IgA rheumatoid factor in rheumatoid arthritis

OBJECTIVES

Rheumatoid factor (RF) is a well-established marker for the diagnosis and classification of rheumatoid arthritis (RA). Most studies evaluated IgM RF or isotype-nonspecific total RF assays. We evaluated the added value of IgA RF in this context.

METHODS

An international sample cohort consisting of samples from 398 RA patients and 1073 controls was tested for IgA RF with 3 commercial assays. For all RA patients and 100 controls essential clinical and serological data for ACR/EULAR classification were available.

RESULTS

The sensitivity of IgA RF for diagnosing RA was lower than the sensitivity of IgM RF. Differences in numerical values between IgA RF assays were observed. With all assays, the highest IgA RF values were found in patients with primary Sjögren's syndrome. Double positivity for IgM RF and IgA RF had a higher specificity for RA than either IgM RF or IgA RF. The sensitivity of double positivity was lower than the sensitivity of either IgA RF or IgM RF. Single positivity for IgA RF was at least as prevalent in controls than in RA patients. Adding IgA RF to IgM RF and anti-citrullinated protein antibodies (ACPA) did not affect RA classification. However, combined positivity for IgA RF, IgM RF and IgG ACPA had a higher specificity and lower sensitivity for RA classification than positivity for either of the antibodies.

CONCLUSIONS

IgA RF showed a lower sensitivity than IgM RF. Combining IgA RF with IgM RF and ACPA did not improve sensitivity of RA classification. Combined positivity (IgA-RF/IgM-RF/ACPA) increased specificity.

Standardisation of ACPA tests: evaluation of a new candidate reference preparation

INTRODUCTION

Commercial assays measuring antibodies to citrullinated protein/peptide (ACPA) show poor quantitative agreement. The diagnostic industry has never adopted the International Union of Immunological Societies-Centers for Disease Control and Prevention (IUIS-CDC) ACPA reference standard. Recently, the National Institute for Biological Standards and Control (NIBSC) prepared a new candidate ACPA standard (18/204). We evaluated both reference materials using different commercially available ACPA assays.

MATERIALS AND METHODS

This is an international study in which the NIBSC candidate ACPA standard and the IUIS-CDC ACPA reference material were analysed together with 398 diagnostic samples from individuals with rheumatoid arthritis (RA) and in 1073 individuals who did not have RA using nine commercial ACPA assays.

RESULTS

For both reference materials and samples from individuals with RA and individuals who did not have RA, there were large differences in quantitative ACPA results between assays. For most assays, values for the IUIS-CDC standard were lower than values for NIBSC 18/204 and the IUIS-CDC/NIBSC ratio was comparable for several, but not all assays. When NIBSC 18/204 was used as a calibrator, an improvement in alignment of ACPA results across several of the evaluated assays was obtained. Moreover, NIBSC 18/204 could align clinical interpretation for some but not all assays.

CONCLUSION

Adoption of an international standard for ACPA determination is highly desirable. The candidate NIBSC 18/204 standard improved the standardisation and alignment of most ACPA assays and might therefore be recommended to be used as reference in commercial assays.

Multicentre study to improve clinical interpretation of rheumatoid factor and anti-citrullinated protein/peptide antibodies test results

BACKGROUND

Rheumatoid factor (RF) and anti-citrullinated protein/peptide antibodies (ACPA) are important biomarkers for diagnosis of rheumatoid arthritis (RA). However, there is poor harmonisation of RF and ACPA assays. The aim of this study was to refine RF and ACPA interpretation across commercial assays.

MATERIALS AND METHODS

Six total RF isotype-non-specific assays, 3 RF IgM isotype-specific assays and 9 ACPA immunoglobulin G assays of 13 different companies were evaluated using 398 diagnostic samples from patients with RA and 1073 disease controls.

RESULTS

Using cut-offs proposed by the manufacturer, there was a large variability in diagnostic sensitivity and specificity between assays. Thresholds of antibody levels were determined based on predefined specificities and used to define test result intervals. Test result interval-specific likelihood ratios (LRs) were concordant across the different RF and ACPA assays. For all assays, the LR for RA increased with increasing antibody level. Higher LRs were found for ACPA than for RF. ACPA levels associated with LRs >80 were found in a substantial fraction (>22%) of patients with RA.

CONCLUSION

Defining thresholds for antibody levels and assigning test result interval-specific LRs allows alignment of clinical interpretation for all RF and ACPA assays.

Circulating calprotectin as biomarker in neutrophil-related inflammation: Pre-analytical recommendations and reference values according to sample type

BACKGROUND

Calprotectin (CLP) is a promising biomarker for the evaluation of neutrophil-related inflammation. Our aim was to establish reference values for circulating CLP in different sample types and to study the effect of pre-analytical variables.

METHODS

Reference values were determined in 100 healthy individuals. Pre-analytical variables were evaluated in 10 healthy controls and four rheumatoid arthritis patients with active disease and covered sample type (serum with/without gel separator, heparin, EDTA and citrate plasma), pre-centrifugation time (<2 h, 6 h, 24 h), storage condition (2-8 °C, 18-25 °C, 30 °C) and storage time (24 h, 72 h, 7 days). CLP measurements were performed with the EliA™Calprotectin 2 assay on Phadia™200 (Thermo Fisher Scientific).

RESULTS

In healthy controls, baseline CLP concentrations in serum were more than double the concentration in EDTA and citrate plasma (0.909 µg/mL versus 0.259 µg/mL and 0.261 µg/mL respectively). Heparin, EDTA and citrate stabilized CLP concentrations for up to 6 h before centrifugation, whereas significant increases in CLP levels were observed when serum was left untreated during that time period.

CONCLUSION

Clinical studies on circulating CLP need to apply sample type-specific reference values and decision limits. To obtain reproducible CLP results in serum, more stringent pre-analytical sample handling instructions are needed.

