Single-nucleotide polymorphisms and expression of IL23R in Chinese ankylosing spondylitis patients

Determination of IL-23 receptor expression and gene polymorphism (rs1884444) in Iranian patients with ankylosing spondylitis

BACKGROUND

Through investigating genetic variations, it has been demonstrated that single nucleotide polymorphisms (SNPs) in the IL-23 receptor (IL23R) gene have a critical role in the pathophysiology of ankylosing spondylitis (AS). Here, we investigated whether the IL23R variant (rs1884444) is associated with AS in the Iranian population.

METHODS AND MATERIAL

In this research, we analyzed rs1884444 in a group of 425 patients with AS and 400 matched controls. For DNA extraction, the phenol/chloroform technique was utilized. Peripheral blood mononuclear cells (PBMCs) were obtained from the whole blood of 39 patients and 43 healthy controls and total RNA was extracted. Genotyping was performed by amplification-refractory mutation system (ARMS)-PCR method. Afterward, the expression level of IL23R was analyzed by the real-time quantitative (Q)-PCR method.

RESULTS

We observed no significant association between the distribution of alleles and genotypes of rs1884444 and susceptibility to AS. In addition, the expression level of IL23R did not differ between PBMCs from AS patients compared to the control group (P = 0.167). Furthermore, the relative expression level of IL23R was positively correlated with the BASDAI (P < 0.01) and BASFI (P < 0.05) scores of the patients.

CONCLUSION

It appears that IL23R polymorphism (rs1884444) and the level of gene expression might not contribute to the susceptibility to AS in the Iranian population. The correlation of IL23R expression with the level of BASDAI and BASFI scores in patients may be due to the role of the IL-23/IL-23R signaling cascade in inflammation and exert a critical role in the development of AS.

Associations between interleukin-23R polymorphisms and ankylosing spondylitis susceptibility: an updated meta-analysis

OBJECTIVE

The aim of this study was to determine whether interleukin-23R (IL-23R) polymorphisms are associated with susceptibility to ankylosing spondylitis (AS).

METHODS

Meta-analyses were conducted to determine the associations between IL-23R polymorphisms and AS susceptibility in Europeans, Asians, and all subjects combined.

RESULTS

A total of 17 studies (21 separate comparisons) were included in this meta-analysis. The meta-analysis revealed a significant association between AS and the two alleles of the rs11209032 polymorphism in all study subjects (odds ratio [OR] = 1.160, 95% confidence interval [CI] = 1.091-1.204, P < 0.001). Stratification by ethnicity identified a significant association between this polymorphism and AS in Europeans (OR = 1.234, 95% CI = 1.159-1.313, P < 0.001), but not in Asians (OR = 1.003, 95% CI = 0.920-1.219, P = 0.942). Meta-analyses of the rs1004819, rs10489629, rs1343151, rs1495965, rs7517847, and rs11465804 polymorphisms showed the same pattern as shown for rs11209032. The meta-analysis also revealed a significant association between the two alleles of the rs2201841 and rs11209026 polymorphisms and the risk of developing AS in Europeans, but not in Asians. Interestingly, the rs10889677 polymorphism was not found to be associated with AS susceptibility in either Europeans or Asians.

CONCLUSIONS

This meta-analysis showed that several IL-23R polymorphisms are associated with the development of AS in Europeans.

The role of IL-17A in axial spondyloarthritis and psoriatic arthritis: recent advances and controversies

Although the pathogenic mechanisms underlying axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) are not fully elucidated, several lines of evidence suggest that immune responses mediated by interleukin 17A (IL-17A) play a pivotal role in both diseases. This is best highlighted by the significant clinical efficacy shown with inhibitors of IL-17A in treating axSpA and PsA. Nevertheless, a number of knowledge gaps exist regarding the role of IL-17A in the pathophysiology of spondyloarthritis in man, including its cellular origin, its precise role in discrete disease processes such enthesitis, bone erosion, and bone formation, and the reasons for the discrepant responses to IL-17A inhibition observed in certain other spondyloarthritis manifestations. In this review, we focus on the latest data from studies investigating the role of IL-17A in ankylosing spondylitis (AS) and PsA that build on existing and emerging scientific knowledge in the field. Key remaining research questions are also highlighted to guide future research.

