Is early rheumatoid arthritis the same disease process as late rheumatoid arthritis?

Inverse-Vaccines for Rheumatoid Arthritis Re-establish Metabolic and Immunological Homeostasis in Joint Tissues

Rheumatoid arthritis (RA) causes immunological and metabolic imbalances in tissue, exacerbating inflammation in affected joints. Changes in immunological and metabolic tissue homeostasis at different stages of RA are not well understood. Herein, the changes in the immunological and metabolic profiles in different stages in collagen induced arthritis (CIA), namely, early, intermediate, and late stage is examined. Moreover, the efficacy of the inverse-vaccine, paKG(PFK15+bc2) microparticle, to restore tissue homeostasis at different stages is also investigated. Immunological analyses of inverse-vaccine-treated group revealed a significant decrease in the activation of pro-inflammatory immune cells and remarkable increase in regulatory T-cell populations in the intermediate and late stages compared to no treatment. Also, glycolysis in the spleen is normalized in the late stages of CIA in inverse-vaccine-treated mice, which is similar to no-disease tissues. Metabolomics analyses revealed that metabolites UDP-glucuronic acid and L-Glutathione oxidized are significantly altered between treatment groups, and thus might provide new druggable targets for RA treatment. Flux metabolic modeling identified amino acid and carnitine pathways as the central pathways affected in arthritic tissue with CIA progression. Overall, this study shows that the inverse-vaccines initiate early re-establishment of homeostasis, which persists through the disease span.

Anti-GM-CSF otilimab versus sarilumab or placebo in patients with rheumatoid arthritis and inadequate response to targeted therapies: a phase III randomised trial (contRAst 3)

OBJECTIVES

To investigate the efficacy and safety of otilimab, an anti-granulocyte-macrophage colony-stimulating factor antibody, in patients with active rheumatoid arthritis and an inadequate response to conventional synthetic (cs) and biologic disease-modifying antirheumatic drugs (DMARDs) and/or Janus kinase inhibitors.

METHODS

ContRAst 3 was a 24-week, phase III, multicentre, randomised controlled trial. Patients received subcutaneous otilimab (90/150 mg once weekly), subcutaneous sarilumab (200 mg every 2 weeks) or placebo for 12 weeks, in addition to csDMARDs. Patients receiving placebo were switched to active interventions at week 12 and treatment continued to week 24. The primary end point was the proportion of patients achieving an American College of Rheumatology ≥20% response (ACR20) at week 12.

RESULTS

Overall, 549 patients received treatment. At week 12, there was no significant difference in the proportion of ACR20 responders with otilimab 90 mg and 150 mg versus placebo (45% (p=0.2868) and 51% (p=0.0596) vs 38%, respectively). There were no significant differences in Clinical Disease Activity Index, Health Assessment Questionnaire-Disability Index, pain Visual Analogue Scale or Functional Assessment of Chronic Illness Therapy-Fatigue scores with otilimab versus placebo at week 12. Sarilumab demonstrated superiority to otilimab in ACR20 response and secondary end points. The incidence of adverse or serious adverse events was similar across treatment groups.

CONCLUSIONS

Otilimab demonstrated an acceptable safety profile but failed to achieve the primary end point of ACR20 and improve secondary end points versus placebo or demonstrate non-inferiority to sarilumab in this patient population.

TRIAL REGISTRATION NUMBER

NCT04134728.