Pre-analytical and analytical confounders of serum calprotectin as a biomarker in rheumatoid arthritis

Background There is a need for additional biomarkers to assist in the diagnosis and prognosis of rheumatoid arthritis (RA). The aim of our study was to evaluate the (pre-analytical, analytical and clinical) performance of serum calprotectin as a marker of inflammation in RA. Methods The study population included 463 rheumatologic patients (including 111 RA patients and 352 controls) who for the first time consulted a rheumatologist, 20 healthy controls and 27 patients with an infectious disease. Calprotectin was measured (using four different assays) in serum or in serum and EDTA plasma (healthy controls and infectious disease group). For rheumatologic patients, results for C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA) were available. Results Results for blood calprotectin were assay- and matrix-dependent, with higher values found in serum than in plasma. Serum calprotectin was higher in RA patients than in rheumatologic diseased controls and in healthy controls. Serum calprotectin was lower in RA patients than in patients with an infectious disease. Serum calprotectin was associated with disease activity (DAS score). The area under the curve (AUC) to discriminate RA from controls was 0.756 for CRP, 0.714 for ESR and 0.726-0.783 for calprotectin. Conclusions Our data document that calprotectin measurement is assay- and matrix-dependent. Serum calprotectin is associated with disease activity. Additional (prospective) studies are warranted to further evaluate the prognostic and diagnostic value of blood calprotectin measurements.

Etanercept in patients with inflammatory hand osteoarthritis (EHOA): a multicentre, randomised, double-blind, placebo-controlled trial

Objective

Hand osteoarthritis is a prevalent disease with limited treatment options. Since joint inflammation is often present, we investigated tumour necrosis factor (TNF) as treatment target in patients with proven joint inflammation in a proof-of-concept study.

Methods

This 1-year, double-blind, randomised, multicentre trial (NTR1192) enrolled patients with symptomatic erosive inflammatory hand osteoarthritis. Patients flaring after non-steroidal anti-inflammatory drug washout were randomised to etanercept (24 weeks 50 mg/week, thereafter 25  mg/week) or placebo. The primary outcome was Visual Analogue Scale (VAS) pain at 24 weeks. Secondary outcomes included clinical and imaging outcomes (radiographs scored using Ghent University Scoring System (GUSS, n=54) and MRIs (n=20)).

Results

Of 90 patients randomised to etanercept (n=45) or placebo (n=45), respectively, 12 and 10 discontinued prematurely. More patients on placebo discontinued due to inefficacy (6 vs 3), but fewer due to adverse effects (1 vs 6). The mean between-group difference (MD) in VAS pain was not statistically significantly different (−5.7 (95% CI −15.9 to 4.5), p=0.27 at 24 weeks; − 8.5 (95% CI −18.6 to 1.6), p=0.10 at 1  year; favouring etanercept). In prespecified per-protocol analyses of completers with pain and inflammation at baseline (n=61), MD was −11.8 (95% CI −23.0 to −0.5) (p=0.04) at 1  year. Etanercept-treated joints showed more radiographic remodelling (delta GUSS: MD 2.9 (95% CI 0.5 to 5.4), p=0.02) and less MRI bone marrow lesions (MD −0.22 (95% CI −0.35 to −0.09), p = 0.001); this was more pronounced in joints with baseline inflammation.

Conclusion

Anti-TNF did not relieve pain effectively after 24 weeks in erosive osteoarthritis. Small subgroup analyses showed a signal for effects on subchondral bone in actively inflamed joints, but future studies to confirm this are warranted.

Performance characteristics of rheumatoid factor and anti-cyclic citrullinated peptide antibody assays may impact ACR/EULAR classification of rheumatoid arthritis

Objectives

Rheumatoid factor (RF) and anti-cyclic citrullinated protein/peptide antibodies (ACPA) are integrated in the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for rheumatoid arthritis (RA). The objectives of this study were to evaluate the technical and diagnostic performance of different RF and ACPA assays and to evaluate whether differences in performance impact RA classification.

Methods

Samples from 594 consecutive patients who for the first time consulted a rheumatologist (44 of whom were diagnosed with RA) and 26 extra newly diagnosed patients with RA were analysed with six different RF assays (Menarini, Thermo Fisher, Inova, Roche, Abbott, Euroimmun) and seven different ACPA assays (Menarini, Thermo Fisher, Inova, Roche, Abbott, Euro Diagnostica, Euroimmun).

Results

We found differences in analytical performance between assays. There was poor numerical agreement between the different RF and ACPA assays. For all assays, the likelihood ratio for RA increased with increasing antibody levels. The areas under the curve of receiver operating characteristic analysis of the RF (range 0.676–0.709) and ACPA assays (range 0.672–0.769) only differed between some ACPA assays. Nevertheless, using the cut-off proposed by the manufacturer, there was a large variation in sensitivity and specificity between assays (mainly for RF). Consequently, depending on the assay used, a subgroup of patients (13% for RF, 1% for ACPA and 9% for RF/ACPA) might or might not be classified as RA according to the 2010 ACR/EULAR criteria.

Conclusion

Due to poor harmonisation of RF and ACPA assays and of test result interpretation, RA classification according to 2010 ACR/EULAR criteria may vary when different assays are used.

A Nationwide Survey on Patient's versus Physician´s Evaluation of Biological Therapy in Rheumatoid Arthritis in Relation to Disease Activity and Route of Administration: The Be-Raise Study

Objectives

Biological treatment of rheumatoid arthritis (RA) is one of the cornerstones of current treatment strategies for the disease. Surprisingly little information exists on whether the route of administration affects patients’ treatment satisfaction. It is equally unclear whether rheumatologists are able to accurately perceive their patients’ appreciation. Thus, the Belgian Be-raise survey aimed to examine whether RA patient’s experience of their current biological treatment coincided with the treating physician’s perception.

Methods

A nationwide cross-sectional survey was conducted by 67 Belgian rheumatologists providing data obtained from 550 RA patients. Patients under stable dose of biologics for at least 6 months, were enrolled consecutively and all completed questionnaires. Separate questionnaires were completed by the treating rheumatologist which evaluated their patient’s perception of the route of treatment administration. This study therefore evaluates whether a treating physician perceives the satisfaction with the route of administration to the same degree as the patient.

Results

Completed questionnaires were obtained from 293 and 257 patients who obtained treatment via the intravenous (IV) or subcutaneous (SC) route of administration, respectively. 58.4% of patients were in DAS28-CRP(3) remission. Patient satisfaction with disease control was higher (44% scored ≥ 9) than that of the treating physician (35%), regardless of the route of administration (p< 0.01). No differences were seen for the patients treated with an IV as opposed to a SC route of administration. The physician´s perception of patient’s satisfaction with disease control was markedly lower for IV treated patients as opposed to SC treated patients (p< 0.001).

