Association between rs2294020 in X-linked CCDC22 and susceptibility to autoimmune diseases with focus on systemic lupus erythematosus.

Autoimmune diseases often share common susceptibility genes. Most genetic variants associated with susceptibility to systemic lupus erythematosus are also associated with other autoimmune diseases. The X-linked variant rs2294020 is positioned in exon 7 of the CCDC22 gene. The encoded protein functions in the regulation of NF-κB, a master regulator in immune response. The aim of this study is to investigate whether the rs2294020 polymorphism may be a general susceptibility factor for autoimmunity. We evaluated case-control association between the occurrence of rs2294020 and different autoimmune diseases, including new data for systemic lupus erythematosus and previous genome-wide association studies (GWAS) (though most did not analyse the X chromosome) of psoriasis, celiac disease, Crohn's disease, ulcerative colitis, multiple sclerosis, vitiligo, type-1 diabetes, rheumatoid arthritis, and ankylosing spondylitis. Cases from patients affected by amyotrophic lateral sclerosis and type-2 diabetes were also included in the study. We detected nominal significant associations of rs2294020 with systemic lupus erythematosus (additive model test: p=0.01), vitiligo (p=0.016), psoriasis (p=0.038), and in only one of two studies of multiple sclerosis (p=0.03). Our results suggest that rs2294020 is associated with the risk of several autoimmune diseases in European populations, specifically with diseases that present themselves, among else, in the skin.

Time-course gene expression data on the transcriptional effects of Aminaphtone on ECV304 endothelial cells.

We previously showed that Aminaphtone, a drug used in the treatment of chronic venous insufficiency, modulates several vasoactive factors, such as endothelin-1 and adhesion molecules. Here, we provide data of time-course experiments about the effects of Aminaphtone on gene expression at the genome-wide level in human endothelial cells undergoing cytokine stimulation in vitro. ECV-304 endothelial cells were incubated with interleukin-1ß (IL-1ß) in the presence or absence of Aminaphtone for 1, 3, and 6 h. Gene expression profiles were analyzed by microarray. This article contains complete data on the genes significantly modulated by the drug over time. The data are supplemental to our original research article reporting detailed analysis of the actions of Aminaphtone on IL-1ß stimulated endothelial cells at the molecular level, "Gene expression profiling reveals novel protective effects of Aminaphtone on ECV304 endothelial cells" (Salazar et al., 2016) [1].

Gene expression profiling reveals novel protective effects of Aminaphtone on ECV304 endothelial cells.

Aminaphtone, a drug used in the treatment of chronic venous insufficiency (CVI), showed a remarkable role in the modulation of several vasoactive factors, like endothelin-1 and adhesion molecules. We analysed in vitro the effects of Aminaphtone on whole-genome gene expression and production of different inflammatory proteins. ECV-304 endothelial cells were stimulated with IL-1ß 100U/ml in the presence or absence of Aminaphtone 6µg/ml. Gene expression profiles were compared at 1, 3, and 6h after stimulation by microarray. Supernatants of ECV-304 cultures were analysed at 3, 6, 12, and 24h by multiplex ELISA for production of several cytokine and chemokines. Microarrays showed a significant down-regulation at all times of a wide range of inflammatory genes. Aminaphtone appeared also able to modulate the regulation of immune response process (down-regulating cytokine biosynthesis, transcripts involved in lymphocyte differentiation and cell proliferation, and cytokine-cytokine receptor interaction) and to regulate genes engaged in homeostasis, secretion, body fluid levels, response to hypoxia, cell division, and cell-to-cell communication and signalling. Results were confirmed and extended analysing the secretome, which showed significant reduction of the release of 14 cytokines and chemokines. These effects are predicted to be mediated by interaction with different transcription factors. Aminaphtone was able to modulate the expression of inflammatory molecules relevant to the pathogenesis of several conditions in which the endothelial dysfunction is the main player and early event, like scleroderma, lung fibrosis, or atherosclerosis.

A gender gap in primary and secondary heart dysfunctions in systemic sclerosis: a EUSTAR prospective study.

