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The production of antibodies to anti-tumor necrosis factor alpha (TNF) agents is one of the main causes of treatment failure in Crohn’s disease (CD). To date, however, the contribution of genetics to anti-TNF immunogenicity in CD is still unknown. The objective of the present study was to identify genetic variation associated with anti-TNF immunogenicity in CD. We performed a two-stage genome-wide association study in a cohort of 96 and 123 adalimumab-treated patients, respectively. In the discovery stage, we identified a genome-wide significant association between the CD96 locus and the production of antibodies to anti-TNF treatment (P = 1.88e–09). This association was validated in the replication stage (P

Background Blocking of the Tumor Necrosis Factor (TNF) activity is a successful therapeutic approach for 50–60% of rheumatoid arthritis (RA) patients. However, there are yet no biomarkers to stratify patients for anti-TNF therapy. Rheumatoid factor (RF) and anti-cyclic-citrullinated antibodies (anti-CCP) have been evaluated as biomarkers of response but the results have shown limited consistency. Anti-carbamylated protein (anti-CarP) and anti-peptidylarginine deiminase type 4 (anti-PAD4) antibodies have been much less studied. Despite being linked to common immune processes, the interaction between these markers has not been evaluated yet. Our aim was to analyze the interaction between these four antibodies in relation to the response to anti-TNF therapy. Methods For this objective, a prospective cohort of n = 80 RA patients starting anti-TNF therapy was recruited. Serum determinations at baseline were performed for RF, anti-CCP, anti-CarP and anti-PAD4 antibodies using enzyme-linked immunosorbent assays (ELISA). The clinical response to anti-TNF therapy was determined at week 12 using the change in DAS28 score. Association was performed using multivariate linear regression adjusting for baseline DAS28, sex and age. Results The interaction between pairs of antibodies was tested by the addition of an interaction term. We found two highly significant antibody interactions associated with treatment response: anti-CarP with anti-PAD4 (p = 0.0062), and anti-CCP with RF (p = 0.00068). The latter antibody interaction was replicated in an independent retrospective cohort of RA patients (n = 199, p = 0.04). Conclusions The results of this study suggest that antibody interaction effects are important factors in the response to anti-TNF therapy in RA., This project was supported by UCB Pharma. The funders had no role in the study design, data analysis, data interpretation or writing the manuscript.

Rheumatoid arthritis (RA) is an immune-mediated inflammatory disease characterized by a defective adaptive immune receptor repertoire (AIRR) that fails to distinguish self from non-self antigens. The AIRR is vast, encompassing four T cell receptor (TCR) and three B cell receptor (BCR) chains, each of which displays an extraordinary amino acid sequence variability in the antigen-binding site. How the concerted action of T and B cell clones is associated with the development and clinical evolution of immune-mediated diseases is still not known. Using a new immunosequencing technology that allows the unbiased amplification of the seven receptor chains, we conducted an in-depth quantitative analysis of the seven-receptor chain variability in RA. Compared to healthy controls, the AIRR in RA was found to be characterized by a lower BCR diversity, the depletion of highly similar BCR clones, an isotype-specific signature as well as a skewed IGL chain and gene segment usage. A predictor based on quantitative multi-chain AIRR information was able to accurately predict disease, including the elusive seronegative subset of RA patients. AIRR features of the seven immune receptor chains were also different between patients with distinct clinically relevant phenotypes. Incorporating HLA variation data, we were able to identify the TCR clones that are specifically associated with the main disease risk variants. The longitudinal analysis of the AIRR revealed that treatment with Tumor Necrosis Factor (TNF) inhibitors selectively restores the diversity of B cell clones in RA patients by reducing the frequency of clones with a similar biochemical profile. The biochemical properties of the TNFi-modulated clones were also found to differ between responders and non-responders, supporting a different antigenic reactivity in the B cell compartment of these two groups of RA patients. Our comprehensive analysis of the TCR and BCR repertoire reveals a complex T and B cell architecture in RA, and provides the basis for precision medicine strategies based on the highly informative features of the adaptive immune response.

Robust protocols and automation now enable large-scale single-cell RNA and ATAC sequencing experiments and their application on biobank and clinical cohorts. However, technical biases introduced during sample acquisition can hinder solid, reproducible results and a systematic benchmarking is required before entering large-scale data production. Here, we report the existence and extent of gene expression and chromatin accessibility artifacts introduced during sampling and identify experimental and computational solutions for their prevention.