Peripheral and central nervous system alterations in a rat model of inflammatory arthritis

It is consistently reported that in inflammatory arthritis (IA), pain may continue despite well-controlled inflammation, most likely due to interactions between joint pathology and pain pathway alterations. Nervous system alterations have been described, but much remains to be understood about neuronal and central non-neuronal changes in IA. Using a rat model of IA induced by intra-articular complete Freund's adjuvant injection, this study includes a thorough characterization of joint pathology and objectives to identify peripheral innervation changes and alterations in the spinal dorsal horn (DH) that could alter DH excitatory balancing. Male and female rats displayed long-lasting pain-related behavior, but, in agreement with our previous studies, other pathological alterations emerged only at later times. Cartilage vascularization, thinning, and decreased proteoglycan content were not detectable in the ipsilateral cartilage until 4 weeks after complete Freund's adjuvant. Sympathetic and peptidergic nociceptive fibers invaded the ipsilateral cartilage alongside blood vessels, complex innervation changes were observed in the surrounding skin, and ipsilateral nerve growth factor protein expression was increased. In the DH, we examined innervation by peptidergic and nonpeptidergic nociceptors, inhibitory terminal density, the KCl cotransporter KCC2, microgliosis, and astrocytosis. Here, we detected the presence of microgliosis and, interestingly, an apparent loss of inhibitory terminals and decreased expression of KCC2. In conclusion, we found evidence of anatomical, inflammatory, and neuronal alterations in the peripheral and central nervous systems in a model of IA. Together, these suggest that there may be a shift in the balance between incoming and outgoing excitation, and modulatory inhibitory tone in the DH.

The Utilization of Autoantibodies in Approaches to Precision Health

Precision health (PH) applied to autoimmune disease will need paradigm shifts in the use and application of autoantibodies and other biomarkers. For example, autoantibodies combined with other multi-analyte “omic” profiles will form the basis of disease prediction allowing for earlier intervention linked to disease prevention strategies, as well as earlier, effective and personalized interventions for established disease. As medical intervention moves to disease prediction and a model of “intent to PREVENT,” diagnostics will include an early symptom/risk-based, as opposed to a disease-based approach. Newer diagnostic platforms that utilize emerging megatrends such as deep learning and artificial intelligence and close the gaps in autoantibody diagnostics will benefit from paradigm shifts thereby facilitating the PH agenda.

High-Resolution US of Rheumatologic Diseases

For the past 15 years, high-resolution ultrasonography (US) is being routinely and increasingly used for initial evaluation and treatment follow-up of rheumatologic diseases. This imaging technique is performed by using high-frequency linear transducers and has proved to be a powerful diagnostic tool in evaluation of articular erosions, simple and complex joint and bursal effusions, tendon sheath effusions, and synovitis, with results comparable to those of magnetic resonance imaging, excluding detection of bone marrow edema. Crystal deposition diseases including gouty arthropathy and calcium pyrophosphate deposition disease (CPPD) have characteristic appearances at US, enabling differentiation between these two diseases and from inflammatory arthropathies. Enthesopathy, which frequently accompanies psoriatic and reactive arthritis, also has a characteristic appearance at high-resolution US, distinguishing these two entities from other inflammatory and metabolic arthropathies. The presence of Doppler signal in examined joints, bursae, and tendon sheaths indicates active synovitis. Microbubble echo contrast agents augment detection of tissue vascularity and may act in the future as a drug delivery vehicle. Frequently, joint, tendon sheath, and bursal fluid aspirations and therapeutic injections are performed under US guidance. The authors describe the high-resolution US technique including gray-scale, color or power Doppler, and contrast agent-enhanced US that is used in evaluation of rheumatologic diseases of the wrist and hand and the ankle and foot in their routine clinical practice. This article demonstrates imaging findings of normal joints, rheumatoid arthritis, gouty arthritis, CPPD, psoriatic and reactive arthritis, and osteoarthritis.

Towards prevention of autoantibody-positive rheumatoid arthritis: from lifestyle modification to preventive treatment

Recent advances in research into the earliest phases of RA have provided additional insights into the processes leading from the healthy to the diseased state. These insights have opened the way for the development of preventive strategies for RA, which represents a significant paradigm shift from treatment to prevention and will have major implications for patients as well as society. It would be a huge step forward if clinical signs and symptoms, disability, impaired quality of life and the need for chronic immunosuppressive treatment could be prevented. RA can be seen as a prototypic autoimmune disease, and discoveries about the preclinical diseased state for RA could potentially facilitate research into prevention of other immune-mediated inflammatory diseases such as type 1 diabetes, SLE and multiple sclerosis. This review focuses on the current knowledge of factors contributing to the development of RA and discusses the opportunities for intervention.

