A study was conducted to determine whether the human leukocyte antigen (HLA) B alleles are implicated in the susceptibility to Henoch-Schönlein purpura (HSP) in the largest series of Caucasian HSP patients ever assessed for genetic studies.

To determine whether the PTPN22 (protein tyrosine phosphatase nonreceptor 22)/CSK (c-src tyrosine kinase) pathway is implicated in the susceptibility and clinical heterogeneity of Henoch-Schönlein purpura (HSP) in the largest series of Caucasian HSP patients ever assessed for genetic studies.

Rheumatoid arthritis (RA) is a polygenic disease associated with accelerated atherosclerosis and increased cardiovascular (CV) mortality. JAK/STAT signalling pathway is involved in autoimmune diseases and in the atherosclerotic process. JAK3 is a highly promising target for immunomodulatory drugs and polymorphisms in JAK3 gene have been associated with CV events in incident dialysis patients. Therefore, the aim of this study was to assess the potential role of JAK3 polymorphisms in the development of CV disease in patients with RA. 2136 Spanish RA patients were genotyped for the rs3212780 and rs3212752 JAK3 gene polymorphisms by TaqMan assays. Subclinical atherosclerosis was evaluated in 539 of these patients by carotid ultrasonography (US). No statistically significant differences were found when each polymorphism was assessed according to carotid intima-media thickness values and presence/absence of carotid plaques in RA, after adjusting the results for potential confounders. Moreover, no significant differences were obtained when RA patients were stratified according to the presence/absence of CV events after adjusting for potential confounders. In conclusion, our results do not confirm association between JAK3 polymorphisms and CV disease in RA.

A rare variant (BAFF-var) of the tumor necrosis factor superfamily 13b (TNFSF13B) gene has been recently associated with multiple sclerosis (MS) and systemic lupus erythematosus (SLE). The aim of this study was to investigate the association between TNFSF13B BAFF-var and susceptibility to rheumatoid arthritis (RA) and replicate that association in SLE. 6,218 RA patients, 2,575 SLE patients and 4,403 healthy controls from three different countries were included in the study. TNFSF13B BAFF-var was genotyped using TaqMan allelic discrimination assay. PLINK software was used for statistical analyses. TNFSF13B BAFF-var was significantly associated with RA (p = 0.015, OR = 1.21, 95% CI = 1.03-1.41) in the Spanish cohort. A trend of association was observed in the Dutch (p = 0.115) and German (p = 0.228) RA cohorts. A meta-analysis of the three RA cohorts included in this study revealed a statistically significant association (p = 0.002, OR = 1.24, 95% CI = 1.10-1.38). In addition, TNFSF13B BAFF-var was significantly associated with SLE in the Spanish (p = 0.001, OR = 1.41, 95% CI = 1.14-1.74) and the German cohorts (p = 0.030, OR = 1.86, 95% CI = 1.05-3.28), with a statistically significant p-value obtained in the meta-analysis (p = 0.0002, OR = 1.46, 95% CI = 1.09-2.32). The results obtained confirm the known association of TNFSF13B BAFF-var with SLE and, for the first time, demonstrate that this variant contributes to susceptibility to RA.

According to genome wide association (GWA) studies as well as candidate gene approaches, Behçet's disease (BD) is associated with human leukocyte antigen (HLA)-A and HLA-B gene regions. The HLA-B51 has been consistently associated with the disease, but the role of other HLA class I molecules remains controversial. Recently, variants in non-HLA genes have also been associated with BD. The aims of this study were to further investigate the influence of the HLA region in BD and to explore the relationship with non-HLA genes recently described to be associated in other populations.

Recently, different genetic variants located within the IL2/IL21 genetic region as well as within both IL2RA and IL2RB loci have been associated to multiple autoimmune disorders. We aimed to investigate for the first time the potential influence of the IL2/IL21, IL2RA and IL2RB most associated polymorphisms with autoimmunity on the endogenous non-anterior uveitis genetic predisposition.