Background Inflammatory bowel disease, either clinical or subclinical is a cardinal pathological process that is central to the spondyloarthropathy (SpA) category of disease that also includes psoriasis, psoriatic arthritis, uveitis and ankylosing spondylitis. Objectives To look for novel genes in familial SpA in large multcase families using a whole genome sequencing approach. Methods We used Whole Genome Sequencing to screen SpA family members with different disease manifestations. We screened 5 multicase SpA families (up to 8 members) with different disease manifestations. Results We found a 1.5MB deletion of the KRT77 gene in 3 of 7 families that segregated with SpA phenotype. Given that KRT77 is a barrier protein and given that tagging SNPs from GWAS studies do not cover the region, and given that both IBD and psoriasis are associated with barrier defects, we looked for an association with KRT77 deletion in 1,000 cases of Psoriasis, 1,000 Crohn’s disease (CD) and 1,001 healthy controls. Deletion genotyping was performed using TaqMan RealTime-PCR assays. The deletion genotype frequencies in controls did not deviate from Hardy-Weinberg Equilibrium (p > .1). We found an association between KRT77 deletion and CD risk (p = 0.03) and also a putative association with pustular psoriasis (p Conclusion Given the strong association between SpA and subclinical gut inflammation and barrier defects in IBD these findings suggest that KRT77 heterozygous deletions with dysregulated gut permeability may play a role in IBD and the wider SpA phenotype. Acknowledgement We would like to thank the clinical researchers and patients participating in the IMID Consortium for their collaboration Disclosure of Interests Antonio Julia: None declared, Richard Cuthbert: None declared, Anton Glueck: None declared, Javier Gisbert: None declared, Eugeni Domenech: None declared, Maria Lopez Lasanta: None declared, Nuria Palau: None declared, Helena Marzo-Ortega Grant/research support from: Janssen, Novartis and Pfizer, Consultant for: AbbVie, Celgene, Janssen, Eli-Lilly, Novartis and UCB, Speakers bureau: AbbVie, Celgene, Janssen, Eli-Lilly, Novartis and UCB, Dennis McGonagle Consultant for: Lilly, Novartis UCB, Speakers bureau: Lilly, Novartis UCB, Sara Marsal: None declared

Background: Abatacept (CTLA4-Ig) is an approved biological therapy for the treatment of rheumatoid arthritis (RA). Similar to other biological agents, most patients (60%) respond significantly to this therapy. To date, however, the biological mechanisms underlying the lack of efficacy for this drug are unknown. Objectives: The objectives of the present study were to characterize the biological processes underlying the lack of efficacy of abatacept and to evaluate the blood transcriptome as a valid source for drug response prediction. Methods: A total of n=57 patients diagnosed with RA were recruited for this study from 16 rheumatology departments in Spain. All patients were >18 years old and, had >6 months of disease evolution. The primary clinical response to abatacept was defined at week 12 using the EULAR criteria. Good and moderate responders were aggregated into a single response group, and compared to the no response group of patients. Blood RNA was collected from all patients at baseline. From a subgroup of patients (n=31), blood RNA was also obtained at weeks 12, 24 and 48 of treatment with abatacept. Gene expression levels were determined using paired-end RNA-seq (Illumina). Differential gene expression, association to biological processes, longitudinal association analysis and building of the multigenic predictor were performed using the R software and the specialized Bioconductor libraries. The the prediction accuracy was evaluated using the ROC AUC. Results: From the 57 patients treated with abatacept, n=10 (17.5%) were good EULAR responders, n=24 (42%) moderate EULAR responders and n=23 (40.5%) non-responders at week 12 of therapy. Biological process analysis identified two significantly distinct biological profiles between responders and non-responders. In responders, we found an association to pathways associated with the effector phase of T cells (e.g. interleukin-15 and 2 signalling, P Conclusion: The analysis of blood RNA profiles of RA patients has enabled the identification of specific biological processes associated with the lack of response to abatacept. Also, we demonstrate that blood expression profiles can be predictive of the response to the drug at week 12 of therapy. Disclosure of Interests: Antonio Julia: None declared, Maria Lopez Lasanta: None declared, Antonio Gomez: None declared, Raimon Sanmarti Grant/research support from: Research support: Bristol-Myers Squibb, Speakers bureau: Speakers bureau: Bristol-Myers Squibb, Carlos Marras Fernandez Cid: None declared, Jose Manuel Pina Salvador: None declared, Susana Romero-Yuste: None declared, Raul Maria Veiga Cabello: None declared, Pilar Navarro: None declared, Carme Moragues Pastor : None declared, Silvia Martinez Pardo: None declared, Javier de Toro-Santos: None declared, Amalia Sanchez: None declared, Dacia Cerda: None declared, Alejandro Prada: None declared, Alba Erra: None declared, Jordi Monfort Speakers bureau: Bioiberica Procare Health, ANA URRUTICOECHEA-ARANA: None declared, Nuria Palau: None declared, Raquel M Lastra: None declared, Raul Tortosa: None declared, Andrea Pluma Sanjurjo: None declared, Sara Marsal: None declared

