Association of STAT4 with susceptibility to rheumatoid arthritis and systemic lupus erythematosus in the Japanese population

Association of STAT4 polymorphisms with susceptibility to type-1 autoimmune hepatitis in the Japanese population

Background/Aims

Recent studies demonstrated an association of STAT4 polymorphisms with autoimmune diseases including systemic lupus erythematosus and rheumatoid arthritis, indicating multiple autoimmune diseases share common susceptibility genes. We therefore investigated the influence of STAT4 polymorphisms on the susceptibility and phenotype of type-1 autoimmune hepatitis in a Japanese National Hospital Organization (NHO) AIH multicenter cohort study.

Methodology/Principal Findings

Genomic DNA from 460 individuals of Japanese origin including 230 patients with type-1 autoimmune hepatitis and 230 healthy controls was analyzed for two single nucleotide polymorphisms in the STAT4 gene (rs7574865, rs7582694). The STAT4 rs7574865T allele conferred risk for type-1 autoimmune hepatitis (OR = 1.61, 95% CI = 1.23–2.11; P = 0.001), and patients without accompanying autoimmune diseases exhibited an association with the rs7574865T allele (OR = 1.50, 95%CI = 1.13–1.99; P = 0.005). Detailed genotype-phenotype analysis of type-1 autoimmune hepatitis patients with (n = 44) or without liver cirrhosis (n = 186) demonstrated that rs7574865 was not associated with the development of liver cirrhosis and phenotype (biochemical data and the presence of auto-antibodies).

Conclusions/Significance

This is the first study to show a positive association between a STAT4 polymorphism and type-1 autoimmune hepatitis, suggesting that autoimmune hepatitis shares a gene commonly associated with risk for other autoimmune diseases.

Meta-analysis reveals an association of STAT4 polymorphisms with systemic autoimmune disorders and anti-dsDNA antibody

Signal transducer and activator of transcription 4 (STAT4) has been recently identified as a susceptibility gene for multiple autoimmune diseases. Here we performed a comprehensive analysis of the association between STAT4 and several different autoimmune disorders to identify potential common inflammatory principles behind this association. Our meta-analysis revealed that the STAT4 rs7574865 polymorphism is associated with four autoimmune diseases with systemic pathology, including systemic lupus erythematosus (OR = 1.52; 95% CI = 1.48 - 1.56, P<1.0 × 10(-16)), rheumatoid arthritis (OR = 1.27; 95% CI = 1.21 - 1.33, P < 1.00 × 10(-16)), systemic sclerosis (OR = 1.38; 95% CI = 1.27 - 1.50, P < 1.44 × 10(-14)), and primary Sjogren's syndrome (OR = 1.32; 95% CI = 1.01 - 1.73, P = 4.40 × 10(-2)), while no association was found with type I diabetes, juvenile idiopathic arthritis, ulcerative colitis and Crohn's disease. Furthermore, the stratified meta-analysis also demonstrate that the STAT4 rs7574865 polymorphism is associated with the presence of autoantibodies with systemic reactivity (anti-ds-DNA antibodies) in SLE patients (OR = 1.37; 95% CI = 1.21 - 1.56, P = 1.12 × 10(-6)). However, no such specific association was seen in RA with regard to the presence of non-systemically reacting antibodies, including rheumatoid factor and anti-cyclic citrullinated peptide antibodies. Taken together, these results suggest that STAT4 polymorphisms are associated with autoimmune diseases which are characterized by a systemic pathology and anti-dsDNA antibody.

PADI4 and HLA-DRB1 are genetic risks for radiographic progression in RA patients, independent of ACPA status: results from the IORRA cohort study

Introduction

Rheumatoid arthritis (RA) is a systemic, chronic inflammatory disease influenced by both genetic and environmental factors, leading to joint destruction and functional impairment. Recently, a large-scaled GWAS meta-analysis using more than 37,000 Japanese samples were conducted and 13 RA susceptibility loci were identified. However, it is not clear whether these loci have significant impact on joint destruction or not. This is the first study focused on the 13 loci to investigate independent genetic risk factors for radiographic progression in the first five years from onset of RA.

Methods

Sharp/van der Heijde score of hands at 5-year disease duration, which represents joint damage, were measured retrospectively and used as an outcome variable in 865 Japanese RA patients. Genetic factors regarded as putative risk factors were RA-susceptible polymorphisms identified by the Japanese GWAS meta-analysis, including HLA-DRB1 (shared epitope, SE), rs2240340 (PADI4), rs2230926 (TNFAIP3), rs3093024 (CCR6), rs11900673 (B3GNT2), rs2867461 (ANXA3), rs657075 (CSF2), rs12529514 (CD83), rs2233434 (NFKBIE), rs10821944 (ARID5B), rs3781913 (PDE2A-ARAP1), rs2841277 (PLD4) and rs2847297 (PTPN2). These putative genetic risk factors were assessed by a stepwise multiple regression analysis adjusted for possible non-genetic risk factors: autoantibody positivity (anti-citrullinated peptide antibody [ACPA] and rheumatoid factor), history of smoking, gender and age at disease onset.

Results

The number of SE alleles (P = 0.002) and risk alleles of peptidyl arginine deiminase type IV gene (PADI4, P = 0.04) had significant impact on progressive joint destruction, as well as following non-genetic factors: ACPA positive (P = 0.0006), female sex (P = 0.006) and younger age of onset (P = 0.02).

Conclusions

In the present study, we found that PADI4 risk allele and HLA-DRB1 shared epitope are independent genetic risks for radiographic progression in Japanese rheumatoid arthritis patients. The results of this study give important knowledge of the risks on progressive joint damage in RA patients.

Association between polymorphism in STAT4 gene and risk of rheumatoid arthritis: a meta-analysis

BACKGROUND

Rheumatoid arthritis (RA) is a common chronic inflammatory autoimmune disease, affecting 1% of the population worldwide. Single nucleotide polymorphisms (SNPs) of signal transducer and activator of transcription 4 (STAT4) gene are suspected to have some relationship with the risk of RA. This meta-analysis aimed to evaluate the relationship between the polymorphism rs7574865 in STAT4 gene with RA and also examine whether the associations that have been reported in these studies differ between ethnic groups.

METHODS

We retrieved the relevant articles from PubMed, EMBASE and the China National Knowledge Infrastructure (CNKI) databases. The odds ratios (ORs) and their 95% confidence intervals (95% CIs) associated with the minor T allele of STAT4 rs7574865 SNP were extracted from the published studies and included in the analysis. Meta-analyses were performed on the total data set and separately for the major ethnic groups and RF and anti-CCP status. All analyses were performed using the Stata software.

