Inflammatory genes TNFα and IL6 display no signs of increased H3K4me3 in circulating monocytes from untreated rheumatoid arthritis patients.

Innate immune cells, such as monocytes, can adopt a long-lasting pro-inflammatory phenotype, a phenomenon called 'trained immunity'. In trained immunity, increased cytokine levels of genes, like interleukin (IL)-6 and tumor necrosis factor (TNF)-α, are observed, which are associated with increased histone 3 lysine 4 trimethylation (H3K4me3) in the promoter region. As systemic IL6 and TNFα levels are increased in rheumatoid arthritis (RA) patients and monocytes are known to be the primary producers of TNFα and IL6, we hypothesized that 'trained immunity' signals may be observed at these genes in monocytes from RA patients. CD14+ monocytes were isolated from untreated RA patients and paired age-matched healthy controls. H3K4me3, mRNA, protein and serum levels of IL6 and TNFα were evaluated by chromatin immunoprecipitation, reverse-transcription quantitative PCR and enzyme-linked immunosorbent assays. Despite elevated serum levels of TNFα and IL6 in the tested RA patients (P<0.05), ex vivo isolated monocytes displayed similar H3K4me3 levels to healthy controls in the promoter region of TNFα and IL6. Concordantly, mRNA and protein levels of IL6 and TNFα were similar before and after lipopolysaccharide stimulation between patients and controls. Together, with the current number of individuals tested we have not detected enhanced trained immunity signals in circulating monocytes from untreated RA patients, despite increased IL6 and TNFα serum levels.

The association between anti-carbamylated protein (anti-CarP) antibodies and radiographic progression in early rheumatoid arthritis: a study exploring replication and the added value to ACPA and rheumatoid factor.

OBJECTIVE: Anti-carbamylated protein (anti-CarP) antibodies are reported to associate with more radiographic progression within the total rheumatoid arthritis (RA) population and anti-citrullinated peptide antibody (ACPA)-negative subgroup. We explored the association of anti-CarP with radiographic progression in RA and aimed to replicate the association and evaluate the added value of anti-CarP antibodies in relation to ACPA and rheumatoid factor (RF). METHODS: 576 Swedish and 628 Dutch patients with RA (2394 and 3247 sets of radiographs, respectively) were longitudinally studied. Replication was restricted to the Swedish patients. In both cohorts, the association of anti-CarP with radiographic progression was determined in strata of patients with similar ACPA and RF status; results of both cohorts were combined in fixed-effect meta-analyses. The net percentage of patients for whom the radiographic progression in 5 years was additionally correctly classified when adding anti-CarP to a model including ACPA and RF was evaluated. RESULTS: Anti-CarP associated with radiographic progression in the total Swedish RA population (beta=1.11 per year, p=8.75×10-13) and in the ACPA-negative subgroup (beta=1.14 per year, p=0.034). Anti-CarP associated with more radiographic progression in the strata of ACPA-positive/RF-negative, ACPA-negative/RF-positive and ACPA-positive/RF-positive patients with RA (respective p values 0.014, 0.019 and 0.0056). A model including ACPA and RF correctly classified 54% and 57% of the patients; adding anti-CarP to this model did not increase these percentages (54% and 56% were correctly classified). CONCLUSIONS: Anti-CarP antibodies associated with more severe radiographic progression in the total and ACPA-negative RA population. Anti-CarP-positivity had a statistically significant additive value to ACPA and RF, but did not improve correct classification of patients.

Rheumatoid arthritis phenotype at presentation differs depending on the number of autoantibodies present.

OBJECTIVES: In rheumatoid arthritis (RA), seropositive and seronegative disease may be two entities with different underlying pathophysiological mechanisms, long-term outcomes and disease presentations. However, the effect of the conjoint presence of multiple autoantibodies, as proxy for a more pronounced humoral autoimmune response, on clinical phenotype remains unclear. Therefore, this study investigates the association between the number of autoantibodies and initial clinical presentation in two independent cohorts of patients with early RA. METHODS: Autoantibody status (rheumatoid factor, anticitrullinated protein antibodies and anticarbamylated protein antibodies) was determined at baseline in the Leiden Early Arthritis Cohort (n=828) and the Swedish BARFOT (Better Anti-Rheumatic Farmaco-Therapy, n=802) study. The association between the number of autoantibodies and baseline clinical characteristics was investigated using univariable and multivariable ordinal regression. RESULTS: In both cohorts, the following independent associations were found in multivariable analysis: patients with a higher number of RA-associated antibodies were younger, more often smokers, had a longer symptom duration and a higher erythrocyte sedimentation rate at presentation compared with patients with few autoantibodies. CONCLUSIONS: The number of autoantibodies, reflecting the breadth of the humoral autoimmune response, is associated with the clinical presentation of RA. Predisease pathophysiology is thus reflected by the initial clinical phenotype.