ObjectivePsoriatic arthritis (PsA) is a chronic inflammatory arthritis affecting up to 30% of patients with psoriasis (Ps). To date, most of the known risk loci for PsA are shared with Ps, and identifying disease-specific variation has proven very challenging. The objective of the present study was to identify genetic variation specific for PsA.MethodsWe performed a genome-wide association study in a cohort of 835 patients with PsA and 1558 controls from Spain. Genetic association was tested at the single marker level and at the pathway level. Meta-analysis was performed with a case–control cohort of 2847 individuals from North America. To confirm the specificity of the genetic associations with PsA, we tested the associated variation using a purely cutaneous psoriasis cohort (PsC, n=614) and a rheumatoid arthritis cohort (RA, n=1191). Using network and drug-repurposing analyses, we further investigated the potential of the PsA-specific associations to guide the development of new drugs in PsA.ResultsWe identified a new PsA risk single-nucleotide polymorphism at B3GNT2 locus (p=1.10e-08). At the pathway level, we found 14 genetic pathways significantly associated with PsA (pFDRConclusionThese findings provide insights into the biological mechanisms that are specific for PsA and could contribute to develop more effective therapies.

Background:Blocking Tumor Necrosis Factor (TNF) activity is a successful therapeutic approach for approximately 60% of patients with rheumatoid arthritis (RA). To date, however, the biological basis of the lack of efficacy of anti-TNF agents is unknown.Objectives:The objective of present study was to characterize the biological basis of anti-TNF lack of efficacy in RA using an epigenomic data approach in two steps: first, to assess the differential methylation changes between responders and non-responders and second, to use this differential methylation profile in a systems biology approach to infer differential methylated biological modules according to anti-TNF response.Methods:A total of n=68 patients diagnosed with RA according to the ACR-EULAR criteria belonging to 16 Hospitals across Spain were recruited. All patients were >18 years old, with more than 6 months of disease evolution and a baseline disease activity of DAS28 > 3.2. Treatment response was defined according to the EULAR criteria at week 12. Good and moderate responders were aggregated into a single responder group. Genomic DNA was collected at baseline and the methylation profile was assessed using the Illumina Infinium EPIC array, which interrogates 850,000 methylation CpG sites across the genome. Differential Methylation analysis, biological pathway association and the systems Biology approach using Protein-Protein Interaction Networks, were conducted using the R statistical language and the Bioconductor libraries.Results:From 68 anti-TNF treated patients, n=27 (39.7%) were good responders, n=26 (38.2%) moderate responders and n=15 (22.05%) non-responders at week 12 of treatment. Differential methylation analysis identified two distinctive biological profiles associated with the clinical response: responders were associated to interleukin and cytokine production, and non-responders were associated with biological pathways associated to TGF-Beta production and T cell regulation. Using these differentially methylated profiles, epigenetic modules with differentially methylated hotspots between responders and non-responders were also found. Two epigenetic modules with significant enrichment in inflammatory and interleukin production and immune regulatory processes were validated in an independent patient cohort.Conclusion:The epigenetic analysis of whole blood from RA patients using a module-based approach shows reproducible biological mechanisms associated with the response to anti-TNF therapy.Acknowledgments:We would like to thank the clinical researchers and patients participating in the IMID Consortium for their collaborationDisclosure of Interests:Antonio Julià: None declared, Antonio Gómez: None declared, Antonio Fernández Nebro: None declared, Francisco J. Blanco Grant/research support from: Sanofi-Aventis, Lilly, Bristol MS, Amgen, Pfizer, Abbvie, TRB Chemedica International, Glaxo SmithKline, Archigen Biotech Limited, Novartis, Nichi-iko pharmaceutical Co, Genentech, Jannsen Research & Development, UCB Biopharma, Centrexion Theurapeutics, Celgene, Roche, Regeneron Pharmaceuticals Inc, Biohope, Corbus Pharmaceutical, Tedec Meiji Pharma, Kiniksa Pharmaceuticals, Ltd, Gilead Sciences Inc, Consultant of: Lilly, Bristol MS, Pfizer, Alba Erra: None declared, Simon Sánchez Fernandez: None declared, Jordi Monfort: None declared, Mercedes Alperi-López: None declared, Isidoro González-Álvaro Grant/research support from: Roche Laboratories, Consultant of: Lilly, Sanofi, Paid instructor for: Lilly, Speakers bureau: Abbvie, MSD, Roche, Lilly, Rosario Garcia de Vicuna Grant/research support from: BMS, Lilly, MSD, Novartis, Roche, Consultant of: Abbvie, Biogen, BMS, Celltrion, Gebro, Lilly, Mylan, Pfizer, Sandoz, Sanofi, Paid instructor for: Lilly, Speakers bureau: BMS, Lilly, Pfizer, Sandoz, Sanofi, Raimón Sanmartí Speakers bureau: Abbvie, Eli Lilly, BMS, Roche and Pfizer, Cesar Diaz Torne: None declared, Carlos Marras Fernandez Cid: None declared, Jesús Tornero Molina: None declared, Núria Palau: None declared, Raquel M Lastra: None declared, Jordi Lladós: None declared, Sara Marsal: None declared