RESULTS

Twenty-three articles were included in the present analysis. Meta-analysis showed an association between the STAT4 polymorphism and RA in all subjects (OR=1.299, 95%CI=1.230-1.371, P<0.001). Stratified analyses indicated that the STAT4 rs7574865 T allele was significantly associated with RA in both Caucasians and Asians, in both positive and negative RF patients versus controls, also significantly in the presence of anti-CCP, both positive and negative. As for genotypes of rs7574865 polymorphism, all the results were significant, no matter in total subjects or stratified analyses by ethnic groups or by RF and anti-CCP status.

CONCLUSION

Genetic polymorphism rs7574865 in STAT4 gene might be associated with RA susceptibility in total subjects, major ethnic groups and different status of anti-CCP or RF.

Abnormal genetic and epigenetic changes in signal transducer and activator of transcription 4 in the pathogenesis of inflammatory bowel diseases

BACKGROUND AND AIMS

Changes in the expression of signal transducer and activator of transcription 4 (STAT4) contribute to the development of a variety of autoimmune diseases including inflammatory bowel diseases (IBDs). Moreover, epigenetic modifications, including DNA methylation, are considered a basis for differentiation of T helper cells and regulation of cytokines. In this study, we investigated the methylation status of STAT4 gene in IBD patients and the associations between its genetic and epigenetic alterations in IBD patients.

METHODS

Blood and colonic mucosa samples were obtained from Korean patients with IBD and healthy controls. Peripheral blood mononuclear cells (PBMCs) were isolated, and total RNA and genomic DNA were isolated from the PBMCs and colon mucosa tissues. The mRNA level and DNA methylation status of the promoter were determined by real-time RT-PCR and pyrosequencing, respectively. The chosen SNPs (rs11889341, rs7574865, rs8179673, rs6752770, rs925847, rs10168266, rs10181656, and rs11685878) were genotyped using the TaqMan nuclease assay.

RESULTS

Elevated expression of STAT4 was observed in the colonic mucosa and PBMCs of IBD patients. IBD patients showed a lower degree of methylation of the STAT4 promoter than did the healthy controls. Moreover, a significant correlation between risk alleles and methylation status at -172 of the STAT4 promoter was observed, and mRNA levels of STAT4 in IBD patients were correlated inversely with the T-risk allele (rs7574865).

CONCLUSIONS

Our data demonstrated that the DNA methylation status of STAT4 is associated with genetic polymorphisms, providing insights into the interactions between genetic and epigenetic aberrances in STAT4 that contribute to the development of IBD.

Contribution of STAT4 gene single-nucleotide polymorphism to systemic lupus erythematosus in the Polish population

The STAT4 has been found to be a susceptible gene in the development of systemic lupus erythematosus (SLE) in various populations. There are evident population differences in the context of clinical manifestations of SLE, therefore we investigated the prevalence of the STAT4 G > C (rs7582694) polymorphism in patients with SLE (n = 253) and controls (n = 521) in a sample of the Polish population. We found that patients with the STAT4 C/G and CC genotypes exhibited a 1.583-fold increased risk of SLE incidence (95 % CI = 1.168–2.145, p = 0.003), with OR for the C/C versus C/G and G/G genotypes was 1.967 (95 % CI = 1.152–3.358, p = 0.0119). The OR for the STAT4 C allele frequency showed a 1.539-fold increased risk of SLE (95 % CI = 1.209–1.959, p = 0.0004). We also observed an increased frequency of STAT4 C/C and C/G genotypes in SLE patients with renal symptoms OR = 2.259 (1.365–3.738, p = 0.0014), (p_corr = 0.0238) and in SLE patients with neurologic manifestations OR = 2.867 (1.467–5.604, p = 0.0016), (p_corr = 0.0272). Moreover, we found a contribution of STAT4 C/C and C/G genotypes to the presence of the anti-snRNP Ab OR = 3.237 (1.667–6.288, p = 0.0003), (p_corr = 0.0051) and the presence of the anti-Scl-70 Ab OR = 2.665 (1.380–5.147, p = 0.0028), (p_corr = 0.0476). Our studies confirmed an association of the STAT4 C (rs7582694) variant with the development of SLE and occurrence of some clinical manifestations of the disease.

Association of STAT4 rs7574865 polymorphism with autoimmune diseases: a meta-analysis

The association between the signal transducer and activator of transcription 4 (STAT4) gene rs7574865 single nucleotide polymorphism and different autoimmune diseases remains controversial and ambiguous. We conducted this study to investigate whether combined evidence shows the association between STAT4 rs7574865 polymorphism and autoimmune diseases. Comprehensive Medline search and review of the references were used to get the relevant reports published before September 2011. Meta-analysis was conducted for genotype T/T (recessive effect), T/T + G/T (dominant effect) and T allele in random effects models. 40 studies with 90 comparisons including 32 systemic lupus erythematosus (SLE), 19 rheumatoid arthritis (RA), 3 type 1 diabetes (T1D), 11 Systemeric Sclerosis (SSc), 4 inflammatory bowed diseases (IBD), 3 Primary Sjogren's syndrome (pSS), 4 juvenile idiopathic arthritis (JIA), 2 Primary antiphospholipid syndrome (APS), 1 Autoimmune thyroid diseases, 1 multiple sclerosis, 1 Psoriasis, 1 Wegener's granulomatosis, 1 Type 2 diabetes, and 1 giant cell arteritis disease were available for this meta-analysis. The overall odds ratios for rs7574865 T-allele significantly increased in SLE, RA, T1D, SSc, JIA, and APS (OR = 1.56, 1.25, 1.13, 1.34, 1.25, and 2.15, respectively, P < 0.00001) and in IBD-UC and pSS (OR = 1.11 and 1.33, respectively, P < 0.05). This meta-analysis demonstrates that the STAT4 rs7574865 T allele confers susceptibility to SLE, RA, T1D, SSc, JIA, APS, IBD-UC, and pSS patients, supporting the hypothesis of association between STAT4 gene polymorphism and subgroup of autoimmune diseases.

