Mammalian Glycosylation Patterns Protect Citrullinated Chemokine MCP-1/CCL2 from Partial Degradation.

Monocyte chemoattractant protein-1 (MCP-1/CCL2) is a potent chemotactic agent for monocytes, primarily produced by macrophages and endothelial cells. Significantly elevated levels of MCP-1/CCL2 were found in synovial fluids of patients with rheumatoid arthritis (RA), compared to osteoarthritis or other arthritis patients. Several studies suggested an important role for MCP-1 in the massive inflammation at the damaged joint, in part due to its chemotactic and angiogenic effects. It is a known fact that the post-translational modifications (PTMs) of proteins have a significant impact on their properties. In mammals, arginine residues within proteins can be converted into citrulline by peptidylarginine deiminase (PAD) enzymes. Anti-citrullinated protein antibodies (ACPA), recognizing these PTMs, have become a hallmark for rheumatoid arthritis (RA) and other autoimmune diseases and are important in diagnostics and prognosis. In previous studies, we found that citrullination converts the neutrophil attracting chemokine neutrophil-activating peptide 78 (ENA-78) into a potent macrophage chemoattractant. Here we report that both commercially available and recombinant bacterially produced MCP-1/CCL2 are rapidly (partially) degraded upon in vitro citrullination. However, properly glycosylated MCP-1/CCL2 produced by mammalian cells is protected against degradation during efficient citrullination. Site-directed mutagenesis of the potential glycosylation site at the asparagine-14 residue within human MCP-1 revealed lower expression levels in mammalian expression systems. The glycosylation-mediated recombinant chemokine stabilization allows the production of citrullinated MCP-1/CCL2, which can be effectively used to calibrate crucial assays, such as modified ELISAs.

Synovial gene signatures associated with the development of rheumatoid arthritis in at risk individuals: A prospective study.

OBJECTIVE: To identify molecular changes in synovium before arthritis development in individuals at risk of developing rheumatoid arthritis (RA). MATERIALS AND METHODS: We included 67 IgM rheumatoid factor and/or anti-citrullinated protein antibody positive individuals with arthralgia but without arthritis. Synovial biopsies were collected after which individuals were prospectively followed for at least 2 years during which 17 developed arthritis. An exploratory genome-wide transcriptional profiling study was performed in 13 preselected individuals to identify transcripts associated with arthritis development (n = 6). Findings were validated using quantitative real-time PCR and immunohistochemistry in the total cohort. RESULTS: Microarray-based survival analyses identified 5588 transcripts whose expression levels in synovium were significantly associated with arthritis development. Pathway analysis revealed that synovial tissue of at risk individuals who later developed arthritis display higher expression of genes involved in adaptive immune response-related pathways compared to at risk individuals who did not develop arthritis. Lower expression was observed for genes involved in extracellular matrix receptor interaction, Wnt-mediated signal transduction and lipid metabolism. Two-way hierarchical clustering analyses of a 27-gene signature separated the total at risk cohort into two groups, where pre-RA individuals preferred to cluster together. Immunohistochemistry studies revealed more podoplanin positive cells and lower lipid droplet staining in synovial tissue from pre-RA individuals. CONCLUSION: Synovial alterations in adaptive immune response and lipid metabolism are associated with future development of arthritis. Since this data show synovial changes without overt cellular infiltration, these may be attributed to preclinical changes in resident synovial tissue cells such as fibroblasts, macrophages and tissue resident T cells.

Is treat-to-target really working in rheumatoid arthritis? a longitudinal analysis of a cohort of patients treated in daily practice (RA BIODAM).