Background:Blocking of the Tumor Necrosis Factor (TNF) activity is a successful therapeutic approach for 2 out of 3 Rheumatoid Arthritis patients. Identifying the patients that will not respond to this therapeutic approach is a major translational goal in RA. Association of seropositivity to rheumatoid factor (RF) or anti-cyclic-citrullinated antibodies (anti-CCP) with anti-TNF response has proven inconclusive, suggesting that other yet unexplored biomarkers could be more informative for this goal.Objectives:We tested the association of two recently introduced biomarkers in RA: anti-carbamylated protein antibodies (anti-CarP) and anti-peptidylarginine deiminase type 4 (anti-PAD4).Methods:A prospective cohort of n=80 RA patients starting anti-TNF therapy was recruited and levels for all four autoantibodies -RF, anti-CCP, anti-CarP and anti-PAD4- were measured at baseline. The change in DAS28 score between baseline and week 12 of therapy was used as the clinical endpoint.Results:Single marker-analysis showed no significant association with drug response. However, when testing for interactions between autoantibodies, we found highly significant associations with drug response. Anti-CCP and RF showed a positive interaction with the response to anti-TNF therapy (P=0.00068), and anti-PAD4 and antiCarP titers showed a negative interaction with the clinical response at week 12 (P=0.0062). Using an independent retrospective sample (n=199 patients), we validated the interaction between anti-CCP and RF with the clinical response to anti-TNF agents. (P=0.044).Conclusion:The results of this study show that interactions between antibodies are important in the response to anti-TNF therapy and suggest potential pathogenic relationships.Acknowledgments :We would like to thank the clinical researchers and patients participating in the IMID Consortium for their collaborationDisclosure of Interests:Antonio Julià: None declared, Maria Lopez Lasanta: None declared, Francisco Blanco: None declared, Antonio Gómez: None declared, Isabel Haro: None declared, Antonio Juan Mas: None declared, Alba Erra: None declared, Mª Luz García Vivar: None declared, Jordi Monfort: None declared, Simon Sánchez Fernandez: None declared, Isidoro González-Álvaro Grant/research support from: Roche Laboratories, Consultant of: Lilly, Sanofi, Paid instructor for: Lilly, Speakers bureau: Abbvie, MSD, Roche, Lilly, Mercedes Alperi-López: None declared, Raúl Castellanos: None declared, Antonio Fernandez-Nebro: None declared, Cesar Diaz Torne: None declared, Núria Palau: None declared, Raquel M Lastra: None declared, Jordi Lladós: None declared, Raimon Sanmarti: None declared, Sara Marsal: None declared