Conclusions

Patients’ satisfaction with biological treatment is high, but there is a considerable mismatch between patients´ and rheumatologists´ appreciation on the route of administration of biological therapy in RA. Physicians consistently consider IV biological therapy to be less satisfactory. Patient´s appreciation is largely dependent on disease control, irrespective of the route of administration. Therefore, and encouraging shared decision making, we suggest that physicians and patients discuss the route of administration of biologicals in an open way.

Effectiveness of methotrexate with step-down glucocorticoid remission induction (COBRA Slim) versus other intensive treatment strategies for early rheumatoid arthritis in a treat-to-target approach: 1-year results of CareRA, a randomised pragmatic open-label superiority trial

Objectives

Combining disease-modifying antirheumatic drugs (DMARDs) with glucocorticoids (GCs) is an effective treatment strategy for early rheumatoid arthritis (ERA), yet the ideal schedule and feasibility in daily practice are debated. We evaluated different DMARD combinations and GC remission induction schemes in poor prognosis patients; and methotrexate (MTX) with or without GC remission induction in good prognosis patients, during the first treatment year.

Methods

The Care in ERA (CareRA) trial is a 2-year investigator-initiated randomised pragmatic open-label superiority trial comparing remission induction regimens in a treat-to-target approach. DMARD-inexperienced patients with ERA were stratified into a high-risk or low-risk group based upon presence of erosions, disease activity, rheumatoid factor and anticitrullinated protein antibodies. High-risk patients were randomised to a COBRA Classic (MTX + sulfasalazine + prednisone step-down from 60 mg), COBRA Slim (MTX + prednisone step-down from 30 mg) or COBRA Avant Garde (MTX + leflunomide + prednisone step-down from 30 mg) scheme. Low-risk patients were randomised to MTX tight step-up (MTX-TSU) or COBRA Slim. Primary outcome was the proportion of patients in 28 joint disease activity score calculated with C-reactive protein remission at week 52 in an intention-to-treat analysis. Secondary outcomes were safety and effectiveness (ClinicalTrial.gov identifier NCT01172639).

Results

98 COBRA Classic, 98 COBRA Slim (high risk), 93 COBRA Avant Garde, 47 MTX-TSU and 43 COBRA Slim (low risk) patients were evaluated. Remission was achieved in 64.3% (63/98) COBRA Classic, 60.2% (59/98) COBRA Slim (high risk) and 62.4% (58/93) COBRA Avant Garde patients at W52 (p=0.840); and in 57.4% (27/47) MTX-TSU and 67.4% (29/43) COBRA Slim (low risk) patients (p=0.329). Less adverse events occurred per patient with COBRA Slim (high risk) compared with COBRA Classic or COBRA Avant Garde (p=0.038). Adverse events were similar in MTX-TSU and COBRA Slim (low risk) patients (p=0.871). At W52, 76.0% patients were on DMARD monotherapy, 5.2% used GCs and 7.5% biologicals.

Conclusions

MTX with a moderate-dose GC remission induction scheme (COBRA Slim) seems an effective, safe, low-cost and feasible initial treatment strategy for patients with ERA regardless of their prognostic profile, provided a treat-to-target approach is followed.

Trial registration numbers

EudraCT-number 2008-007225-39 and NCT01172639; Results.

Patients lacking classical poor prognostic markers might also benefit from a step-down glucocorticoid bridging scheme in early rheumatoid arthritis: week 16 results from the randomized multicenter CareRA trial

Introduction

Considering a lack of efficacy data in patients with early rheumatoid arthritis (eRA) presenting without classical markers of poor prognosis, we compared methotrexate (MTX) with or without step-down glucocorticoids in the CareRA trial.

Methods

Disease-modifying antirheumatic drug–naïve patients with eRA were stratified into a low-risk group based on prognostic markers that included non-erosiveness, anti–citrullinated protein antibodies and rheumatoid factor negativity and low disease activity (Disease Activity Score in 28 joints based on C-reactive protein (DAS28(CRP)) ≤3.2). Patients were randomized to 15 mg of MTX weekly (MTX with tight step-up (MTX-TSU)) or 15 mg of MTX weekly with prednisone bridging, starting at 30 mg and tapered to 5 mg daily from week 6 (COmbinatie therapie bij Reumatoïde Artritis (COBRA Slim)). A TSU approach was applied. Outcomes assessed were DAS28(CRP)-determined remission, cumulative disease activity, Health Assessment Questionnaire (HAQ) scores and adverse events (AEs) after 16 treatment weeks.

Results

We analyzed 43 COBRA Slim and 47 MTX-TSU patients and found that 65.1% in the COBRA Slim group and 46.8% in the MTX-TSU group reached remission (P = 0.081). Mean ± standard deviation area under the curve values of DAS28(CRP) were 13.84 ± 4.58 and 11.18 ± 4.25 for the MTX-TSU and COBRA Slim patients, respectively (P = 0.006). More COBRA Slim patients had an HAQ score of 0 (51.2% versus 23.4%, P = 0.006) at week 16. Therapy-related AEs between groups did not differ.

Conclusion

In patients with low-risk eRA, MTX with step-down glucocorticoid bridging seems more efficacious than MTX step-up monotherapy, with a comparable number of AEs observed over the first 16 treatment weeks.

Trial registration

EU Clinical Trials Register Identifier: EudraCT number 2008-007225-39. Registered 5 November 2008.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0611-8) contains supplementary material, which is available to authorized users.

Comparison of the clinical expression of patients with ankylosing spondylitis from Europe and Latin America

OBJECTIVE

To compare the clinical, demographic, and serologic characteristics and the treatment of patients diagnosed with ankylosing spondylitis (AS) from Europe (EU) and Latin America (LA).

METHODS

We included 3439 patients from national registries: the Spanish Registry of Spondyloarthritis (REGISPONSER), the Belgian registry (ASPECT), and the Latin American Registry of Spondyloarthropathies (RESPONDIA). We selected patients with diagnosis of AS who met the modified New York classification criteria. Demographic, clinical, disease activity, functional, and metrological measurement data were recorded. Current treatment was recorded. The population was classified into 2 groups: patients with disease duration < 10 years and those with disease duration ≥ 10 years. A descriptive and comparative analysis of variables of both groups was carried out.