Biomarkers for systemic lupus erythematosus

The urgent need for lupus biomarkers was demonstrated in September 2011 during a Workshop sponsored by the Food and Drug Administration: Potential Biomarkers Predictive of Disease Flare. After 2 days of discussion and more than 2 dozen presentations from thought leaders in both industry and academia, it became apparent that highly sought biomarkers to predict lupus flare have not yet been identified. Even short of the elusive biomarker of flare, few biomarkers for systemic lupus erythematosus (SLE) diagnosis, monitoring, and stratification have been validated and employed for making clinical decisions. This lack of reliable, specific biomarkers for SLE hampers proper clinical management of patients with SLE and impedes development of new lupus therapeutics. As such, the intensity of investigation to identify lupus biomarkers is climbing a steep trajectory, lending cautious optimism that a validated panel of biomarkers for lupus diagnosis, monitoring, stratification, and prediction of flare may soon be in hand.

Interactions between IL17A, IL23R, and STAT4 polymorphisms confer susceptibility to intestinal Behcet's disease in Korean population

AIMS

Although polymorphisms in IL23R have recently been proposed to predispose to Behcet's disease (BD), associations between IL23R polymorphisms and intestinal BD have yet to be elucidated. We therefore performed a study to evaluate whether IL17A, IL23R, and STAT4 polymorphisms are associated with susceptibility to intestinal BD in the Korean population.

MAIN METHODS

Single nucleotide polymorphisms (SNP) in the IL17A, IL23R, and STAT4 genes were analyzed using DNA sequencing, denaturing high performance liquid chromatography, and TaqMan genotyping assays.

KEY FINDINGS

Individual polymorphism analysis revealed that the TT genotype of IL17A rs8193036 (odds ratio (OR) 2.10, 95% confidence interval (CI) (1.12-3.92), p=0.021), and GG+GT genotype of IL23R rs1884444 (OR 1.92, 95% CI (1.03-3.57), p=0.034) was associated with the development of intestinal BD. When these two genotypes were combined, the risk of BD increased compared to that of patients with no-risk or one-risk genotype (OR 2.21, 95% CI (1.13-4.34), p=0.021). Furthermore, statistically significant gene-gene interactions were observed between G149R in IL23R vs. rs11685878 in STAT4, rs2275913 in IL17A vs. rs7574865 in STAT4, and rs11889341 in STAT4 vs. rs2275913 in IL17A. The haplotypes of IL17A had a positive association with intestinal BD risks, whereas those of IL23R were protective for disease development.

SIGNIFICANCE

Our results indicate that the interaction of specific IL17A, IL23R, and STAT4 SNPs modulate susceptibility to intestinal BD in the Korean population, suggesting that the IL-17/23 axis plays a significant role in disease pathogenesis.

Influence of TRAF1/C5 and STAT4 genes polymorphisms on susceptibility and severity of rheumatoid arthritis in Egyptian population

Rheumatoid arthritis (RA) is the most common cause of adult inflammatory arthritis. Recent genome-wide association scans have disclosed several single-nucleotide polymorphisms associated with RA susceptibility. The aim of this study was to determine whether the polymorphisms of TRAF1/C5 (tumor necrosis factor (TNF)-receptor associated factor 1)/(complement component 5) and STAT4 (signal transducers and activators of transcription 4) confer susceptibility, activity and severity to RA in Egyptian populations. One hundred and seventy-two RA patients and 160 controls were enrolled in the study. Polymorphisms of TRAF1/C5 and STAT4 genes were determined using restriction fragment length polymorphism-polymerase chain reaction. The TRAF1/C5 A and STAT4 T alleles were significantly associated with RA in Egyptian population. TRAF1/C5 A allele and STAT4 TT genotype were significantly associated with RA severity. In conclusion the mutant alleles or genotypes of both examined polymorphisms are associated with the development of RA in Egyptian population.

The human AIRE gene at chromosome 21q22 is a genetic determinant for the predisposition to rheumatoid arthritis in Japanese population

Rheumatoid arthritis (RA) is a typical complex trait and the major cause of chronic inflammation worldwide. Although multiple genetic loci have been shown for their association with the onset of RA, they cover only a part of its genetic components and are largely ethnicity-specific. To identify novel genetic factors related to the predisposition and prognosis of RA in Japanese, we conducted a large-scale genome-wide association (GWA) study. We performed a GWA analysis by scanning the genome of 1247 RA cases and 1486 controls for 277 420 single nucleotide polymorphisms (SNPs), followed by replication analysis using two independent sample sets consisting of 1865 cases and 1623 controls, and 2303 cases and 3380 controls. We identified two SNPs, rs2075876 and rs760426, in intron of the autoimmune regulator AIRE gene at chromosome 21q22 that showed strong associations with the disease (P= 3.6 × 10(-9) and P= 4.4 × 10(-8), respectively). Rs1800250, in exon7 of AIRE, was in strong linkage disequilibrium (r(2)= 0.94) with rs2075876 and introduced an amino acid alteration (S278R) in the SAND domain of the AIRE protein. In silico analysis showed the decreased transcription of AIRE by the risk allele of rs2075876 compared with the alternative allele (P= 6.8 × 10(-5)). No correlation was observed between the rs2075876 genotype and quantitative traits reflecting the progression of RA. As AIRE is a key molecule which regulates the expression and presentation of self-antigens in thymic negative selection, its downregulation by genetic polymorphisms may result in the survival of auto-reactive T cells to trigger auto-inflammation in RA.

Association of STAT4 polymorphisms with susceptibility to primary membranous glomerulonephritis and renal failure

BACKGROUND

Membranous glomerulonephritis (MGN) is one of common causes of idiopathic nephrotic syndrome in adults, and 25% of MGN patients proceed to end-stage renal disease. STAT4 gene polymorphisms have been reported to be associated with many inflammatory diseases. The objective of this study was to clarify the relationship between STAT4 gene polymorphisms and the pathogenesis of MGN.

METHODS

We investigated the association of three STAT4 gene polymorphisms (rs3024912, rs3024908, and rs3024877) with the susceptibility to MGN in 403 Taiwanese populations (138 MGN patients and 265 controls).

RESULTS

The results indicated that the statistically significant difference in genotype frequency distribution was found at rs3024908 SNP in MGN patients and control groups (p=0.014). In addition, the individuals with the GG genotype at rs3024912 SNP may have a higher risk in kidney failure of MGN patients (adjusted odds ratio [OR]=3.255; 95% confidence interval [CI]=1.155-9.176, p=0.026).

CONCLUSIONS

Our data provide a new information that the STAT4 (rs3024912 and rs3024908) polymorphisms may be the underlying cause of MGN, and these polymorphisms revealed by this study warrant further investigation.