OBJECTIVES: In agreement with other autoimmune diseases, systemic sclerosis (SSc) is associated with a strong sex bias. However, unlike lupus, the effects of sex on disease phenotype and prognosis are poorly known. Therefore, we aimed to determine sex effects on outcomes. METHOD: We performed a prospective observational study using the latest 2013 data extract from the EULAR scleroderma trials and research (EUSTAR) cohort. We looked at (i) sex influence on disease characteristics at baseline and (ii) then focused on patients with at least 2 years of follow-up to estimate the effects of sex on disease progression and survival. RESULTS: 9182 patients with SSc were available (1321 men) for the baseline analyses. In multivariate analysis, male sex was independently associated with a higher risk of diffuse cutaneous subtype (OR: 1.68, (1.45 to 1.94); p<0.001), a higher frequency of digital ulcers (OR: 1.28 (1.11 to 1.47); p<0.001) and pulmonary hypertension (OR: 3.01 (1.47 to 6.20); p<0.003). In the longitudinal analysis (n=4499), after a mean follow-up of 4.9 (±2.7) years, male sex was predictive of new onset of pulmonary hypertension (HR: 2.66 (1.32 to 5.36); p=0.006) and heart failure (HR: 2.22 (1.06 to 4.63); p=0.035). 908 deaths were recorded, male sex predicted deaths of all origins (HR: 1.48 (1.19 to 1.84); p<0.001), but did not significantly account for SSc-related deaths. CONCLUSIONS: Although more common in women, SSc appears as strikingly more severe in men. Our results obtained through the largest worldwide database demonstrate a higher risk of severe cardiovascular involvement in men. These results raise the point of including sex in the management and the decision-making process.

The HLA-B*35 allele modulates ER stress, inflammation and proliferation in PBMCs from Limited Cutaneous Systemic Sclerosis patients.

INTRODUCTION: HLA-B*35 is associated with increased risk of developing pulmonary hypertension in SSc patients. We previously reported that HLA-B*35 induces endothelial cell dysfunction via activation of ER stress/UPR and upregulation of the inflammatory response. Because PBMCs from lcSSc-PAH patients are also characterized by activation of ER stress/UPR and inflammation, the goal of this study was to assess whether the presence of HLA-B*35 contributes to those characteristics. METHODS: PBMCs were purified from healthy controls (n = 49 HC) and lcSSc patients, (n = 44 with PAH, n = 53 without PAH). PBMCs from each group were stratified for the presence of HLA-B*35. Global changes in gene expression in response to HLA-B*35, HLA-B*8 or empty lentivirus were investigated by microarray analysis in HC PBMCs. Total RNA was extracted and qPCR was performed to measure gene expression. RESULTS: ER stress markers, in particular the chaperones BiP and DNAJB1 were significantly elevated in PBMC samples carrying the HLA-B*35 allele. IL-6 expression was also significantly increased in HLA-B*35 lcSSc PBMCs and positively correlated with ER stress markers. Likewise, HMGB1 was increased in HLA-B*35-positive lcSSc PBMCs. Global gene expression analysis was used to further probe the role of HLA-B*35. Among genes downregulated by HLA-B*35 lentivirus were genes related to complement (C1QB, C1QC), cell cycle (CDNK1A) and apoptosis (Bax, Gadd45). Interestingly, complement genes (C1QC and C1QB) showed elevated expression in lcSSc without PAH, but were expressed at the low levels in lcSSc-PAH. The presence of HLA-B*35 correlated with the decreased expression of the complement genes. Furthermore, HLA-B*35 correlated with decreased expression of cyclin inhibitors (p21, p57) and pro-apoptotic genes (Bax, Gadd45) in lcSSc B35 subjects. FYN, a tyrosine kinase involved in proliferation of immune cells, was among the genes that were positively regulated by HLA-B*35. HLA-B*35 correlated with increased levels of FYN in lcSSc PBMCs. CONCLUSIONS: Our study demonstrates that HLA-B*35 contributes to the dysregulated expression of selected ER stress, inflammation and proliferation related genes in lcSSc patient PBMCs, as well as healthy individuals, thus supporting a pathogenic role of HLA-B*35 in the development of PAH in SSc patients.

Rare variants in the TREX1 gene and susceptibility to autoimmune diseases.