RESULTS

There were 2356 patients in EU group and 1083 in LA group. Prevalence of HLA-B27 was 71% in LA group and 83% in EU group (p < 0.001). We found a greater frequency of peripheral arthritis and enthesitis (p < 0.001) in the LA population; prevalence of arthritis was 57% in LA and 42% in EU, and for enthesitis, 54% and 38%. Except for treatment with anti-tumor necrosis factor (anti-TNF), the use of nonsteroidal antiinflammatory drugs (NSAID), corticosteroids, and disease-modifying antirheumatic drugs (DMARD), and the association of anti-TNF and methotrexate use showed a significant difference (p < 0.001) in the 2 populations.

CONCLUSION

The principal differences in the clinical manifestations of patients with AS from EU and LA were the greater frequency of peripheral arthritis and enthesitis in LA group, the higher percentage of HLA-B27 in EU group, and the form of treatment, with a greater use of NSAID, steroids, and DMARD in the LA group.

Predictors of functional impairment and pain in erosive osteoarthritis of the interphalangeal joints: comparison with controlled inflammatory arthritis

OBJECTIVE

To compare levels of pain and functional limitation in patients with erosive osteoarthritis (OA) of the interphalangeal finger joints with those in patients with nonerosive OA and patients with controlled inflammatory arthritis affecting the hands, and to explore predictors of functional impairment in erosive OA.

METHODS

A cross-sectional study including 270 patients with OA of the hands who were referred to rheumatology clinics was performed. A group of patients with inflammatory arthritis (rheumatoid arthritis or psoriatic arthritis) with a low Disease Activity Score in 28 joints (<3.2; n = 79) was examined. Levels of functional impairment (measured by the Functional Index for Hand OA [FIHOA] and Australian/Canadian OA Hand Index [AUSCAN]) and pain were compared between the groups. Predictors of functional impairment in erosive OA were evaluated by generalized linear models.

RESULTS

Of 270 patients with hand OA, 167 (61.9%) were classified as having erosive OA. Despite a higher percentage of patients taking analgesics (almost 60%), patients with erosive OA had worse functional outcome and pain scores than patients with controlled inflammatory arthritis or nonerosive OA. Pain scores remained significantly higher in patients with erosive OA after correction for potential confounders. FIHOA and AUSCAN function scores showed a trend toward more disability in patients with erosive OA. Female sex and the number of radiographic affected joints (consisting of joints in the erosive and remodeled radiographic phases) were the strongest predictors of functional impairment in erosive OA. Whether the carpometacarpal joints were affected did not influence functional status in patients with erosive OA.

CONCLUSION

Our findings indicate that patients with erosive OA have more functional impairment and significantly more pain compared to patients with controlled inflammatory arthritis affecting the hands. This highlights the significant clinical burden of erosive OA and warrants the search for new treatment strategies.

Tumour necrosis factor blockade for the treatment of erosive osteoarthritis of the interphalangeal finger joints: a double blind, randomised trial on structure modification

Background

Adalimumab blocks the action of tumor necrosis factor-α and reduces disease progression in rheumatoid arthritis and psoriatic arthritis. The effects of adalimumab in controlling progression of structural damage in erosive hand osteoarthritis (HOA) were assessed.

Methods

Sixty patients with erosive HOA on radiology received 40 mg adalimumab or placebo subcutaneously every two weeks during a 12-month randomized double-blind trial. Response was defined as the reduction in progression of structural damage according to the categorical anatomic phase scoring system. Furthermore, subchondral bone, bone plate erosion, and joint-space narrowing were scored according to the continuous Ghent University Score System (GUSSTM).

Results

The disease appeared to be active since 40.0% and 26,7% of patients out of the placebo and adalimumab group, respectively, showed at least one new interphalangeal (IP) joint that became erosive during the 12 months follow-up. These differences were not significant and the overall results showed no effect of adalimumab.

Risk factors for progression were then identified and the presence of palpable soft tissue swelling at baseline was recognized as the strongest predictor for erosive progression. In this subpopulation at risk, statistically significant less erosive evolution on the radiological image (3.7%) was seen in the adalimumab treated group compared to the placebo group (14.5%) (P = 0.009). GUSSTM scoring confirmed a less rapid rate of mean increase in the erosion scores during the first 6 months of treatment in patients in adalimumab-treated patients.

Conclusion

Palpable soft tissue swelling in IP joints in patients with erosive HOA is a strong predictor for erosive progression. In these joints adalimumab significantly halted the progression of joint damage compared to placebo.

Optimized alkylated cyclodextrin polysulphates with reduced risks on thromboembolic accidents improve osteoarthritic chondrocyte metabolism

OBJECTIVES

To compare the ability of different cyclodextrin polysulphate (CDPS) derivatives to affect human articular cartilage cell metabolism in vitro.

METHODS

OA chondrocytes were cultured in alginate and exposed to 5 µg/ml of 2,3,6-tri-O-methyl-β-cyclodextrin (ME-CD), 2,3-di-O-methyl-6-sulphate-β-cyclodextrin (ME-CD-6-S), 2,6-di-O-methyl-3-sulphate-β-cyclodextrin (ME-CD-3-S), (2-carboxyethyl)-β-CDPS (CE-CDPS), (2-hydroxypropyl)-β-CDPS (HP-CDPS), 6-monoamino-6-monodeoxy-β-CDPS (MA-CDPS) or β-CDPS for 5 days. Effects on IL-1-driven chondrocyte extracellular matrix (ECM) metabolism were assayed by analysis of the accumulation of aggrecan in the interterritorial matrix, IL-6 secretion and qPCR. MA-CDPS, HP-CDPS, CE-CDPS and CDPS were analysed for their in vitro effect on coagulation and their ability to activate platelets in an in vitro assay to detect possible cross-reactivity with heparin-induced thrombocytopenia (HIT) antibodies.

RESULTS

The monosulphated cyclodextrins ME-CD-6-S and -3-S failed to affect aggrecan synthesis and IL-6 secretion by the OA chondrocytes. Polysulphated cyclodextrins MA-CDPS, HP-CDPS, CE-CDPS and CDPS at 5 µg/ml concentrations, on the other hand, significantly induced aggrecan production and repressed IL-6 release by the chondrocytes in culture. aPTT and PT for all derivatives were lengthened for polysaccharide concentrations >50 µg/ml. Five micrograms per millilitre of β-CDPS concentrations that significantly modulated ECM ground substance production in vitro did not affect aPTT or PT. Furthermore, CE-CDPS, in contrast to MA-CDPS, HP-CDPS and CDPS, did not significantly activate platelets, suggesting a minimal potential to induce HIT thromboembolic accidents in vivo.