Disease-modifying antirheumatic drug-free sustained remission in rheumatoid arthritis: an increasingly achievable outcome with subsidence of disease symptoms.

OBJECTIVE: Disease-modifying antirheumatic drug (DMARD)-free sustained remission, the sustained absence of synovitis after cessation of DMARD therapy, is a relevant long-term outcome of rheumatoid arthritis (RA) if (1) its occurrence is promoted by treatment and (2) this status reflects resolution of symptoms and disability. This study investigated both items. METHODS: 1007 patients with RA diagnosed between 1993 and 2011, included in the Leiden Early Arthritis Clinic, were studied on achieving DMARD-free sustained remission. Patients included in 1993-1995 were initially treated with non-steroidal anti-inflammatory drugs, in 1996-1998 mild DMARDs were started early, from 1999 onwards methotrexate was initiated promptly and from 2005 onwards disease activity score (DAS)-steered treatment was common. Remission rates were compared using Kaplan-Meier curves and Cox proportional regression. RESULTS: In total, 155 patients achieved DMARD-free sustained remission. Specific treatment strategies were significantly associated with achieving remission (p<0.001). Cox regression adjusted for anticitrullinated protein antibody/rheumatoid factor, swollen joint count, erythrocyte sedimentation rate, C-reactive protein revealed HRs for DMARD-free sustained remission of 1.13 (95% CI 0.48 to 2.64) in patients diagnosed in 1996-1998, 2.39 (1.07 to 5.32) in patients treated with early methotrexate (inclusion 1999-2004) and 3.72 (1.60 to 8.62) in those treated early with methotrexate and DAS-steered therapy (inclusion 2005-2011). At the time of remission, the Health Assessment Questionnaire was at the level of the general population (median 0.13, IQR 0-0.63). Also, patient-rated visual analogue scale (VAS) morning stiffness, fatigue, pain and disease activity were low (median (IQR) mm, 14 (2-27), 10 (0-47), 6 (0-20), 7 (0-20), respectively). CONCLUSIONS: More intensive treatment strategies increased the chance for DMARD-free sustained remission, indicating that RA chronicity can be influenced. Patients with RA achieving DMARD-free sustained remission have a normalised functional status.

Anticitrullinated protein antibodies and rheumatoid factor are associated with increased mortality but with different causes of death in patients with rheumatoid arthritis: a longitudinal study in three European cohorts.

OBJECTIVE: Patients with rheumatoid arthritis (RA)-related autoantibodies have an increased mortality rate. Different autoantibodies are frequently co-occurring and it is unclear which autoantibodies associate with increased mortality. In addition, association with different causes of death is thus far unexplored. Both questions were addressed in three early RA populations. METHODS: 2331 patients with early RA included in Better Anti-Rheumatic Farmaco-Therapy cohort (BARFOT) (n=805), Norfolk Arthritis Register (NOAR) (n=678) and Leiden Early Arthritis Clinic cohort (EAC) (n=848) were studied. The presence of anticitrullinated protein antibodies (ACPA), rheumatoid factor (RF) and anticarbamylated protein (anti-CarP) antibodies was studied in relation to all-cause and cause-specific mortality, obtained from national death registers. Cox proportional hazards regression models (adjusted for age, sex, smoking and inclusion year) were constructed per cohort; data were combined in inverse-weighted meta-analyses. RESULTS: During 26 300 person-years of observation, 29% of BARFOT patients, 30% of NOAR and 18% of EAC patients died, corresponding to mortality rates of 24.9, 21.0 and 20.8 per 1000 person-years. The HR for all-cause mortality (95% CI) was 1.48 (1.22 to 1.79) for ACPA, 1.47 (1.22 to 1.78) for RF and 1.33 (1.11 to 1.60) for anti-CarP. When including all three antibodies in one model, RF was associated with all-cause mortality independent of other autoantibodies, HR 1.30 (1.04 to 1.63). When subsequently stratifying for death cause, ACPA positivity associated with increased cardiovascular death, HR 1.52 (1.04 to 2.21), and RF with increased neoplasm-related death, HR 1.64 (1.02 to 2.62), and respiratory disease-related death, HR 1.71 (1.01 to 2.88). CONCLUSIONS: The presence of RF in patients with RA associates with an increased overall mortality rate. Cause-specific mortality rates differed between autoantibodies: ACPA associates with increased cardiovascular death and RF with death related to neoplasm and respiratory disease.