Early start and stop of biologics: has the time come?

Despite considerable advances in the management of rheumatoid arthritis, results are still not satisfactory for all patients. The treatment goal in rheumatoid arthritis is remission, and there currently are numerous conventional and biological medications available to reach this aim. There are also different treatment strategies but with only limited comparative evidence about their efficacies. More patients now achieve remission while on treatment, but it remains elusive in the majority of patients. Treatment-free remission, the ultimate goal of therapy, is only achieved in very few patients; even when this happens, it is most likely due to the natural course of the disease rather than to any specific therapies. Modern treatment is based on the initiation of aggressive therapy as soon as the diagnosis is established, and on modifying or intensifying therapy guided by frequent assessment of disease activity. In this commentary we will discuss the current treatment paradigm as well as the possibility of an induction-maintenance regimen with biological disease-modifying antirheumatic drugs in early rheumatoid arthritis.

Upregulation of tumor necrosis factor receptor-associated factor 6 correlated with synovitis severity in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory disease leading to joint destruction and disability. Focal bone erosion is due to excess bone resorption of osteoclasts. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is one of the critical mediators both in inflammatory signal pathway and differentiation and resorption activity of osteoclasts. Here we aimed to investigate TRAF6 expression in RA synovium and its correlation with histological synovitis severity and radiological joint destruction in RA.

METHODS

Synovitis score was determined in needle biopsied synovium from 44 patients with active RA. Synovium from nine patients with osteoarthritis (OA) and seven with orthopedic arthropathies (Orth.A) were enrolled as "less inflamed" disease controls. Serial sections were stained immunohistochemically for TRAF6 as well as CD68 (macrophage), CD3 (T cell), CD20 (B cell), CD38 (plasmocyte), CD79a (B lineage cells from pre-B cell to plasmocyte stage), and CD34 (endothelial cell). Double immunofluorescence staining of TRAF6 and CD68 were tested. Densities of positive staining cells were determined and correlated with histological disease activity (synovitis score) and radiographic joint destruction (Sharp score).

RESULTS

TRAF6 expression was found in the intimal and subintimal area of RA synovium, with intense staining found in the endochylema and nucleus of intimal synoviocytes and subintimal inflammatory cells. Double immunofluorescence staining showed TRAF6 was expressed in most of the intimal cells and obviously expressed in CD68+ cells and some other CD68- cells in subintimal area. Synovial TRAF6 was significantly over-expressed in the RA group compared with the OA and Orth.A group (2.53 ± 0.94 vs. 0.72 ± 0.44 and 0.71 ± 0.49, P < 0.0001). Synovial TRAF6 expression in RA correlated significantly with synovitis score (r = 0.412, P = 0.006), as well as the inflammatory cell infiltration (r = 0.367, P = 0.014). Significant correlation was detected between synovial TRAF6 expression and intimal CD68+ cells, as well as the cell density of subintimal CD68+ cells, CD3+ cells, CD20+ cells, CD38+ cells, and CD79a+ cells (all P < 0.05).

CONCLUSIONS

Elevated synovial TRAF6 expression correlated with synovitis severity and CD68+ cell density in RA. It is, therefore, hypothesized that synovial TRAF6 is involved in the pathogenesis of synovial inflammation and osteoclast differentiation in RA.