CD40, BLK and BANK1 genes involved in the development and signaling of B-cells are identified as susceptibility loci for numerous inflammatory diseases. Accordingly, we assessed the potential influence of CD40, BLK and BANK1 on the pathogenesis of immunoglobulin-A vasculitis (IgAV), predominantly a B-lymphocyte inflammatory condition. Three genetic variants within CD40 (rs1883832, rs1535045, rs4813003) and BLK (rs2254546, rs2736340, rs2618476) as well as two BANK1 polymorphisms (rs10516487, rs3733197), previously associated with inflammatory diseases, were genotyped in 382 Caucasian patients with IgAV and 955 sex- and ethnically matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of CD40, BLK and BANK1 when IgAV patients and healthy controls were compared. Similar results were found when CD40, BLK and BANK1 genotypes or alleles frequencies were compared between patients with IgAV stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. Moreover, no CD40, BLK and BANK1 haplotype differences were disclosed between patients with IgAV and healthy controls and between patients with IgAV stratified according to the clinical characteristics mentioned above. Our findings indicate that CD40, BLK and BANK1 do not contribute to the genetic background of IgAV.

Genome-wide association studies (GWASs) have identified a number of genetic risk loci associated with systemic sclerosis (SSc) and Crohn's disease (CD), some of which confer susceptibility to both diseases. In order to identify new risk loci shared between these two immune-mediated disorders, we performed a cross-disease meta-analysis including GWAS data from 5,734 SSc patients, 4,588 CD patients and 14,568 controls of European origin. We identified 4 new loci shared between SSc and CD, IL12RB2, IRF1/SLC22A5, STAT3 and an intergenic locus at 6p21.31. Pleiotropic variants within these loci showed opposite allelic effects in the two analysed diseases and all of them showed a significant effect on gene expression. In addition, an enrichment in the IL-12 family and type I interferon signaling pathways was observed among the set of SSc-CD common genetic risk loci. In conclusion, through the first cross-disease meta-analysis of SSc and CD, we identified genetic variants with pleiotropic effects on two clinically distinct immune-mediated disorders. The fact that all these pleiotropic SNPs have opposite allelic effects in SSc and CD reveals the complexity of the molecular mechanisms by which polymorphisms affect diseases.

Sjögren's disease is a complex autoimmune disease with twelve established susceptibility loci. This genome-wide association study (GWAS) identifies ten novel genome-wide significant (GWS) regions in Sjögren's cases of European ancestry: CD247, NAB1, PTTG1-MIR146A, PRDM1-ATG5, TNFAIP3, XKR6, MAPT-CRHR1, RPTOR-CHMP6-BAIAP6, TYK2, SYNGR1. Polygenic risk scores yield predictability (AUROC = 0.71) and relative risk of 12.08. Interrogation of bioinformatics databases refine the associations, define local regulatory networks of GWS SNPs from the 95% credible set, and expand the implicated gene list to >40. Many GWS SNPs are eQTLs for genes within topologically associated domains in immune cells and/or eQTLs in the main target tissue, salivary glands.

Endogenous uveitis is a major cause of visual loss mediated by the immune system. The protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene encodes a lymphoid-specific phosphatase that plays a key role in T-cell receptor (TCR) signaling. Two independent functional missense single nucleotide polymorphisms (SNPs) located within the PTPN22 gene (R263Q and R620W) have been associated with different autoimmune disorders. We aimed to analyze for the first time the influence of these PTPN22 genetic variants on endogenous non-anterior uveitis susceptibility.

Rheumatoid arthritis (RA) is a polygenic disease associated with accelerated atherosclerosis and increased cardiovascular (CV) mortality. Recent studies have identified the ABO rs579459, PPAP2B rs17114036, and ADAMTS7 rs3825807 polymorphisms as genetic variants associated with coronary artery disease and the PIK3CG rs17398575 and EDNRA rs1878406 polymorphisms as the most significant signals related to the presence of carotid plaque in nonrheumatic Caucasian individuals. Accordingly, we evaluated the potential relationship between these 5 polymorphisms and subclinical atherosclerosis (assessed by carotid intima-media thickness (cIMT) and presence/absence of carotid plaques) and CV disease in RA.