Introduction After the modification of the Spanish law of smoke-free places in 2010 (42/2010), the acute hospital psychiatric wards have become also smoke-free. This fact meant a radical change in conceptualization of tobacco consumption in mental health settings. The Mental Health-Tobacco group of the Catalan Network of Smoke Free Hospitals (XCHsF) promotes actions to raise awareness among professionals, and also motivational and cessation programs for hospitalized patients (PDT-SM). Methods The PDT-SM program offers to inpatients the possibility to participate in a tobacco cessation treatment at discharge, receiving free medication and psychological treatment for one year. During hospitalization, weekly information group is carried out and nicotine substitution is allowed. At discharge, interested patients follow a multi-component cessation program. Professionals involved in the program, assessed their implication, the produced organizational changes and the usefulness of intervention. Data for 2013-2017 inpatients is presented. Results 12 participating hospitals: psychiatric units (28.7%) and detoxification (68.2%). 315 included patients: 60.8% males, age: 46.7 (SD 10.0). Tobacco variables: Cig / d 26.5 (SD 12.4). Fagerström test 6,8 (SD 2.3). Richmond test 8.4 (SD 1.5). Carbon monoxide: 18.5 ppm (SD 14.4). Main admission diagnoses were: 48.6% alcohol, 16.8% cocaine, 11.7% affective disorder, 10.4% psychotic disorder. Pathological antecedents: 35.8% respiratory, cardiovascular or oncological pathology. At discharge 48.2% patients were derived to outpatient specialized smoking units. Follow-up results: 67.6% abstinent first week, 45.4% first month, 25.1% third month, 14.4% 6th month and 9.8% in a year. Professionals evaluated the intervention very positively and an increase in awareness to smoking intervention was observed. Conclusions Programs as PDT-SM facilitate to perform actions in order to promote smoking cessation in psychiatric units. And even more important, mental health professionals are more aware about the importance of smoking cessation in these patients. Funding The XCHsF is partially funded by the Government of Catalonia through the Public Health Agency of Catalonia (contract SA-2017-N111).

Background: Systemic lupus erythematosus (SLE) is a genetically complex rheumatic disease characterized by heterogeneous clinical manifestations of unknown etiology. Recent studies have suggested the existence of a genetic basis for SLE heterogeneity. The objective of the present study was to identify new genetic variation associated with the clinically relevant phenotypes in SLE. Methods: A two-stage pathway-based approach was used to identify the genetic variation associated with the main clinical phenotypes in SLE. In the discovery stage, 482 SLE patients were genotyped using Illumina Human Quad610 microarrays. Association between 798 reference genetic pathways from the Molecular Signatures Database and 11 SLE phenotypes was tested using the set-based method implemented in PLINK software. Pathways significantly associated after multiple test correction were subsequently tested for replication in an independent cohort of 425 SLE patients. Using an in silico approach, we analyzed the functional effects of common SLE therapies on the replicated genetic pathways. The association of known SLE risk variants with the development of the clinical phenotypes was also analyzed. Results: In the discovery stage, we found a significant association between the vascular endothelial growth factor (VEGF) pathway and oral ulceration (P value for false discovery rate (P FDR ) < 0.05), and between the negative regulation signaling pathway of retinoic acid inducible gene-I/melanoma differentiation associated gene 5 and the production of antinuclear antibodies (P FDR < 0.05). In the replication stage, we validated the association between the VEGF pathway and oral ulceration. Therapies commonly used to treat mucocutaneous phenotypes in SLE were found to strongly influence VEGF pathway gene expression (P = 4.60e-4 to 5.38e-14). Analysis of known SLE risk loci identified a strong association between PTPN22 and the risk of hematologic disorder and with the development of antinuclear antibodies. Conclusions: The present study has identified VEGF genetic pathway association with the risk of oral ulceration in SLE. New therapies targeting the VEGF pathway could be more effective in reducing the severity of this phenotype. These findings represent a first step towards the understanding of the genetic basis of phenotype heterogeneity in SLE, This study was funded by the Spanish Ministry of Economy and Competitiveness (grant numbers: PSE-010000-2006-6 and IPT-010000-2010-36 and by the “Agència de Gestió d’Ajuts Universitaris i de Recerca” (AGAUR, Generalitat de Catalunya, FI-DGR 2016, grant number: 00587)