TREX1 (DNase III) is an exonuclease involved in response to oxidative stress and apoptosis. Heterozygous mutations in TREX1 were previously observed in patients with systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). We performed a mutational analysis of the TREX1 gene on three autoimmune diseases: SLE (210 patients) and SS (58 patients), to confirm a TREX1 involvement in the Italian population, and systemic sclerosis (SSc, 150 patients) because it shares similarities with SLE (presence of antinuclear antibodies and connective tissue damage). We observed 7 variations; two of these are novel nonsynonymous variants (p.Glu198Lys and p.Met232Val). They were detected in one SS and in one SSc patient, respectively, and in none of the 200 healthy controls typed in this study and of the 1712 published controls. In silico analysis predicts a possibly damaging role on protein function for both variants. The other 5 variations are synonymous and only one of them is novel (p.Pro48Pro). This study contributes to the demonstration that TREX1 is involved in autoimmune diseases and proposes that the spectrum of involved autoimmune diseases can be broader and includes SSc. We do not confirm a role of TREX1 variants in SLE.

A systemic sclerosis and systemic lupus erythematosus pan-meta-GWAS reveals new shared susceptibility loci.

Systemic sclerosis (SSc) and systemic lupus erythematosus (SLE) are two archetypal systemic autoimmune diseases which have been shown to share multiple genetic susceptibility loci. In order to gain insight into the genetic basis of these diseases, we performed a pan-meta-analysis of two genome-wide association studies (GWASs) together with a replication stage including additional SSc and SLE cohorts. This increased the sample size to a total of 21,109 (6835 cases and 14,274 controls). We selected for replication 19 SNPs from the GWAS data. We were able to validate KIAA0319L (P = 3.31 × 10(-11), OR = 1.49) as novel susceptibility loci for SSc and SLE. Furthermore, we also determined that the previously described SLE susceptibility loci PXK (P = 3.27 × 10(-11), OR = 1.20) and JAZF1 (P = 1.11 × 10(-8), OR = 1.13) are shared with SSc. Supporting these new discoveries, we observed that KIAA0319L was overexpressed in peripheral blood cells of SSc and SLE patients compared with healthy controls. With these, we add three (KIAA0319L, PXK and JAZF1) and one (KIAA0319L) new susceptibility loci for SSc and SLE, respectively, increasing significantly the knowledge of the genetic basis of autoimmunity.

Carbohydrate antigen 15.3 as a serum biomarker of interstitial lung disease in systemic sclerosis patients.

BACKGROUND: To determine the usefulness of Ca 15.3 as a candidate biomarker in systemic sclerosis (SSc) patients with interstitial lung disease (ILD). METHODS: Two-hundred-twenty-one SSc patients with Ca 15.3 determinations were considered; 168 had evidence of interstitial lung involvement on high-resolution computed tomography (HRCT); digitalized scans were available for scoring in 84 subjects. Discrimination between patients with or without ILD, was assessed by receiving operating characteristics (ROC) analysis; correlations between HRCT scores and Ca 15.3 were performed. Survival and serial pulmonary function tasting (PFT) data were used for prognostication. RESULTS: Ca 15.3 serum levels strongly correlated with HRCT scores (r=0.734, p<0.0001) which were predictors of survival at the 20% threshold (p=3.1∗10(-4)). Ca 15.3 had an area under ROC to detect the meaningful 20% fibrosis extent equal to 0.927 and abnormal Ca 15.3 values were capable of differentiating between patients at hi- or low-risk for progression in the group with undetermined disease extent (HR=3.209, confidence interval [CI95]=1.56-6.602, p=0.002). Ca 15.3 outperformed other PFT measures in providing a separation of survival estimates where HRCT scans are unavailable. The combined use of HRCT scores and Ca 15.3 in SSc-ILD patients was more discriminatory (HR=4.824, CI95=2.612-8.912, p<0.0001) than the staging system based on HRCT scores plus FVC (HR=2.657, CI95=1.703-4.147, p<0.0001) and characterized by lower prediction errors (0.2134 vs 0.2234). CONCLUSION: Ca 15.3 is a rapid and inexpensive candidate biomarker for SSc-ILD being proportional to the extent of lung injury and specific and sensitive in assessing meaningful extents of the disease with prognostic significance.

Genetic polymorphisms of FOXP3 in Italian patients with systemic sclerosis.