OBJECTIVES: To investigate whether following a treat-to-target (T2T)-strategy in daily clinical practice leads to more patients with rheumatoid arthritis (RA) meeting the remission target. METHODS: RA patients from 10 countries starting/changing conventional synthetic or biological disease-modifying anti-rheumatic drugs were assessed for disease activity every 3 months for 2 years (RA BIODAM (BIOmarkers of joint DAMage) cohort). Per visit was decided whether a patient was treated according to a T2T-strategy with 44-joint disease activity score (DAS44) remission (DAS44 <1.6) as the target. Sustained T2T was defined as T2T followed in ≥2 consecutive visits. The main outcome was the achievement of DAS44 remission at the subsequent 3-month visit. Other outcomes were remission according to 28-joint disease activity score-erythrocyte sedimentation rate (DAS28-ESR), Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI) and American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) Boolean definitions. The association between T2T and remission was tested in generalised estimating equations models. RESULTS: In total 4356 visits of 571 patients (mean (SD) age: 56 (13) years, 78% female) were included. Appropriate application of T2T was found in 59% of the visits. T2T (vs no T2T) did not yield a higher likelihood of DAS44 remission 3 months later (OR (95% CI): 1.03 (0.92 to 1.16)), but sustained T2T resulted in an increased likelihood of achieving DAS44 remission (OR: 1.19 (1.03 to 1.39)). Similar results were seen with DAS28-ESR remission. For more stringent definitions (CDAI, SDAI and ACR/EULAR Boolean remission), T2T was consistently positively associated with remission (OR range: 1.16 to 1.29), and sustained T2T had a more pronounced effect on remission (OR range: 1.49 to 1.52). CONCLUSION: In daily clinical practice, the correct application of a T2T-strategy (especially sustained T2T) in patients with RA leads to higher rates of remission.

Promotion of macrophage activation by Tie2 in the context of the inflamed synovia of rheumatoid arthritis and psoriatic arthritis patients.

OBJECTIVE: To examine the role of Tie2 signalling in macrophage activation within the context of the inflammatory synovial microenvironment present in patients with RA and PsA. METHODS: Clinical responses and macrophage function were examined in wild-type and Tie2-overexpressing (Tie2-TG) mice in the K/BxN serum transfer model of arthritis. Macrophages derived from peripheral blood monocytes from healthy donors, RA and PsA patients, and RA and PsA synovial tissue explants were stimulated with TNF (10 ng/ml), angiopoietin (Ang)-1 or Ang-2 (200 ng/ml), or incubated with an anti-Ang2 neutralizing antibody. mRNA and protein expression of inflammatory mediators was analysed by quantitative PCR, ELISA and Luminex. RESULTS: Tie2-TG mice displayed more clinically severe arthritis than wild-type mice, accompanied by enhanced joint expression of IL6, IL12B, NOS2, CCL2 and CXCL10, and activation of bone marrow-derived macrophages in response to Ang-2 stimulation. Ang-1 and Ang-2 significantly enhanced TNF-induced expression of pro-inflammatory cytokines and chemokines in macrophages from healthy donors differentiated with RA and PsA SF and peripheral blood-derived macrophages from RA and PsA patients. Both Ang-1 and Ang-2 induced the production of IL-6, IL-12p40, IL-8 and CCL-3 in synovial tissue explants of RA and PsA patients, and Ang-2 neutralization suppressed the production of IL-6 and IL-8 in the synovial tissue of RA patients. CONCLUSION: Tie2 signalling enhances TNF-dependent activation of macrophages within the context of ongoing synovial inflammation in RA and PsA, and neutralization of Tie2 ligands might be a promising therapeutic target in the treatment of these diseases.

The costimulatory molecule CD27 maintains clonally diverse CD8(+) T cell responses of low antigen affinity to protect against viral variants.

CD70 and CD27 are costimulatory molecules that provide essential signals for the expansion and differentiation of CD8(+) T cells. Here, we show that CD27-driven costimulation lowered the threshold of T cell receptor activation on CD8(+) T cells and enabled responses against low-affinity antigens. Using influenza infection to study in vivo consequences, we found that CD27-driven costimulation promoted a CD8(+) T cell response of overall low affinity. These qualitative effects of CD27 on T cell responses were maintained into the memory phase. On a clonal level, CD27-driven costimulation established a higher degree of variety in memory CD8(+) T cells. The benefit became apparent when mice were reinfected, given that CD27 improved CD8(+) T cell responses against reinfection with viral variants, but not with identical virus. We propose that CD27-driven costimulation is a strategy to generate memory clones that have potential reactivity to a wide array of mutable pathogens.

Human Lymph Node Stromal Cells Have the Machinery to Regulate Peripheral Tolerance during Health and Rheumatoid Arthritis.

