The effect of rituximab on patient reported outcomes in the preclinical phase of rheumatoid arthritis: 2 year data from the PRAIRI study.

OBJECTIVES: Early treatment of individuals at risk of developing rheumatoid arthritis (RA-risk) in the preclinical phase has the potential to positively impact both patients and society by preventing disease onset and improving patients' quality of life. The PRAIRI study was a randomised, double-blind, placebo-controlled trial with the B-cell depleting agent rituximab (RTX), which resulted in a significant delay of arthritis development of up to 12 months in seropositive RA-risk individuals. Here, we report our findings on patient-reported outcomes (PROs) in this study population. METHODS: Seventy-eight RA-risk individuals were treated with one single dose of either placebo (PBO) or 1000 mg RTX plus 100 mg methylprednisolone (MP) and anti-histamines, regardless of treatment allocation, as co-medication. Data on quality of life were collected at baseline and 1, 4, 6, 12 and 24 months using established PRO questionnaires (visual analogue scale (VAS) pain, health assessment questionnaire disability index (HAQ-DI) score, EuroQol five dimension (EQ-5D) and both physical and mental component score of the 36-item short-form heath survey (SF-36)). RESULTS: No significant changes in quality of life over a 2 year follow-up were observed in at-risk individuals treated with RTX compared to PBO given the PRO scores at 24 months (mean difference±SEM: HAQ score=0.07±0.16; EQ-5D=-0.02±0.05; VAS pain=11.11±7.40). Furthermore, no significant effect of treatment on perceived arthritis severity at the time of clinically manifest disease (arthritis) was found. CONCLUSION: One single dose of RTX plus MP administered to RA-risk individuals does not have a meaningful and measurable positive effect on PROs after 2 years of follow-up and/or perceived disease severity at the time of arthritis development. TRIAL REGISTRATION NUMBER: Trial registered at EU Clinical Trial Register, EudraCT Number: 2009-010955-29 (https://www.clinicaltrialsregister.eu/ctr-search/search?query=Prevention+of+RA+by+B+cell+directed+therapy).

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.

Increased Frequency of CD4+ Follicular Helper T and CD8+ Follicular T Cells in Human Lymph Node Biopsies during the Earliest Stages of Rheumatoid Arthritis.

Follicular T helper cells (Tfh cells) provide key B-cell help and are essential in germinal center formation and (auto) antibody generation. To gain more insight into their role during the earliest phase of rheumatoid arthritis (RA), we analyzed their frequencies, phenotypes, and cytokine profiles in peripheral blood and lymph node biopsies of healthy controls (HCs), autoantibody-positive individuals at risk for developing RA (RA-risk individuals), and early RA patients. Subsequently, we confirmed their presence in lymph nodes and synovial tissue of RA patients using immunofluorescence microscopy. In the blood, the frequency of Tfh cells did not differ between study groups. In lymphoid and synovial tissues, Tfh cells were localized in B-cell areas, and their frequency correlated with the frequency of CD19+ B cells. Compared to lymphoid tissues of healthy controls, those of RA patients and RA-risk individuals showed more CD19+ B cells, CD4+CXCR5+ follicular helper T cells, and CD8+CXCR5+ follicular T cells. These Tfh cells produced less IL-21 upon ex vivo stimulation. These findings suggest that Tfh cells may present a novel rationale for therapeutic targeting during the preclinical stage of RA to prevent further disease progression.

Impact of Adalimumab Treatment on Interleukin-17 and Interleukin-17 Receptor Expression in Skin and Synovium of Psoriatic Arthritis Patients with Mild Psoriasis.

