Anti-Carbamylated Fibrinogen Antibodies Might Be Associated With a Specific Rheumatoid Phenotype and Include a Subset Recognizing In Vivo Epitopes of Its γ Chain One of Which Is Not Cross Reactive With Anti-Citrullinated Protein Antibodies

To identify the targets recognized by anti-carbamylated protein antibodies (anti-CarP) in patients with early Rheumatoid Arthritis (RA), to study the cross-reactivity between anti-CarP and anti-citrullinated protein antibodies (ACPA) and to evaluate their prognostic value. 331 patients (184 RA and 147 other rheumatisms) from the Very Early Arthritis (VErA) French cohort were analyzed. We performed mass spectrometry analysis of RA sera displaying anti-CarP activity and epitope mapping of the carbamylated fibrinogen γ chain to identify immunodominant peptides. The specificity of these targets was studied using competition assays with the major antigens recognized by ACPA. The prognostic value of anti-carbamylated fibrinogen IgG antibodies (ACa-Fib IgG) was compared to that of anti-cyclic citrullinated peptide antibodies (anti-CCP) and anti-CarP using an in-house ELISA. Besides the α chain, the γ chain of fibrinogen, particularly one immunodominant epitope that has a specific reactivity, was identified as a circulating carbamylated target in sera. The prevalence of ACa-Fib was 37% at baseline and 10.9% for anti-CCP-negative RA. In anti-CCP-negative patients, ACa-Fib positivity was associated with a more inflammatory and erosive disease at baseline but not with rapid radiological progression, which remains strongly related to anti-CCP antibodies. Fibrinogen seems to be one of the antigens recognized in vivo by the anti-CarP response, particularly 2 epitopes of the γ chain, one of which is not cross reactive with ACPA. This specificity might be associated with a distinct clinical phenotype since ACa-Fib IgG were shown to be linked to systemic inflammation in very early RA but not to rapid radiological progression.

The rs7574865 polymorphism of the STAT4 gene and risk of early rheumatoid arthritis development (the REMARKA study)

The aim of the study was investigation of association of the rs7574865 polymorphism of STAT4 gene (Signal Transducer and Activator of Transcription 4, a family of signal transduction and transcription activation molecules 4) with very early rheumatoid arthritis (RA) in Russian patients, and the study of the relationship of "phenotype – genotype", particularly of positivity for antibodies to cyclic citrullinated peptides (ACCP), their concentration, the presence of erosive joint damage at inclusion in patients the study with the STAT4 gene polymorphism. Material and methods. The study was conducted in the framework of the program REMARKA (Russian study of Methotrexate and biological drugs in Early active Arthritis). 85 patients with very early RA with a duration of symptoms no more than 6 months, not receiving disease modifying anti-rheumatic drugs (DMARD) and biologicals were included. Results and discussion. The analysis of the distribution of genotypes and alleles of STAT4 rs7574865 polymorphism showed that the frequencies of g/G, G/T and T/T genotypes differ at the level of the prominent tendency to statistical significance between patients with RA and the control group (p=0.05). The frequency of minor allele T in RA is significantly higher than that in the control group, and this allele is associated with a predisposition to RA [odds ratio (OR) 1.7; 95% confidence interval (CI) 1.1–2.8; p=0.03]. In the study of the "genotype – phenotype" relationship, STAT4 gene polymorphism correlated with erosive joint damage (r2=0.289; p=0.008). In carriers of the homozygous genotype TT, the number of erosions at inclusion in the study was significantly higher compared with carriers of genotypes GG/GT (median 5.50 [0.754; 7.5] and 0.00 [0.00; 2.00], respectively; p=0.003). The risk of erosion is also associated with the polymorphism of the STAT4 gene (OR 8.6; 95% CI 1.0–204.9; p=0.03). A difference of the ACCP level depending on STAT4 gene polymorphism was revealed: carriers of at least one minor allele T (G/T+T/T) had significantly higher concentration of ACCP than that in carriers of homozygous GG genotype: 248.97±151.00 and 179.51±147.01 U/ml, respectively; p=0.048).Conclusion. The study showed that in Russian patients with very early RA, the STAT4 gene rs7574865 polymorphism is associated with both predisposition to the disease and prognostically unfavorable manifestations (phenotypes) of the disease, namely, with the development of erosion in the early stages of the disease and an increase of the ACCP level.

Identification of a transitional fibroblast function in very early rheumatoid arthritis

ObjectivesSynovial fibroblasts actively regulate the inflammatory infiltrate by communicating with neighbouring endothelial cells (EC). Surprisingly, little is known about how the development of rheumatoid arthritis (RA) alters these immunomodulatory properties. We examined the effects of phase of RA and disease outcome (resolving vs persistence) on fibroblast crosstalk with EC and regulation of lymphocyte recruitment.MethodsFibroblasts were isolated from patients without synovitis, with resolving arthritis, very early RA (VeRA; symptom ≤12 weeks) and established RA undergoing joint replacement (JRep) surgery. Endothelial-fibroblast cocultures were formed on opposite sides of porous filters. Lymphocyte adhesion from flow, secretion of soluble mediators and interleukin 6 (IL-6) signalling were assessed.ResultsFibroblasts from non-inflamed and resolving arthritis were immunosuppressive, inhibiting lymphocyte recruitment to cytokine-treated endothelium. This effect was lost very early in the development of RA, such that fibroblasts no longer suppressed recruitment. Changes in IL-6 and transforming growth factor beta 1 (TGF-β1) signalling appeared critical for the loss of the immunosuppressive phenotype. In the absence of exogenous cytokines, JRep, but not VeRA, fibroblasts activated endothelium to support lymphocyte.ConclusionsIn RA, fibroblasts undergo two distinct changes in function: first a loss of immunosuppressive responses early in disease development, followed by the later acquisition of a stimulatory phenotype. Fibroblasts exhibit a transitional functional phenotype during the first 3 months of symptoms that contributes to the accumulation of persistent infiltrates. Finally, the role of IL-6 and TGF-β1 changes from immunosuppressive in resolving arthritis to stimulatory very early in the development of RA. Early interventions targeting ‘pathogenic’ fibroblasts may be required in order to restore protective regulatory processes.

