Alba Erra

All-cause and cause-specific mortality in rheumatoid arthritis are not greater than expected when treated with tumour necrosis factor antagonists

Background: Mortality is increased in rheumatoid arthritis (RA), mainly because of cardiovascular (CV) events, cancer and infections. Recent data suggest that treatment with tumour necrosis factor (TNF) antagonists may affect this trend. Objective: To assess whether treatment with TNF antagonists is associated with reduction in CV events, cancer and infection rates, and in mortality in patients with RA treated and not treated with TNF antagonists. Methods: BIOBADASER is a registry for active long-term follow-up of safety of biological treatments in patients with RA. It includes 4459 patients with RA treated with TNF antagonists. EMECAR is an external RA cohort (n = 789) established to define the characteristics of the disease in Spain and to assess comorbidity. The incidence density (ischaemic heart disease) of CV events, cancer and infections was estimated and compared. The standardised mortality ratio was compared with the rate in the general population. A propensity score was used to match cohorts by the probability of being treated. Results: Rates of CV and cancer events are significantly higher in EMECAR than in BIOBADASER (RR 5–7 for different CV events, and RR 2.9 for cancer), whereas the rate of serious infections is significantly higher in BIOBADASER (RR 1.6). Mortality ratio of BIOBADASER by EMECAR is 0.32 (0.20–0.53) for all causes of death, 0.58 (0.24–1.41) for CV events, 0.52 (0.21–1.29) for infection and 0.36 (0.10–1.30) for cancer-related deaths. Conclusion: Morbidity, other than infection, and mortality are not higher than expected in patients with RA treated with TNF antagonists.

Genome‐wide association study of rheumatoid arthritis in the Spanish population: KLF12 as a risk locus for rheumatoid arthritis susceptibility

OBJECTIVE To identify new genes associated with susceptibility to rheumatoid arthritis (RA), using a 2-stage genome-wide association study. METHODS Following a liability-based study design, we analyzed 317,503 single-nucleotide polymorphisms (SNPs) in 400 patients with RA and 400 control subjects. We selected a group of candidate SNPs for replication in an independent group of 410 patients with RA and 394 control subjects. Using data from the 3 previous genome-wide association studies in RA, we also looked for genomic regions showing evidence of common association signals. Finally, we analyzed the presence of genome-wide epistasis using the binary test implemented in the PLINK program. RESULTS We identified several genomic regions showing evidence of genome-wide association (P < 1 x 10(-5)). In the replication analysis, we identified KLF12 SNP rs1324913 as the most strongly associated SNP (P = 0.01). In our study, we observed that this SNP showed higher significance than PTPN22 SNP rs2476601, in both the genome-wide association studies and the replication analyses. Furthermore, the integration of our data with those from previous genome-wide association studies showed that KLF12 and PTPRT are the unique loci that are commonly associated in 3 different studies (P = 0.004 and P = 0.002 for KLF12 in the Wellcome Trust Case Control Consortium study and the Brigham and Womens Rheumatoid Arthritis Sequential Study genome-wide association study, respectively). The genome-wide epistasis analysis identified several SNP pairs close to significance after multiple test correction. CONCLUSION The present genome-wide association study identified KLF12 as a new susceptibility gene for RA. The joint analysis of our results and those from previous genome-wide association studies showed genomic regions with a higher probability of being genuine susceptibility loci for RA.

An Eight-Gene Blood Expression Profile Predicts the Response to Infliximab in Rheumatoid Arthritis

Background TNF alpha blockade agents like infliximab are actually the treatment of choice for those rheumatoid arthritis (RA) patients who fail standard therapy. However, a considerable percentage of anti-TNF alpha treated patients do not show a significant clinical response. Given that new therapies for treatment of RA have been recently approved, there is a pressing need to find a system that reliably predicts treatment response. We hypothesized that the analysis of whole blood gene expression profiles of RA patients could be used to build a robust predictor to infliximab therapy. Methods and Findings We performed microarray gene expression analysis on whole blood RNA samples from RA patients starting infliximab therapy (n = 44). The clinical response to infliximab was determined at week 14 using the EULAR criteria. Blood cell populations were determined using flow cytometry at baseline, week 2 and week 14 of treatment. Using complete cross-validation and repeated random sampling we identified a robust 8-gene predictor model (96.6% Leave One Out prediction accuracy, P = 0.0001). Applying this model to an independent validation set of RA patients, we estimated an 85.7% prediction accuracy (75–100%, 95% CI). In parallel, we also observed a significantly higher number of CD4+CD25+ cells (i.e. regulatory T cells) in the responder group compared to the non responder group at baseline (P = 0.0009). Conclusions The present 8-gene model obtained from whole blood expression efficiently predicts response to infliximab in RA patients. The application of the present system in the clinical setting could assist the clinician in the selection of the optimal treatment strategy in RA.