A case control study to evaluate the possible influence of FOXP3 polymorphisms (rs3761548 and rs2280883) in the susceptibility of systemic sclerosis in an Italian Caucasian population. Subgroup analysis was also performed to test association between these SNPs and specific disease phenotypes. The study groups consisted of 467 individuals: 228 patients (194 with limited cutaneous form and 34 with diffuse cutaneous form of the disease) and 239 healthy control subjects. Genotyping was performed by high resolution melting analysis. Genotype distribution and allele frequency of the FOXP3 polymorphisms were analyzed statistically, using χ(2) or Fisher exact test. Single-marker analysis of allelic and genotype frequencies revealed that SNP rs3761548 was not associated with systemic sclerosis susceptibility. Analysis of genotype and allele distributions of the rs2280883 genetic variant was associated, only in female subjects with systemic sclerosis, its limited subtype, and anti-centromere autoantibodies. Although these findings require replication in a larger set and other populations, FOXP3 rs2280883 may represent a novel susceptibility locus for systemic sclerosis in female subjects.

In vivo confocal evaluation of the ocular surface morpho-functional unit in dry eye.

PURPOSE: To study, by a new, integrated, laser scanning confocal microscopy approach, the ocular surface morpho-functional unit in patients with primary Sjogren syndrome (SSI), non-Sjogren syndrome dry eye (non-SSDE), and meibomian gland disease (MGD). METHODS: Patients and age- and sex-matched control subjects (N = 60; 15 each) were consecutively enrolled in a prospective case-control study. Laser scanning confocal microscopy was used to obtain simultaneous optical sampling of the ocular surface components: cornea, bulbar and tarsal conjunctiva, MGs, and eyelid margin. RESULTS: For all superficial epithelia, except eyelid margins, there were reduced cell densities in each group compared with that in controls (p < 0.001). The lowest cell densities were in the SSI group (p < 0.001). Eyelid margin superficial cell density was decreased only in MGD (p < 0.001). Basal epithelial cell density at the corneal apex was increased in both SSI and non-SSDE compared with that in controls (p < 0.01). In the conjunctiva, it was decreased in each group compared with that in controls (p < 0.01). Subbasal dendritic cell density was significantly increased in both SSI and MGD compared with that in controls (p < 0.01). Conjunctival inflammatory cell density and MG inflammation were increased in each group compared with those in controls (p < 0.001), with the highest values in SSI. Subbasal nerve plexi had fewer fibers and higher bead density in each group compared with those in controls (p < 0.001). There was increased tortuosity in both SSI and MGD (p < 0.001). Patients with MGD had the lowest MG acinar density, the largest diameter of acini and acinar orifices, and the highest secretion reflectivity (p < 0.001). CONCLUSIONS: Laser scanning confocal microscopy can provide an in vivo, noninvasive, high-resolution overview of the ocular surface morpho-functional unit. This confocal integrated approach may be useful in both research and clinical settings.

The systemic lupus erythematosus IRF5 risk haplotype is associated with systemic sclerosis.

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.

Increased expression of endoplasmic reticulum stress and unfolded protein response genes in peripheral blood mononuclear cells from patients with limited cutaneous systemic sclerosis and pulmonary arterial hypertension.

OBJECTIVE: Pulmonary arterial hypertension (PAH), a common complication of limited cutaneous systemic sclerosis (lcSSc), is associated with alterations of markers of inflammation and vascular damage in peripheral blood mononuclear cells (PBMCs). Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) have been implicated in autoimmune and inflammatory diseases. The goal of this study was to assess whether markers of ER stress and the UPR are present in PBMCs from lcSSc patients with PAH. METHODS: PBMCs were purified from 36 healthy controls, 32 lcSSc patients with PAH, and 34 lcSSc patients without PAH. Gene expression in healthy control PBMCs stimulated with thapsigargin was analyzed by DNA microarray. Genes were validated by quantitative real-time reverse transcription-polymerase chain reaction in PBMCs from healthy controls and lcSSc patients. RESULTS: Several ER stress/UPR genes, including BiP, activating transcription factor 4 (ATF-4), ATF-6, and a spliced form of X-box binding protein 1, were up-regulated in PBMCs from lcSSc patients, with the highest levels in patients with PAH. Thapsigargin up-regulated heat-shock proteins (HSPs) and interferon (IFN)-regulated genes in PBMCs from healthy controls. Selected HSP genes (particularly DnaJB1) and IFN-related genes were also found at significantly elevated levels in PBMCs from lcSSc patients, while IFN regulatory factor 4 expression was significantly decreased. There was a positive correlation between DnaJB1 and severity of PAH (measured by pulmonary artery pressure) (r = 0.56, P < 0.05) and between ER stress markers and interleukin-6 levels (r = 0.53, P < 0.0001) in PBMCs from lcSSc patients. CONCLUSION: This study demonstrates an association between select ER stress/UPR markers and lcSSc with PAH, suggesting that ER stress and the UPR may contribute to the altered function of circulating immune cells in lcSSc.