CONCLUSIONS

CE-CDPS is a new, structurally adjusted, sulphated β-cyclodextrin derivative with preserved chondroprotective capacity and a promising safety profile.

Predicting the outcome of ankylosing spondylitis therapy

Objectives

To create a model that provides a potential basis for candidate selection for anti-tumour necrosis factor (TNF) treatment by predicting future outcomes relative to the current disease profile of individual patients with ankylosing spondylitis (AS).

Methods

ASSERT and GO–RAISE trial data (n=635) were analysed to identify baseline predictors for various disease-state and disease-activity outcome instruments in AS. Univariate, multivariate, receiver operator characteristic and correlation analyses were performed to select final predictors. Their associations with outcomes were explored. Matrix and algorithm-based prediction models were created using logistic and linear regression, and their accuracies were compared. Numbers needed to treat were calculated to compare the effect size of anti-TNF therapy between the AS matrix subpopulations. Data from registry populations were applied to study how a daily practice AS population is distributed over the prediction model.

Results

Age, Bath ankylosing spondylitis functional index (BASFI) score, enthesitis, therapy, C-reactive protein (CRP) and HLA-B27 genotype were identified as predictors. Their associations with each outcome instrument varied. However, the combination of these factors enabled adequate prediction of each outcome studied. The matrix model predicted outcomes as well as algorithm-based models and enabled direct comparison of the effect size of anti-TNF treatment outcome in various subpopulations. The trial populations reflected the daily practice AS population.

Conclusion

Age, BASFI, enthesitis, therapy, CRP and HLA-B27 were associated with outcomes in AS. Their combined use enables adequate prediction of outcome resulting from anti-TNF and conventional therapy in various AS subpopulations. This may help guide clinicians in making treatment decisions in daily practice.

Evidence for significant overlap between common risk variants for Crohn's disease and ankylosing spondylitis

Background

A multicenter genome-wide association scan for Crohn's Disease (CD) has recently reported 40 CD susceptibility loci, including 29 novel ones (19 significant and 10 putative). To gain insight into the genetic overlap between CD and ankylosing spondylitis (AS), these markers were tested for association in AS patients.

Principal Findings

Two previously established associations, namely with the MHC and IL23R loci, were confirmed. In addition, rs2872507, which maps to a locus associated with asthma and influences the expression of the ORMDL3 gene in lymphoblastoid cells, showed a significant association with AS (p = 0.03). In gut biopsies of AS and CD patients, ORMDL3 expression was not significantly different from controls and no correlation was found with the rs2872507 genotype (Spearman's rho: −0.067). The distribution of p-values for the remaining 36 SNPs was significantly skewed towards low p-values unless the top 5 ranked SNPs (ORMDL3, NKX2–3, PTPN2, ICOSLG and MST1) were excluded from the analysis.

Conclusions

Association analysis using risk variants for CD led to the identification of a new risk variant associated with AS (ORMDL3), underscoring a role for ER stress in AS. In addition, two known and five potentially relevant associations were detected, contributing to common susceptibility of CD and AS.

The Belgian MIRA (MabThera In Rheumatoid Arthritis) registry: clues for the optimization of rituximab treatment strategies

INTRODUCTION

This study describes the results of the Belgian 'MabThera In Rheumatoid Arthritis (MIRA)' registry: effectiveness, safety and evaluation of the current retreatment practice on the background of the Belgian reimbursement criteria for rituximab.

METHODS

All Belgian rheumatologists had the possibility to participate in the study. Patients entered the registry in November 2006 and the entry is still open.

RESULTS

By mid-September 2009, 401 patients had entered the registry with a mean follow-up time of 70 weeks. Overall, DAS28-ESR decreased from 6.0 at baseline to 4.2 at week 16. Further decrease of disease activity was observed at the end of year 1 and year 2 with mean DAS28-ESR of 4.0 and 3.7 at these respective time points. More than 80% of patients showed a EULAR response at week 16. Patients could be retreated if they had DAS scores of > 3.2 at least 6 months after the previous course. Second and third courses were given in 224 and 104 patients, respectively. At month 6 after the second course, significantly lower DAS28-ESR values were observed compared to the first course. This was especially the case for patients who were retreated before they showed an obvious flare (DAS increase > 1.2).

CONCLUSIONS

This study describes the follow-up of a daily clinical practice cohort of 401 RA patients with long-standing refractory disease treated with rituximab. Relatively high DAS28 values at the start of each retreatment, compared to values 6 months after each treatment course, were noted. Moreover, further decrease of DAS28 scores after the second course was significantly more pronounced in those patients who didn't show an obvious flare. These two elements suggest that treatment of RA patients with rituximab could be optimized by earlier retreatment.

Morbid anatomy of 'erosive osteoarthritis' of the interphalangeal finger joints: an optimised scoring system to monitor disease progression in affected joints

Objectives

To develop and validate a quantitative radiographic scoring system, the Ghent University Scoring System (GUSS), with better ability to detect progression over a shorter period of time in erosive osteoarthritis (OA) of the interphalangeal (IP) finger joints compared with the existing anatomic phase scoring system.

Methods

Thirty IP finger joints showing erosive features at baseline or follow-up were selected from 18 patients with erosive hand OA. Posteroanterior radiographs of these joints obtained at baseline, 6 and 12 months—totalling 90 images—were used for the study. All joints were first scored according to the original anatomic phase scoring system. Erosive progression and signs of repair or remodelling were then scored by indicating the proportion of normal subchondral bone, subchondral plate and joint space on an 11-point rating scale (range 0–100 with 10 unit increases). Inter- and intrareader reproducibility was studied using intraclass correlation coefficients (ICCs). Based on the within-variance of two readers, the smallest detectable change (SDC) was calculated and allowed identification of joints with changes above the SDC as ‘progressors’.

Results

Longitudinal inter-reader ICC scores rated well for all variables and the total score (ICC 0.86–0.93). To identify ‘real’ change over background noise, a change of at least 40 units on the total score (range 0–300) over 12 months (SDC 0–12:36.0), and 50 units over 6 months (SDC 0–6:47.6) had to be present. 60% of the 30 joints were identified as ‘progressors’ over 6 months compared with 33.3% with the classical anatomical scoring system, and 70% versus 56.6%, respectively, over 12 months.

Conclusion

GUSS, is a reliable method to score radiographic change over time in erosive IP OA and detects more progression over a shorter period of time than the classical scoring system.