GWAS replication study confirms the association of PDE3A–SLCO1C1 with anti-TNF therapy response in rheumatoid arthritis

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.

Identification of candidate genes for rituximab response in rheumatoid arthritis patients by microarray expression profiling in blood cells

AIMS Transient CD20+ B-cell depletion with rituximab is an effective treatment for rheumatoid arthritis (RA). However, there is a subgroup of patients that do not show significant clinical response to rituximab and for these patients, other modes of treatment are preferred. Finding biomarkers for drug response in RA has immense potential for improving treatment and lowering healthcare costs for treating RA patients by facilitating the optimization of their pharmacotherapy. In the present study, we report on gene expression profiles of three different blood cell types in rituximab responders and nonresponder RA patients identifying new candidate genes associated with rituximab response. MATERIALS & METHODS Transcriptional profiles of whole-blood, CD4+ T cells and B cells were analyzed from nine female patients (mean age 53 +/- 11 years) with active RA disease (DAS28 > 5.1), starting rituximab therapy using Illumina (CA, USA) gene-expression microarrays. Whole-blood RNA was extracted using the PAXgene system (PreAnalytix, Hombrechtikon, Switzerland) whilst the lymphocyte RNA was obtained following cell isolation using negative selection. Flow cytometry analysis was performed to determine whole blood subpopulations, as well as the lymphocyte isolation purity. A whole-genome expression profiling was performed on the RNA samples prepared from the three blood cell populations using the Illumina Human 6 Beadchip array system version 1 (Illumina). From the group of statistically significant genes showing differential expression in rituximab responders compared with nonresponder RA patients, we selected a group of candidate genes that were subsequently validated in the same RNA samples using TaqMan real-time PCR assays. RESULTS Several genes were identified whose level of expression is associated significantly with the response to rituximab in all three blood cell types evaluated (multiple-test corrected p-value < 0.05). Real-time PCR-validated genes include ARG1 (1.6-fold downregulated in responders) and TRAF1 (1.4-fold upregulated in responders) genes in whole blood and TLR4 (1.3-fold upregulated in responders) in CD4+ T cells. CONCLUSIONS The present study is the first gene expression microarray analysis reporting on biomarkers of the clinical response to rituximab in RA in blood cells. Following validation in larger cohorts, the identified genes may serve as biomarkers for treatment choice in RA.

A genome-wide association study identifies a new locus associated with the response to anti-TNF therapy in rheumatoid arthritis

Anti-Tumor Necrosis Factor (anti-TNF) drugs are biologic agents commonly used to treat rheumatoid arthritis (RA). However, anti-TNFs are not effective in approximately one out of four treated patients. We conducted a Genome-Wide Association Study (GWAS) to identify the genetic variation associated with the response to anti-TNF therapy in RA. In the discovery stage, 372 RA patients treated with an anti-TNF agent (infliximab, adalimumab or etanercept) were analyzed and treatment response was defined at 12 weeks of therapy. We found a genome-wide significant association in the MED15 gene with the response to etanercept (P<1.5e-8). Using an independent cohort of 245 RA patients, we performed a replication study of the most significant GWAS associations. We replicated the association at the MED15 locus and found suggestive evidence of association in the previously associated MAFB locus. The results of this study suggest novel mechanisms associated with the response to anti-TNF therapies.

Variation at FCGR2A and functionally related genes is associated with the response to anti-TNF therapy in rheumatoid arthritis

Objective Anti-TNF therapies have been highly efficacious in the management of rheumatoid arthritis (RA), but 25–30% of patients do not show a significant clinical response. There is increasing evidence that genetic variation at the Fc receptor FCGR2A is associated with the response to anti-TNF therapy. We aimed to validate this genetic association in a patient cohort from the Spanish population, and also to identify new genes functionally related to FCGR2A that are also associated with anti-TNF response. Methods A total of 348 RA patients treated with an anti-TNF therapy were included and genotyped for FCGR2A polymorphism rs1081274. Response to therapy was determined at 12 weeks, and was tested for association globally and independently for each anti-TNF drug (infliximab, etanercept and adalimumab). Using gene expression profiles from macrophages obtained from synovial fluid of RA patients, we searched for genes highly correlated with FCGR2A expression. Tag SNPs were selected from each candidate gene and tested for association with the response to therapy. Results We found a significant association between FCGR2A and the response to adalimumab (P=0.022). Analyzing the subset of anti-CCP positive RA patients (78%), we also found a significant association between FCGR2A and the response to infliximab (P=0.035). DHX32 and RGS12 were the most consistently correlated genes with FCGR2A expression in RA synovial fluid macrophages (P<0.001). We found a significant association between the genetic variation at DHX32 (rs12356233, corrected P=0.019) and a nominally significant association between RGS12 and the response to adalimumab (rs4690093, uncorrected P=0.040). In the anti-CCP positive group of patients, we also found a nominally significant association between RGS12 and the response to infliximab (rs2857859, uncorrected P=0.042). Conclusions In the present study we have validated the FCGR2A association in an independent population, and we have identified new genes associated with the response to anti-TNF therapy in RA.

