Marcel D. Posthumus

Genome-wide association study meta-analysis identifies seven new rheumatoid arthritis risk loci

To identify new genetic risk factors for rheumatoid arthritis, we conducted a genome-wide association study meta-analysis of 5,539 autoantibody-positive individuals with rheumatoid arthritis (cases) and 20,169 controls of European descent, followed by replication in an independent set of 6,768 rheumatoid arthritis cases and 8,806 controls. Of 34 SNPs selected for replication, 7 new rheumatoid arthritis risk alleles were identified at genome-wide significance (P < 5 × 10−8) in an analysis of all 41,282 samples. The associated SNPs are near genes of known immune function, including IL6ST, SPRED2, RBPJ, CCR6, IRF5 and PXK. We also refined associations at two established rheumatoid arthritis risk loci (IL2RA and CCL21) and confirmed the association at AFF3. These new associations bring the total number of confirmed rheumatoid arthritis risk loci to 31 among individuals of European ancestry. An additional 11 SNPs replicated at P < 0.05, many of which are validated autoimmune risk alleles, suggesting that most represent genuine rheumatoid arthritis risk alleles.

Implementation of a Treat-to-Target Strategy in Very Early Rheumatoid Arthritis Results of the Dutch Rheumatoid Arthritis Monitoring Remission Induction Cohort Study

OBJECTIVE Clinical remission is the ultimate therapeutic goal in rheumatoid arthritis (RA). Although clinical trials have proven this to be a realistic goal, the concept of targeting at remission has not yet been implemented. The objective of this study was to develop, implement, and evaluate a treat-to-target strategy aimed at achieving remission in very early RA in daily clinical practice. METHODS Five hundred thirty-four patients with a clinical diagnosis of very early RA were included in the Dutch Rheumatoid Arthritis Monitoring remission induction cohort study. Treatment adjustments were based on the Disease Activity Score in 28 joints (DAS28), aiming at a DAS28 of <2.6 (methotrexate, followed by the addition of sulfasalazine, and exchange of sulfasalazine with biologic agents in case of persistent disease activity). The primary outcome was disease activity after 6 months and 12 months of followup, according to the DAS28, the European League Against Rheumatism (EULAR) response criteria, and the modified American College of Rheumatology (ACR) remission criteria. Secondary outcomes were time to first DAS28 remission and outcome of radiography. RESULTS Six-month and 12-month followup data were available for 491 and 389 patients, respectively. At 6 months, 47.0% of patients achieved DAS28 remission, 57.6% had a good EULAR response, and 32.0% satisfied the ACR remission criteria. At 12 months, 58.1% of patients achieved DAS28 remission, 67.9% had a good EULAR response, and 46.4% achieved ACR remission. The median time to first remission was 25.3 weeks (interquartile range 13.0-52.0). The majority of patients did not have clinically relevant radiographic progression after 1 year. CONCLUSION The successful implementation of this treat-to-target strategy aiming at remission demonstrated that achieving remission in daily clinical practice is a realistic goal.

Meta-Analysis of Genome-Wide Association Studies in Celiac Disease and Rheumatoid Arthritis Identifies Fourteen Non-HLA Shared Loci

Epidemiology and candidate gene studies indicate a shared genetic basis for celiac disease (CD) and rheumatoid arthritis (RA), but the extent of this sharing has not been systematically explored. Previous studies demonstrate that 6 of the established non-HLA CD and RA risk loci (out of 26 loci for each disease) are shared between both diseases. We hypothesized that there are additional shared risk alleles and that combining genome-wide association study (GWAS) data from each disease would increase power to identify these shared risk alleles. We performed a meta-analysis of two published GWAS on CD (4,533 cases and 10,750 controls) and RA (5,539 cases and 17,231 controls). After genotyping the top associated SNPs in 2,169 CD cases and 2,255 controls, and 2,845 RA cases and 4,944 controls, 8 additional SNPs demonstrated P<5×10−8 in a combined analysis of all 50,266 samples, including four SNPs that have not been previously confirmed in either disease: rs10892279 near the DDX6 gene (Pcombined = 1.2×10−12), rs864537 near CD247 (Pcombined = 2.2×10−11), rs2298428 near UBE2L3 (Pcombined = 2.5×10−10), and rs11203203 near UBASH3A (Pcombined = 1.1×10−8). We also confirmed that 4 gene loci previously established in either CD or RA are associated with the other autoimmune disease at combined P<5×10−8 (SH2B3, 8q24, STAT4, and TRAF1-C5). From the 14 shared gene loci, 7 SNPs showed a genome-wide significant effect on expression of one or more transcripts in the linkage disequilibrium (LD) block around the SNP. These associations implicate antigen presentation and T-cell activation as a shared mechanism of disease pathogenesis and underscore the utility of cross-disease meta-analysis for identification of genetic risk factors with pleiotropic effects between two clinically distinct diseases.