The diagnostic accuracy of the squeeze test to identify arthritis: a cross-sectional cohort study.

OBJECTIVES: In daily practice, the squeeze test is used to screen for arthritis in metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints. This cross-sectional cohort study determined the diagnostic accuracy of this test. METHODS: Patients referred with arthralgia of recent onset that had either a clinical suspicion for progression to arthritis or clinically apparent arthritis were studied. The main outcome was swelling at physical examination of ≥1 MCP or MTP joint. Joint inflammation detected at extremity MRI was the secondary outcome. RESULTS: Both at MCP and MTP joints, a positive squeeze test associated with swollen joints (p<0.005). The sensitivity of the test at the MCP joints was 53%, specificity 82%, positive likelihood ratio (LR+) 3.0, negative likelihood ratio (LR-) 0.6 and area under the receiver operator characteristic curve (AUC) 0.68. At the MTP joints, the sensitivity was 54%, specificity 74%, LR+ 2.1, LR- 0.6 and AUC 0.64. With MRI-detected inflammation as outcome, the sensitivity and specificity were 39% and 86% and 31% and 69% for the test at the MCP and MTP joints, respectively. CONCLUSIONS: A positive squeeze test is associated with local joint inflammation but the sensitivity is low, indicating a high percentage of swollen joints with a negative squeeze test. When the test is used on its own, it is insufficient to detect early arthritis.

Evaluating relationships between symptom duration and persistence of rheumatoid arthritis: does a window of opportunity exist? Results on the Leiden early arthritis clinic and ESPOIR cohorts.

BACKGROUND: A prolonged symptom or disease duration at treatment initiation is associated with unfavourable outcomes in rheumatoid arthritis (RA). It is unknown whether this relation is linear, referring to a common 'the-earlier-the-better principle', or whether a transient time frame in which the disease is more susceptible to treatment exists, referring to a 'window of opportunity'. To elucidate this, we evaluated the shape of the associations of symptom duration with persistence of RA. METHODS: Patients with 1987 RA treated with disease modifying antirheumatic drugs (DMARDs) in the Leiden Early Arthritis Clinic (EAC, n=738) and Evaluation et Suivi de POlyarthrites Indifférenciées Récentes (ESPOIR) (n=533) were studied. Cox proportional hazards regression models using natural cubic splines were performed; the log-HR on DMARD-free sustained remission (the opposite of RA persistence) during 5-year follow-up was plotted against symptom duration. Discrimination was measured using time-dependent receiver operator characteristic curves. Subanalyses were performed stratified for the DMARDs used (methotrexate or other conventional DMARDs) and for anticitrullinated peptide antibody (ACPA). RESULTS: 11.5% (85/738) and 5.4% (29/533) of EAC and ESPOIR RA patients achieved DMARD-free sustained remission. In both cohorts and all analyses, the curves depicting the log-HRs on remission in relation to symptom duration were not linear. The symptom duration with optimal discriminative ability was 14.9 weeks (95% CI 12.3 to 16.0; area under the curve (AUC) 0.61) in the EAC and 19.1 weeks (95% CI 12.3 to 28.0; AUC 0.59) in ESPOIR. For ACPA-positive RA, this was 11.4 weeks (95% CI 7.7 to 79.0; AUC 0.56) and for ACPA-negative RA 15.0 weeks (95% CI 9.7 to 48.7; AUC 0.56). CONCLUSIONS: The association between symptom duration and RA persistence is not linear, suggesting the presence of a confined period in which RA is more susceptible to treatment.

Concordance between inflammation at physical examination and on MRI in patients with early arthritis.