BACKGROUND: In rheumatoid arthritis (RA) the cause for loss of tolerance and anti-citrullinated protein antibody (ACPA) production remains unidentified. Mouse studies showed that lymph node stromal cells (LNSCs) maintain peripheral tolerance through presentation of peripheral tissue antigens (PTAs). We hypothesize that dysregulation of peripheral tolerance mechanisms in human LNSCs might underlie pathogenesis of RA. METHOD: Lymph node (LN) needle biopsies were obtained from 24 RA patients, 23 individuals positive for RA-associated autoantibodies but without clinical disease (RA-risk individuals), and 14 seronegative healthy individuals. Ex vivo human LNs from non-RA individuals were used to directly analyze stromal cells. Molecules involved in antigen presentation and immune modulation were measured in LNSCs upon interferon γ (IFNγ) stimulation (n = 15). RESULTS: Citrullinated targets of ACPAs were detected in human LN tissue and in cultured LNSCs. Human LNSCs express several PTAs, transcription factors autoimmune regulator (AIRE) and deformed epidermal autoregulatory factor 1 (DEAF1), and molecules involved in citrullination, antigen presentation, and immunomodulation. Overall, no clear differences between donor groups were observed with exception of a slightly lower induction of human leukocyte antigen-DR (HLA-DR) and programmed cell death 1 ligand (PD-L1) molecules in LNSCs from RA patients. CONCLUSION: Human LNSCs have the machinery to regulate peripheral tolerance making them an attractive target to exploit in tolerance induction and maintenance.

Effects of B-cell directed therapy on the preclinical stage of rheumatoid arthritis: the PRAIRI study.

OBJECTIVES: We explored the effects of B-cell directed therapy in subjects at risk of developing autoantibodypositive rheumatoid arthritis (RA), who never experienced inflammatory arthritis before, and explored biomarkers predictive of arthritis development. METHODS: Individuals positive for both anti-citrullinated peptide antibodies and rheumatoid factor but without arthritis were included in a randomised, double-blind, placebo-controlled study to receive a single infusion of 1000 mg rituximab or placebo. RESULTS: Eighty-one individuals received treatment and were followed up for a mean of 29.0 (0-54) months, during which 30/81 (37%) individuals developed arthritis. The observed risk of developing arthritis in the placebo-treated group was 40%, which was decreased by 55% (HR 0.45, 95% CI 0.154 to 1.322) in the rituximab-treated group at 12 months. Rituximab treatment caused a delay in arthritis development of 12 months compared with placebo treatment at the point when 25% of the subjects had developed arthritis (p<0.0001). Erythrocyte sedimentation rate and the presence of anti-citrullinated α-enolase peptide 1 at baseline were significant predictors of arthritis development. CONCLUSIONS: A single infusion of 1000 mg rituximab significantly delays the development of arthritis in subjects at risk of developing RA, providing evidence for the pathogenetic role of B cells in the earliest, prearthritis stage of autoantibody positive RA.

Non-response to rituximab therapy in rheumatoid arthritis is associated with incomplete disruption of the B cell receptor repertoire.

OBJECTIVE: To gain more insight into the dynamics of lymphocyte depletion and develop new predictors of clinical response to rituximab in rheumatoid arthritis (RA). METHODS: RNA-based next-generation sequencing was used to analyse the B cell receptor (BCR) repertoire in peripheral blood and synovial tissue samples collected from 24 seropositive patients with RA treated with rituximab. Clonal expansion, mutation load and clonal overlap were assessed in samples collected before, at week 4 and at week 16 or 24 after treatment and correlated to the patients' clinical response. RESULTS: After 4 weeks of rituximab-induced B cell depletion, the peripheral blood BCR repertoire of treated patients consisted of fewer, more dominant and more mutated BCR clones. No significant changes in the synovial tissue BCR repertoire were detected until week 16 post-treatment, when a reduced clonal overlap with baseline and an increased mutation load were observed. In patients who were non-responders at month 3 (n=5) using the European League Against Rheumatism response criteria, peripheral blood samples taken at week 4 after rituximab treatment showed more dominant clones compared with moderate responders (n=9) (median (IQR): 36 (27-52) vs 18 (16-26); p<0.01) and more clonal overlap with the baseline (median (IQR): 5% (2%-20%) vs 0% (0%-0%); p≤0.01). CONCLUSION: Significant changes in BCR clonality are observed in peripheral blood of patients 4 weeks after rituximab treatment, while changes in synovial tissue were observed at later time points. Incomplete depletion of the dominant baseline peripheral blood BCR repertoire in the first month of treatment might predict clinical non-response at 3 months.