Established rheumatoid arthritis: rationale for best practice: physicians' perspective of how to realise tight control in clinical practice

Developments in the understanding of the pathogenesis of rheumatoid arthritis (RA) and the introduction of targeted biologic therapies have greatly advanced the management of RA in clinical practice. The management of RA is now aimed at achieving remission, to prevent joint damage and disability. In particular, a critical period early in disease is recognised, in which early aggressive treatment with disease-modifying therapy is advocated. Although a state of remission is the ideal, this chapter discusses the difficulties which may arise in achieving this goal in patients with established disease. The evidence for best management, aimed at achieving clinical remission in established disease, is reviewed. The consequences of incomplete control of chronic inflammation in established disease, including pain, disability and co-morbidities (such as cardiovascular disease and osteoporosis), also pose a significant clinical challenge. The rationale for a multidisciplinary team approach in reducing the associated morbidity and mortality of the disease are examined.

Early diagnosis of arthritis in mice with collagen-induced arthritis, using a fluorogenic matrix metalloproteinase 3-specific polymeric probe

OBJECTIVE

Early treatment based on an early diagnosis of rheumatoid arthritis (RA) could halt progression of the disease, but early diagnosis is often difficult. Matrix metalloproteinase 3 (MMP-3) is thought to be particularly important in the pathogenesis of RA. The aim of this study was to investigate whether an MMP-3-specific polymeric probe could be used for early diagnosis and for visualizing the progression of arthritis, using a near-infrared fluorescence (NIRF) imaging system.

METHODS

The MMP-3-specific polymeric probe was developed by conjugating NIRF dye, MMP substrate peptide, and dark quencher to self-assembled chitosan nanoparticles. One hour after intravenous administration of the probe, fluorescent images of mice with collagen-induced arthritis at different stages of disease development were obtained. The correlation between the fluorescence recovered in in vivo imaging when using an MMP-3-specific polymeric probe and up-regulated MMP-3 activity in the joint tissues was evaluated by Western blotting and immunohistochemical staining. Histologic analysis and micro-computed tomography (micro-CT) were also used to assess arthritis progression.

RESULTS

A significantly higher NIRF signal was recovered from arthritic joints compared with normal joints at 14 days after the first immunization, before any erythema or swelling could be observed with the naked eye or any erosion was detected by histologic analysis or micro-CT. The results of immunohistochemical analysis and Western blotting confirmed that the fluorescence recovered in the in vivo imaging was related to up-regulated MMP-3 activity in the joint tissues.

CONCLUSION

An MMP-3-specific polymeric probe provided clear early diagnosis of arthritis and visualization of arthritis progression using an NIRF imaging system. This approach could be used for early diagnosis and for monitoring drug and surgical therapies in individual cases.

The synovium in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease targeting multiple joints. The synovium is the primary site of the inflammatory process, which if untreated leads to irreversible damage to the adjacent cartilage and bone. It is now well established that autoantibodies that are characteristic of RA, including rheumatoid factor (RF) and anti-citrulluninated protein antibodies (ACPA), are present before clinical disease onset. Studies in both humans and animal models are beginning to provide new insights into how this asymptomatic autoimmunity evolves into an inflammatory process that is localized in the synovium.Once RA synovitis established, a number of amplification mechanisms serve to sustain the process leading to the persistence of the disease. These mechanisms include engagement of the resident mesenchymal cells and the establishment of ectopic lymphoid structures in the synovium, although the relationship between these lymphoid structures and the presence of RA autoantibodies remains unclear.An enhanced understanding of the mechanisms that initiate and sustain RA synovitis offers unprecedented opportunities for therapeutics, and ultimately prevention strategies.

MR imaging of early rheumatoid arthritis

Early diagnosis and treatment have been recognized as essential for improving clinical outcomes in patients with early rheumatoid arthritis. However, diagnosis is somewhat difficult in the early stages of the disease because the diagnostic criteria were developed from data obtained in patients with established rheumatoid arthritis and therefore are not readily applicable. Magnetic resonance (MR) imaging is increasingly being used in the assessment of rheumatoid arthritis due to its capacity to help identify the key pathologic features of this disease entity at presentation. MR imaging has demonstrated greater sensitivity for the detection of synovitis and erosions than either clinical examination or conventional radiography and can help establish an early diagnosis of rheumatoid arthritis. It also allows the detection of bone marrow edema, which is thought to be a precursor for the development of erosions in early rheumatoid arthritis as well as a marker of active inflammation. In addition, MR imaging can help differentiate rheumatoid arthritis from some clinical subsets of peripheral spondyloarthropathies by allowing identification of inflammation at the insertions of ligaments and tendons (enthesitis).