The TNFSF13B (TNF superfamily member 13b) gene encodes BAFF, a cytokine with a crucial role in the differentiation and activation of B cells. An insertion-deletion variant (GCTGT→A) of this gene, leading to increased levels of BAFF, has been recently implicated in the genetic predisposition to several autoimmune diseases, including multiple sclerosis, systemic lupus erythematosus, and rheumatoid arthritis. Based on the elevated levels of this cytokine found in patients with giant cell arteritis (GCA) and systemic sclerosis (SSc), we aimed to assess whether this functional variant also represents a novel genetic risk factor for these two disorders.

To determine whether the interleukin-33 (IL-33)-interleukin-1 receptor like 1 (IL-1RL1) signaling pathway is implicated in the risk of subclinical atherosclerosis in patients with rheumatoid arthritis (RA).

Prostaglandin E receptor 4 (PTGER4) is implicated in immune regulation and bone metabolism. The aim of this study was to analyze its role in radiological joint damage in rheumatoid arthritis (RA).

Rheumatoid arthritis is an inflammatory disease with high incidence of cardiovascular disease due to accelerated atherosclerosis. Osteoprotegerin (OPG) has been associated with increased risk of atherosclerotic disease in the general population. Several polymorphisms in the OPG gene with functional effects on cardiovascular disease in non-rheumatic individuals have been described. Therefore, we aimed to analyze the effect of three of these functional OPG polymorphisms on the risk of cardiovascular disease in a large and well-characterized cohort of Spanish patients with rheumatoid arthritis.

Increased expression of IL-33 and its receptor ST2, encoded by the IL1RL1 gene, has been detected in the inflamed arteries of giant cell arteritis (GCA) patients. The aim of the present study was to investigate for the first time the potential influence of the IL33 and IL1RL1 loci on GCA predisposition.

We conducted a large-scale genetic analysis on giant cell arteritis (GCA), a polygenic immune-mediated vasculitis. A case-control cohort, comprising 1,651 case subjects with GCA and 15,306 unrelated control subjects from six different countries of European ancestry, was genotyped by the Immunochip array. We also imputed HLA data with a previously validated imputation method to perform a more comprehensive analysis of this genomic region. The strongest association signals were observed in the HLA region, with rs477515 representing the highest peak (p = 4.05 × 10(-40), OR = 1.73). A multivariate model including class II amino acids of HLA-DRβ1 and HLA-DQα1 and one class I amino acid of HLA-B explained most of the HLA association with GCA, consistent with previously reported associations of classical HLA alleles like HLA-DRB1(∗)04. An omnibus test on polymorphic amino acid positions highlighted DRβ1 13 (p = 4.08 × 10(-43)) and HLA-DQα1 47 (p = 4.02 × 10(-46)), 56, and 76 (both p = 1.84 × 10(-45)) as relevant positions for disease susceptibility. Outside the HLA region, the most significant loci included PTPN22 (rs2476601, p = 1.73 × 10(-6), OR = 1.38), LRRC32 (rs10160518, p = 4.39 × 10(-6), OR = 1.20), and REL (rs115674477, p = 1.10 × 10(-5), OR = 1.63). Our study provides evidence of a strong contribution of HLA class I and II molecules to susceptibility to GCA. In the non-HLA region, we confirmed a key role for the functional PTPN22 rs2476601 variant and proposed other putative risk loci for GCA involved in Th1, Th17, and Treg cell function.