Association of response to TNF inhibitors in rheumatoid arthritis with quantitative trait loci for CD40 and CD39.

OBJECTIVES: We sought to investigate whether genetic effects on response to TNF inhibitors (TNFi) in rheumatoid arthritis (RA) could be localised by considering known genetic susceptibility loci for relevant traits and to evaluate the usefulness of these genetic loci for stratifying drug response. METHODS: We studied the relation of TNFi response, quantified by change in swollen joint counts ( Δ SJC) and erythrocyte sedimentation rate ( Δ ESR) with locus-specific scores constructed from genome-wide assocation study summary statistics in 2938 genotyped individuals: 37 scores for RA; scores for 19 immune cell traits; scores for expression or methylation of 93 genes with previously reported associations between transcript level and drug response. Multivariate associations were evaluated in penalised regression models by cross-validation. RESULTS: We detected a statistically significant association between Δ SJC and the RA score at the CD40 locus (p=0.0004) and an inverse association between Δ SJC and the score for expression of CD39 on CD4 T cells (p=0.00005). A previously reported association between CD39 expression on regulatory T cells and response to methotrexate was in the opposite direction. In stratified analysis by concomitant methotrexate treatment, the inverse association was stronger in the combination therapy group and dissipated in the TNFi monotherapy group. Overall, ability to predict TNFi response from genotypic scores was limited, with models explaining less than 1% of phenotypic variance. CONCLUSIONS: The association with the CD39 trait is difficult to interpret because patients with RA are often prescribed TNFi after failing to respond to methotrexate. The CD39 and CD40 pathways could be relevant for targeting drug therapy.

Effect of rituximab treatment on T and B cell subsets in lymph node biopsies of patients with rheumatoid arthritis.

OBJECTIVES: The exact underlying mechanism of rituximab treatment in patients with RA is poorly defined and knowledge about the effect of B cell depletion on immune cells in secondary lymphoid organs is lacking. We analysed lymphoid tissue responses to rituximab in RA patients. METHODS: Fourteen RA patients received 2 × 1000 mg rituximab intravenously, and lymph node (LN) biopsies were obtained before and 4 weeks after the first infusion. Tissues were examined by flow cytometry, immunohistochemistry and quantitative PCR. LN biopsies from five healthy individuals (HC) served as controls. RESULTS: LN biopsies of RA patients showed increased frequencies of CD21+CD23+IgDhighIgMvariable follicular B cells and CD3+CD25+CD69+ early activated, tissue resident T cells when compared with HCs. After treatment, there was incomplete depletion of LN B cells. There was a significant decrease in CD27-IgD+ naïve B cells, and CD27+IgD+ unswitched memory B cells including the CD27+IgD+IgM+ subset and follicular B cells. Strikingly, CD27+IgD- switched memory B cells persisted in LN biopsies after rituximab treatment. In the T cell compartment, a significant decrease was observed in the frequency of early activated, tissue resident T cells after rituximab treatment, but late activated T cells persisted. B cell proliferation inducing cytokine IL-21 was higher expressed in LN biopsies of RA patients compared with HC and expression was not affected by rituximab treatment. CONCLUSION: Rituximab does not cure RA, possibly due to persistence of switched memory B cells in lymphoid tissues suggesting that factors promoting B cell survival and differentiation need to be additionally targeted.

Vagus nerve stimulation inhibits cytokine production and attenuates disease severity in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a heterogeneous, prevalent, chronic autoimmune disease characterized by painful swollen joints and significant disabilities. Symptomatic relief can be achieved in up to 50% of patients using biological agents that inhibit tumor necrosis factor (TNF) or other mechanisms of action, but there are no universally effective therapies. Recent advances in basic and preclinical science reveal that reflex neural circuits inhibit the production of cytokines and inflammation in animal models. One well-characterized cytokine-inhibiting mechanism, termed the "inflammatory reflex," is dependent upon vagus nerve signals that inhibit cytokine production and attenuate experimental arthritis severity in mice and rats. It previously was unknown whether directly stimulating the inflammatory reflex in humans inhibits TNF production. Here we show that an implantable vagus nerve-stimulating device in epilepsy patients inhibits peripheral blood production of TNF, IL-1ß, and IL-6. Vagus nerve stimulation (up to four times daily) in RA patients significantly inhibited TNF production for up to 84 d. Moreover, RA disease severity, as measured by standardized clinical composite scores, improved significantly. Together, these results establish that vagus nerve stimulation targeting the inflammatory reflex modulates TNF production and reduces inflammation in humans. These findings suggest that it is possible to use mechanism-based neuromodulating devices in the experimental therapy of RA and possibly other autoimmune and autoinflammatory diseases.