BACKGROUND: MRI is increasingly used to measure inflammation in rheumatoid arthritis (RA) research, but the correlation to clinical assessment is unexplored. This study determined the association and concordance between inflammation of small joints measured with MRI and physical examination. METHODS: 179 patients with early arthritis underwent a 68 tender joint count and 66 swollen joint count and 1.5T MRI of MCP (2-5), wrist and MTP (1-5) joints at the most painful side. Two readers scored synovitis and bone marrow oedema (BME) according to the OMERACT RA MRI scoring method and assessed tenosynovitis. The MRI data were first analysed continuously and then dichotomised to analyse the concordance with inflammation at joint examination. RESULTS: 1790 joints of 179 patients were studied. Synovitis and tenosynovitis on MRI were independently associated with clinical swelling, in contrast to BME. In 86% of the swollen MCP joints and in 92% of the swollen wrist joints any inflammation on MRI was present. In 27% of the non-swollen MCP joints and in 66% of the non-swollen wrist joints any MRI inflammation was present. Vice versa, of all MCP, wrist and MTP joints with inflammation on MRI 64%, 61% and 77%, respectively, were not swollen. BME, also in case of severe lesions, occurred frequently in clinically non-swollen joints. Similar results were observed for joint tenderness. CONCLUSIONS: Inflammation on MRI is not only present in clinically swollen but also in non-swollen joints. In particular BME occurred in clinically non-inflamed joints. The relevance of subclinical inflammation for the disease course is a subject for further studies.

A genome-wide association study of rheumatoid arthritis without antibodies against citrullinated peptides.

INTRODUCTION: Rheumatoid arthritis (RA) patients can be classified based on presence or absence of anticitrullinated peptide antibodies (ACPA) in their serum. This heterogeneity among patients may reflect important biological differences underlying the disease process. To date, the majority of genetic studies have focused on the ACPA-positive group. Therefore, our goal was to analyse the genetic risk factors that contribute to ACPA-negative RA. METHODS: We performed a large-scale genome-wide association study (GWAS) in three Caucasian European cohorts comprising 1148 ACPA-negative RA patients and 6008 controls. All patients were screened using the Illumina Human Cyto-12 chip, and controls were genotyped using different genome-wide platforms. Population-independent analyses were carried out by means of logistic regression. Meta-analysis with previously published data was performed as follow-up for selected signals (reaching a total of 1922 ACPA-negative RA patients and 7087 controls). Imputation of classical HLA alleles, amino acid residues and single nucleotide polymorphisms was undertaken. RESULTS: The combined analysis of the studied cohorts resulted in identification of a peak of association in the HLA-region and several suggestive non-HLA associations. Meta-analysis with previous reports confirmed the association of the HLA region with this subset and an observed association in the CLYBL locus remained suggestive. The imputation and deep interrogation of the HLA region led to identification of a two amino acid model (HLA-B at position 9 and HLA-DRB1 at position 11) that accounted for the observed genome-wide associations in this region. CONCLUSIONS: Our study shed light on the influence of the HLA region in ACPA-negative RA and identified a suggestive risk locus for this condition.

What is the evidence for the presence of a therapeutic window of opportunity in rheumatoid arthritis? A systematic literature review.

OBJECTIVE: Initiation of DMARD-therapy in the 'window of opportunity' is thought to result in a more effective modification of the processes underlying rheumatoid arthritis (RA). We questioned whether this effect is true or hyped and performed a systematic literature review. METHODS: Medical literature databases up to June 2012 were systematically reviewed for cohort studies and randomised controlled trials reporting outcome data of early RA in relation with symptom duration at treatment initiation. The quality of these studies was assessed by two independent reviewers using a criteria scoring system of 15 items. Studies were dichotomised with the median score (79%) as cut-off. Best-evidence synthesis was applied to determine the level of evidence per outcome category. A meta-analysis was performed on the studies reporting on achieving DMARD-free sustained remission (the reverse of disease persistency). RESULTS: Out of 836 screened articles, 18 fulfilled the selection criteria and were not duplicates. Ten were scored as high quality. Remission (various definitions) and radiographic progression were frequently studied outcomes. There was strong evidence for an association between symptom duration and radiographic progression. A meta-analysis on datasets evaluating DMARD-free sustained remission showed that symptom duration was independently associated with such remission; HR 0.989 (95% CI 0.983 to 0.995) per week increase in symptom duration. A moderate level of evidence was observed for other remission outcomes. CONCLUSIONS: Even when heterogeneity of patients is taken into account, prolonged symptom duration is associated with radiographic progression and a lower chance on DMARD-free sustained remission. These data may support the presence of a 'window of opportunity'.

Long-term outcome of rheumatoid arthritis defined according to the 2010-classification criteria.