Genetics of rheumatoid arthritis: GWAS and beyond

The study of complex genetics in autoimmune diseases has progressed at a tremendous pace over the last 4 years, as a direct result of the enormous gains made by genome wide association studies (GWAS). Novel genetic findings are continuously being reported alongside the rapid development of genetic technologies, sophisticated statistical analysis, and larger sample collections. It is now becoming clear that multiple genes contribute to disease risk in many complex genetic disorders including rheumatoid arthritis (RA) and that there are common genetic risk factors that underlie a spectrum of autoimmune diseases. This review details the current genetic landscape of RA, and describes what GWAS has taught us in terms of missing heritability, subsets of disease, existence of genetic heterogeneity, and shared autoimmune risk loci. Finally, this review addresses the initial challenges faced in translating the wealth of genetic findings into determining the biological mechanisms that contribute to the relationship between genotype and phenotype. Unraveling the mechanism of how genes directly influence the cause of RA will lead to a better understanding of the disease and will ultimately have a direct clinical impact, informing the development of new therapies that can be utilized in the treatment of RA.

Myelin basic protein as a novel genetic risk factor in rheumatoid arthritis--a genome-wide study combined with immunological analyses

Rheumatoid arthritis (RA) is a major cause of adult chronic inflammatory arthritis and a typical complex trait. Although several genetic determinants have been identified, they account for only a part of the genetic susceptibility. We conducted a genome-wide association study of RA in Japanese using 225,079 SNPs genotyped in 990 cases and 1,236 controls from two independent collections (658 cases and 934 controls in collection1; 332 cases and 302 controls in collection2), followed by replication studies in two additional collections (874 cases and 855 controls in collection3; 1,264 cases and 948 controls in collection4). SNPs showing p<0.005 in the first two collections and p<10⁻⁴ by meta-analysis were further genotyped in the latter two collections. A novel risk variant, rs2000811, in intron2 of the myelin basic protein (MBP) at chromosome 18q23 showed strong association with RA (p = 2.7×10⁻⁸, OR 1.23, 95% CI: 1.14–1.32). The transcription of MBP was significantly elevated with the risk allele compared to the alternative allele (p<0.001). We also established by immunohistochemistry that MBP was expressed in the synovial lining layer of RA patients, the main target of inflammation in the disease. Circulating autoantibody against MBP derived from human brain was quantified by ELISA between patients with RA, other connective tissue diseases and healthy controls. As a result, the titer of anti-MBP antibody was markedly higher in plasma of RA patients compared to healthy controls (p<0.001) and patients with other connective tissue disorders (p<0.001). ELISA experiment using citrullinated recombinant MBP revealed that a large fraction of anti-MBP antibody in RA patients recognized citrullinated MBP. This is the first report of a genetic study in RA implicating MBP as a potential autoantigen and its involvement in pathogenesis of the disease.

An overview on the genetic of rheumatoid arthritis: a never-ending story

Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory, multi-factorial disease sustained by environmental and genetic factors. These seem to be necessary but not sufficient in the disease development, nonetheless they can be responsible of different clinical pictures and response to therapy, and they can represent potential therapeutic targets. Several genes have been indicated so far in the pathogenesis of RA. The most important region is the Human Leukocyte Antigen (HLA) that contributes to approximately half of the genetic susceptibility for RA. The association seems to be stronger or specific for anti-citrullinated protein antibodies positive disease. Several alleles in the epitope-recognition part of the HLA molecule that show the highest association with RA susceptibility, also share a common string of amminoacid residues (the so-called shared-epitope hypothesis). Other variants in potentially pathogenic genes located in non-MHC regions have been implicated by recently performed genome wide analysis studies. These genes include PTPN22, TRAF1-C5, PADI4, STAT4. Other polymorphisms seem to be responsible for more aggressive disease phenotype such as those located at TNF, IL-1, IL-6, IL-4, IL-5, OPN, PRF1. However, still nowadays, the genetic background of RA remains to be clearly depicted, and the efforts in the post-genomic era can bring to an estimation of the real likelihood of the genetic effect on RA. Finally, the discovery of new genes associated with the disease can be relevant in finding potential biomarkers, potentially useful in disease diagnosis and treatment.

Single nucleotide polymorphisms at the TRAF1/C5 locus are associated with rheumatoid arthritis in a Han Chinese population

BACKGROUND

Genetic variants in TRAF1C5 and PTPN22 genes have been shown to be significantly associated with arthritis rheumatoid in Caucasian populations. This study investigated the association between single nucleotide polymorphisms (SNPs) in TRAF1/C5 and PTPN22 genes and rheumatoid arthritis (RA) in a Han Chinese population. We genotyped SNPs rs3761847 and rs7021206 at the TRAF1/C5 locus and rs2476601 SNP in the PTPN22 gene in a Han Chinese cohort composed of 576 patients with RA and 689 controls. The concentrations of anti-cyclic citrullinated peptide antibodies (CCP) and rheumatoid factor (RF) were determined for all affected patients. The difference between the cases and the controls was compared using χ2 analysis.

RESULTS

Significant differences in SNPs rs3761847 and rs7021206 at TRAF1/C5 were observed between the case and control groups in this cohort; the allelic p-value was 0.0018 with an odds ratio of 1.28 for rs3761847 and 0.005 with an odds ratio of 1.27 for rs7021206. This significant association between rs3761847 and RA was independent of the concentrations of anti-CCP and RF. No polymorphism of rs2476601 was observed in this cohort.

CONCLUSIONS

We first demonstrated that genetic variants at the TRAF1/C5 locus are significantly associated with RA in Han Chinese, suggesting that TRAF1/C5 may play a role in the development of RA in this population, which expands the pathogenesis role of TRAF1/C5 in a different ethnicity.

Current advances in lupus genetic and genomic studies in Asia

The genetic components in systemic lupus erythematosus (SLE) have long been established, however, it has been unclear for many years whether the same genetic risk factors for SLE are shared across different ethnic groups. Over the past few years, a number of genetic and genomic studies have been conducted in Asian populations to address this question. These studies have demonstrated that genetic heterogeneity does exist in SLE across different ethnic groups. With these studies, it has been established that a number of genes associated with SLE in Caucasians are also risk factors in Asians: HLA class II genes, STAT4, BANK1, BLK, IRF5, TNFSF4, ITGAM, etc., while there are also novel genetic risk factors identified by these studies in Asians, for instance, the ETS1 and WDFY4 in Chinese. For the genomic studies, the interferon signature has been confirmed as a major lupus molecular phenotype in Asians the same as in Caucasians; microRNA expression profiling and its novel role in regulating the interferon pathway has been first revealed in Asians. Further understanding of the function of lupus disease genes and delineating the key molecular pathway(s) will enhance the development of novel therapeutic targets and biomarkers for individualized clinical management for lupus patients.