Efficacy and safety of sirukumab in patients with active rheumatoid arthritis refractory to anti-TNF therapy (SIRROUND-T): a randomised, double-blind, placebo-controlled, parallel-group, multinational, phase 3 study.

BACKGROUND: Sirukumab, a human monoclonal antibody that selectively binds to the interleukin-6 cytokine with high affinity, is under development for the treatment of rheumatoid arthritis and other diseases. We aimed to assess the efficacy and safety of sirukumab for rheumatoid arthritis in a phase 3 study (SIRROUND-T). METHODS: We did a randomised, double-blind, placebo-controlled, parallel-group, multicentre study at 183 hospitals and private rheumatology clinics in 20 countries (Argentina, Australia, Austria, Belgium, Canada, France, Germany, Italy, Japan, Lithuania, Mexico, Netherlands, Poland, Portugal, Russia, South Korea, Spain, Taiwan, UK, and USA). Eligible participants were patients with active rheumatoid arthritis aged at least 18 years, with four or more of 68 tender joints and four or more of 66 swollen joints, who were refractory or intolerant to previous treatment with at least one anti-TNF drug. We randomly assigned patients (1:1:1) via a central interactive voice or web response system to either placebo every 2 weeks, 50 mg sirukumab every 4 weeks, or 100 mg sirukumab every 2 weeks, all given for 52 weeks or less. We allowed participants to continue using any concomitant disease-modifying antirheumatic drugs (DMARDs). We based the randomisation on a computer-generated, permuted-block schedule stratified by use of methotrexate at baseline (0, >0 to <12·5 mg/week, or ≥12·5 mg/week). Masking was achieved with the use of multipart labels on the study drug containers which contained directions for use and other information, but not the drug's identity. Treatments were administered by subcutaneous injection; patients assigned to 50 mg sirukumab given every 4 weeks also received a placebo injection every 2 weeks to maintain masking. At week 18, placebo-treated patients meeting early escape criteria (<20% improvement in swollen and tender joint counts) were randomly reassigned to either 50 mg or 100 mg of sirukumab. All remaining placebo-treated patients were subsequently randomly reassigned at week 24 to either sirukumab dose (crossover). The primary outcome was the proportion of patients who achieved a response of at least 20% improvement at week 16 according to American College of Rheumatology criteria (ACR20) in the intention-to-treat population (all randomly assigned participants). Safety analyses included all participants who received at least one dose (partial or complete) of study drug. This study is registered at EudraCT (number: 2010-022243-38) and ClinicalTrials.gov (number: NCT01606761). FINDINGS: Between July 25, 2012, and Jan 12, 2016, we randomly assigned 878 patients to treatment: 294 to placebo, 292 to 50 mg sirukumab every 4 weeks, and 292 to 100 mg sirukumab every 2 weeks. 523 (60%) of 878 patients had previously received two or more biological treatments including non-TNF drugs, and 166 (19%) of 878 were not taking a DMARD at baseline. The proportions of patients who achieved an ACR20 response at week 16 were 117 (40%) of 292 with 50 mg sirukumab every 4 weeks, and 132 (45%) of 292 with 100 mg sirukumab every 2 weeks versus 71 (24%) of 294 with placebo; differences compared with placebo were 0·16 (95% CI 0·09-0·23) for 50 mg sirukumab every 4 weeks and 0·21 (0·14-0·29) for 100 mg sirukumab every 2 weeks (both p<0·0001). Adverse event incidences in the 24-week placebo-controlled period were similar across groups (at least one event occurred for 182 patients assigned to placebo [62%, including early escape patients switched to sirukumab at week 18] of 294; 194 [66%] of 292 with 50 mg sirukumab every 4 weeks; and 207 [71%] of 292 with 100 mg sirukumab every 2 weeks). The most common adverse events in this period were injection-site erythema (four [1%] with placebo, 22 [8%] with 50 mg sirukumab every 4 weeks, and 41 [14%] with 100 mg sirukumab every 2 weeks). At week 52, of all patients receiving sirukumab including those reassigned from placebo, the most common adverse events were again injection-site erythema (33 [8%] of 416 with 50 mg sirukumab every 4 weeks and 66 [16%] of 418 with 100 mg sirukumab every 2 weeks). INTERPRETATION: In patients with active rheumatoid arthritis who were refractory or intolerant to anti-TNF drugs and other biological treatments, both dosing regimens of sirukumab were well tolerated and significantly improved signs and symptoms of the disease, compared with placebo, in this difficult-to-treat population. FUNDING: Janssen Research & Development, LLC, and GlaxoSmithKline.