Association between cytokine gene polymorphisms and ankylosing spondylitis susceptibility: a systematic review and meta-analysis

PURPOSE OF THE STUDY

The aim of this study was to perform a meta-analysis to derive precise estimation of the association of interleukin-23 receptor (IL-23R), IL-1 receptor 2 (IL-1R2), IL-12 beta (IL-12B), IL-10 and tumour necrosis factor (TNF)-α polymorphisms with ankylosing spondylitis (AS) susceptibility.

STUDY DESIGN

A systematic literature search was conducted to identify the relevant studies. Pooled OR with 95% CI was calculated to assess the strength of the association in a fixed or random-effects model.

RESULTS

A total of 13 917 cases and 19 849 controls in 43 eligible studies were included in the meta-analysis. Seventeen single-nucleotide polymorphisms (SNPs) in the abovementioned five cytokine genes were evaluated. The results indicate that the nine SNPs (rs11209026, rs1004819, rs10489629, rs11465804, rs1343151, rs11209032, rs1495965, rs7517847, rs2201841) of IL-23R are associated with AS susceptibility in all study subjects in the allelic model. Moreover, stratification by ethnicity identified a significant association between seven SNPs of IL-23R and AS susceptibility in Europeans and Americans, but not in Asians. In addition, the IL-10-819  C/T and TNF-α-857 C/T polymorphisms also confer susceptibility to AS, especially in Asian population.

CONCLUSION

The results suggested that the genetic susceptibility for AS is associated with the nine SNPs of IL-23R in overall population. In the subgroup analysis, significant associations were shown in European and American population, but not in Asian population. Our results also suggest that IL-10-819  C/T and TNF-α-857 C/T polymorphism might be associated with AS risk, especially in Asian population.

Interleukin-23 receptor polymorphism (rs10889677 A/C) in ankylosing spondylitis: Meta-analysis in Caucasian and Asian populations

BACKGROUND

The association between interleukin-23 receptor (IL23R) gene rs10889677 polymorphism and ankylosing spondylitis (AS) susceptibility was inconsistent in the recent literatures. A systematic review and meta-analysis was therefore performed.

METHODS

Online electronic databases were searched for relevant studies published up to November 2017. Meta-analyses were performed for the comparisons of allele (A versus C) and multiple genetic models, including dominant, recessive, heterozygous, and homozygous models using fixed or random effects models. Odds ratios (OR) with 95% confidence intervals (95%CI) were utilized to assess the potential relationship.

RESULTS

Sixteen studies containing 19 separate comparisons, totaling 6450 cases and 8009 controls were included. A significant association between rs10889677 A allele and AS susceptibility was detected (OR=1.136, 95%CI=1.043-1.236, P=0.003). Stratified analysis by ethnicity indicated that rs10889677 A allele was significantly associated with AS in Europeans (OR=1.192, 95%CI=1.080-1.315, P<0.001), but not Asians (OR=1.045, 95%CI=0.913-1.197, P=0.523). In addition, there were no significant associations between rs10889677 polymorphism and AS susceptibility in any of dominant, recessive, homozygous and heterozygous models.

CONCLUSION

This meta-analysis demonstrates that IL23R gene rs10889677 A allele confers increased risk of AS in Europeans, but its role in Asian populations needs further exploration.

Association study of rs924080 and rs11209032 polymorphisms of IL23R-IL12RB2 in a Northern Chinese Han population with Behcet's disease

OBJECTIVES

Two genome-wide association studies (GWAS) have identified the IL-23 receptor- IL-12 receptor β2 (IL23R-IL12RB2) as the susceptibility genetic region in Turkish and Japanese population with Behçet's disease (BD). We investigated the association of this region with BD in a Northern Chinese Han population.