Systemic sclerosis (SSc) is a fibrotic autoimmune disease in which the genetic component plays an important role. One of the strongest SSc association signals outside the human leukocyte antigen (HLA) region corresponds to interferon (IFN) regulatory factor 5 (IRF5), a major regulator of the type I IFN pathway. In this study we aimed to evaluate whether three different haplotypic blocks within this locus, which have been shown to alter the protein function influencing systemic lupus erythematosus (SLE) susceptibility, are involved in SSc susceptibility and clinical phenotypes. For that purpose, we genotyped one representative single-nucleotide polymorphism (SNP) of each block (rs10488631, rs2004640, and rs4728142) in a total of 3,361 SSc patients and 4,012 unaffected controls of Caucasian origin from Spain, Germany, The Netherlands, Italy and United Kingdom. A meta-analysis of the allele frequencies was performed to analyse the overall effect of these IRF5 genetic variants on SSc. Allelic combination and dependency tests were also carried out. The three SNPs showed strong associations with the global disease (rs4728142: P  = 1.34×10(-8), OR  = 1.22, CI 95%  = 1.14-1.30; rs2004640: P  = 4.60×10(-7), OR  = 0.84, CI 95%  = 0.78-0.90; rs10488631: P  = 7.53×10(-20), OR  = 1.63, CI 95%  = 1.47-1.81). However, the association of rs2004640 with SSc was not independent of rs4728142 (conditioned P  = 0.598). The haplotype containing the risk alleles (rs4728142*A-rs2004640*T-rs10488631*C: P  = 9.04×10(-22), OR  = 1.75, CI 95%  = 1.56-1.97) better explained the observed association (likelihood P-value  = 1.48×10(-4)), suggesting an additive effect of the three haplotypic blocks. No statistical significance was observed in the comparisons amongst SSc patients with and without the main clinical characteristics. Our data clearly indicate that the SLE risk haplotype also influences SSc predisposition, and that this association is not sub-phenotype-specific.

In this study we investigated the association of functional single nucleotide polymorphisms of tumor necrosis factor-alfa (TNFA) and TNF receptor 2 (TNFR2) genes in determining the susceptibility to Chagas' disease. This study included 313 patients from Colombia serologically positive for Trypanosoma cruzi antigens (cardiomyopathic, N=159; asymptomatic, N=154). Genotypes were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism method. We found a significant difference in the distribution of the TNFA -1031C (p=0.0153, OR=1.69, CI=1.10-2.58) and -308A (p=0.0002, OR=2.60, CI=1.53-4.39) alleles between cardiomyopathic and asymptomatic subjects. In addition, we observed that the TNFR2 +676T allele was monomorphic in our population. Our results suggest that TNFA -1031C and -308A gene polymorphisms may influence the susceptibility to develop chagasic cardiomyopathy in the population under study.

Genetic susceptibility to Trypanosoma cruzi infection and the development of cardiomyopathy is complex, heterogeneous, and likely involves several genes. Previous studies have implicated cytokine and chemokine genes in susceptibility to Chagas disease. Here we investigated the association between the interferon-gamma gene (IFNG) +874T/A polymorphism and Chagas disease, focusing on susceptibility and severity. This study included 236 chagasic patients (asymptomatic, n=116; cardiomyopathic, n=120) and 282 healthy controls from a Colombian population where T. cruzi is highly endemic. Individuals were genotyped for functional single nucleotide polymorphism (SNP; rs2430561; A/T) of the IFNG gene by amplification refractory mutational system PCR (ARMS-PCR). Moreover, clinical manifestations of Chagas in patients were analyzed. We found a significant difference in the distribution of the IFNG +874 "A" allele between patients and healthy controls (P=0.003; OR=1.46, 95% CI, 1.13-1.89). The frequency of the IFNG +874 genotype A/A, which is associated with reduced production of interferon-gamma, was increased in the patients relative to controls (38.1% vs. 26.6%). We compared the frequencies of IFNG alleles and genotypes between asymptomatic patients and those with chagasic cardiomyopathy and found no significant difference. Our data suggest that the IFNG +874T/A genetic polymorphism may be involved in susceptibility but not in the progression of Chagas disease in this Colombian population.