Genome-wide association study of response to methotrexate in early rheumatoid arthritis patients.

Methotrexate (MTX) monotherapy is a common first treatment for rheumatoid arthritis (RA), but many patients do not respond adequately. In order to identify genetic predictors of response, we have combined data from two consortia to carry out a genome-wide study of response to MTX in 1424 early RA patients of European ancestry. Clinical endpoints were change from baseline to 6 months after starting treatment in swollen 28-joint count, tender 28-joint count, C-reactive protein and the overall 3-component disease activity score (DAS28). No single nucleotide polymorphism (SNP) reached genome-wide statistical significance for any outcome measure. The strongest evidence for association was with rs168201 in NRG3 (p = 10-7 for change in DAS28). Some support was also seen for association with ZMIZ1, previously highlighted in a study of response to MTX in juvenile idiopathic arthritis. Follow-up in two smaller cohorts of 429 and 177 RA patients did not support these findings, although these cohorts were more heterogeneous.

Efficacy and safety of monotherapy with sirukumab compared with adalimumab monotherapy in biologic-naïve patients with active rheumatoid arthritis (SIRROUND-H): a randomised, double-blind, parallel-group, multinational, 52-week, phase 3 study.

OBJECTIVE: This randomised, double-blind, parallel-group, phase 3 study compared monotherapy with sirukumab, an anti-interleukin-6 cytokine monoclonal antibody, with adalimumab monotherapy in patients with rheumatoid arthritis (RA). METHODS: Biologic-naïve patients with active RA who were inadequate responders or were intolerant to, or inappropriate for, methotrexate were randomised to subcutaneous sirukumab 100 mg every 2 weeks (n=187), sirukumab 50 mg every 4 weeks (n=186) or adalimumab 40 mg every 2 weeks (n=186). Primary endpoints at week 24 were change from baseline in Disease Activity Score in 28 joints (DAS28) using erythrocyte sedimentation rate (ESR) and proportion of patients achieving an American College of Rheumatology (ACR) 50 response; these endpoints were tested in sequential order. This study is registered at EudraCT (number: 2013-001417-32) and ClinicalTrials.gov (number: NCT02019472). RESULTS: Significantly greater improvements from baseline in mean (SD) DAS28 (ESR) were observed at week 24 with sirukumab 100 mg every 2 weeks (-2.96 (1.580)) versus adalimumab 40 mg every 2 weeks (-2.19 (1.437); P<0.001). Sirukumab 50 mg every 4 weeks also showed significantly greater improvement from baseline at week 24 in DAS28 (ESR) (-2.58 (1.524)) compared with adalimumab (P=0.013). The ACR50 response rates with the 100 mg (35.3%) and 50 mg (26.9%) doses of sirukumab were comparable to that with adalimumab (31.7%) at week 24. The safety profile of sirukumab was consistent with that observed with anti-interleukin-6 receptor antibodies. A dose-related effect on the incidence of injection-site reactions was observed with sirukumab. CONCLUSION: Sirukumab monotherapy showed greater improvements in DAS28 (ESR), but similar ACR50 response rates, versus adalimumab monotherapy.

Class 3 semaphorins modulate the invasive capacity of rheumatoid arthritis fibroblast-like synoviocytes.