Interleukin (IL)-17 and tumor necrosis factor-alpha (TNF)-α are key players in psoriatic arthritis (PsA) pathogenesis. While both cytokines can be therapeutically targeted with beneficial clinical outcome, it is unclear whether inhibiting one cytokine will affect the other at sites of inflammation. If both act independently, this might provide a rationale for dual or combined inhibition of both cytokines. Here, we evaluated the effect of TNF blockade in PsA patients on IL-17 levels in both skin and synovial tissue biopsies. PsA patients with mild psoriatic skin lesions were randomized to receive either adalimumab or placebo for four weeks. Synovial and skin biopsies were obtained at weeks zero and four. Skin from healthy donors (HDs) was used for comparison. Expression of IL-17A, IL-17F, IL-17RA and IL-17RC was assessed by immunohistochemistry and analyzed with digital image analysis. We found relatively low levels of IL-17 and its receptors in the skin of PsA patients compared to HD, and only IL-17F in the dermis of lesional psoriatic skin was significantly higher compared to HD skin (p = 0.0002). Histologically IL-17A, IL-17F, IL-17RA and IL-17RC in skin and synovial tissue were not downregulated by adalimumab treatment. Thus, in this cohort of PsA patients with mild psoriasis, TNF blockade did not affect the protein levels of IL-17 cytokines and its receptors in skin and synovium, despite reduced cellular inflammation and improved clinical outcome for joint involvement.

Novel Insights Into Rheumatoid Arthritis Through Characterization of Concordant Changes in DNA Methylation and Gene Expression in Synovial Biopsies of Patients With Differing Numbers of Swollen Joints.

In this study, we sought to characterize synovial tissue obtained from individuals with arthralgia and disease-specific auto-antibodies and patients with established rheumatoid arthritis (RA), by applying an integrative multi-omics approach where we investigated differences at the level of DNA methylation and gene expression in relation to disease pathogenesis. We performed concurrent whole-genome bisulphite sequencing and RNA-Sequencing on synovial tissue obtained from the knee and ankle from 4 auto-antibody positive arthralgia patients and thirteen RA patients. Through multi-omics factor analysis we observed that the latent factor explaining the variance in gene expression and DNA methylation was associated with Swollen Joint Count 66 (SJC66), with patients with SJC66 of 9 or more displaying separation from the rest. Interrogating these observed differences revealed activation of the immune response as well as dysregulation of cell adhesion pathways at the level of both DNA methylation and gene expression. We observed differences for 59 genes in particular at the level of both transcript expression and DNA methylation. Our results highlight the utility of genome-wide multi-omics profiling of synovial samples for improved understanding of changes associated with disease spread in arthralgia and RA patients, and point to novel candidate targets for the treatment of the disease.

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.

Development and formative evaluation of patient research partner involvement in a multi-disciplinary European translational research project.

PLAIN ENGLISH SUMMARY: Patient and public involvement (PPI) improves the quality of health research and ensures that research is relevant to patients' needs. Though PPI is increasingly evident in clinical and health services research, there are few examples in the research literature of effective PPI in translational and laboratory-based research. In this paper, we describe the development and evaluation of PPI in a multi-centre European project (EuroTEAM - Towards Early biomarkers in Arthritis Management) that included both translational and laboratory-based and psychosocial research. We found that although most PPI in EuroTEAM was centred around the psychosocial research, there were examples of PPI in the laboratory studies. As the project evolved, researchers became better at accommodating PPI and identifying PPI opportunities. It was generally agreed that PPI had a positive impact on the project overall, particularly on public engagement with the research. We concluded that the inclusion of both psychosocial and laboratory-based research in the same project facilitated PPI across all aspects of the research. In future projects, we would try to specify individual PPI activities in more detail at the project-planning stage, and better accommodate patient partners who are not native speakers of English. ABSTRACT: Background Patient and public involvement (PPI) enhances research quality and relevance and is central to contemporary health policy. The value of PPI has been recognised in rheumatology research, though there are limited examples of PPI in basic and translational science. The EU FP7 funded 'EuroTEAM' (Towards Early biomarkers in Arthritis Management) project was established to develop biomarker-based approaches to predict the future development of rheumatoid arthritis and incorporated psychosocial research to investigate the perceptions of 'at risk' individuals about predictive testing, and to develop informational resources about rheumatoid arthritis (RA) risk. Patient involvement was central to EuroTEAM from the inception of the project. The objective of this paper is to describe the development of PPI in EuroTEAM, formatively assess the impact of PPI from the perspectives of researchers and patient research partners (PRPs), reflect on successes and lessons learned, and formulate recommendations to guide future projects.Methods Two mixed-methods surveys (for PRPs and researchers) and a teleconference were undertaken to assess the impact of PPI on individual work packages and on EuroTEAM overall.Results There was consensus about the positive impact of PPI on the research and on the experiences of those involved. In particular, the positive impact of PPI on the personal development of researchers, and on effective public engagement with EuroTEAM research were highlighted. Researchers described adapting their practice in future projects to facilitate PPI. Spin-off projects and ongoing collaborations between PRPs and researchers reflected the value of PPI to participants. PPI was more frequently integrated in psychosocial research, though examples of PPI in laboratory/translational science were also described. PRPs asked for more opportunities to contribute meaningfully to basic scientific research and for more extensive feedback on their contributions.Conclusions The findings were used to formulate recommendations to guide effective involvement of patients in future similar projects, including identifying specific training requirements for PRPs and researchers, the identification of PRP focused tasks/deliverables at the project planning stage, and supporting access to involvement for all PRPs. Importantly, the distinctive multidisciplinary approach of EuroTEAM, incorporating both basic science and psychosocial research, facilitated patient involvement in the project overall.