Interleukin-18 promoter polymorphisms in Japanese patients with rheumatoid arthritis: protective effect of the T allele and T/T genotype at rs360722

Rheumatoid arthritis (RA) is a chronic inflammatory disease with a strong genetic contribution to its pathogenesis. Among numerous candidate genes, cytokine gene polymorphisms have been implicated. Interleukin-18 (IL-18) induces production of tumor necrosis factor-α and promotes T helper (Th)1-type immune responses. This study investigates the association between IL-18 promoter polymorphisms and RA susceptibility. A total of 2471 Japanese case-control samples (1493 RA patients and 978 healthy controls) were examined. Three haplotype tag single-nucleotide polymorphisms, rs1946518A/C, rs360718T/G, and rs360722T/C, spanning from the 5'UTR to intron 1 were genotyped using allelic discrimination with the use of specific TaqMan probes, and three haplotypes (A-T-T, C-T-C, and A-G-C) were determined. Among these polymorphisms, the frequency of the T allele at rs360722, which tags the A-T-T haplotype, was significantly lower in the RA patient group compared with the normal subjects [0.46 versus 0.49, P = 0.0061, Fisher's exact probability test, odds ratio (OR) = 0.85, 95% confidence interval (CI) = 0.75-0.95]. Having the T/T genotype further increased the significance (0.20 versus 0.27, P = 0.0006, OR = 0.72, 95% CI = 0.58-0.86). Therefore, presence of the T allele and T/T genotype at rs360722 reduces the susceptibility of Japanese people to RA.

Herbal medicinal products target defined biochemical and molecular mediators of inflammatory autoimmune arthritis

Rheumatoid arthritis (RA) is a chronic debilitating disease characterized by synovial inflammation, damage to cartilage and bone, and deformities of the joints. Several drugs possessing anti-inflammatory and immunomodulatory properties are being used in the conventional (allopathic) system of medicine to treat RA. However, the long-term use of these drugs is associated with harmful side effects. Therefore, newer drugs with low or no toxicity for the treatment of RA are actively being sought. Interestingly, several herbs demonstrate anti-inflammatory and anti-arthritic activity. In this review, we describe the role of the major biochemical and molecular mediators in the pathogenesis of RA, and highlight the sites of action of herbal medicinal products that have anti-arthritic activity. With the rapidly increasing use of CAM products by patients with RA and other inflammation-related disorders, our review presents timely information validating the scientific rationale for the use of natural therapeutic products.

Association study of single nucleotide polymorphisms in pre-miRNA and rheumatoid arthritis in a Han Chinese population

The aim of this study was to perform an association study between two single nucleotide polymorphisms (SNPs) rs2910164 G>C and rs3746444 T>C in pre-miRNA (hsa-mir-146a and hsa-mir-499) and rheumatoid arthritis (RA) in the Han Chinese population. 208 Han Chinese patients with RA and 240 healthy controls were recruited in this study. The SNPs was genotyped by polymerase chain reaction-restriction fragment length polymorphism. Anti-cyclic citrullinated peptide (anti-CCP) antibody was measured by enzyme linked immunosorbent assay and rheumatoid factor (RF) was measured by rate nephelometry. The genotype frequencies between cases and controls were compared by χ(2) analysis. No significant association between the SNPs (rs2910164 and rs3746444) and RA was observed (P = 0.631 and 0.775, respectively), and the SNPs did not show any association with the RF-positive (P = 0.631 and 0.775, respectively). However, there was a significant difference on the level of anti-CCP antibody between different genotypes in rs3746444 (P = 0.007). The heterozygote CT had significantly higher level of anti-CCP antibody compared with homozygote CC and TT (P = 0.054 and 0.003, respectively). We first investigated the association between the SNPs (rs2910164 G>C and rs3746444 T>C) in the pre-miRNA (hsa-mir-146a and hsa-mir-499) and RA in a Han Chinese population. We did not find a significant association between the SNPs and the susceptibility to RA, while the SNP rs3746444 may affect anti-CCP antibody production.

Association of genetic variations in the STAT4 and IRF7/KIAA1542 regions with systemic lupus erythematosus in a Northern Han Chinese population

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease with complex genetic inheritance. Genome-wide association studies have identified SLE susceptibility variations at the IRF7/KIAA1542 locus and with STAT4 gene in European populations. We decided to investigate the association of single-nucleotide polymorphisms (SNPs) in the IRF7/KIAA1542 region (rs4963128, rs2246614, and rs702966) and in STAT4 (rs7574865 and rs7582694) with SLE disease in a Northern Han Chinese population of 748 patients and 750 healthy controls. Our study indicated a strong association between rs7574865 (odds ratio = 0.68; 95% confidence interval 0.59-0.79; p = 1.57 × 10(-6)) and SLE and between rs7574865 and the production of anti-Sm antibodies. Additionally, rs4963128 and rs2246614 were correlated with a variety of clinical subphenotypes, such as lupus nephritis, arthritis, and the production of anti-SSA/B autoantibodies, despite a lack of significant association between these two SNPs and SLE disease susceptibility in general.

Association ofEMCNwith Susceptibility to Rheumatoid Arthritis in a Japanese Population

Objective.

Endomucin, an endothelial-specific sialomucin, is thought to facilitate “lymphocyte homing” to synovial tissues, resulting in the major histopathologies of rheumatoid arthritis (RA). We examined the association between RA susceptibility and the gene coding endomucin,EMCN.

Methods.

Association studies were conducted with 2 DNA sample sets (initial set of 1504 patients, 752 controls; and validation set, 1113 patients, 940 controls) using 6 tag single-nucleotide polymorphisms (SNP) from the Japanese HapMap database. Immunohistochemistry for the expression of endomucin was conducted with synovial tissues from 4 patients with RA during total knee arthroplasty. Electromobility shift assays were performed for the functional study of identified polymorphisms.

Results.

Within the initial sample set, the strongest evidence of an association with RA susceptibility was SNP rs3775369 (OR 1.20, p = 0.0075). While the subsequent replication study did not initially confirm the observed significant association (OR 1.13, p = 0.062), an in-depth stratified analysis revealed significant association in patients testing positive to anti-cyclic citrullinated peptide (anti-CCP) antibody in the replication data set (OR 1.15, p = 0.044). Investigating 2 sample sets, significant associations were detected in overall and stratified samples with anti-CCP antibody status (OR 1.17, p = 0.0015). Positive staining for endomucin was detected in all patients. The allele associated with RA susceptibility had a higher binding affinity for HEK298-derived nuclear factors compared to the nonsusceptible allelic variant of rs3775369.