Objective: Class 3 semaphorins regulate diverse cellular processes relevant to the pathology of RA, including immune modulation, angiogenesis, apoptosis and invasive cell migration. Therefore, we analysed the potential role of class 3 semaphorins in the pathology of RA. Methods: Protein and mRNA expression in RA synovial tissue, SF and fibroblast-like synoviocytes (FLS) were determined by immunoblotting and quantitative PCR (qPCR). RA FLS migration and invasion were determined using wound closure and transwell invasion assays, respectively. PlexinA1, neuropilin-1 and neuropilin-2 expression was knocked down using small interfering RNA (siRNA). Activation of FLS intracellular signalling pathways was assessed by immunoblotting. Results: mRNA expression of semaphorins (Sema)3B, Sema3C, Sema3F and Sema3G was significantly lower in the synovial tissue of early arthritis patients at baseline who developed persistent disease compared with patients with self-limiting disease after 2 years follow-up. Sema3B and Sema3F expression was significantly lower in arthritis patients fulfilling classification criteria for RA compared with those who did not. FLS expression of Sema3A was induced after stimulation with TNF, IL-1ß or lipopolysaccharides (LPS), while Sema3B and Sema3F expression was downregulated. Exogenously applied Sema3A induced the migration and invasive capacity of FLS, while stimulation with Sema3B or Sema3F reduced spontaneous FLS migration, and platelet-derived growth factor induced cell invasion, effects associated with differential regulation of MMP expression and mediated by the PlexinA1 and neuropilin-1 and -2 receptors. Conclusion: Our data suggest that modulation of class 3 semaphorin signaling could be a novel therapeutic strategy for modulating the invasive behaviour of FLS in RA.

Lymph node biopsy analysis reveals an altered immunoregulatory balance already during the at-risk phase of autoantibody positive rheumatoid arthritis.

The balance between proinflammatory and regulatory CD4+ T cells is tightly controlled in lymphoid organs. In autoimmune diseases this balance is altered in the periphery and target tissue of patients. However, not much is known about the balance initiated in lymphoid organs during the development of disease. Since systemic autoimmunity is present years before the clinical manifestations of rheumatoid arthritis (RA), it is possible to study the immunoregulatory balance during the earliest (preclinical) phases of disease. Here, we report for the first time the frequency and phenotype of proinflammatory and regulatory CD4+ T cells in lymph node biopsies obtained from autoantibody positive individuals at risk for developing RA, patients with established disease and healthy controls. The frequency of proinflammatory LN Th1 cells was increased in RA patients compared with HCs, while the frequency of regulatory T cells was lower in LN biopsies of RA-risk individuals. Upon in vitro stimulation LN CD4+ T cells produced lower levels of proinflammatory cytokines, IFN-γ and IL-17A, in both RA-risk individuals and early RA patients. This study shows that already during the earliest phases of systemic autoimmunity the immunoregulatory balance between proinflammatory and regulatory CD4+ T cells is altered in LN tissue.

Sirukumab for rheumatoid arthritis: the phase III SIRROUND-D study.

OBJECTIVES: Interleukin-6 (IL-6) is implicated in rheumatoid arthritis (RA) pathophysiology. Unlike IL-6 receptor inhibitors, sirukumab is a human monoclonal antibody that selectively binds to the IL-6 cytokine. The phase III, multicentre, randomised, double-blind, placebo-controlled, parallel-group SIRROUND-D study (ClinicalTrials.gov identifier NCT01604343) evaluated the efficacy and safety of sirukumab in patients with active RA refractory to disease-modifying antirheumatic drugs. METHODS: Patients were randomised 1:1:1 to treatment with sirukumab 100 mg every 2 weeks, 50 mg every 4 weeks or placebo every 2 weeks subcutaneously. Results through week 52 are reported. RESULTS: Of 1670 randomised patients, significantly more patients achieved American College of Rheumatology 20% (ACR20) response at week 16 (coprimary endpoint) with sirukumab 100 mg every 2 weeks (53.5%) or 50 mg every 4 weeks (54.8%) versus placebo (26.4%; both p<0.001). Mean (SD) change from baseline in modified Sharp/van der Heijde score at week 52 (coprimary endpoint) was significantly lower with sirukumab (100 mg every 2 weeks: 0.46 (3.26); 50 mg every 4 weeks: 0.50 (2.96)) versus placebo (3.69 (9.25); both p<0.001). All major secondary endpoints (week 24 Health Assessment Questionnaire-Disability Index change from baseline, ACR50 response, 28-joint Disease Activity Score based on C reactive protein and major clinical response (ACR70 for six continuous months by week 52)) were met. The most common adverse events with sirukumab were elevated liver enzymes, upper respiratory tract infection, injection site erythema and nasopharyngitis. CONCLUSIONS: Sirukumab 100 mg every 2 weeks and 50 mg every 4 weeks led to significant reductions in RA symptoms, inhibition of structural damage progression and physical function and quality of life improvements, with an expected safety profile. TRIAL REGISTRATION NUMBER: NCT01604343; Results.