Novel association in chromosome 4q27 region with rheumatoid arthritis and confirmation of type 1 diabetes point to a general risk locus for autoimmune diseases.

Recently, association of celiac disease with common single-nucleotide polymorphism (SNP) variants in an extensive linkage-disequilibrium block of 480 kb containing the KIAA1109, Tenr, IL2, and IL21 genes has been demonstrated in three independent populations (rs6822844P combined=1.3 x 10(-14)). The KIAA1109/Tenr/IL2/IL21 block corresponds to the Idd3 locus in the nonobese diabetic mouse model of type 1 diabetes (T1D). This block was recently found to be associated with T1D in a genomewide association study, although this finding lacks unequivocal confirmation. We therefore aimed to investigate whether the KIAA1109/Tenr/IL2/IL21 region is involved in susceptibility to multiple autoimmune diseases. We tested SNP rs6822844 for association with disease in 350 T1D-affected and 1,047 rheumatoid arthritis (RA)-affected Dutch patients and in 929 controls. We replicated the association with T1D (P=.0006; OR 0.64 [95% CI 0.50-0.83]), and revealed a similar novel association with RA (P=.0002; OR 0.72 [95% CI 0.61-0.86]). Our results replicate and extend the association found in the KIAA1109/Tenr/IL2/IL21 gene region with autoimmune diseases, implying that this locus is a general risk factor for multiple autoimmune diseases.

Humoral responses after influenza vaccination are severely reduced in patients with rheumatoid arthritis treated with rituximab

OBJECTIVE For patients with rheumatoid arthritis (RA), yearly influenza vaccination is recommended. However, its efficacy in patients treated with rituximab is unknown. The objectives of this study were to investigate the efficacy of influenza vaccination in RA patients treated with rituximab and to investigate the duration of the possible suppression of the humoral immune response following rituximab treatment. We also undertook to assess the safety of influenza vaccination and the effects of previous influenza vaccination. METHODS Trivalent influenza subunit vaccine was administered to 23 RA patients who had received rituximab (4-8 weeks after rituximab for 11 patients [the early rituximab subgroup] and 6-10 months after rituximab for 12 patients [the late rituximab subgroup]), 20 RA patients receiving methotrexate (MTX), and 29 healthy controls. Levels of antibodies against the 3 vaccine strains were measured before and 28 days after vaccination using hemagglutination inhibition assay. The Disease Activity Score in 28 joints (DAS28) was used to assess RA activity. RESULTS Following vaccination, geometric mean titers (GMTs) of antiinfluenza antibodies significantly increased for all influenza strains in the MTX-treated group and in healthy controls, but for no strains in the rituximab-treated group. However, in the late rituximab subgroup, a rise in GMT for the A/H3N2 and A/H1N1 strains was demonstrated, in the absence of a repopulation of CD19+ cells at the time of vaccination. Seroconversion and seroprotection occurred less often in the rituximab-treated group than in the MTX-treated group for the A/H3N2 and A/H1N1 strains, while seroprotection occurred less often in the rituximab-treated group than in the healthy controls for the A/H1N1 strain. Compared with unvaccinated patients in the rituximab-treated group, previously vaccinated patients in the rituximab-treated group had higher pre- and postvaccination GMTs for the A/H1N1 strain. The DAS28 did not change after vaccination. CONCLUSION Rituximab reduces humoral responses following influenza vaccination in RA patients, with a modestly restored response 6-10 months after rituximab administration. Previous influenza vaccination in rituximab-treated patients increases pre- and postvaccination titers. RA activity was not influenced.

LRegulation of cytokine-induced HW-1 alpha expression in rheumatoid synovial fibroblasts