METHODS

A total of 407 patients with BD and 421 healthy controls were genotyped for single nucleotide polymorphisms (SNPs) rs924080 and rs11209032 using the Sequenom MassArray system.

RESULTS

Statistically significant associations with BD were detected at two SNPs namely, rs924080 and rs11209032, both, by allele analysis (OR=1.58, 95% CI=1.25-2.00, P_c=2.52×10^-4, and OR=1.45, 95% CI=1.19-1.76, P_c=3.46×10^-4, respectively), and genotype analysis (P_c=1.22×10^-3andP_c=1.77×10^-3, respectively). Significant differences were observed in the genotype frequency distribution for these SNPs under the additive, dominant and recessive models (all P_c<0.05). The haplotypes (AT and GC) formed by the two SNPs were associated with BD (all permutation P<0.05). A meta-analysis also appeared to support the association of the two SNPs with BD.

CONCLUSION

SNPs (rs924080 and rs11209032) of the IL23R-IL12RB2 region were found to be associated with BD in a Northern Chinese Han population.

Association of rs11209032 and rs1004819 Polymorphisms in Interleukin-23 Receptor Gene With Ankylosing Spondylitis

Objectives

This study aims to investigate the distribution of human leukocyte antigen B27 (HLA-B27) alleles (+/-) and interleukin-23 receptor (IL-23R) gene rs11209032 and rs1004819 polymorphisms among ankylosing spondylitis (AS) patients in a Turkish cohort.

Patients and methods

The study sample comprised 106 AS patients (89 males, 18 females; mean age 38.9±10 years; range 19 to 65 years) and 82 healthy controls (70 males, 12 females; mean age 32.15±7.07 years; range 19 to 51 years). Distribution of HLA-B27 alleles (+)/(-) in AS patients were observed by reverse hybridization technique. Genotyping of IL-23R rs11209032 and rs1004819 polymorphisms of AS patients and healthy controls were performed by real time polymerase chain reaction.

Results

Of the AS patients, 69 (65.1%) were HLA-B27 positive. Distribution of rs11209032 genotype frequencies in AS group were 31.1% for GG, 50.9% for GA, and 17.9% for AA; while in control group, it was 34.1% for GG, 53.7% for GA, and 12.2% for AA. Distribution of rs1004819 genotype frequencies in AS group were 30.2% for CC, 52.8% for CT, and 17.0% for TT; while in control group, it was 42.7% for CC, 46.3% for CT, and 11.0% for TT. There was no significant difference between AS patients and controls in terms of genotype frequencies of IL-23R gene rs11209032 and rs1004819 polymorphisms.

Conclusion

No association was found between AS and IL23R rs11209032 and rs1004819 polymorphisms in this Turkish AS cohort.

Investigation of the association of Vogt-Koyanagi-Harada syndrome with IL23R-C1orf141 in Han Chinese Singaporean and ADO-ZNF365-EGR2 in Thai

BACKGROUND

We performed a multistage genome-wide association study of Vogt-Koyanagi-Harada (VKH) syndrome in a Han Chinese population and identified two novel non-human leukocyte antigen candidate regions previously. The aim of the study was to replicate the association of IL23R-C1orf141 and ADO-ZNF365-EGR2 with VKH syndrome in four sets of multinational populations in Asia.

METHOD

We conducted a candidate genes association study involving 185 patients with VKH syndrome and 287 normal controls from Han Chinese Singaporeans, non-Han Chinese, Thais and Koreans. Genotyping of 16 single nucleotide polymorphisms (SNPs) within IL23R-C1orf141 and ADO-ZNF365-EGR2 loci was performed using the Sequenom MassARRAY system or by Taqman SNP assays.