Clinical observations programme in SpA: disease parameters, treatment options and practical management issues

Spondyloarthritides (SpAs) are a cluster of chronic inflammatory rheumatic diseases that typically involve inflammation of axial and peripheral joint or tendon and ligament insertions, distinct radiographic changes and diverse extra-articular features. Conventional treatments relieve the signs and symptoms but do not prevent disease progression. TNFalpha inhibitors provide clinicians with the potential to treat the underlying pathology and to alter disease progression. By targeting the underlying inflammatory mechanisms, TNFalpha blockade can treat any extra-articular manifestations of SpA.

Altered subcellular distribution of MSK1 induced by glucocorticoids contributes to NF-kappaB inhibition

Glucocorticoids are widely used anti-inflammatory and immunomodulatory agents, of which the action mechanism is mainly based on interference of hormone-activated glucocorticoid receptor (GR) with the activity of transcription factors, such as nuclear factor-kappaB (NF-kappaB). In addition to the well described interaction-based mutual repression mechanism between the GR and NF-kappaB, additional mechanisms are at play, which help to explain the efficacy of glucocorticoid-mediated gene repression. In this respect, we found that glucocorticoids counteract the recruitment of activated Mitogen- and Stress-activated protein Kinase-1 (MSK1) at inflammatory gene promoters resulting in the inhibition of NF-kappaB p65 transactivation and of concurrent histone H3 phosphorylation. Additionally, we observed that activated GR can trigger redistribution of nuclear MSK1 to the cytoplasm through a CRM1-dependent export mechanism, as a result of an interaction between liganded GR and activated MSK1. These findings unveil a novel aspect within the GR-mediated NF-kappaB-targeting anti-inflammatory mechanism.

A plant-derived ligand favoring monomeric glucocorticoid receptor conformation with impaired transactivation potential attenuates collagen-induced arthritis

The glucocorticoid receptor (GR) is a transcription factor regulating its target genes either positively, through direct binding to the promoter of target genes, or negatively by the interference with the activity of transcription factors involved in proinflammatory gene expression. The well-known adverse effects of glucocorticoids are believed to be mainly caused by their GR-mediated gene-activating properties. Although dimerization of GR is thought to be essential for gene-activating properties, no compound has yet been described which selectively imposes GR monomer formation and interference with other transcription factors. In the present study, we report on a GR-binding, plant-derived compound with marked dissociative properties in rheumatoid arthritis fibroblast-like synoviocytes, which are important effector cells in inflammation and matrix degradation in rheumatoid arthritis. In addition, these findings could be extended in vivo in murine collagen-induced arthritis, in which joint inflammation was markedly inhibited without inducing hyperinsulinemia. Therefore, we conclude that GR monomers are sufficient for inhibition of inflammation in vivo.

Clinical and genetic factors associated with sacroiliitis in Crohn's disease

BACKGROUND AND AIM

Radiographic sacroiliitis (SI), often asymptomatic, is considered the most frequent extra-intestinal manifestation (EIM) of Crohn's disease (CD). Data on the association of SI with other clinical features of CD are limited. Association of SI with CARD15 polymorphisms has recently been suggested. In a multicenter study, we investigated the association of SI in CD patients with clinical phenotypes, other EIM and CARD15 polymorphisms.

METHODS

Radiographs of the sacroiliac joints were taken in 251 CD patients from three Belgian university hospitals and scored by two blinded rheumatologists. Clinical features were obtained from medical records. Forty-three percent of patients carried at least one CARD15 polymorphism.

RESULTS

Sacroiliitis, defined as the presence of at least grade 2 unilateral changes, was diagnosed in 65 of the 244 scorable radiographs (27%). Only 16 of these patients were previously diagnosed with ankylosing spondylitis (AS). HLA-B27 positivity was observed in 53% of patients with AS and 7% of patients with radiographic SI. In univariate and multivariate analysis, associations between the presence of SI and peripheral arthritis (P = 0.005) and between AS and uveitis (P = 0.005) were found. No associations with other recorded clinical features or with CARD15 polymorphisms were observed.

CONCLUSION

We confirm the high prevalence of radiographic sacroiliitis in a multicenter CD cohort. Uveitis is only associated with AS whereas all patients with SI are more prone to develop peripheral arthritis during their disease course, suggesting similar pathogenetic mechanisms in the development of these EIM. The previously reported association between SI and CARD15 polymorphisms was not confirmed.

Decrease of disease activity under ineffective therapy in DMARD-naive patients with early rheumatoid arthritis: role of antibody profiles and carriage of the HLA shared epitope in predicting decrease of disease activity

OBJECTIVE

To evaluate whether the baseline presence of rheumatoid arthritis (RA)-associated biomarkers could define subgroups of patients that are more prone to show a spontaneous decrease of RA disease activity. In a previous placebo-controlled phase II trial that failed to show any superiority of the experimental compound versus placebo, a remarkable decrease of such disease activity was observed despite the lack of effective treatment.

METHODS

A subgroup of 83 disease modifying antirheumatic drug-naive RA patients with disease duration < 3 years was analyzed. Rheumatoid factor (RF), anti-citrullinated protein/peptide antibodies (ACPA), and HLA shared epitope (SE) were determined at baseline.

RESULTS

RF-positive patients tended to have higher levels of disease activity at baseline compared to RF-negative patients [Disease Activity Score (DAS) 6.12 vs 5.65, p = 0.02 at screening], but the decrease in disease activity was similar in both subgroups (DAS -1.23 vs -1.07). In contrast, ACPA-positive patients showed similar baseline disease activity scores compared to ACPA-negative patients, but tended to show a smaller decrease of disease activity than patients without ACPA (Delta DAS -1.53 vs -0.79, p = 0.013). Presence of the HLA-SE seemed not to have any effect on the baseline DAS or on the spontaneous decrease of DAS.

CONCLUSION

The predictive value of baseline RA-associated biomarkers for spontaneous decrease of disease activity under placebo or ineffective treatment is limited. Yet the data analyzed here might be useful for the design of future placebo-controlled trials in RA.