Abstract:  The transcription factor hypoxia‐inducible factor (HIF)‐1 plays a central physiological role in oxygen and energy homeostasis, and is activated during hypoxia by stabilization of the subunit HIF‐1α. Activation can also occur by proinflammatory cytokines during inflammation. Hypoxia, as well as proinflammatory cytokines, plays an important role in the synovia in rheumatoid arthritis (RA) patients. Expression of HIF‐1α has been demonstrated in RA synovial lining layer. The aim of the study was to investigate the regulation of the intracellular signal transduction pathways, involved in the expression of HIF‐1α, and in the expression of genes regulated by HIF‐1α in rheumatoid synovial fibroblasts (RSF). RSF were cultured under proinflammatory conditions (IL‐1β and TNF‐α stimulation) and under chemical hypoxia (CoCl2 treatment). Expression of HIF‐1α was analyzed in nuclear extracts by Western blotting. The effect of inhibitors of the PI3K and the ERK pathway on HIF‐1α protein expression was measured. mRNA expression of HIF‐1α, COX‐2, vascular endothelial growth factor (VEGF), and stromal cell‐derived factor (SDF)‐1 was determined by real‐time RT‐PCR, and protein production of VEGF and SDF‐1 by ELISA. Treatment of the synovial fibroblasts with 150 mM CoCl2 as well as stimulation with 10 ng/mL IL‐1β or TNF‐α resulted in strong protein expression of HIF‐1α, measured with Western blotting. Pretreatment with the MEK1/2 inhibitor PD98059 as well as the PI3K inhibitor LY294002 resulted in inhibition of the cytokine‐induced HIF‐1α expression. Furthermore, it was shown that cytokine‐induced mRNA expression of HIF‐1α was inhibited by the PI3K inhibitor. We found that cytokine stimulation induced VEGF mRNA and protein production, but no significant effect of kinase inhibition was found on VEGF production in cytokine‐stimulated RSF. Both the ERK pathway and the PI3K pathway are involved in the cytokine‐induced HIF‐1α expression in RSF and in the expression of proangiogenic factors.

Adherence to a treat-to-target strategy in early rheumatoid arthritis: results of the DREAM remission induction cohort

IntroductionClinical trials have demonstrated that treatment-to-target (T2T) is effective in achieving remission in early rheumatoid arthritis (RA). However, the concept of T2T has not been fully implemented yet and the question is whether a T2T strategy is feasible in daily clinical practice. The objective of the study was to evaluate the adherence to a T2T strategy aiming at remission (Disease Activity Score in 28 joints (DAS28) < 2.6) in early RA in daily practice. The recommendations regarding T2T included regular assessment of the DAS28 and advice regarding DAS28-driven treatment adjustments.MethodsA medical chart review was performed among a random sample of 100 RA patients of the DREAM remission induction cohort. At all scheduled visits, it was determined whether the clinical decisions were compliant to the T2T recommendations.ResultsThe 100 patients contributed to a total of 1,115 visits. The DAS28 was available in 97.9% (1,092/1,115) of the visits, of which the DAS28 was assessed at a frequency of at least every three months in 88.3% (964/1,092). Adherence to the treatment advice was observed in 69.3% (757/1,092) of the visits. In case of non-adherence when remission was present (19.5%, 108/553), most frequently medication was tapered off or discontinued when it should have been continued (7.2%, 40/553) or treatment was continued when it should have been tapered off or discontinued (6.2%, 34/553). In case of non-adherence when remission was absent (42.1%, 227/539), most frequently medication was not intensified when an intensification step should have been taken (34.9%, 188/539). The main reason for non-adherence was discordance between disease activity status according to the rheumatologist and DAS28.ConclusionsThe recommendations regarding T2T were successfully implemented and high adherence was observed. This demonstrates that a T2T strategy is feasible in RA in daily clinical practice.

Genetic variants in IL15 associate with progression of joint destruction in rheumatoid arthritis: a multicohort study

Background Interleukin (IL)-15 levels are increased in serum, synovium and bone marrow of patients with rheumatoid arthritis (RA). IL-15 influences both the innate and the adaptive immune response; its major role is activation and proliferation of T cells. There are also emerging data that IL-15 affects osteoclastogenesis. The authors investigated the association of genetic variants in IL15 with the rate of joint destruction in RA. Method 1418 patients with 4885 x-ray sets of both hands and feet of four independent data sets were studied. First, explorative analyses were performed on 600 patients with early RA enrolled in the Leiden Early Arthritis Clinic. Twenty-five single-nucleotide polymorphisms (SNPs) tagging IL-15 were tested. Second, SNPs with significant associations in the explorative phase were genotyped in data sets from Groningen, Sheffield and Lund. In each data set, the relative increase of the progression rate per year in the presence of a genotype was assessed. Subsequently, data were summarised in an inverse weighting meta-analysis. Results Five SNPs were significantly associated with rate of joint destruction in phase 1 and typed in the other data sets. Patients homozygous for rs7667746, rs7665842, rs2322182, rs6821171 and rs4371699 had respectively 0.94-, 1.04-, 1.09-, 1.09- and 1.09-fold rate of joint destruction compared to other patients (p=4.0×10−6, p=3.8×10−4, p=5.0×10−3, p=5.0×10−3 and p=9.4×10−3). Discussion Independent replication was not obtained, possibly due to insufficient power. Meta-analyses of all data sets combined resulted in significant results for four SNPs (rs7667746, p<0.001; rs7665842, p<0.001; rs4371699, p=0.01; rs6821171, p=0.01). These SNPs were also significant after correction for multiple testing. Conclusion Genetic variants in IL-15 are associated with progression of joint destruction in RA.