OBJECTIVE: The 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria for rheumatoid arthritis (RA) have been thoroughly studied for the test characteristics but it is unclear whether '2010 RA' has a different phenotype than '1987 RA' when assessing the severity of the disease course. Therefore this study compared two long-term disease outcomes. METHODS: 1502 early arthritis patients that had no other diagnoses than RA or undifferentiated arthritis (UA) were studied on fulfilling the 1987 ACR criteria, 2010 criteria or both. The severity of joint damage was studied with yearly radiographs over 7 years. Achieving disease-modifying anti-rheumatic drug (DMARD)-free sustained remission was assessed over 10-years follow-up. Multivariate normal regression and Cox-proportional hazard regression were used, adjusting for age, gender and treatment. RESULTS: 550 patients fulfilled the 1987 criteria, 788 patients the 2010 criteria and 489 both criteria sets. Patients fulfilling the 2010 criteria developed less severe radiological joint damage (p=0.023) and achieved DMARD-free sustained remission more often (HR=1.18 (0.93-1.50)) than patients fulfilling the 1987 criteria, though the latter was not statistically significant. All 1987+2010- patients were anti-citrullinated peptide antibody (ACPA)-negative. When also applying the radiologic criterion of the 2010-criteria, half of the 1987+2010- patients became 2010 criteria positive, but results on the long-term outcome remained similar. CONCLUSIONS: '2010 RA' has a milder disease course than '1987 RA'. This may have important implications for basic scientific studies and clinical trials in RA.

MRI-detected subclinical joint inflammation is associated with radiographic progression.

BACKGROUND: We recently demonstrated that MRI inflammation is prevalent in clinically non-swollen joints of early arthritis patients. In this study, we assessed the relevance of this subclinical inflammation with regard to radiographic progression. METHODS: 1130 joints (unilateral metacarpophalangeal 2-5, wrist and metatarsophalangeal 1-5) of 113 early arthritis patients underwent clinical examination and 1.5 T MRI at baseline, and radiographs at baseline and 1 year. Two readers scored the MRIs for synovitis, bone marrow oedema (BME) and tenosynovitis according to Rheumatoid Arthritis (RA) Magnetic Resonance Imaging (MRI) Scoring System (RAMRIS). Radiographic progression over 1 year was determined using the Sharp-van der Heijde scoring method. RESULTS: On patient level, BME, synovitis and tenosynovitis were associated with radiographic progression, independent of known risk factors (p=0.003, 0.001 and 0.011, respectively). Of all non-swollen joints (n=932), 232 joints (26%) had subclinical inflammation (≥1 MRI-inflammation feature present). These joints were distributed among 91% of patients. Radiographic progression was present in 4% of non-swollen joints with subclinical inflammation compared to 1% of non-swollen joints without subclinical inflammation (relative risks (RR) 3.5, 95% CI 1.3 to 9.6). Similar observations were done for BME (RR5.3, 95% CI 2.0 to 14.0), synovitis (RR3.4, 95% CI 1.2 to 9.3) and tenosynovitis (RR3.0, 95% CI 0.7 to 12.7) separately. CONCLUSIONS: Radiographic progression was infrequent, but joints with subclinical inflammation had an increased risk of radiographic progression within year 1. This demonstrates the relevance of MRI-detected subclinical inflammation.

A genetic variant in the region of MMP-9 is associated with serum levels and progression of joint damage in rheumatoid arthritis.

OBJECTIVES: The severity of joint destruction is highly variable between rheumatoid arthritis (RA) patients. The majority of its heritability is still unexplained. Several autoimmune diseases share genetic risk variants that may also influence disease progression. We aimed to identify genetic risk factors for the severity of joint damage in RA by studying genetic susceptibility loci of several autoimmune diseases. METHODS: In phase 1, 3143 sets of x-rays of 646 Dutch RA patients taken over 7 years (Sharp van der Heijde (SHS) scored) were studied. Genotyping was done by Immunochip. Associations of single-nucleotide polymorphisms (SNPs) with minor allele frequency (MAF) >0.01 and joint destruction were analysed. In phase 2, 686 North American RA patients with 926 SHS-scored x-rays over 15 years of follow-up were evaluated. In both phases multiple testing corrections were done for the number of uncorrelated SNPs; the thresholds for significance were p<1.1×10(-6) and p<0.0036. Matrix metalloproteinase 9 (MMP-9) levels were measured with ELISA in baseline serum samples. RESULTS: In phase 1, 109 SNPs associated significantly with joint destruction (p<1.1×10(-6)). Of these, 76 were located in the HLA region; the 33 non-HLA variants were studied in phase 2. Here two variants were associated with the severity of joint destruction: rs451066 on chromosome 14 (p=0.002, MAF=0.20) and rs11908352 on chromosome 20 (p=0.002, MAF=0.21). Rs11908352 is located near the gene encoding MMP-9. Serum levels of MMP-9 were significantly associated with the rs11908352 genotypes (p=0.007). CONCLUSIONS: These data indicate that two loci that confer risk to other autoimmune diseases also affect the severity of joint destruction in RA. Rs11908352 may influence joint destruction via MMP-9 production.