Conclusion.

A significant association betweenEMCNand RA susceptibility was detected in our Japanese study population. TheEMCNallele conferring RA susceptibility may also contribute to the pathogenesis of RA.

ELF1 is associated with systemic lupus erythematosus in Asian populations

Systemic lupus erythematosus (SLE) is an autoimmune disease with a strong genetic involvement. The susceptibility genes identified so far can only explain a small proportion of disease heritability. Through a genome-wide association in a Hong Kong Chinese cohort and subsequent replication in two other Asian populations, with a total of 3164 patients and 4482 matched controls, we identified association of ELF1 (E74-like factor 1) with SLE (rs7329174, OR = 1.26, joint P= 1.47 × 10(-8)). ELF1 belongs to the ETS family of transcription factors and is known to be involved in T cell development and function. Database analysis revealed transcripts making use of three alternative exon1s for this gene. Near equivalent expression levels of distinct transcripts initiated from alternative exon1s were detected in peripheral blood mononuclear cells from both SLE patients and healthy controls. Although a direct association of rs7329174 with the three forms of transcripts for this gene was not detected, these findings support an important role of ELF1 in SLE susceptibility and suggest a potentially tight regulation for the expression of this gene.

What can we learn from genetic studies of systemic lupus erythematosus? Implications of genetic heterogeneity among populations in SLE

Recent progress in genetics has expanded the number of the genes associated with SLE to more than 20 in the past 2 years. One might assign these candidate genetic factors into several pre-existing biological pathways: (i) innate immune response including TLR/interferon signaling pathways (IRF5, STAT4, TNFAIP3, and TREX1); (ii) adaptive immune response (HLA-DR, PTPN22, PDCD1, STAT4, LYN, BLK, and BANK1) including B, T cells, and antigen-presenting cells; and (iii) immune complex clearance mechanism (FCGRs, CRP, and ITGAM). In addition, there are also several genes and loci that could not be assigned into previous known pathways (KIAA1542, PXK, XKR6, ATG5, etc), providing possible novel mechanisms in SLE. It has also been evident that there are similarities and differences in SLE susceptibility loci across ethnic groups. Here we categorize the susceptible genes into four groups. The first group is the consistently associated genes with similar risk allele frequency between multiple ethnic populations such as STAT4, TNFAIP3, BANK1, and IRAK1/MECP2. The second group is the genes that are consistently associated but show marked difference in risk allele frequency (BLK, IRF5). The third group is the genes in which different risk variants exist within a gene or genetic loci (allelic heterogeneity) such as HLA-DR, FCGRs, and IRF5. The fourth group is the genes that show consistently discrepancy between populations such as PTPN22 and possibly ITGAM, PXK, and LYN (genetic heterogeneity). The possible explanations for differences of susceptible genetic factors between populations could be different genetic backgrounds, contribution of gene—gene or gene—environment interaction, and the relation between marker and causal variants. Therefore, efforts to identify ethnic-specific genetic factors or disease causing variants should be necessary for individualized therapy for SLE in future.

Synthetic associations in the context of genome-wide association scan signals

Genome-wide association studies (GWAS) have successfully identified a large number of genetic variants associated with complex traits, but these only explain a small proportion of the total heritability. It has been recently proposed that rare variants can create 'synthetic association' signals in GWAS, by occurring more often in association with one of the alleles of a common tag single nucleotide polymorphism. While the ultimate evaluation of this hypothesis will require the completion of large-scale sequencing studies, it is informative to place it in the broader context of what is known about the genetic architecture of complex disease. In this review, we draw from empirical and theoretical data to summarize evidence showing that synthetic associations do not underlie many reported GWAS associations.

Down-regulated expression of IKZF1 mRNA in peripheral blood mononuclear cells from patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease with complex genetic inheritance. IKZF1 was established as a new susceptibility gene for SLE in a recent genome-wide association study (GWAS) in Chinese Han population. In order to examine whether expression levels of IKZF1 contribute to the pathogenesis of SLE, we estimated IKZF1 mRNA expression levels in peripheral blood mononuclear cells (PBMCs) via fluorescent quantitative reverse transcription polymerase chain reaction (RT-PCR) in 60 patients with SLE and 60 controls. We also explored whether the IKZF1 mRNA expression levels are associated with the variant of the SNP rs4917014 and the SLE Disease Activity Index (SLEDAI). The expression levels of IKZF1 mRNA in patients with SLE were significantly decreased compared with those in healthy controls (P<0.001). No significant differences were found between IKZF1 mRNA expression levels and SLEDAI scores, SNP rs4917014. Our results suggest that decreased expression of IKZF1 mRNA may be correlated with the pathogenesis of SLE.

Serum peptidome patterns of human systemic lupus erythematosus based on magnetic bead separation and MALDI-TOF mass spectrometry analysis

OBJECTIVES

Currently few studies have been reported to utilize matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in rheumatic disease, especially in systemic lupus erythematosus (SLE). Our aim was to find differentially expressed disease-related and condition-specific peptides in sera from patients with SLE, as well as to develop and validate the peptide classification model for the diagnosis of SLE.

METHODS

Based on the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) 2000, 50 SLE patients were divided into two subgroups: 25 were defined as stable SLE (SLEDAI < or = 8) and 25 as active SLE (SLEDAI > 8). Twenty-five patients with rheumatoid arthritis (RA) and 24 healthy donors were also included and underwent analysis. We performed magnetic beads-based weak cation exchange chromatography (MB-WCX) for sample processing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for peptide profiling. ClinProt software 2.1 was used for data analysis and a genetic algorithm was modelled for class prediction.

RESULTS

A series of significant short peptides was detected. Classification models were developed to classify samples across normal controls, active SLE patients, and stable SLE patients, and achieved high capability of prediction and cross-validation. Blinded verification of the classification model showed 91.7% sensitivity in active SLE, 83.3% sensitivity in stable SLE, and 86.7% specificity in normal controls.

CONCLUSION

We have completed a preliminary study to describe the serum peptide profile of SLE and improve the diagnosis of SLE from an integrated perspective of peptide mass patterns.