Diagnostic Performance and Prognostic Value of Extravascular Retention of 123I-Labeled Serum Amyloid P Component in Systemic Amyloidosis

Serum amyloid P component (SAP) binds to amyloid. 123I-SAP scintigraphy is used to evaluate the extent and distribution of amyloid in systemic amyloidosis and has great clinical value in the detection of systemic amyloidosis. The aim of the study was to assess during scintigraphy the diagnostic performance and prognostic value of a simple parameter describing extravascular 123I-SAP retention in systemic amyloidosis. Methods: Two hundred megabecquerels of 123I-labeled human SAP was injected intravenously for scintigraphy in 20 controls and in 189 consecutive patients with systemic and localized amyloidosis. Extravascular retention of 123I-SAP was quantified from serum and urine measurements after 24 h (EVR24) and 48 h. Sensitivity and specificity were assessed, and retention was correlated with kidney, heart, liver, and nerve involvement and with survival. Results: The cutoff value representing a desired specificity of 90% of EVR24 was 50%. The associated sensitivity of EVR24 for detecting reactive systemic, immunocyte-derived (AL), and hereditary amyloidosis was 65%, 61%, and 22%, respectively, using a cutoff point of 50%. In AL amyloidosis, the EVR24 increased with the number of organs involved (from a mean of 43% for 1 organ to a mean of 81% for 4 organs). The EVR24 correlated with serum alkaline phosphatase (r = 0.63) and with creatinine clearance (r = −0.36). In AL amyloidosis, both cardiac involvement (hazard ratio, 3.9; 95% CI, 2.0–7.8) and EVR24 (hazard ratio, 2.0; 95% CI, 1.1–3.9) were independent predictors of survival. Conclusion: In AL amyloidosis, the EVR24 is strongly associated with organ involvement and with prognosis and might serve as an indicator of the body amyloid load. Quantification of SAP retention using the EVR24 has no additional value over 123I-SAP scintigraphy in the detection of systemic amyloidosis.

Expression and regulation of HIF-1alpha in macrophages under inflammatory conditions; significant reduction of VEGF by CaMKII inhibitor

BackgroundMacrophages expressing the pro-angiogenic transcription factor hypoxia-inducible factor (HIF)-1alpha have been demonstrated in rheumatoid arthritis (RA) in the synovial tissue. Aim of the present study was to investigate intracellular signal transduction regulation of pro-inflammatory HIF-1 alpha expression in macrophages to identify possible new intervention strategies. We investigated the effects of CaMKII-inhibitors amongst other kinase inhibitors, on HIF-1 alpha expression and downstream production of pro-angiogenic factors in macrophages.MethodsDifferentiated THP-1 cells and synovial fluid (SF) macrophages were stimulated with 1 μg/ml LPS with or without pretreatment with specific inhibitors of the ERK pathway (PD98059), the PI3K pathway (LY294002), and the CaMKII pathway (KN93 and SMP-114). mRNA and protein expression of HIF-1 alpha, VEGF, MMP-9, and IL-8 was measured in cell lysates and cell supernatants.ResultsHIF-1 alpha protein expression in LPS-stimulated THP-1 macrophages could be blocked by ERK- and PI3K-inhibitors, but also by the CaMKII inhibitor KN93. THP-1 and SF macrophages produced high levels of VEGF, IL-8, and MMP-9, and VEGF protein production was significantly inhibited by PI3K-inhibitor, and by both CaMKII inhibitors. LPS stimulation in an hypoxic environment did not change VEGF levels, suggesting that LPS induced VEGF production in macrophages is more important than the hypoxic induction.ConclusionsExpression of HIF-1 alpha and downstream effects in macrophages are regulated by ERK-, PI3K, but also by CaMKII pathways. Inhibition of HIF-1α protein expression and significant inhibition of VEGF production in macrophages was found using CaMKII inhibitors. This is an unknown but very interesting effect of the CaMKII inhibitor SMP-114, which has been in clinical trial as DMARD for the treatment of RA. This effect may contribute to the anti-arthritic effects of SMP-114.