RESULTS

Eight SNPs in IL23R-Clorf141 showed an association with VKH syndrome only in Han Chinese Singaporeans (p=8.49×10(-5) to 1.02×10(-3), pcorrection=1.69×10(-4) to 2.04×10(-3)) but not in the other groups tested. One SNP rs1884444 in IL23R-Clorf141 was found to be weakly associated with VKH syndrome in the Han Chinese Singaporeans, but significance was lost following Bonferroni correction for multiple comparisons. Five SNPs in ADO-ZNF365-EGR2 were found to be associated with VKH syndrome in Thai patients with VKH (p=0.014, pc=0.028) but not in the other three ethnic groups tested.

CONCLUSIONS

This study confirmed the genetic associations between SNPs in IL23R-C1orf141 and VKH syndrome in Han Chinese Singaporeans but not in other Asian populations. In addition, we also successfully replicated the association of VKH syndrome with ADO-ZNF365-EGR2 in a Thai population.

Interleukin-23R rs7517847 T/G Polymorphism Contributes to the Risk of Crohn's Disease in Caucasians: A Meta-Analysis

The association between Interleukin-23R gene polymorphism and Crohn's disease (CD) in Caucasians is still controversial. Thus, a meta-analysis was performed to evaluate the correlation between this gene variant and CD risk. We retrieved the available data from EMBASE and PUBMED until May 1, 2014, and evaluated the effect of rs7517847 in Caucasians. The significant associations were confirmed between rs7517847 and CD risk in dominant models (TT/TG versus GG: OR = 1.652, 95% CI 1.277, 2.137), allelic model (T allele versus G allele: OR = 1.327, 95% CI 1.198, 1.469), homozygote comparison (TT versus GG: OR = 1.890, 95% CI 1.465, 2.437), heterozygote comparison (TG versus GG: OR = 1.509, 95% CI 1.161, 1.960), and recessive model (TT versus TG/GG: OR = 1.409, 95% CI 1.279, 1.552). In conclusion, this meta-analysis demonstrates that rs7517847 is associated with the risk of CD in Caucasians. These findings show that IL-23R genes confer susceptibility to CD in the Caucasians.

Association between rs7517847 and rs2201841 polymorphisms in IL-23 receptor gene and risk of ankylosing spondylitis: a meta-analysis

To comprehensively evaluate the association between rs7517847 and rs2201841 polymorphisms in the Interleukin-23 (IL-23) receptor gene and ankylosing spondylitis (AS), a meta-analysis was performed. The Pubmed, Embase, MEDLINE, Cochrane, China National Knowledge Infrastructure (CNKI), VIP, Wanfang and China Biology Medicine disc (CBMdisc) databases were searched to identify eligible studies on rs7517847 and rs2201841 polymorphisms in the IL-23 receptor gene and AS that were published through September 2014. Data of interest were extracted from each study, and the meta-analysis was performed using STATA 12.0. Four studies were eligible for the meta-analysis and included a total patient population of 2,465. With regards to rs7517847, the current study showed that the genotype GG and allele G might play a protective role during AS (OR = 0.76, 95% CI [0.59-0.99]; OR = 0.88, 95% CI [0.78-0.99] for homozygote and allelic models, respectively). However, according to the meta-analysis, there was no statistical association between the genotype or allele of rs2201841 and an individual's susceptibility to AS in all genetic models. In conclusion, it was the IL-23 rs7517847 polymorphism rather than the rs2201841 polymorphism that had a statistical association with AS. Nevertheless, more evidence is needed to confirm this result. Consequently, it is necessary to carry out more high-quality studies to confirm the associations between these two single nucleotide polymorphisms and AS.