Variation at interleukin-6 receptor gene is associated to joint damage in rheumatoid arthritis.

IntroductionInterleukin-6 (IL-6) cytokine signaling is key in Rheumatoid Arthritis (RA) pathophysiology. Blocking IL-6 receptor (IL6R) has proven to be a highly effective treatment to prevent joint damage. This study was performed to investigate the association between the genetic variation at IL6R gene and the severity of joint damage in RA.MethodsIL6R gene tagging SNPs (n = 5) were genotyped in a discovery group of 527 RA patients from 5 different university hospitals from Spain. For each marker, a linear regression analysis was performed using an additive model and adjusting for the years of evolution of the disease, autoantibody status, gender and age. Haplotypes combining the SNPs were also estimated and tested for association with the level of joint destruction. Using an independent cohort of 705 RA patients from 6 university hospitals we performed a validation study of the SNPs associated in the discovery phase.ResultsIn the discovery group we found a highly significant association between IL6R SNP rs4845618 and the level of joint destruction in RA (P = 0.0058, Pcorrected = 0.026), and a moderate association with SNP rs4453032 (P = 0.02, Pcorrected = 0.05). The resulting haplotype from both SNPs was more significantly associated with joint damage (P = 0.0037, Pcorrected = 0.011). Using the validation cohort, we replicated the association between the two IL-6R SNPs with the degree of joint destruction in RA (P = 0.007 and P = 0.04, meta-analysis P = 0.00011 and P = 0.0021, respectively), and the haplotype association (P = 0.0058, meta-analysis P = 6.64 e-5).ConclusionsGenetic variation at IL6R gene is associated with joint damage in RA.

A deletion at ADAMTS9-MAGI1 locus is associated with psoriatic arthritis risk

Objective Copy number variants (CNVs) have been associated with the risk to develop multiple autoimmune diseases. Our objective was to identify CNVs associated with the risk to develop psoriatic arthritis (PsA) using a genome-wide analysis approach. Methods A total of 835 patients with PsA and 1498 healthy controls were genotyped for CNVs using the Illumina HumanHap610 BeadChip genotyping platform. Genomic CNVs were characterised using CNstream analysis software and analysed for association using the χ2 test. The most significant genomic CNV associations with PsA risk were independently tested in a validation sample of 1133 patients with PsA and 1831 healthy controls. In order to test for the specificity of the variants with PsA aetiology, we also analysed the association to a cohort of 822 patients with purely cutaneous psoriasis (PsC). Results A total of 165 common CNVs were identified in the genome-wide analysis. We found a highly significant association of an intergenic deletion between ADAMTS9 and MAGI1 genes on chromosome 3p14.1 (p=0.00014). Using the independent patient and control cohort, we validated the association between ADAMTS9-MAGI1 deletion and PsA risk (p=0.032). Using next-generation sequencing, we characterised the 26 kb associated deletion. Finally, analysing the PsC cohort we found a lower frequency of the deletion compared with the PsA cohort (p=0.0088) and a similar frequency to that of healthy controls (p>0.3). Conclusions The present genome-wide scan for CNVs associated with PsA risk has identified a new deletion associated with disease risk and which is also differential from PsC risk.

Association Between Vitamin D Status and Schizophrenia: A First Psychotic Episode Study

Abstract Vitamin D deficiency has been linked with schizophrenia. We aimed to determine whether patients with a first episode of psychosis (FEP) had lower vitamin D levels compared with controls considering their final diagnosis. We conducted a cross-sectional study determining 25-hydroxyvitamin D blood levels. 25-Hydroxyvitamin D levels were considered optimum at 20 ng/mL or greater. A group of 45 adult patients with FEP and a group of 22 healthy controls matched for age were recruited. The patient group was subdivided in two final diagnosis groups (schizophrenia versus other psychoses) after a 6-month follow-up. Average vitamin D values were deficient for FEP patients, especially those 22 with a final diagnosis of schizophrenia. These results relating vitamin D and schizophrenia generate interest to further examine this association.