Background Recent genome-wide association studies (GWAS) have identified more than 50 loci associated with systemic lupus erythematosus but they explain less than 30% of the heritability of the disease. Meta-analysis including new populations can contribute to identify additional genetic risk factors. Objectives The aim of the presents study was to identify additional genetic risk loci for SLE. Methods We performed a meta-analysis using data from a recent large scale GWAS from 4,036 cases and 6,959 controls from Caucasian European ancestry [1] and a newly genotyped cohort of 907 SLE patients and 1,524healthy controls from Spain. Genetic association was tested at the single-marker level using linear regression and at the pathway-level using Fisher9s modified method. Results Combining the two cohorts we identified genome-wide significant association (P Conclusions In conclusion, we have identified five new risk loci for SLE through a meta-analysis including a new GWAS. References Bentham J, Morris DL et al. Nature Genetics 2015. Acknowledgements We would like to thank the clinical researchers and patients participating in the IMID Consortium for their collaboration. We would also like to thank the international SLE consortium for access to the data. Disclosure of Interest None declared

Background PsA has a higher heritability than PsV, indicating the existence of additional PsA-specific genetic factors. To date, however, the specific genetic basis underlying PsA is poorly understood. Objectives The objective the present study was to identify new genetic variation specifically associated with PsA risk. Methods In order to characterize the genetic basis of PsA, we performed a GWAS meta-analysis at the single-marker level as well as at the pathway level (GWPA). A cohort of 835 PsA patients and 1,558 controls from the Spanish population was genotyped for >550,000 SNPs. GWAS data from a second cohort of 1,430 PsA patients and 1,417 controls from the North American population was also used. In order to confirm the specificity of the new genetic variation associated with PsA risk, we analyzed the association with purely cutaneous psoriasis (PsC, n=614) and rheumatoid arthritis (RA, n=1,191). We performed a pharmacogenetic analysis to investigate the new PsA-specific pathways as a source for drug discovery in PsA. Results GWAS meta-analysis identified a new association between B3GNT2 gene and PsA (P Conclusions The present study represents an important step towards the characterization of the genetic factors specific to PsA risk. Disclosure of Interest None declared

Background Autoimmune diseases are highly disabling chronic disorders characterized by the activation of multiple immune and inflammatory pathways against self-components. Clinical studies have demonstrated that autoimmune diseases have a higher prevalence of cardiovascular events compared to the general population. Understanding the genetic and biological mechanisms underlying cardiovascular disease (CVD) risk in autoimmunity could therefore be fundamental to develop more efficient preventive and therapeutic strategies. Objectives The objective of this study was to characterize the genetic basis of CVD risk in autoimmune diseases. Methods A total of 6,485 patients from the six autoimmune diseases RA, PA, SLE, PS, CD and UC were recruited by the Spanish biomedical consortium IMID Consortium. All patients were Caucasian European from the Spain. CVD patients were defined as having ≥1 out of the 3 most frequent cardiovascular phenotypes: (i) ischemic heart disease (ii) cerebrovascular accident and (iii) peripheral arterial disease. In order to characterize the genetic basis of CVD risk in autoimmune diseases, we used genome-wide genotyping data from all autoimmune disease patients included in the study. First, we tested the association of established CVD risk variants within each autoimmune disease. Second, we analyzed the association of autoimmune disease risk variants with an increase in CVD risk. Finally, we used the cross-phenotype meta-analysis approach (CPMA) to perform a genome-wide meta-analysis and identify global genetic patterns associated with CVD risk in autoimmune diseases. Results A total of 17 loci previously associated with CVD risk in the general population were significantly associated with CVD risk in the autoimmune patient cohorts ( P P CFLAR-CASP8 . The CPMA identified a total of 10 genetic patterns significantly associated with CVD risk across all autoimmune diseases. Two of these patterns showed a highly significant association with CVD risk in RA, PsA and SLE. The functional analysis of these two genetic patterns revealed a significant enrichment in key pathways related to the etiology of rheumatic diseases like TNFα ( FDR (FDR Conclusions The results of the present study represent an important step towards the characterization of the genetic basis of CVD in autoimmune diseases. These findings contribute to explain the higher prevalence of cardiovascular events observed in patients with autoimmune diseases compared to the general population. Disclosure of Interest None declared