Effects of Tripterygium glycosides on interleukin-17 and CD4+CD25+CD127low regulatory T-cell expression in the peripheral blood of patients with ankylosing spondylitis

The aim of this study was to investigate the possible mechanisms of action of Tripterygium glycosides (TG) in the treatment of ankylosing spondylitis (AS). In total, 20 patients with active AS received treatment with 20 mg TG tablet (TGT) 3 times per day for 6 weeks. In addition, 20 healthy age- and gender-matched individuals were recruited as the control group. The efficacy measures included the Bath AS disease activity index (BASDAI), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels. The serum interleukin (IL)-17 levels were measured using ELISA. The expression of CD4⁺CD25⁺CD127^low regulatory T cells (Tregs) in the peripheral blood was evaluated by flow cytometry. A bivariate correlation analysis was used to determine the association of IL-17 levels with BASDAI, ESR, CRP and CD4⁺CD25⁺CD127^low Tregs in AS patients. Prior to treatment, the BASDAI, ESR and CRP levels in AS patients were found to be elevated compared to those in healthy controls and were significantly reduced following TGT treatment (P<0.05, P<0.05 and P<0.05, respectively). Prior to treatment, the AS patients exhibited significantly higher IL-17 levels compared to those in healthy controls (P<0.05). Following TGT treatment, the IL-17 levels were significantly reduced in AS patients (P<0.01) but were not significantly different in the control subjects (P>0.05). In addition, prior to treatment, the ratio of CD4⁺CD25⁺CD127^low Tregs in AS patients was significantly lower compared to that in healthy controls (P<0.05) and it was significantly increased following TGT treatment (P<0.05). The correlation analysis between the BASDAI, ESR or CRP levels and IL-17 revealed a positive linear correlation (P<0.001, P<0.001 and P<0.01, respectively), whereas CD4⁺CD25⁺CD127^low Tregs were found to be negatively correlated with IL-17 (P<0.01). In conclusion, TGT is efficient for the treatment of AS patients and its mechanism of action may be correlated with the upregulation of CD4⁺CD25⁺CD127^low Tregs and the downregulation of IL-17 in the peripheral blood.

Marked differences of haplotype tagging SNP distribution, linkage, and haplotype profile of IL23 receptor gene in Roma and Hungarian population samples

Polymorphisms of the interleukin-23 receptor (IL23R) gene have been found to play an important role in the development of several autoimmune diseases. We examined five susceptible (rs10889677, rs1004819, rs2201841, rs11805303, rs11209032), one protective (rs7517847) and two neutral variants (rs7530511, rs1884444) of the IL23R gene in pooled DNA of healthy Roma (Gipsy) and Hungarian population samples. Our aim was to determine the genetic variability of the major haplotype tagging polymorphisms, and the haplotype profile of IL23R between the two groups. We analyzed 273 healthy Roma and 253 Hungarian DNA samples using PCR/RFLP assay. Comparing the five susceptible conferring alleles, there were significant increase (p<0.05), while in the protective alleles, there were decrease in the allele frequencies in Roma population (p<0.05). One of the neutral alleles showed increase, the another one did not differ between the two groups. The haplotype analysis of the SNPs revealed fundamentally different association types of SNPs in the two groups; moreover, the frequencies of the various haplotypes also exhibited strong differences, as of ht4 and ht5 haplotypes were significantly higher, whereas the frequencies of ht2 and ht3 haplotypes were significantly lower in the Roma population than in Hungarians (p<0.05). The data presented here show profound differences in the IL23R genetic profiles in the Roma population, that likely has also clinical implications in respect their possible role in the development of certain immunological diseases.

The association of IL1α and IL1β polymorphisms with susceptibility to systemic lupus erythematosus: a meta-analysis