Dominant B cell receptor clones in peripheral blood predict onset of arthritis in individuals at risk for rheumatoid arthritis.

BACKGROUND: The onset of seropositive rheumatoid arthritis (RA) is preceded by the presence of specific autoantibodies in the absence of synovial inflammation. Only a subset of these at-risk individuals will develop clinical disease. This impedes efforts to implement early interventions that may prevent onset of clinically manifest disease. Here we analyse whether clonal changes in the B cell receptor (BCR) repertoire can reliably predict onset of signs and symptoms. METHODS: In a prospective cohort study in 21 individuals at risk for RA based on the presence of autoantibodies, the BCR repertoire of paired peripheral blood and synovial tissue samples was analysed using next-generation BCR sequencing. BCR clones that were expanded beyond 0.5% of the total repertoire were labelled dominant. The relative risk (RR) for onset of arthritis was assessed using the presence of ≥5 dominant BCR clones as cut-off. Findings in peripheral blood were validated in an independent prospective cohort of 50 at-risk individuals. Based on the test cohort, individuals in the validation cohort were considered positive if peripheral blood at study entry showed ≥5 dominant BCR clones. FINDINGS: Both in the test and validation cohort, the presence of ≥5 dominant BCR clones in peripheral blood was significantly associated with arthritis development after follow-up (validation cohort RR 6.3, 95% CI 2.7 to 15, p<1×10-4). Even when adjusted for a recently described clinical prediction rule the association remained intact (RR 5.0, 95% CI 1.2 to 20, p=0.024). When individuals developed arthritis, dominant BCR clones disappeared from peripheral blood and appeared in synovial tissue, suggesting a direct role of these clones in disease pathogenesis. INTERPRETATION: Dominant BCR clones in peripheral blood predict onset of clinical signs and symptoms of RA in at-risk individuals with high accuracy. Our data suggest that during onset of RA these clones shift from peripheral blood to the target tissue.

Histone deacetylase 3 regulates the inflammatory gene expression programme of rheumatoid arthritis fibroblast-like synoviocytes.

OBJECTIVES: Non-selective histone deacetylase (HDAC) inhibitors (HDACi) have demonstrated anti-inflammatory properties in both in vitro and in vivo models of rheumatoid arthritis (RA). Here, we investigated the potential contribution of specific class I and class IIb HDACs to inflammatory gene expression in RA fibroblast-like synoviocytes (FLS). METHODS: RA FLS were incubated with pan-HDACi (ITF2357, givinostat) or selective HDAC1/2i, HDAC3/6i, HDAC6i and HDAC8i. Alternatively, FLS were transfected with HDAC3, HDAC6 or interferon (IFN)-α/ß receptor alpha chain (IFNAR1) siRNA. mRNA expression of interleukin (IL)-1ß-inducible genes was measured by quantitative PCR (qPCR) array and signalling pathway activation by immunoblotting and DNA-binding assays. RESULTS: HDAC3/6i, but not HDAC1/2i and HDAC8i, significantly suppressed the majority of IL-1ß-inducible genes targeted by pan-HDACi in RA FLS. Silencing of HDAC3 expression reproduced the effects of HDAC3/6i on gene regulation, contrary to HDAC6-specific inhibition and HDAC6 silencing. Screening of the candidate signal transducers and activators of transcription (STAT)1 transcription factor revealed that HDAC3/6i abrogated STAT1 Tyr701 phosphorylation and DNA binding, but did not affect STAT1 acetylation. HDAC3 activity was required for type I IFN production and subsequent STAT1 activation in FLS. Suppression of type I IFN release by HDAC3/6i resulted in reduced expression of a subset of IFN-dependent genes, including the chemokines CXCL9 and CXCL11. CONCLUSIONS: Inhibition of HDAC3 in RA FLS largely recapitulates the effects of pan-HDACi in suppressing inflammatory gene expression, including type I IFN production in RA FLS. Our results identify HDAC3 as a potential therapeutic target in the treatment of RA and type I IFN-driven autoimmune diseases.