Gene discovery in rheumatoid arthritis highlights the CD40/NF-kappaB signaling pathway in disease pathogenesis

During the past several years, substantial progress has been made in the identification of genetic variants that predispose to rheumatoid arthritis (RA) and other autoimmune disorders. Progress in this area has been facilitated by the availability of new technology that allows for a much more comprehensive screen of the genome than was possible before, in conjunction with large samples of RA patients with well-characterized disease. Recent RA genetic studies have identified genes with important functions related to intracellular signaling mechanisms, transcription factors, cytokines, membrane receptors, costimulatory molecules, and enzymes. In particular, recent discoveries highlight the importance of the CD40/NF-kappaB signaling pathway in RA, based on genetic association with several genes relevant to this pathway, including CD40, TRAF1, TNFAIP3, and REL. Progress in the identification of genes that contribute to RA is proceeding at a very rapid pace. These genetic discoveries shed light on underlying disease mechanisms in RA and provide targets for the development of novel diagnostic and therapeutic tools for future use in this chronic inflammatory disorder.

STAT4 polymorphism in a Chinese Han population with Vogt-Koyanagi-Harada syndrome and Behçet's disease

This study investigated the association of rs7574865 polymorphism in STAT4 with Vogt-Koyanagi-Harada (VKH) syndrome and Behçet's disease (BD) in a Chinese Han population. Genotyping of rs7574865 polymorphism in the STAT4 gene was performed using polymerase chain reaction restriction fragment length polymorphisms in 379 VKH patients, 366 BD patients, and 414 controls. Of the samples, 20% were sequenced to validate polymerase chain reaction restriction fragment length polymorphism results. A binary logistic regression analysis was used to assess the influence of the gender on the association of STAT4 polymorphism with BD. A significantly increased frequency of TT genotype of the STAT4 rs7574865 was observed in VKH patients (p = 0.013). GT genotypic frequency was significantly lower in BD patients than in controls (p = 0.003) However the significance of rs7574865 was lost in all tested BD patients when adjusted for gender (p = 0.775). A significantly lower frequency of GT genotype and a significantly higher frequency of GG genotype was found in male BD patients compared with male controls (p = 0.000458 and p = 0.009, respectively). Stratification analysis according to tinnitus, alopecia, poliosis, headache, and vitiligo for VKH syndrome and oral ulceration, genital ulceration, skin lesions and arthritis for BD failed to find any association between the tested single nucleotide polymorphism and any of the extraocular findings. Our results suggest that TT genotype of rs7574865 may be a susceptible factor for VKH syndrome in a Chinese Han population, and that GG genotype of this SNP may confer susceptibility in male BD patients.

A regulatory variant in CCR6 is associated with rheumatoid arthritis susceptibility

Rheumatoid arthritis is a common autoimmune disease with a complex genetic etiology. Here, through a genome-wide association study of rheumatoid arthritis, we identified a polymorphism in CCR6, the gene encoding chemokine (C-C motif) receptor 6 (a surface marker for Th17 cells) at 6q27, that was associated with rheumatoid arthritis susceptibility and was validated in two independent replication cohorts from Japan (rs3093024, a total of 7,069 individuals with rheumatoid arthritis (cases) and 20,727 controls, overall odds ratio = 1.19, P = 7.7 x 10(-19)). We identified a triallelic dinucleotide polymorphism of CCR6 (CCR6DNP) in strong linkage disequilibrium with rs3093024 that showed effects on gene transcription. The CCR6DNP genotype was correlated with the expression level of CCR6 and was associated with the presence of interleukin-17 (IL-17) in the sera of subjects with rheumatoid arthritis. Moreover, CCR6DNP was associated with susceptibility to Graves' and Crohn's diseases. These results suggest that CCR6 is critically involved in IL-17-driven autoimmunity in human diseases.

Single nucleotide polymorphisms of CD244 gene predispose to renal and neuropsychiatric manifestations with systemic lupus erythematosus

The objective of this study was to explore the association of single nucleotide polymorphisms (SNPs) of the CD244 gene with several clinical features of systemic lupus erythematosus (SLE). Two hundred and forty-three patients with SLE and 369 healthy controls were enrolled. Two SNPs (rs6682654 and rs3766379) in the CD244 gene were determined by allelic discrimination using a specific TaqMan probe. Only SNP rs3766379 was significantly associated with susceptibility to SLE [P = 0.009; odds ratio (OR) 1.28; 95% confidence interval (CI) 1.04-1.57]. The association was preferentially observed in subsets of SLE patients with nephritis and neuropsychiatric lupus. The frequency of the rs6682654 C allele was strongly associated with nephritis and neuropsychiatric lupus (P = 0.00065; OR 1.99; 95% CI 1.34-2.95, and P = 1.6 × 10(-7); OR 3.47; 95% CI 2.12-5.70, respectively), as was the frequency of the rs3766379 T allele (P = 0.0014; OR 1.86; 95% CI 1.27-2.71, and P = 2.6 × 10(-7); OR 3.15; 95% CI 2.00-4.96, respectively). In this study, an SNP of the CD244 gene was associated with susceptibility to SLE. There was a strikingly strong association in SLE patients with nephritis and neuropsychiatric lupus, suggesting that this genetic marker could predict involvement of those severe complications.

Update on the genetic risk factors for rheumatoid arthritis

Rheumatoid arthritis (RA) is a complex disease, meaning that multiple genetic variants, environmental factors and random events interact to trigger pathological pathways. Although many of these etiological factors have not yet been identified, recent groundbreaking advances have expanded our knowledge about the genetic factors that contribute to RA. Here, we review the most recent findings on the genetic risk factors for RA. First, we give an overview of the genetics of RA and briefly describe the susceptibility loci discovered prior to the availability of genome-wide association studies (GWAS). Second, we focus on the newly discovered RA loci that have arisen from GWAS in populations of European ancestry. Through these studies, the number of established RA susceptibility loci has now grown to 13. Third, we discuss several important issues emerging from GWAS, such as ethnic heterogeneity and shared autoimmunity risk loci. Finally, we discuss what still needs to be accomplished before a more complete picture of the genetic risk to RA can be attained.

Genetic associations in type I interferon related pathways with autoimmunity

Type I interferons play an outstanding role in innate and adaptive immunity by enhancing functions of dendritic cells, inducing differentiation of monocytes, promoting immunoglobulin class switching in B cells and stimulating effector functions of T cells. The increased production of IFNα/β by plasmacytoid dendritic cells could be responsible for not only efficient antiviral defence, but it also may be a pathological factor in the development of various autoimmune disorders. The first evidence of a genetic link between type I interferons and autoimmune diseases was the observation that elevated IFNα activity is frequently detected in the sera of patients with systemic lupus erythematosus, and that this trait shows high heritability and familial aggregation in their first-degree healthy relatives. To date, a number of genes involved in interferon signalling have been associated with various autoimmune diseases. Patients with systemic lupus erythematosus, Sjögren's syndrome, dermatomyositis, psoriasis, and a fraction of patients with rheumatoid arthritis display a specific expression pattern of interferon-dependent genes in their leukocytes, termed the interferon signature. Here, in an attempt to understand the role of type I interferons in the pathogenesis of autoimmunity, we review the recent advances in the genetics of autoimmune diseases focusing on the association of genes involved in type I interferon pathways.