Many epidemiological studies have investigated IL1α and IL1β polymorphisms with SLE risk, but no conclusions are available because of conflicting results. This meta-analysis was performed to more precisely estimate the relationships. The databases of PubMed updated to September 1st, 2012 were retrieved. Odds ratio (OR) and corresponding 95% confidence interval (95% CI) as effect size were calculated by a fixed- or random-effect model. In total, six case-control studies for IL1β-511C/T, four studies for IL1β+3953C/T, three studies for IL1α-889C/T and three studies for IL1α+4845G/T were involved in this analysis. The results indicated that for IL1α-889C/T polymorphism T allele was associated with decreased risk of SLE (OR (95% CI)) (T vs. C: 0.802 (0.679-0.949); TT+CT vs. CC: 0.615 (0.380-0.995); TT vs. CC: 0.679 (0.466-0.989)). However, when analysis for TT vs. CT+CC was conducted, the result indicated that IL1α-889C/T polymorphism was not associated with SLE (OR (95% CI): 0.847 (0.595-1.205)). Combined analysis indicated that IL1β-511C/T polymorphism was not overall associated with risk of SLE (OR (95% CI)) (T vs. C: 1.113 (0.954-1.298); TT vs. CT+CC: 1.146 (0.889-1.447); TT+CT vs. CC: 1.145 (0.903-1.452); TT vs. CC: 1.255 (0.928-1.698)). When subgroup analysis for Asian ethnicity was conducted, the results indicated that IL1β-511C/T polymorphism was associated with SLE only for TT vs. CT+CC (OR (95% CI): 1.468 (1.001-2.152)), but was not associated for T vs. C (OR (95% CI): 1.214 (0.955-1.544)), TT+CT vs. CC (OR (95% CI): 1.112 (0.765-1.615)) and TT vs.CC (OR (95% CI): 1.411 (0.896-2.222)). In addition, overall analyses indicated that IL1β+3953C/T and IL1α+4845G/C polymorphisms were also not associated with risk of SLE (OR (95% CI)) (for IL1β+3953C/T T vs. C: 0.996 (0.610-1.626), TT vs. CT+CC: 0.658 (0.318-1.358), TT+CT vs. CC: 1.021 (0.618-1.687), TT vs. CC: 0.640 (0.309-1.325); for IL1α+4845G/T T vs. G: 1.067 (0.791-1.440), TT+GT vs. GG: 0.934 (0.646-1.351)).This study inferred that IL1α-889C/T polymorphism might be moderately associated with SLE, but no sufficient evidence was available to support any associations between IL1β+3953C/T or IL1α+4845G/C polymorphisms and SLE. We could not draw a definite conclusion between IL1β-511C/T polymorphism and risk of SLE owing to the limited data. Further large sample-sized studies should be required.

Difference of interleukin-23 receptor gene haplotype variants in ulcerative colitis compared to Crohn's disease and psoriasis

OBJECTIVE

Polymorphisms of the interleukin-23 receptor (IL23R) gene have been found to play a role in the development of several autoimmune diseases. Our aim was to examine the possible effect of not only simple individual variants, but of haplotypes composed of them.

SUBJECTS

We analysed 263 patients with psoriasis, 199 patients with Crohn's disease (CD), 282 patients with ulcerative colitis (UC), and 253 controls for rs1884444, rs11805303, rs7517847, rs2201841, rs10889677 and rs11209032 variants.

METHODS

The genotypes were determined by using PCR/RFLP assay. Logistic regression analysis was used to compare the genotype distribution of the polymorphisms and haplotypes between the examined autoimmune diseases and healthy controls.

RESULTS

Rs1884444 was found to confer risk for UC and psoriasis, rs10889677 for CD and psoriasis, while rs2201841 and rs7517847 had effect only in CD. Using these SNPs we could study the susceptibility haplotype profiles in these diseases with special attention to UC. Eight different haplotypes could be differentiated. We found that the SNPs exert their susceptibility character in specific haplotype blocks, and the frequency of one haplotype differed significantly in UC compared with both other diseases and also with healthy controls. This haplotype conferred risk for UC, even while it had a somewhat lower frequency in the other diseases than in controls.

CONCLUSIONS

The data presented here serve as evidence for the need of haplotype analysis instead of just single standing SNP analysis when susceptibility is interpreted.