Smoking as a risk factor for the radiological severity of rheumatoid arthritis: a study on six cohorts.

BACKGROUND: Smoking is a risk factor for the development of anti -citrullinated protein antibodies (ACPA) positive rheumatoid arthritis (RA). Whether smoking predisposes to severe joint damage progression is not known, since deleterious, protective and neutral observations have been made. OBJECTIVE: To determine the effect of smoking on joint damage progression. METHODS: Smoking status was assessed in 3158 RA patients included in six cohorts (Leiden Early Arthritis Clinic (Leiden-EAC), BARFOT, Lund, Iceland, NDB and Wichita). In total 9412 radiographs were assessed. Multivariate normal regression and linear regression analyses were performed. Data were summarised in a random effects inverse variance meta-analysis. RESULTS: When comparing radiological progression for RA patients that were never, past and current smokers, smoking was significantly associated with more severe joint damage in Leiden-EAC (p=0.042) and BARFOT (p=0.015) RA patients. No significant associations were found in the other cohorts, though a meta-analysis on the six cohorts showed significantly more severe joint damage progression in smokers (p=0.01). Since smoking predisposes to ACPA, analyses were repeated with ACPA as additional adjustment factor. Then the association was lost (meta-analysis p=0.29). CONCLUSIONS: This multi-cohort study indicated that the effect of smoking on joint damage is mediated via ACPA and that smoking is not an independent risk factor for radiological progression in RA.

Macrophage migration inhibitory factor (MIF) -173 polymorphism is associated with clinical erythema nodosum in Löfgren's syndrome.

INTRODUCTION: Macrophage migration inhibitory factor (MIF) has been shown to be a key regulator in innate and adaptive immune responses. A single nucleotide polymorphism in the 5' region of the MIF gene, MIF -173∗G/C, is associated with increased MIF protein production, in vivo and in vitro. Associations have been shown between the minor MIF -173C allele and sarcoidosis patients with erythema nodosum (EN). Löfgren's syndrome is an acute and usually self-remitting phenotype of sarcoidosis. It is defined as having an acute onset with bilateral hilar lymphadenopathy (BHL), fever, erythema nodosum (EN) and/or arthritis. The aim of this study was to investigate whether MIF -173G/C associates with the susceptibility to and the clinical manifestations, i.e. arthritis or EN, of Löfgren's syndrome. A total of 171 patients with Löfgren's syndrome and 313 controls were genotyped for a single nucleotide polymorphism at position -173 of the MIF gene (SNP rs755622), using a PCR and a restriction enzyme technique. RESULTS: There were no significant differences found in the MIF -173C allele frequencies between patients with Löfgren's syndrome and controls. In patients with Löfgren's syndrome with only EN, a significantly increased frequency of the C minor allele was observed compared to patients with arthritis only (p=0.0095; OR 3.08, CI: 1.28-7.39). Patients with only EN compared to patients with EN and arthritis showed a significantly increased frequency of the minor C allele (p=0.044; OR 1.97, CI: 1.01-3.85). But patients with only arthritis compared to patients with EN and arthritis did not show a significant difference in C allele frequency (p=0.270; OR 0.64, CI: 0.29-1.42). CONCLUSIONS: The MIF -173C allele is associated with erythema nodosum in Löfgren's syndrome, but not with susceptibility to sarcoidosis. This indicates a role for MIF after antigen presenting to the T cell has taken place and the sarcoid inflammatory response has begun.

Association of variants in IL2RA with progression of joint destruction in rheumatoid arthritis.