Terminal monosaccharide screening of synovial immunoglobulins G and A for the early detection of rheumatoid arthritis

The expressions of some terminal glycotopes of synovial immunoglobulins G, A, and M were analysed in relation to rheumatoid arthritis (RA) progression defined according to early and advanced radiological changes in patients' hands. The relative amounts of terminal monosaccharides were determined by lectin-immunoblotting of immunoglobulin preparations using appropriate lectins able to recognize alpha2,6-linked (Sambucus nigra agglutinin) and alpha2,3-linked (Maackia amurensis agglutinin) sialic acid, galactose (Ricinus communis agglutinin I), N-acetylglucosamine (Griffonia simplicifolia agglutinin II) as well as alpha1,6-linked (Aleuria aurantia lectin), alpha1,3-linked (Lotus tetragonolobus agglutinin), and alpha1,2-linked (Ulex europaeus agglutinin) fucose. The results indicate differences between early and advanced RA stages in the terminal sugar exposition of synovial IgG and IgA, but not IgM. The galactose-deficient glycotope with exposed N-acetylglucosamine of the synovial 33.1-kDa IgG fragment appeared exclusively in the early stage of RA. In contrast, this glycotope of intact synovial IgG and IgA was present in both groups, although with higher proportions in advanced RA. The proportions of the sialyl and fucosyl determinants of intact synovial A and G immunoglobulins were clearly lower in the early RA group than in the advanced. The analysis of terminal oligosaccharide exposition in IgG, IgG fragments, and IgA present in the synovial fluid of RA patients might be applicable as a stage-specific marker in the diagnosis and therapy of RA patients.

The role of chemokines in rheumatoid arthritis and osteoarthritis

The directed movement of immune cells is highly dependent on the chemokine network. Chemokines are key molecules early in the embryogenesis of lymph nodes and throughout adult life, where they regulate immune responses against pathogens. Although immune cells are best known for expressing chemokine receptors, through which they can respond to matching chemokines, endothelial cells also express chemokine receptors. The directed movement of endothelial cells facilitates angiogenesis. In chronic inflammatory conditions, such as rheumatoid arthritis (RA), chemokines are abundantly present at the site of inflammation and form a group of potential therapeutic targets. Some agents that block chemokine-chemokine receptor interaction are already under clinical investigation. The expression of chemokine receptors has also been found in cell types other than immune cells and endothelial cells. Chondrocytes, for instance, express several chemokine receptors. Elucidating their function may provide new insights into joint degradation in RA as well as in other conditions, including osteoarthritis (OA).

Overexpression of toll-like receptors 3 and 4 in synovial tissue from patients with early rheumatoid arthritis: toll-like receptor expression in early and longstanding arthritis

OBJECTIVE

To analyze the expression, regulation, and biologic relevance of Toll-like receptors (TLRs) 1-10 in synovial and skin fibroblasts and to determine the expression levels of TLRs 2, 3, and 4 in synovial tissues from patients with early rheumatoid arthritis (RA), longstanding RA, and osteoarthritis (OA).

METHODS

Expression of TLRs 1-10 in RA synovial fibroblasts (RASFs), OASFs, and skin fibroblasts was analyzed by real-time polymerase chain reaction (PCR). Fibroblasts were stimulated with tumor necrosis factor alpha, interleukin-1beta (IL-1beta), bacterial lipopeptide, poly(I-C), lipopolysaccharide, and flagellin. Production of IL-6 was determined by enzyme-linked immunosorbent assay and induction of TLRs 2-5, matrix metalloproteinases (MMPs) 3 and 13 messenger RNA by real-time PCR. Expression of TLRs 2-4 in synovial tissues was analyzed by immunohistochemistry.