Toll-like receptor polymorphisms and rheumatoid arthritis: a systematic review

The aim of this study was to determine whether toll-like receptor (TLR) polymorphisms confer susceptibility to rheumatoid arthritis (RA) and influence the clinical characteristics of RA. The authors conducted a systematic review on associations between TLR polymorphisms and RA susceptibility and clinical findings. Meta-analysis was performed if at least three comparisons of an issue were available. A total of 14 studies were included in this systematic review, which included European and Asian studies. Meta-analysis of five European studies showed no association between the TLR4 Asp299Gly (rs4986790) polymorphism and RA (OR for the minor allele = 0.907, 95% CI = 0.755-1.088, p = 0.291). Furthermore, none of these studies found any association between the polymorphism and clinical characteristics. A significant difference between TLR9 rs187084 allele frequencies in RA patients and controls was found in one Turkish study (p = 0.003), and a moderate association between RF positivity and TLR8 rs5741883 was found in an European study (p = 0.001). The numbers of guanine-thymine [(GT)n] repeats in intron II of the TLR2 gene were found a significantly higher S-allele frequency in Korean patients with RA than in controls (30.3 vs. 23.0 %, p = 0.03). This meta-analysis shows lack of an association between the TLR4 Asp299Gly polymorphism and RA. However, our finding suggests the possibility that TLR polymorphisms are associated with the development and clinical characteristics of RA. Because of a paucity of data of the TLR polymorphisms, case-control studies are required to determine whether TLR2, 4, 8, 9 polymorphisms contribute to RA susceptibility or severity in more than 2,000 patients and controls.

Immunogenetic study in Chinese population with ankylosing spondylitis: are there specific genes recently disclosed?

Purpose. Ankylosing spondylitis (AS) is a systemic, autoimmune disease resulting in the destruction of the affected joints. Over the past 5 years, several new genes or genetic regions associated with AS have been identified in the Chinese population. This paper aims to discuss the major findings and related potential mechanisms of these studies in our population. Recent Findings. In recent years, due to the rapid advances in computational genetics and technology, there has been an increasing list of well-validated genes or genetic regions associated with AS susceptibility. So far, several genes or genetic regions have now been reported in the Han ethnic Chinese population, containing the major histocompatibility complex (MHC), ERAP1, IL-23R, 12q12, 2p15, 5q14.3, and so on. Different hypotheses for disease mechanisms have been investigated on the basis of the functional studies of these genes or genetic regions. Summary. This paper tries to summarize the association of several candidate genes with risk for AS in the Han ethnic Chinese population and aims to identify the novel inflammatory pathways and provide potential strategies for better therapies.

Marked diversity of IL23R gene haplotype variants in rheumatoid arthritis comparing with Crohn's disease and ankylosing spondylitis

Haplotype tagging SNPs of interleukin-23 receptor gene rs1004819, rs7517847, rs7530511, rs2201841, rs1343151 and rs10889677 were determined in 396 patients with rheumatoid arthritis, 190 patients with Crohn's disease, 206 patients with ankylosing spondylitis and 182 controls. Using regression analysis models the rs1004819, rs2201841, and rs10889677 SNPs were found to confer risk for Crohn's disease and ankylosing spondylitis, while rs1343151 had a protective effect in both of these diseases, and the rs2201841 and rs10889677 SNPs showed susceptibility nature for rheumatoid arthritis. Using these SNPs we could study the susceptibility haplotype profiles in these diseases with special attention to the rheumatoid arthritis, first in the literature. Seven different haplotypes could be differentiated. We found that the SNPs exert their susceptibility character in specific haplotype blocks: thus, for rheumatoid arthritis the rs1343151 SNP was risk factor only in a specific haplotype surrounding; this can explain the controversial results published so far about this variant. More importantly, we observed, that while a specific haplotype can confer risk for rheumatoid arthritis, the same haplotype tended to protect against the development of the other two diseases. The data presented here serve evidence for the need of haplotype analysis instead of just single standing SNP analysis when susceptibility to or protection against a certain disease are interpreted.