Quantifying disease activity in rheumatoid arthritis with the TSPO PET ligand 18F-GE-180 and comparison with 18F-FDG and DCE-MRI.

PURPOSE: While the aetiology of rheumatoid arthritis (RA) remains unclear, many of the inflammatory components are well characterised. For diagnosis and therapy evaluation, in vivo insight into these processes would be valuable. Various imaging probes have shown value including dynamic contrast-enhanced (DCE) MRI and PET/CT using 18F-fluorodeoxyglucose (18F-FDG) or tracers targeting the translocator protein (TSPO). To evaluate 18F-GE-180, a novel TSPO PET tracer, for detecting and quantifying disease activity in RA, we compared 18F-GE-180 uptake with that of 18F-FDG and DCE-MRI measures of inflammation. METHODS: Eight RA patients with moderate-to-high, stable disease activity and active disease in at least one wrist were included in this study (NCT02350426). Participants underwent PET/CT examinations with 18F-GE-180 and 18F-FDG on separate visits, covering the shoulders and from the pelvis to the feet, including hands and wrists. DCE-MRI was performed on one affected hand. Uptake was compared visually between tracers as judged by an experienced radiologist and quantitatively using the maximum standardised uptake value (SUVmax). Uptake for both tracers was correlated with DCE-MRI parameters of inflammation, including the volume transfer coefficient Ktrans using Pearson correlation (r). RESULTS: PET/CT imaging with 18F-GE-180 in RA patients showed marked extra-synovial uptake around the affected joints. Overall sensitivity for detecting clinically affected joints was low (14%). 18F-GE-180 uptake did not or only weakly correlate with DCE-MRI parameters in the wrist (r = 0.09-0.31). 18F-FDG showed higher sensitivity for detecting symptomatic joints (34%), as well as strong positive correlation with DCE-MRI parameters (SUVmax vs. Ktrans: r = 0.92 for wrist; r = 0.68 for metacarpophalangeal joints). CONCLUSIONS: The correlations between DCE-MRI parameters and 18F-FDG uptake support use of this PET tracer for quantification of inflammatory burden in RA. The TSPO tracer 18F-GE-180, however, has shown limited use for the investigation of RA due to its poor sensitivity and ability to quantify disease activity in RA.

Phenotypic Analysis of Human Lymph Nodes in Subjects With New-Onset Type 1 Diabetes and Healthy Individuals by Flow Cytometry.