OBJECTIVE: Heritability studies have suggested an important role of genetic predisposition in the progression of joint destruction in rheumatoid arthritis (RA); the heritability is estimated at 45-58%. Several single-nucleotide polymorphisms (SNPs) have been identified as being associated with RA susceptibility. Our objective was to study the association of several of these loci with progression of joint destruction. METHODS: We studied 1,750 RA patients in 4 independent data sets with 4,732 radiographs scored using the modified Sharp/van der Heijde method. Thirteen susceptibility SNPs that were not previously associated with joint destruction were tested in 596 Dutch RA patients. Subsequently, significant SNPs were studied in data sets of RA patients from North America and Iceland. Data were summarized in inverse-weighted variance meta-analyses. Further, the association with circulating protein levels was studied and the associated region was fine-mapped. RESULTS: In stage 1, 3 loci (AFF3, IL2RA, and BLK) were significantly associated with the rate of joint destruction and were further analyzed in the additional data sets. In the combined meta-analyses, the minor (C) allele of IL2RA (rs2104286) was associated with less progression of joint destruction (P = 7.2 × 10(-4) ). Furthermore, the IL2RA (rs2104286) protective genotype was associated with lower (0.85-fold [95% confidence interval 0.77-0.93], P = 1.4 × 10(-3) ) circulating levels of soluble interleukin-2 receptor α (sIL-2Rα). Additionally, lower sIL-2Rα levels were associated with a lower rate of joint destruction (P = 3.4 × 10(-3) ). The association of IL2RA with the rate of joint destruction was further localized to a 40-kb region encompassing the IL2RA intron 1 and the 5' region of IL2RA and RBM17. CONCLUSION: The present genetic and serologic data suggest that inherited altered genetic constitution at the IL2RA locus may predispose to a less destructive course of RA.

Association of genetic variants in the IL4 and IL4R genes with the severity of joint damage in rheumatoid arthritis: a study in seven cohorts.

OBJECTIVE: The progression of joint destruction in rheumatoid arthritis (RA) is determined by genetic factors. Changes in IL4 and IL4R genes have been associated with RA severity, but this finding has not been replicated. This study was undertaken to investigate the association between IL4- and IL4R-tagging single-nucleotide polymorphisms (SNPs) and the progression rate of joint damage in RA in a multicohort candidate gene study. METHODS: IL4- and IL4R-tagging SNPs (n = 8 and 39, respectively) were genotyped in 600 RA patients for whom 2,846 sets of radiographs of the hands and feet were obtained during 7 years of followup. Subsequently, SNPs significantly associated with the progression of joint damage were genotyped and studied in relation to 3,415 radiographs of 1,953 RA patients; these included data sets from Groningen (The Netherlands), Lund (Sweden), Sheffield (UK), the North American Rheumatoid Arthritis Consortium (US), Wichita (US), and the National Data Bank (US). The relative increase in progression rate per year in the presence of a genotype was determined in each cohort. An inverse variance weighting meta-analysis was performed on the 6 data sets that together formed the replication phase. RESULTS: In the discovery phase, none of the IL4 SNPs and 7 of the IL4R SNPs were significantly associated with the joint damage progression rate. In the replication phase, 2 SNPs in the IL4R gene were significantly associated with the joint damage progression rate (rs1805011 [P = 0.02] and rs1119132 [P = 0.001]). CONCLUSION: Genetic variants in IL4R were identified, and their association with the progression rate of joint damage in RA was independently replicated.

A genetic variant in granzyme B is associated with progression of joint destruction in rheumatoid arthritis.

OBJECTIVE: Genetic factors account for an estimated 45-58% of the variance in joint destruction in rheumatoid arthritis (RA). The serine proteinase granzyme B induces target cell apoptosis, and several in vitro studies suggest that granzyme B is involved in apoptosis of chondrocytes. Serum levels of granzyme B are increased in RA and are also associated with radiographic erosions. The aim of this study was to investigate GZMB as a candidate gene accounting for the severity of joint destruction in RA. METHODS: A total of 1,418 patients with 4,885 radiograph sets of the hands and feet from 4 independent cohorts were studied. First, explorative analyses were performed in 600 RA patients in the Leiden Early Arthritis Clinic cohort. Fifteen single-nucleotide polymorphisms (SNPs) tagging GZMB were tested. Significantly associated SNPs were genotyped in data sets representing patients from the Groningen, Sheffield, and Lund cohorts. In each data set, the relative increase in the annual rate of progression in the presence of a genotype was assessed. Data were summarized in a meta-analysis. The association of GZMB with the RNA expression level of the GZMB genomic region was tested by mapping expression quantitative trait loci (QTLs) on 1,469 whole blood samples. RESULTS: SNP rs8192916 was significantly associated with the rate of joint destruction in the first cohort and in the meta-analysis of all data sets. Patients homozygous for the minor allele of rs8192916 had a higher rate of joint destruction per year compared with other patients (P = 7.8 × 10(-4)). Expression QTL of GZMB identified higher expression in the presence of the minor allele of rs8192916 (P = 2.27 × 10(-5)). CONCLUSION: SNP rs8192916 located in GZMB is associated with the progression of joint destruction in RA as well as with RNA expression in whole blood.