Associations between interleukin-23R polymorphisms and ankylosing spondylitis susceptibility: a meta-analysis

OBJECTIVE

The aim of this study was to determine whether interleukin-23R (IL-23R) polymorphisms confer susceptibility to ankylosing spondylitis (AS).

METHODS

The authors conducted meta-analyses on associations between IL-23R polymorphisms and AS susceptibility, using fixed and random effects models.

RESULTS

A total of 10 studies (14 separate comparisons) were included in this meta-analysis, which included European and Asian populations. Meta-analysis revealed a significant association between AS and the two alleles of rs11209032 polymorphism in all study subjects (OR = 1.182, 95% CI 1.120-1.249, P = 0.000). Stratification by ethnicity identified a significant association between this polymorphism and AS in the European (OR = 1.234, 95% CI 1.159-1.313, P = 0.000), but not in the Asian populations (OR = 1.030, 95% CI 0.921-1.152, P = 0.608). Meta-analyses of rs1004819, rs10489629, rs1343151, rs1495965, and rs2201841 polymorphisms showed the same pattern as that shown by rs11209032 meta-analysis. Meta-analysis also revealed a significant association between the two alleles of the rs11209026 and the rs11465804 polymorphisms and the risk of developing AS in Europeans. Interestingly, the rs7517847 polymorphism was found to be significantly associated with AS susceptibility in both Europeans and Asians.

CONCLUSIONS

This meta-analysis shows that the IL-23R polymorphisms are associated with the development of AS in Europeans.

The association between interleukin-6 polymorphisms and systemic lupus erythematosus: a meta-analysis

The aim of this study was to determine whether the functional interleukin-6 (IL-6) promoter -174 G/C and -572 G/C polymorphisms confer susceptibility to systemic lupus erythematosus (SLE) in ethnically different populations. Meta-analysis was conducted on the associations between the IL-6 polymorphisms and SLE using; 1) allele contrast, 2) the recessive model, 3) the dominant model, and 4) the additive model. A total of 11 studies were considered in this study, and ethnicity-specific meta-analysis was performed on European and Asian populations. Meta-analysis of the IL-6 -174 G/C polymorphism showed an association between SLE and the IL-6 -174 G allele in all study subjects (odds ratio (OR) = 1.344, 95% confidence interval (CI) = 1.052-1.718, p = 0.018). Furthermore, stratification by ethnicity indicated an association between the IL-6 -174 G allele and SLE in Europeans (OR = 1.264, 95% CI = 1.037-1.541, p = 0.020). Meta-analysis of the IL-6 -572 G/C polymorphism revealed that an association was found between SLE and the IL-6 -572 G/C polymorphism using the recessive model, but ethnicity-specific meta-analysis revealed no association between SLE and the IL-6 -572 G/C polymorphism in Asians. In conclusion, this meta-analysis demonstrates that the IL-6 -174 G/C polymorphism may confer susceptibility to SLE in Europeans, but that the IL-6 -572 G/C polymorphism is not associated with susceptibility to SLE in Asians.

Genetic variations associated with psoriasis and psoriatic arthritis found by genome-wide association

Psoriasis and psoriatic arthritis are immune disorders with a complex polygenic basis. HLA-Cw6, which lies in the major histocompatibility region on chromosome 6, is considered the major genetic determinant of psoriasis. Recent genome-wide association studies have identified new variants outside of the MHC with relevance to the immunology of psoriasis. Variants in or near genes that encode subunits of cytokines (IL12B, IL23A) or cytokine receptors (IL23R) are interesting given that the gene product of IL12B, p40, is the target of a recently approved monoclonal antibody therapy for psoriasis (ustekinumab). Association with psoriasis and psoriatic arthritis has been found in TNFAIP3 and TNFIP1, ubiquitin ligases in the NF-kappaB pathway, and IL13, a Th2 cytokine. Copy number variation of human beta-defensin and late cornified envelope genes also associate with psoriasis. Many of these genetic variations also associate with immune disorders considered psoriatic co-morbidities, including Crohn's disease and diabetes.