HLA-B35 and dsRNA induce endothelin-1 via activation of ATF4 in human microvascular endothelial cells.

Endothelin 1 (ET-1) is a key regulator of vascular homeostasis. We have recently reported that the presence of Human antigen class I, HLA-B35, contributes to human dermal microvascular endothelial cell (HDMEC) dysfunction by upregulating ET-1 and proinflammatory genes. Likewise, a Toll-like receptor 3 (TLR3) ligand, Poly(I:C), was shown to induce ET-1 expression in HDMECs. The goal of this study was to determine the molecular mechanism of ET-1 induction by these two agonists. Because HLA-B35 expression correlated with induction of Binding Immunoglobulin Protein (BiP/GRP78) and several heat shock proteins, we first focused on ER stress and unfolded protein response (UPR) as possible mediators of this response. ER stress inducer, Thapsigargin (TG), HLA-B35, and Poly(I:C) induced ET-1 expression with similar potency in HDMECs. TG and HLA-B35 activated the PERK/eIF2α/ATF4 branch of the UPR and modestly increased the spliced variant of XBP1, but did not affect the ATF6 pathway. Poly(I:C) also activated eIF2α/ATF4 in a protein kinase R (PKR)-dependent manner. Depletion of ATF4 decreased basal expression levels of ET-1 mRNA and protein, and completely prevented upregulation of ET-1 by all three agonists. Additional experiments have demonstrated that the JNK and NF-κB pathways are also required for ET-1 upregulation by these agonists. Formation of the ATF4/c-JUN complex, but not the ATF4/NF-κB complex was increased in the agonist treated cells. The functional role of c-JUN in responses to HLA-B35 and Poly(I:C) was further confirmed in ET-1 promoter assays. This study identified ATF4 as a novel activator of the ET-1 gene. The ER stress/UPR and TLR3 pathways converge on eIF2α/ATF4 during activation of endothelial cells.

Effect of dihydropyridine calcium channel blockers and glucocorticoids on the prevention and development of scleroderma renal crisis in an Italian case series.

OBJECTIVES: Scleroderma renal crisis (SRC) is a relative rare yet dramatic event in the history of systemic sclerosis (SSc). Several factors that may precipitate or protect from the development of SRC have been described in previous case-control studies. To date, no attempt has been made to evaluate these factors in an observational fashion. METHODS: Retrospective data from 410 SSc patients with disease duration <5 years at referral were evaluated in an observational fashion for the development of hypertensive or normotensive SRC within 5 years from the first visit at our centre. Baseline characteristics as well as the use of steroids or dhiydropyridine calcium-channel blockers (CCB) were analysed via the Cox regression method with time-dependent covariates. RESULTS: In the multivariate model the diffuse subset the disease (HR=5.728 CI(95)=2.199-14.918, p<0.001) and the use of prednisone (HR=1.015, CI(95)=1.004-1.026, p=0.006) resulted to be predictors for the development of SRC, with a risk to develop SRC increased by 1.5% for every mg of prednisone/day consumed the trimester prior SRC. Contrariwise, the risk to develop SRC was highly reduced in those who were prescribed CCBs (HR=0.094, CI(95)=0.038-0.236, p<0.001). CONCLUSIONS: Steroids exhibits a weak effect on the risk to progress toward SRC in our case series, whilst dhyidrophyridines CCB appeared to be protective against that. Further larger prospective studies are warranted to better define the role of CCB in this setting or as a background therapy for SSc.

Confirmation of TNIP1 but not RHOB and PSORS1C1 as systemic sclerosis risk factors in a large independent replication study.