A Single Early Activation of Invariant NK T Cells Confers Long-Term Protection against Collagen-Induced Arthritis in a Ligand-Specific Manner

The glycosphingolipid alpha-galactosylceramide (alpha-GalCer) has been shown to be a potent activator of invariant NKT (iNKT) cells, rapidly inducing large amounts of both Th1 and Th2 cytokines upon injection in mice. The C-glycoside analog of alpha-GalCer (alpha-C-GalCer), by contrast, results in an enhanced Th1-type response upon activation of iNKT cells. We administered a single dose of these Ags to DBA/1 mice during the early induction phase of collagen-induced arthritis and demonstrated therapeutic efficacy of alpha-GalCer when administered early rather than late during the disease. Surprisingly, the Th1-polarizing analog alpha-C-GalCer also conferred protection. Furthermore, a biphasic role of IFN-gamma in the effect of iNKT cell stimulation was observed. Whereas in vivo neutralization of IFN-gamma release induced by either alpha-GalCer or alpha-C-GalCer early during the course of disease resulted in partial improvement of clinical arthritis symptoms, blockade of IFN-gamma release later on resulted in a more rapid onset of arthritis. Although no phenotypic changes in conventional T cells, macrophages, or APCs could be detected, important functional differences in T cell cytokine production in serum were observed upon polyclonal T cell activation, 2 wk after onset of arthritis. Whereas alpha-GalCer-treated mice produced significantly higher amounts of IL-10 upon systemic anti-CD3 stimulation compared with PBS controls, T cells from alpha-C-GalCer-treated mice, by contrast, produced substantially lower levels of cytokines, suggesting the involvement of different protective mechanisms. In conclusion, these findings suggest long-term, ligand-specific, time-dependent, and partially IFN-gamma-dependent immunomodulatory effects of iNKT cells in collagen-induced arthritis.

Osteochondral repair in synovial joints

PURPOSE OF REVIEW

One of the major challenges in rheumatology remains the induction of osteochondral repair in synovial joints. Remarkable progress has been made in controlling the inflammatory pathways of chronic synovitis and tissue damage in rheumatoid arthritis and spondyloarthropathy. Here, we provide an overview of the current knowledge on the mechanisms involved in osteochondral repair in degenerative joint diseases, as well as in immune mediated inflammatory arthritides, with special emphasis on tumor necrosis factor alpha and IL-1.

RECENT FINDINGS

Homeostasis of articular cartilage and subchondral bone are essential for maintaining the integrity of osteochondral structures within synovial joints. This is achieved by the regulation of a delicate balance between anabolic and catabolic signals. In articular cartilage one cell type, the chondrocyte, is responsible for regulation of homeostasis. In bone, however, two distinct cell types, osteoblasts and osteoclasts, are responsible for anabolic and catabolic pathways, respectively. In inflammatory joint disorders, this tight regulation is profoundly dysregulated, with tumor necrosis factor alpha acting as an important catalyst of a disturbed homeostasis, together with IL-1. Targeting these cytokines may restore the intrinsic repair capacity of osteochondral structures.

SUMMARY

To restore catabolic cytokine balances appears to be a suitable strategy to promote osteochondral repair.

Diagnostic value of anti-human citrullinated fibrinogen ELISA and comparison with four other anti-citrullinated protein assays

We studied the diagnostic performance of the anti-human citrullinated fibrinogen antibody (AhFibA) ELISA for rheumatoid arthritis (RA) in a consecutive cohort (population 1) and evaluated the agreement between the AhFibA ELISA and four other assays for anti-citrullinated protein/peptide antibodies (ACPAs) as well as rheumatoid factor in patients with longstanding RA (population 2). Population 1 consisted of 1024 patients with rheumatic symptoms; serum samples from these patients were sent to our laboratory for ACPA testing within the context of a diagnostic investigation for RA. Ninety-two of these patients were classified as having RA according to the American College of Rheumatology criteria and 463 were classified as non-RA patients. Population 2 consisted of 180 patients with longstanding RA and was used to assess agreement and correlations between five ACPA assays: anti-cyclic citrullinated peptide (CCP)1 and anti-CCP2 antibodies were detected using a commercially available ELISA, AhFibA using ELISA, and anti-PepA and anti-PepB antibodies using line immunoassay. Applying previously proposed cut-offs for AhFibA, we obtained a sensitivity of 60.9% and a specificity of 98.7% in population 1. Receiver operating characteristic curve analysis could not detect a significant difference in diagnostic performance between the AhFibA ELISA and anti-CCP2 assay. Performing a hierarchical nearest neighborhood cluster analysis of the five different ACPA assays in population 2, we identified two clusters: a cluster of anti-pepA, anti-pepB and anti-CCP1, and a cluster of AhFibA and anti-CCP2. In conclusion, we found that AhFibA and anti-CCP2 antibodies had similar diagnostic performance. However, disagreement between ACPA tests may occur.

The epidemiology of ankylosing spondylitis and the commencement of anti-TNF therapy in daily rheumatology practice

OBJECTIVES

This study aimed to describe the epidemiology of ankylosing spondylitis (AS) in rheumatology practice at the beginning of the anti-TNF (tumour necrosis factor) era, and to evaluate the initiation of anti-TNF therapy in a clinical setting where prescription is regulated by the authority's imposed reimbursement criteria.

METHODS

Between February 2004 and February 2005, all Belgian rheumatologists in academic and non-academic outpatient settings were invited to register all AS patients who visited their practice. A random sample of these patients was further examined by an in-depth clinical profile. In a follow-up investigation, we recorded whether patients initiated anti-TNF therapy and compared this to their eligibility at baseline evaluation.

RESULTS

89 rheumatologists participated and registered 2141 patients; 1023 patients were clinically evaluated. These 847 fulfilled the New York modified criteria for definite AS and 176 for probable AS. The profile of AS in rheumatology practice is characterised by longstanding and active disease with a high frequency of extra-articular manifestations and metrological and functional impairment. At a median of 2 months after the clinical evaluation, anti-TNF therapy was initiated in 263 of 603 (44%) evaluable patients with definite AS and in 22 of 138 (16%) evaluable patients with probable AS (total 38%). More than 85% of the patients who started anti-TNF therapy had an increased Bath Ankylosing Spondylitis Disease Activity Index despite previous NSAID (non-steroidal anti-inflammatory drug) use.

CONCLUSIONS

Of a representative cohort of 1023 Belgian AS patients seen in daily rheumatology practice, about 40% commenced anti-TNF therapy. Decision factors to start anti-TNF therapy may include disease activity and severity.