Patients with obesity have more inflamed joints and higher CRP levels during the disease course in ACPA-positive RA but not in ACPA-negative RA.

BACKGROUND: Obese RA patients have higher disease activity scores (DAS). Previous research showed that obese RA patients have higher tender joint count (TJC) and VAS general health. However, it remains unclear whether DAS components measuring local and systemic inflammation (swollen joint count (SJC), CRP) are increased and if this is present in the total RA population or confined to an ACPA subgroup. As ACPA is suggested to enhance inflammatory responses, we hypothesized that the association of obesity with SJC and CRP is present especially in ACPA-positive RA. We therefore studied associations of obesity with courses of DAS components in ACPA subgroups. METHODS: We studied 649 RA patients (291 ACPA-positive), included in the Leiden Early Arthritis Clinic. Five-year courses of DAS44 and DAS44 components (SJC-44, TJC-53, CRP, VAS (0-100)) were compared between RA patients with normal weight (BMI 18.5-24.9), overweight (25.0-29.9), and obesity (≥ 30.0), stratified for ACPA. Linear/Poisson mixed models with a knot at 4 months were used. RESULTS: Obese RA patients had + 0.32 higher DAS compared to normal weight during the 5-year follow-up. In ACPA-positive RA, obese patients had + 0.43 (95% CI: 0.22, 0.64) higher DAS, whereas in ACPA-negative RA, this difference was smaller and not statistically significant: + 0.19 (95% CI: - 0.01, 0.38). In ACPA-positive RA, all DAS components were significantly higher in obese patients compared to normal weight: SJC + 60% (IRR1.60; 95% CI: 1.18, 2.16), CRP + 3.7 mg/L (95% CI:0.95, 6.53), TJC + 55% (IRR1.55; 95% CI:1.15, 2.10), and VAS + 9 (95% CI: 4.0, 14.2). ACPA-negative obese RA patients tended to have higher TJC (IRR1.22; 95% CI: 0.96, 1.55) and VAS (ß4.3; 95% CI: - 0.4, 9.0), while SJC (IRR1.07; 95% CI:0.85, 1.33) and CRP (ß0.24; 95% CI: - 1.29, 3.32) were unaffected. CONCLUSION: The association of obesity with a worse DAS course is mainly present in ACPA-positive RA; especially SJC and CRP levels remain higher in ACPA-positive RA patients with obesity but not ACPA-negative RA patients. This is the first demonstration that obesity influences the disease course of ACPA-positive and ACPA-negative RA differently.

Evaluating joint destruction in rheumatoid arthritis: is it necessary to radiograph both hands and feet?

BACKGROUND: Radiological damage is an important outcome measure in rheumatoid arthritis (RA), both for research and clinical purposes. Depending on the setting, both hands and feet are radiographed, or only a part of these. It is unknown whether radiographing part of the four extremities gives comparable information to radiographing both hands and feet. This study therefore aimed to compare the radiological information obtained both when evaluating single time point radiographs and progression over time, in early and advanced RA. METHODS: 6261 sets of hands and feet x-rays of 2193 RA patients from Leiden, Groningen (both from The Netherlands) and North America were studied. Correlations between joint damage at different regions were compared (unilateral vs bilateral and hands vs feet). Analyses were done at single time points (cross-sectional) and for progression over time (longitudinal), both for continuous severity measures (Sharp/van der Heijde score; SHS) and binomial measures of erosiveness. RESULTS: When studying single time points, the severity of joint damage (SHS) is highly correlated between left and right, but weakly correlated between hands and feet. Correlation coefficients were higher in advanced than early RA. These findings were comparable in the three datasets. When evaluating erosiveness using only unilateral x-rays or hands without feet, 19.3% and 24.0-40.4% are incorrectly classified as non-erosiveness. Similarly, when evaluating disease progression by imaging only unilateral x-rays or only hand x-rays, progression would have been missed in 11.6-16.2% and 21.2-31.0% of patients. CONCLUSION: Performing x-rays of both hands and feet yields additive information compared with imaging only a part of these.