RESULTS

Synovial fibroblasts expressed TLRs 1-6, but not TLRs 7-10. Among the expressed TLRs, TLR-3 and TLR-4 were the most abundant in synovial fibroblasts, and stimulation of synovial fibroblasts with the TLR-3 ligand poly(I-C) led to the most pronounced increase in IL-6, MMP-3, and MMP-13. In contrast, skin fibroblasts did not up-regulate MMP-3 or MMP-13 after stimulation with any of the tested stimuli. In synovial tissues from patients with early RA, TLR-3 and TLR-4 were highly expressed and were comparable to the levels of patients with longstanding RA. These expression levels were elevated as compared with those in OA.

CONCLUSION

Our findings of high expression of TLRs, particularly TLRs 3 and 4, at an early stage of RA and the reactivity of synovial fibroblasts in vitro to TLR ligands suggest that TLR signaling pathways resulting in persistent inflammation and joint destruction are activated early in the disease process.

Relative sialylation and fucosylation of synovial and plasma fibronectins in relation to the progression and activity of rheumatoid arthritis

The expressions of terminal sugars in synovial and plasma fibronectins were studied in relation to rheumatoid arthritis (RA) progression defined according to the early, established and late radiological changes in the patients' hands. The relative amounts of sialic acid and fucose were analyzed by lectin-ELISA using appropriate sialic acid-linked alpha2-3 (Maackia amurensis) and alpha2-6 (Sambucus nigra) lectins as well as fucose-linked alpha1-6 (Aleuria aurantia), alpha1-2 (Ulex europaeus), and alpha1-3 (Tetragonolobus purpureus). In the early RA group, the synovial fibronectin reactivities were the lowest with the all lectins used. In the established and late groups, relative sialylation and fucosylation significantly increased. However, sialylation negligibly decreased, whereas fucosylation remained at nearly the same level in the late group. Moreover, the expression of alpha1-6-linked fucose was found to be related to disease activity. In contrast, plasma fibronectin reactivity with lectins showed different dynamic alterations. In the early RA group, the reactivity of fibronectin with the lectins used was similar to that of healthy individuals, whereas it increased significantly in the established RA group compared with the early and normal plasma groups. In the late RA group it decreased to a level similar to that of the normal group. The lower expressions of terminal sugars in synovial fibronectin were mainly associated with the early degenerative processes of RA. In conclusion, such alterations may be applicable as a stage-specific marker for diagnosis and therapy of RA patients. The higher expression of terminal sugars in fibronectin could be associated with repair and adaptation processes in longstanding disease.

Preclinical models of arthritic disease in non-human primates

The costs for the development of new drugs have increased dramatically over the past 30 years. One of the main reasons for this increase is the low success rate of new drugs being approved for patient use, which is, in part, a consequence of the common use of rodent models for preclinical validation of efficacy. Especially in the development of biologicals, which are now successfully used in the treatment of rheumatoid arthritis, the selection of the right animal model is pivotal. Non-human primates could help to bridge the evolutionary gap between rodent models and human patients.

Chemokine inhibition in inflammatory arthritis

Synovial inflammation in rheumatoid arthritis (RA) and other arthritides is, in part, dependent on migration of inflammatory cells as well as retention of these cells at the site of inflammation. Chemokines play a critical role in these processes and represent an attractive target for therapeutic intervention. Animal models of RA have shown that it is possible to induce clinical improvement by specifically targeting chemokines or their receptors. Although at present only very limited data exist, initial data suggest that it may be possible to reduce synovial inflammation in patients with RA by specific chemokine blockade. Innovative trial design may help to screen for potentially interesting chemokine antagonists in an early stage of development.

Expression of CXCR-1 and CXCR-2 chemokine receptors on synovial neutrophils in inflammatory arthritides: Does persistent or increasing expression of CXCR-2 contribute to the chronic inflammation or erosive changes?