Four-year follow-up of infliximab therapy in rheumatoid arthritis patients with long-standing refractory disease: attrition and long-term evolution of disease activity

Although there is strong evidence supporting the short-term efficacy and safety of anti-tumour necrosis factor-alpha agents, few studies have examined the long-term effects. We evaluated 511 patients with long-standing refractory rheumatoid arthritis treated with intravenous infusions of infliximab 3 mg/kg at weeks 0, 2, 6, and 14 and every 8 weeks thereafter for 4 years. Among the initial 511 patients included in the study, 479 could be evaluated; of these, 295 (61.6%) were still receiving infliximab treatment at year 4 of follow-up. The most common reasons for treatment discontinuation were lack of efficacy (65 patients, 13.6%), safety (81 patients, 16.9%), and elective change (38 patients, 7.9%). Analysis of disease activity scores (DAS28 [disease activity score based on the 28-joint count]) over time showed that, after the initial rapid improvement during the first 6 to 22 weeks of therapy, a further decrease in disease activity of 0.2 units in the DAS28 score per year was observed. DAS28 scores, measured at week 14 or 22, were found to predict subsequent discontinuation due to lack of efficacy. In conclusion, long-term maintenance therapy with infliximab 3 mg/kg is effective in producing further reductions in disease activity. Disease activity measured by the DAS28 at week 14 or 22 of infliximab therapy was the best predictor of long-term attrition.

Prediction models for rheumatoid arthritis during diagnostic investigation: evaluation of combinations of rheumatoid factor, anti-citrullinated protein/peptide antibodies and the human leucocyte antigen-shared epitope

OBJECTIVES

To calculate the probabilities for rheumatoid arthritis in a consecutive cohort of patients during diagnostic investigation. Different logistic regression models evaluating the value of human leucocyte antigen (HLA)-shared epitope determination and testing for rheumatoid factor and anti-citrullinated protein/peptide antibodies (ACPA) were fitted.

METHODS

1003 consecutive patients were included in the study, presenting a new diagnostic problem for which rheumatoid arthritis was included in the differential diagnosis. All patients were tested for ACPA, rheumatoid factor and HLA-shared epitope.

RESULTS

After 1 year, diagnoses were established: 153 patients had definite rheumatoid arthritis and 629 patients had rheumatoid arthritis excluded. Rheumatoid factor, used as a continuous marker, is useful in evaluating the probability for rheumatoid arthritis. Combined rheumatoid factor and shared epitope testing may provide additional predictive information, but combined ACPA and rheumatoid factor testing is superior. The redundancy of shared epitope testing in a model that includes ACPA testing can be explained by the high association between ACPA and shared epitope both in patients with rheumatoid arthritis and in those with non-rheumatoid arthritis. The value of rheumatoid factor testing increased if patients presented with at least one swollen joint at baseline.

CONCLUSION

Valid probabilities for rheumatoid arthritis during routine diagnostic investigation were calculated, and showed that the potential additional value of shared epitope testing disappears when ACPA testing is available. Combined rheumatoid factor and ACPA testing is useful, especially when rheumatoid factor is considered as a continuous parameter reflecting an increasing probability for rheumatoid arthritis at higher rheumatoid factor titres. The value of (continuous) rheumatoid factor testing increases when the a priori chance is higher.

Altered gut transcriptome in spondyloarthropathy

BACKGROUND

Intestinal inflammation is a common feature of spondyloarthropathy (SpA) and Crohn's disease. Inflammation is manifested clinically in Crohn's disease and subclinically in SpA. However, a fraction of patients with SpA develops overt Crohn's disease.

AIMS

To investigate whether subclinical gut lesions in patients with SpA are associated with transcriptome changes comparable to those seen in Crohn's disease and to examine global gene expression in non-inflamed colon biopsy specimens and screen patients for differentially expressed genes.

METHODS

Macroarray analysis was used as an initial genomewide screen for selecting a comprehensive set of genes relevant to Crohn's disease and SpA. This led to the identification of 2625 expressed sequence tags that are differentially expressed in the colon of patients with Crohn's disease or SpA. These clones, with appropriate controls (6779 in total), were used to construct a glass-based microarray, which was then used to analyse colon biopsy specimens from 15 patients with SpA, 11 patients with Crohn's disease and 10 controls.

RESULTS

95 genes were identified as differentially expressed in patients with SpA having a history of subclinical chronic gut inflammation and also in patients with Crohn's disease. Principal component analysis of this filtered set of genes successfully distinguished colon biopsy specimens from the three groups studied. Patients with SpA having subclinical chronic gut inflammation cluster together and are more related to those with Crohn's disease.

CONCLUSION

The transcriptome in the intestine of patients with SpA differs from that of controls. Moreover, these gene changes are comparable to those seen in patients with Crohn's disease, confirming initial clinical observations. On the basis of these findings, new (genetic) markers for detection of early Crohn's disease in patients with SpA can be considered.

DAS28 best reflects the physician's clinical judgment of response to infliximab therapy in rheumatoid arthritis patients: validation of the DAS28 score in patients under infliximab treatment

This study is based on an expanded access program in which 511 patients suffering from active refractory rheumatoid arthritis (RA) were treated with intravenous infusions of infliximab (3 mg/kg+methotrexate (MTX)) at weeks 0, 2, 6 and every 8 weeks thereafter. At week 22, 474 patients were still in follow-up, of whom 102 (21.5%), who were not optimally responding to treatment, received a dose increase from week 30 onward. We aimed to build a model to discriminate the decision to give a dose increase. This decision was based on the treating rheumatologist's clinical judgment and therefore can be considered as a clinical measure of insufficient response. Different single and composite measures at weeks 0, 6, 14 and 22, and their differences over time were taken into account for the model building. Ranking of the continuous variables based on areas under the curve of receiver-operating characteristic (ROC) curve analysis, displayed the momentary DAS28 (Disease Activity Score including a 28-joint count) as the most important discriminating variable. Subsequently, we proved that the response scores and the changes over time were less important than the momentary evaluations to discriminate the physician's decision. The final model we thus obtained was a model with only slightly better discriminative characteristics than the DAS28. Finally, we fitted a discriminant function using the single variables of the DAS28. This displayed similar scores and coefficients as the DAS28. In conclusion, we evaluated different variables and models to discriminate the treating rheumatologist's decision to increase the dose of infliximab (+MTX), which indicates an insufficient response to infliximab at 3 mg/kg in patients with RA. We proved that the momentary DAS28 score correlates best with this decision and demonstrated the robustness of the score and the coefficients of the DAS28 in a cohort of RA patients under infliximab therapy.