Background Epigenetic regulation of immune cell types could be critical for the development and maintenance of autoimmune diseases like Rheumatoid Arthritis (RA). B cells are highly relevant in RA, since patients express autoantibodies and depleting this cell type is a successful therapeutic approach. Epigenetic variation, such as DNA methylation, may mediate the pathogenic activity of B cells. Objectives In this study, we performed an epigenome-wide association study (EWAS) for RA with three different replication cohorts, to identify disease-specific alterations in DNA methylation in B cells. Methods Genomic methylation in isolated B lymphocytes was assayed on the Illumina HumanMethylation450 BeadChip, assaying >450,000 different CpG sites. Differential methylated positions (DMPs) were identified in a discovery cohort using a single-point analysis using logistic regression, as well as a pathway-level analysis using a newly developed permutation-based method. A discovery cohort of 50 RA patients and 75 healthy controls from Spain was used to identify the most differentially methylated regions after multiple test correction. Using an independent sample of 15 patients and 15 controls from the same population we performed a replication analysis of the most significant CpG sites and pathways. Using an additional case-control sample of 24 individuals from the UK we provided further evidence of association of the DMPs with RA. Finally, in silico datta from a cohort of systemic lupus erythematosus patients (SLE, n=47) and controls (n=56) from the US, we tested the association of the associated DMPs. Results A total of 64 CpG sites were found to be differentially methylated in RA patients compared to controls in the discovery stage after multiple test correction (q Conclusions Our results highlight genes that may drive the pathogenic activity of B cells in RA and suggest shared methylation patterns with SLE. Disclosure of Interest None declared

Epigenetic regulation of immune cell types could be critical for the development and maintenance of autoimmune diseases like rheumatoid arthritis (RA). B cells are highly relevant in RA, since patients express autoantibodies and depleting this cell type is a successful therapeutic approach. Epigenetic variation, such as DNA methylation, may mediate the pathogenic activity of B cells. In this study, we performed an epigenome-wide association study (EWAS) for RA with three different replication cohorts, to identify disease-specific alterations in DNA methylation in B cells. CpG methylation in isolated B lymphocytes was assayed on the Illumina HumanMethylation450 BeadChip in a discovery cohort of RA patients (N = 50) and controls (N = 75). Differential methylation was observed in 64 CpG sites (q

This study was funded by the Spanish Ministry of Economy and Competitiveness (grant numbers PSE-010000-2006-6 and IPT-010000-2010-36), Lopez-Lasanta, M., Julià, A., Maymó, J., Fernández-Gutierrez, B., Ureña-Garnica, I., Blanco, F.J., Cañete, J.D., Alperi-López, M., Olivè, A., Corominas, H., Tornero, J., Erra, A., Almirall, M., Palau, N., Ortiz, A., Avila, G., Rodriguez-Rodriguez, L., Alonso, A., Tortosa, R., Gonzalez-Alvaro, I., Marsal, S.

Psoriasis is a chronic inflammatory disease with a complex genetic architecture. To date, the psoriasis heritability is only partially explained. However, there is increasing evidence that the missing heritability in psoriasis could be explained by multiple genetic variants of low effect size from common genetic pathways. The objective of this study was to identify new genetic variation associated with psoriasis risk at the pathway level. We genotyped 598,258 single nucleotide polymorphisms in a discovery cohort of 2,281 case-control individuals from Spain. We performed a genome-wide pathway analysis using 1,053 reference biological pathways. A total of 14 genetic pathways (PFDR ≤ 2.55 × 10(-2)) were found to be significantly associated with psoriasis risk. Using an independent validation cohort of 7,353 individuals from the UK, a total of 6 genetic pathways were significantly replicated (PFDR ≤ 3.46 × 10(-2)). We found genetic pathways that had not been previously associated with psoriasis risk such as retinol metabolism (Pcombined = 1.84 × 10(-4)), the transport of inorganic ions and amino acids (Pcombined = 1.57 × 10(-7)), and post-translational protein modification (Pcombined = 1.57 × 10(-7)). In the latter pathway, MGAT5 showed a strong network centrality, and its association with psoriasis risk was further validated in an additional case-control cohort of 3,429 individuals (P < 0.05). These findings provide insights into the biological mechanisms associated with psoriasis susceptibility. This study was funded by of the Spanish Ministry of Economy and Competitiveness, grant numbers: PSE-010000-2006-6 and IPT-010000-2010-36