Evaluation of the rheumatoid arthritis susceptibility loci HLA-DRB1, PTPN22, OLIG3/TNFAIP3, STAT4 and TRAF1/C5 in an inception cohort

INTRODUCTION

This study investigated five confirmed rheumatoid arthritis (RA) susceptibility genes/loci (HLA-DRB1, PTPN22, STAT4, OLIG3/TNFAIP3 and TRAF1/C5) for association with susceptibility and severity in an inception cohort.

METHODS

The magnitude of association for each genotype was assessed in 1,046 RA subjects from the Yorkshire Early RA cohort and in 5,968 healthy UK controls. Additional exploratory subanalyses were undertaken in subgroups defined by autoantibody status (rheumatoid factor and anti-cyclic citrullinated peptide) or disease severity (baseline articular erosions, Health Assessment Questionnaire (HAQ) score and swollen joint count (SJC)).

RESULTS

In the total RA inception cohort, the HLA-DRB1 shared epitope (per-allele odds ratio (OR) = 2.1, trend P < 0.0001), PTPN22 (per-allele OR = 1.5, trend P < 0.0001), OLIG3/TNFAIP3 locus (per-allele OR = 1.2, trend P = 0.009) and TRAF1/C5 locus (per-allele OR = 1.1, trend P = 0.04) were associated with RA. The magnitude of association for these loci was increased in those patients who were autoantibody-positive. PTPN22 was associated with autoantibody-negative RA (per-allele OR = 1.3, trend P = 0.04). There was no evidence of association between these five genetic loci and baseline erosions or SJC in the total RA cohort, after adjustment for symptom duration. TRAF1/C5 was significantly associated with baseline HAQ, however, following adjustment for symptom duration (P trend = 0.03).

CONCLUSIONS

These findings support the mounting evidence that different genetic loci are associated with autoantibody-positive and autoantibody-negative RA, possibly suggesting that many of the genes identified to date are associated with autoantibody production. Additional studies with a specific focus on autoantibody-negative RA will be needed to identify the genes predisposing to this RA subgroup. The TRAF1/C5 locus in particular warrants further investigation in RA as a potential disease severity locus.

Association of signal transducer and activator of transcription 4 genetic variants with extra-intestinal manifestations in inflammatory bowel disease

AIMS

The STAT4 gene encodes a transcription factor which plays an important role in the development of inflammation of many immune-mediated diseases. We investigated the relationship between STAT4 single nucleotide polymorphisms (SNPs) and susceptibility to ulcerative colitis (UC) and Crohn's disease (CD) and disease phenotypes in the Korean population.

MAIN METHODS

We performed a case-control association study in individuals with UC (N=246), CD (N=182), and healthy controls (N=229).

KEY FINDINGS

We genotyped 8 STAT4 SNPs (rs11889341, rs7574865, rs8179673, rs6752770, rs925847, rs10168266, rs10181656, and rs11685878) in the STAT4 gene in patients and controls. SNP rs925847 in the STAT4 gene was significantly associated with susceptibility to UC (P=0.025; OR=0.63) in dominant genotype analysis, though none of these SNPs were associated with CD susceptibility. Moreover, a significant association was identified between SNP rs11889341 and joint involvement (P=0.040; OR=3.79), and between SNP rs925847 and eye involvement (P=0.030; OR=2.42) in UC patients. For CD, rs925847 genetic variant was associated with joint (P=0.029; OR=3.93) and perianal lesions (P=0.033; OR=2.27).

SIGNIFICANCE

Our data demonstrated that the STAT4 genetic variants could predispose an individual to IBD and its extra-intestinal ailments in Koreans, suggesting the common pathogenesis of IBD (especially, extra-intestinal manifestations) and other autoimmune diseases.

A meta-analysis of the association of STAT4 polymorphism with systemic lupus erythematosus

STAT4 has been newly identified as a susceptibility gene for systemic lupus erythematosus (SLE) in recent reports. To more precisely estimate the association between STAT4 polymorphism and SLE risk, a meta-analysis was performed. Studies on the association of STAT4 rs7574865 or rs7601754 with SLE were fully considered and carefully selected using three electronic databases (PubMed, Embase, and Web of Science). A total of 17 comparisons from 8 relevant studies involving 7,381 patients and 11,431 controls were included to analyze the association between STAT4 rs7574865 and SLE risk. The pooled OR for the minor T allele of STAT4 rs7574865 was 1.65 (95% CI 1.56-1.75, P < 0.001) in SLE. In a subgroup analysis by ethnicity, the degree of risk of STAT4 rs7574865 with SLE susceptibility was similar in populations of European or Asian origin, although significant differences in the minor T allele frequencies were observed in the two population controls. As for rs7601754, there were five comparisons from four relevant studies involving 2,498 patients and 4,825 controls in this meta-analysis. The pooled OR for the minor C allele of STAT4 rs7601754 was 0.67 (95% CI 0.59-0.75, P < 0.001) in SLE. Conversely, the major T allele of STAT4 rs7601754 might be a risk factor for SLE risk. In conclusion, our results do support STAT4 rs7574865 polymorphism as a susceptibility factor for SLE in populations of European and Asian origin. Our results also suggest that STAT4 rs7601754 polymorphism might be associated with SLE risk.

Genetics of systemic lupus erythematosus and Sjögren's syndrome

PURPOSE OF REVIEW

To determine the advances made in the genetics of systemic lupus erythematosus (SLE) or Sjögren's syndrome as the era of genome-wide association and high-throughput single nucleotide typing begins.

RECENT FINDINGS

Several genome-wide association studies have been performed in SLE but there are no such studies published or in progress for Sjögren's syndrome. Genetics and the functional significance of risk alleles in the interferon pathway are being worked out in detail. This is especially true for STAT4 and IRF5. Gene copy number variation, a major source of genetic variability, is important for several genes that impart risk for SLE. An X chromosome copy number dose effect has recently been identified. Genetic evaluation of Sjögren's syndrome is limited to small studies that have concentrated on genes already shown to be risk factors in SLE.

SUMMARY

Knowledge of the genetics of SLE is advancing rapidly, whereas that of Sjögren's syndrome lags behind considerably.