INTRODUCTION: A recent genome-wide association study in European systemic sclerosis (SSc) patients identified three loci (PSORS1C1, TNIP1 and RHOB) as novel genetic risk factors for the disease. The aim of this study was to replicate the previously mentioned findings in a large multicentre independent SSc cohort of Caucasian ancestry. METHODS: 4389 SSc patients and 7611 healthy controls from different European countries and the USA were included in the study. Six single nucleotide polymorphisms (SNP): rs342070, rs13021401 (RHOB), rs2233287, rs4958881, rs3792783 (TNIP1) and rs3130573 (PSORS1C1) were analysed. Overall significance was calculated by pooled analysis of all the cohorts. Haplotype analyses and conditional logistic regression analyses were carried out to explore further the genetic structure of the tested loci. RESULTS: Pooled analyses of all the analysed SNPs in TNIP1 revealed significant association with the whole disease (rs2233287 p(MH)=1.94×10(-4), OR 1.19; rs4958881 p(MH)=3.26×10(-5), OR 1.19; rs3792783 p(MH)=2.16×10(-4), OR 1.19). These associations were maintained in all the subgroups considered. PSORS1C1 comparison showed association with the complete set of patients and all the subsets except for the anti-centromere-positive patients. However, the association was dependent on different HLA class II alleles. The variants in the RHOB gene were not associated with SSc or any of its subsets. CONCLUSIONS: These data confirmed the influence of TNIP1 on an increased susceptibility to SSc and reinforced this locus as a common autoimmunity risk factor.

Implication of IL-2/IL-21 region in systemic sclerosis genetic susceptibility.

OBJECTIVE: The interleukin 2 (IL-2) and interleukin 21 (IL-21) locus at chromosome 4q27 has been associated with several autoimmune diseases, and both genes are related to immune system functions. The aim of this study was to evaluate the role of the IL-2/IL-21 locus in systemic sclerosis (SSc). PATIENTS AND METHODS: The case control study included 4493 SSc Caucasian patients and 5856 healthy controls from eight Caucasian populations (Spain, Germany, The Netherlands, USA, Italy, Sweden, UK and Norway). Four single nucleotide polymorphisms (rs2069762, rs6822844, rs6835457 and rs907715) were genotyped using TaqMan allelic discrimination assays. RESULTS: We observed evidence of association of the rs6822844 and rs907715 variants with global SSc (pc=6.6E-4 and pc=7.2E-3, respectively). Similar statistically significant associations were observed for the limited cutaneous form of the disease. The conditional regression analysis suggested that the most likely genetic variation responsible for the association was the rs6822844 polymorphism. Consistently, the rs2069762A-rs6822844T-rs6835457G-rs907715T allelic combination showed evidence of association with SSc and limited cutaneous SSc subtype (pc=1.7E-03 and pc=8E-4, respectively). CONCLUSIONS: These results suggested that the IL-2/IL-21 locus influences the genetic susceptibility to SSc. Moreover, this study provided further support for the IL-2/IL-21 locus as a common genetic factor in autoimmune diseases.

Association of TIMP-1 +372 SNP with digital ulcer manifestation in female systemic sclerosis patients.

A candidate gene for TIMP-1 gene located on the X-chromosome (rs4898) was selected for a control case study to investigate a possible association of this SNP with the susceptibility to systemic sclerosis and its digit ulcer manifestation. A total of 461 individuals of Italian Caucasian origin (228 SSc patients and 233 healthy control subjects) were genotyped for TIMP-1 +372 T/C single nucleotide polymorphism rs4898. Subgroups were analyzed according to the presence or absence of digital ulcers. The CC genotype and C allele frequencies were significantly lower in female SSc patients than in controls (OR 0.53, CI 0.29-0.96, p=0.03 and OR 0.72, CI 0.53-0.98 p=0.04, respectively). CC genotypes frequency was lower also in female patients with ulcers than those without ulcers (OR 0.37, CI 0.14-1.00, p=0.03). Furthermore, CC genotype and C allele frequencies were lower also in female patients with ulcers in comparison to female healthy control subjects (OR 0.27, CI 0.10-0.70, p=0.004; OR 0.60, CI 0.40-0.89, p=0.01, respectively). The TIMP-1 rs4898 polymorphism may play a protective role in the susceptibility to SSC in females, and in particular to digital ulcer formation.

Identification of CSK as a systemic sclerosis genetic risk factor through Genome Wide Association Study follow-up.