Aim: The present study was undertaken to replicate the association of candidate genes for anti-TNF response in rheumatoid arthritis. Candidate genes were selected from a recent genome-wide association study on anti-TNF response performed in a population from Denmark. Materials & methods: Genomic DNA was obtained from 315 Spanish rheumatoid arthritis patients having received an anti-TNF agent as their first biological therapy. SNPs from NR2FR2, MAP2K6, CBLN2 and PDE3A–SLCO1C1 candidate loci were genotyped. Results: The PDE3A–SLCO1C1 locus rs3794271 SNP showed a highly significant association with anti-TNF treatment response (p = 1.74 × 10-5). Combining the statistical evidence from the Spanish and Danish rheumatoid arthritis cohorts, the associated rs3794271 SNP reached a genome-wide significance level of association (p = 3.3 × 10-10). Conclusion: The present findings establish the PDE3A–SLCO1C1 locus as a strong genetic marker of anti-TNF therapy response. Original submitted 9 January 2013; Revision submitted 13 March 2013

Background Joint damage is a key pathological feature of Rheumatoid Arthritis (RA) and is characterized by a high level of heterogeneity. There is recent evidence suggesting an association of IL2RA and C5orf3 loci with the degree of joint destruction in RA. Objectives Using a large cohort of RA patients we have performed the validation of this two candidate genes for joint destruction and analyzed in relation to the main disease phenotypes. Methods A total of 857 RA patients were recruited and their level of joint destruction was measured. The previously reported single nucleotide polymorphisms at IL2RA (rs2104286) and C5orf30 (rs26232) loci were genotyped in the patient cohort using Taqman RealTime-PCR. The two loci were tested for association with the level of joint destruction using linear regression. Clinically relevant variables were analyzed independently with the level of joint damage and in relation to the genetic polymorphisms using linear regression analysis. Results We found a highly significant association between IL2RA locus SNP rs2104286 with the level of joint destruction in RA ( P =0.0017). In our cohort, variation at C5orf30 locus did not show any evidence of association. Years of disease duration ( P =2.6e-54), number of previous biological therapies ( P =4.3e-9), body-mass index (BMI, P =6.9e-5), Anti-Citrullinated Peptide Antibodies (ACPA) status ( P =0.0001) and Rheumatoid Factor (RF) status ( P =0.009) were also found to be significantly associated with the level of joint damage in RA. The genetic association between IL2RA locus and bone erosions was found to be restricted to autoantibody-positive (74% ACPA-positive, P =0.001; 74% RF-positive, P =0.004) and female (77%, P =0.01) patients. Conclusions The results of this study confirm the association of IL2RA with joint destruction in RA and suggest that this genetic variation is relevant to a specific patient phenotype. Acknowledgements This work was supported by the Spanish Ministry of Economy and Competitiveness Strategic Project grants [PSE-010000-2006-6, IPT-010000-2010-36] and the Fondo de Investigaciόn Sanitaria grant [11/0551]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Disclosure of Interest None declared

Background Psoriasis is a chronic autoimmune disease in which T cells have a predominant role in initiating and perpetuating the chronic inflammation in skin. However, the mechanisms that regulate T cell activation in psoriasis are still incompletely understood. The objective of the present study was to characterize the main genetic pathways associated with T cell activation in psoriasis. Results Gene expression profiles from in vitro activated T cells were obtained from 17 psoriasis patients and 7 healthy controls using Illumina HT-12 v4 microarrays. From a total of 47,321 analyzed transcripts, 42 genes were found to be differentially expressed between psoriasis and controls (FDR p-value 1.2). Using an independent cohort of 8 patients and 8 healthy controls we validated the overexpression of SPATS2L (p-value =0.0009) and KLF6 (p-value =0.0012) genes in activated T cells from psoriasis patients. Using weighted correlation analysis we identified SPATS2L and KLF6 coexpression networks, which were also significantly associated with psoriasis (p-value Conclusions This study has identified two new genes, SPATS2L and KLF6, strongly associated with T cell activation in psoriasis. Functional analyses of the gene expression profiles also revealed new biological processes and genetic pathways associated with psoriasis. The results of this study provide an important insight into the biology of this common chronic inflammatory disease.