OBJECTIVE

To analyze the CXCR-1 and CXCR-2 chemokine receptor expression on peripheral blood neutrophils (PBN) and synovial fluid neutrophils (SFN) of patients with rheumatoid arthritis (RA) and Behçet's disease (BD) (characterized by erosive and non-erosive arthritis, respectively), and to compare them with those of patients with osteoarthritis (OA).

METHODS

We used flow cytometry to investigate the expression of CXCR-1 and CXCR-2 chemokine receptors on PBN and SFN of fifty-five (22 RA, 22 BD and 11 OA) age and sex-matched patients.

RESULTS

In respect to chemokine receptor expression on neutrophils isolated from patients with RA, mean fluorescein intensity (MFI) of CXCR-1 chemokine receptors on PBN from active and inactive RA patients, and SFN from patients with RA were 151 (90-395), 129 (81-539) and 136 (64-220), respectively, and there were not statistically significant difference each other. But MFI of CXCR-2 chemokine receptors on SFN of patients with RA was 18 (10-32), and significantly higher than PBN of active and inactive RA patients (MFI: 10 (6-15) and 12 (7-16), P=0.002 and 0.037, respectively). In respect to chemokine receptor expression on neutrophils isolated from patients with BD, MFI of CXCR-1 chemokine receptors on PBN of active BD patients was 245 (97-844), and higher than PBN of active RA patients and SFN of BD patients (MFI: 151 (90-395) and 134 (61-231), P=0.047 and 0.017, respectively). MFI of CXCR-2 chemokine receptors on PBN of active and inactive BD patients, and SFN of patients BD were 10 (6-14), 10 (2-16), and 12 (8-24), respectively, there were not statistically significant difference each other. MFI of CXCR-1 chemokine receptors on SFN from patients with RA, BD, and OA were 136 (64-220), 134 (61-231), and 114 (60-180), respectively, and there was no difference between the study groups. MFI of CXCR-2 chemokine receptors on SFN of patients with RA was 18 (10-32), and higher than patients with BD and OA (MFI: 12 (8-24) and 11 (9-18), P=0.037 and 0.005, respectively), though there was no difference between last two groups.

CONCLUSION

Our study points that CXCR-1 and CXCR-2 chemokine receptors of SFN may have diverse functions in the course of inflammatory arthritides. These results indicate that CXCR-2 chemokine receptor might play more critical role in long lasting accumulation of neutrophils within the synovial fluid of patients with RA.

Chemokines: their role in rheumatoid arthritis

Chemokines are small proteins that can act on cells that express matching receptors. They are best known for their role in migration of cells, especially immune cells. Chemokine/chemokine-receptor pairs are often functionally categorized into three groups: inflammatory, homeostatic, and angiogenic/angiostatic, although functions sometimes overlap. Interfering with the interaction between chemokines and their receptors is currently under investigation as a therapeutic strategy in rheumatoid arthritis.

Pathogenesis of rheumatoid arthritis: how early is early?

Studies of cytokine expression in rheumatoid arthritis have provided key insights into the pathogenesis of disease and have offered clues for effective therapy. Patterns of T-cell products in chronic rheumatoid synovitis suggest that T helper type 1 cells contribute to the perpetuation of disease. However, there is no guarantee that the mechanisms of late disease are identical to very early rheumatoid arthritis. Evaluation of the cytokine profile at the earliest time points after onset of symptoms could identify novel targets that prevent progression to chronic arthritis.