Systemic sclerosis (SSc) is complex autoimmune disease affecting the connective tissue; influenced by genetic and environmental components. Recently, we performed the first successful genome-wide association study (GWAS) of SSc. Here, we perform a large replication study to better dissect the genetic component of SSc. We selected 768 polymorphisms from the previous GWAS and genotyped them in seven replication cohorts from Europe. Overall significance was calculated for replicated significant SNPs by meta-analysis of the replication cohorts and replication-GWAS cohorts (3237 cases and 6097 controls). Six SNPs in regions not previously associated with SSc were selected for validation in another five independent cohorts, up to a total of 5270 SSc patients and 8326 controls. We found evidence for replication and overall genome-wide significance for one novel SSc genetic risk locus: CSK [P-value = 5.04 × 10(-12), odds ratio (OR) = 1.20]. Additionally, we found suggestive association in the loci PSD3 (P-value = 3.18 × 10(-7), OR = 1.36) and NFKB1 (P-value = 1.03 × 10(-6), OR = 1.14). Additionally, we strengthened the evidence for previously confirmed associations. This study significantly increases the number of known putative genetic risk factors for SSc, including the genes CSK, PSD3 and NFKB1, and further confirms six previously described ones.

Polymorphisms of the IgH enhancer HS1.2 and risk of systemic lupus erythematosus.

OBJECTIVE: To determine whether the allelic frequency variation of the HS1.2 enhancer of the immunoglobulin heavy chain (IgH) 3' regulatory region (3'RR-1) locus represents a risk factor for systemic lupus erythematosus (SLE) and to identify a possible functional difference in the two most frequent alleles (*1 and *2) in binding nuclear factor- κB (NF-κB) and Sp1. METHODS: The frequency of the enhancer HS1.2 alleles was determined in two cohorts of patients with SLE (n=293) and in 1185 controls. Electrophoretic mobility shift assays (EMSA) were carried out with B cell nuclear extracts with different probes of HS1.2 alleles *1 and *2 to map the consensus binding sites of the nuclear factors. A confirmatory cohort of 121 patients with SLE was also included. RESULTS: The frequency of allele *2 of the HS1.2 enhancer was significantly increased in patients with SLE compared with controls (OR 1.60, 95% CI 1.33 to 1.92, p<0.001). EMSA experiments showed the presence of the Sp1 binding site in both alleles whereas only allele *2 carried the consensus for the NF-κB factor. The presence versus absence of allele *2 in patients with SLE correlated with a higher concentration of IgM levels and with the expression of B cell activating factor receptor (BAFF-R). CONCLUSIONS: The increased frequency of allele *2 in patients with SLE identifies a new genetic risk factor for SLE. A possible biological effect of the polymorphism could be the difference observed in the localisation of an NF-κB binding site which is specific for allele *2 and absent in allele *1. These observations suggest a functional effect of the HS1.2 enhancer in this disease.

A GWAS follow-up study reveals the association of the IL12RB2 gene with systemic sclerosis in Caucasian populations.

A single-nucleotide polymorphism (SNP) at the IL12RB2 locus showed a suggestive association signal in a previously published genome-wide association study (GWAS) in systemic sclerosis (SSc). Aiming to reveal the possible implication of the IL12RB2 gene in SSc, we conducted a follow-up study of this locus in different Caucasian cohorts. We analyzed 10 GWAS-genotyped SNPs in the IL12RB2 region (2309 SSc patients and 5161 controls). We then selected three SNPs (rs3790567, rs3790566 and rs924080) based on their significance level in the GWAS, for follow-up in an independent European cohort comprising 3344 SSc and 3848 controls. The most-associated SNP (rs3790567) was further tested in an independent cohort comprising 597 SSc patients and 1139 controls from the USA. After conditional logistic regression analysis of the GWAS data, we selected rs3790567 [P(MH)= 1.92 × 10(-5) odds ratio (OR) = 1.19] as the genetic variant with the firmest independent association observed in the analyzed GWAS peak of association. After the first follow-up phase, only the association of rs3790567 was consistent (P(MH)= 4.84 × 10(-3) OR = 1.12). The second follow-up phase confirmed this finding (P(χ2) = 2.82 × 10(-4) OR = 1.34). After performing overall pooled-analysis of all the cohorts included in the present study, the association found for the rs3790567 SNP in the IL12RB2 gene region reached GWAS-level significant association (P(MH)= 2.82 × 10(-9) OR = 1.17). Our data clearly support the IL12RB2 genetic association with SSc, and suggest a relevant role of the interleukin 12 signaling pathway in SSc pathogenesis.