Expression of chemokines CXCL4 and CXCL7 by synovial macrophages defines an early stage of rheumatoid arthritis

Background and objectivesFor our understanding of the pathogenesis of rheumatoid arthritis (RA), it is important to elucidate the mechanisms underlying early stages of synovitis. Here, synovial cytokine production was investigated in patients with very early arthritis.MethodsSynovial biopsies were obtained from patients with at least one clinically swollen joint within 12 weeks of symptom onset. At an 18-month follow-up visit, patients who went on to develop RA, or whose arthritis spontaneously resolved, were identified. Biopsies were also obtained from patients with RA with longer symptom duration (>12 weeks) and individuals with no clinically apparent inflammation. Synovial mRNA expression of 117 cytokines was quantified using PCR techniques and analysed using standard and novel methods of data analysis. Synovial tissue sections were stained for CXCL4, CXCL7, CD41, CD68 and von Willebrand factor.ResultsA machine learning approach identified expression of mRNA for CXCL4 and CXCL7 as potentially important in the classification of early RA versus resolving arthritis. mRNA levels for these chemokines were significantly elevated in patients with early RA compared with uninflamed controls. Significantly increased CXCL4 and CXCL7 protein expression was observed in patients with early RA compared with those with resolving arthritis or longer established disease. CXCL4 and CXCL7 co-localised with blood vessels, platelets and CD68+macrophages. Extravascular CXCL7 expression was significantly higher in patients with very early RA compared with longer duration RA or resolving arthritisConclusionsTaken together, these observations suggest a transient increase in synovial CXCL4 and CXCL7 levels in early RA.

The Need to Better Classify and Diagnose Early and Very Early Rheumatoid Arthritis

Early rheumatoid arthritis (RA) and very early RA are major targets of research and clinical practice. Remission has become a realistic goal in the management of RA, particularly in early disease. The 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) RA classification criteria, the EULAR treatment recommendations for RA, and the EULAR recommendations for the management of early arthritis focus on early disease and translate the knowledge related to early RA into classification and management. Nevertheless, there is a need for further improvement and progress. Results from 6 recent studies are summarized, evaluating the performance of the 2010 ACR/EULAR RA classification criteria. The data show a significant risk of misclassification, and highlight that overdiagnosis and underdiagnosis may become important issues if the criteria recommend synthetic and biological disease-modifying antirheumatic drugs. Therefore, some considerations are presented on how the current problems and limitations could be overcome in clinical practice and future research. A consensus is needed to better define the early phase of RA and differentiate from other early arthritis. The possible effect of misclassification on spontaneous and drug-induced remission of early and very early RA awaits further elucidation. Such research will eventually lead to more reliable diagnostic and classification criteria for new-onset RA.

Impact of T-cell costimulation modulation in patients with undifferentiated inflammatory arthritis or very early rheumatoid arthritis: a clinical and imaging study of abatacept (the ADJUST trial)

BackgroundSeveral agents provide treatment for established rheumatoid arthritis (RA), but a crucial therapeutic goal is to delay/prevent progression of undifferentiated arthritis (UA) or very early RA.ObjectiveTo determine the impact of T-cell costimulation modulation in patients with UA or very early RA.MethodsIn this double-blind, phase II, placebocontrolled, 2-year study, anti-cyclic citrullinated peptide (CCP)2-positive patients with UA (not fulfilling the ACR criteria for RA) and clinical synovitis of two or more joints were randomised to abatacept (∼10 mg/kg) or placebo for 6 months; the study drug was then terminated. The primary end point was development of RA (by ACR criteria) at year 1. Patients were monitored by radiography, MRI, CCP2, rheumatoid factor and 28 joint count Disease Activity Score (DAS28) over 2 years.ResultsAt year 1, 12/26 (46%) abatacept-treated versus 16/24 (67%) placebo-treated patients developed RA (difference (95% CI) −20.5% (−47.4% to 7.8%)). Adjusted mean changes from baseline to year 1 in Genant-modified Sharp radiographic scores for abatacepttreated versus placebo-treated patients, respectively, were 0 versus 1.1 for total score, and 0 versus 0.9 for erosion score. Mean changes from baseline to year 1 in MRI erosion, osteitis and synovitis scores were 0, 0.2 and 0.2, respectively, versus 5.0, 6.7 and 2.3 in the abatacept versus placebo groups. Safety was comparable between groups; serious adverse events occurred in one patient (3.6%) in each group.ConclusionAbatacept delayed progression of UA/very early RA in some patients. An impact on radiographic and MRI inhibition was seen, which was maintained for 6 months after treatment stopped. This suggests that it is possible to alter the progression of RA by modulating T-cell responses at a very early stage of disease.Trial registration numberNCT00124449.