Wnt signalling in rheumatoid arthritis

Rheumatoid arthritis (RA) is a symmetrical polyarticular disease of unknown aetiology that affects primarily the diarthrodial joints. Characteristic features of RA pathogenesis are synovial hyperplasia and inflammation accompanied by cartilage loss and joint destruction. Synovial hyperplasia and inflammation are a consequence of an increase in the macrophage-like and fibroblast-like synoviocytes of the synovial intimal lining associated with infiltration of leucocytes into the subintimal space. Although therapeutic interventions are available, the disease persists despite therapy in a significant fraction of patients. Several lines of evidence have substantiated a crucial role of activated fibroblast-like synoviocytes (FLS) during RA pathogenesis. The hyperplastic FLS population potentially promotes leucocyte infiltration and retention. The rheumatoid synovium eventually transforms into a pannus that destroys articular cartilage and bone. There are no approved drugs that are known to target the FLS in RA, and the underlying mechanisms driving FLS activation remain unresolved. In this review, the importance of Wnt-frizzled (Fz)-mediated signalling in the autonomous activation of FLS is discussed. Anti-Wnt/anti-Fz antibodies, Fz receptor antagonists or small-molecule inhibitors of Wnt-Fz signalling might be useful for therapeutic interventions in refractory RA.

A gene expression signature for recent onset rheumatoid arthritis in peripheral blood mononuclear cells

BACKGROUND

In previous studies the presence of a distinct gene expression pattern has been shown in peripheral blood cells from patients with autoimmune disease.

OBJECTIVE

To determine whether other specific signatures might be used to identify subsets of these autoimmune diseases and whether gene expression patterns in early disease might identify pathogenetic factors.

METHODS

Peripheral blood mononuclear cells were acquired from patients with rheumatoid arthritis (RA) and analysed by microarrays containing over 4300 named human genes. Patients with RA for <2 years were compared with subjects with longstanding RA (average duration 10 years) and with patients with other immune or autoimmune diagnoses.

RESULTS

Cluster analyses permitted separation of the patients with early RA (ERA) from those with longstanding disease. Comparison with other patient groups suggested that the ERA signature showed some overlap with that seen in the normal immune response to viral antigen as well as with a subset of patients with systemic lupus erythematosus.

CONCLUSIONS

The ERA signature may reflect, in part, a response to an unknown infectious agent. Furthermore, shared features with some lupus patients suggest that common aetiological factors and pathogenetic pathways may be involved in these two autoimmune disorders.

Analysis of the cell infiltrate and expression of proinflammatory cytokines and matrix metalloproteinases in arthroscopic synovial biopsies: comparison with synovial samples from patients with end stage, destructive rheumatoid arthritis

BACKGROUND

Synovial tissue (ST) from end stage destructive rheumatoid arthritis (RA) and arthroscopic biopsies obtained during active inflammation might exhibit different characteristics.

OBJECTIVE

To define the cell infiltrate and the expression of proinflammatory cytokines, angiogenic factors, and matrix metalloproteinases (MMPs) in ST selected at arthroscopy compared with that from end stage RA.

METHODS

Synovial biopsy specimens were obtained from the actively inflamed knee joints of 13 patients with chronic RA by arthroscopy and compared with ST from 10 patients with end stage, destructive RA. Immunohistological analysis was performed to detect T cells, plasma cells, macrophages, fibroblast-like synoviocytes (FLS), and the expression of interleukin (IL)1beta, IL6, tumour necrosis factor alpha (TNFalpha), MMP-1, MMP-3, MMP-13, TIMP-1, and VEGF.

RESULTS

The expression of CD68+ macrophages was significantly higher in ST selected at arthroscopy than in samples obtained at surgery, both in the intimal lining layer and in the synovial sublining. The expression of CD3+ T cells also tended to be higher in arthroscopic samples. The expression of TNFalpha, IL6, MMP-1, MMP-3, MMP-13, TIMP-1, and VEGF was on average higher in ST obtained at arthroscopy. In contrast, the expression of IL1beta was on average higher in surgical samples.

CONCLUSION

Active arthritis activity is associated with increased cell infiltration, expression of proinflammatory cytokines, MMPs, and angiogenic growth factors in synovial biopsy samples selected at arthroscopy. Increased expression of IL1beta in the synovium of patients with destructive RA requiring joint replacement may well reflect the important role of IL1beta in cartilage and bone destruction.