = 0.005). This association was confiexrmed in the Ningxia population (P = 0.015). Carriers of the haplotype TAT for rs12574073, rs1128334 and rs4937333 were associated with increased risk of AS and haplotype CGC with reduced risk as compared to controls. In addition, ETS1 expression was lower in AS patients than controls. The risk allele A of rs1128334 and haplotype A-T of rs1128334 and rs4937333 were associated with decreased expression of ETS1.

Conclusions

Common variants in ETS1 may contribute to AS susceptibility in Han Chinese people.     

Association of rs4552569 and rs17095830 single-nucleotide polymorphisms with susceptibility to ankylosing spondylitis in east Asian population: a meta-analysis

Several studies have been conducted in east Asian population to evaluate the association between rs4552569 and rs17095830 single-nucleotide polymorphisms (SNPs) with susceptibility to ankylosing spondylitis (AS), but the outcomes are inconsistent. A summary evaluation of the evidence supporting the associations has not been performed. Therefore, we performed this meta-analysis to access whether the two SNPs are related to ankylosing spondylitis. We systematically searched PubMed, EMBASE, Web of Science and Cochrane Library for papers published up until 3 February 2017, to obtain relevant studies using our research strategy. The allele/genotype frequencies were extracted from each study. We calculated the summary odds ratios (ORs) and 95% confidence intervals (CIs) to evaluate the associations between the two SNPs and AS risk. Four papers including five studies were obtained for this meta-analysis. The included studies suggested that there was no significant association between rs4552569 SNP and AS (C vs T, OR = 1.08, 95% CI: 0.96–1.22, P = 0.20). With regard to rs17095830 SNP, significant association was observed (G vs A, OR = 1.19, 95% CI: 1.06–1.33, P = 0.002). Based on a comprehensive analysis of the currently available evidence, rs4552569 SNP is not significantly associated with the predisposition of AS, while rs17095830 SNP is likely a susceptibility variant for AS in east Asian population. Further studies with different population groups are needed to confirm these potential associations.