Background: Ultrasound guided sampling of human lymph node (LN) combined with advanced flow cytometry allows phenotypic analysis of multiple immune cell subsets. These may provide insights into immune processes and responses to immunotherapies not apparent from analysis of the blood. Methods: Ultrasound guided inguinal LN samples were obtained by both fine needle aspiration (FNA) and core needle biopsy in 10 adults within 8 weeks of diagnosis of type 1 diabetes (T1D) and 12 age-matched healthy controls at two study centers. Peripheral blood mononuclear cells (PBMC) were obtained on the same occasion. Samples were transported same day to the central laboratory and analyzed by multicolour flow cytometry. Results: LN sampling was well-tolerated and yielded sufficient cells for analysis in 95% of cases. We confirmed the segregation of CD69+ cells into LN and the predominance of CD8+ Temra cells in blood previously reported. In addition, we demonstrated clear enrichment of CD8+ naïve, FOXP3+ Treg, class-switched B cells, CD56bright NK cells and plasmacytoid dendritic cells (DC) in LNs as well as CD4+ T cells of the Th2 phenotype and those expressing Helios and Ki67. Conventional NK cells were virtually absent from LNs as were Th22 and Th1Th17 cells. Paired correlation analysis of blood and LN in the same individuals indicated that for many cell subsets, especially those associated with activation: such as CD25+ and proliferating (Ki67+) T cells, activated follicular helper T cells and class-switched B cells, levels in the LN compartment could not be predicted by analysis of blood. We also observed an increase in Th1-like Treg and less proliferating (Ki67+) CD4+ T cells in LN from T1D compared to control LNs, changes which were not reflected in the blood. Conclusions: LN sampling in humans is well-tolerated. We provide the first detailed "roadmap" comparing immune subsets in LN vs. blood emphasizing a role for differentiated effector T cells in the blood and T cell regulation, B cell activation and memory in the LN. For many subsets, frequencies in blood, did not correlate with LN, suggesting that LN sampling would be valuable for monitoring immuno-therapies where these subsets may be impacted.

Molecular Characterization of Human Lymph Node Stromal Cells During the Earliest Phases of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a progressive, destructive autoimmune arthritis. Break of tolerance and formation of autoantibodies occur years before arthritis. Adaptive immunity is initiated in lymphoid tissue where lymph node stromal cells (LNSCs) play a crucial role in shaping the immune response and maintaining peripheral tolerance. Here we performed the first epigenomic characterization of LNSCs during health and early RA, by analyzing their transcriptome and DNA methylome in LNSCs isolated from lymph node needle biopsies obtained from healthy controls (HC), autoantibody positive RA-risk individuals and patients with established RA. Of interest, LNSCs from RA-risk individuals and RA patients revealed a common significantly differential expressed gene signature compared with HC LNSCs. Pathway analysis of this common signature showed, among others, significant enrichment of pathways affecting the extracellular matrix (ECM), cholesterol biosynthesis and immune system. In a gel contraction assay LNSCs from RA-risk individuals and RA patients showed impaired collagen contraction compared to healthy LNSCs. In RA LNSCs a significant enrichment was observed for genes involved in cytokine signaling, hemostasis and packaging of telomere ends. In contrast, in RA-risk LNSCs pathways in cancer (cell cycle related genes) were differentially expressed compared with HC, which could be validated in vitro using a proliferation assay, which indicated a slower proliferation rate. DNA methylation analyses revealed common and specific differentially methylated CpG sites (DMS) in LNSC from RA patients and RA-risk individuals compared with HC. Intriguingly, shared DMS were all associated with antigen processing and presentation. This data point toward alterations in cytoskeleton and antigen-processing and presentation in LNSC from RA-risk individuals and RA patients. Further studies are required to investigate the consequence of this LNSC abnormality on LNSC-mediated immunomodulation.

Nomenclature for the Phases of the Development of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a common immune-mediated inflammatory disease. Research on RA is increasingly focused on the earliest stages of the disease, and has provided strong evidence that clinical signs and symptoms may be preceded by a preclinical phase during which evidence of systemic autoimmunity may be present. To facilitate research in this area, a number of international initiatives have proposed definitions of the phases of disease leading up to RA. The first of these initiatives was the European League Against Rheumatism's (EULAR) set of recommendations on terminology in persons at risk for RA, which suggested that the "at-risk phases" be described in terms of patients variably having: (A) genetic risk factors for RA; (B) environmental risk factors for RA; (C) systemic autoimmunity associated with RA; (D) symptoms without clinical arthritis; and (E) unclassified arthritis. The phrase clinically suspect arthralgia (CSA) is now widely used and can be regarded as describing a subgroup of patients in phase D. A definition of CSA was recently proposed by a EULAR taskforce, and primary research has begun to explore the full range of symptoms, as well as their sensitivity and specificity alone and in combination with other factors, that characterize this phase. Similarly, immune abnormalities at mucosal and others sites that precede and/or are associated with the onset of musculoskeletal symptoms are being increasingly studied and understood. Whether some of these at-risk phases, in particular CSA, represent entities meriting their own classification criteria is an essential area for consensus and will be discussed.

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.

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.

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.

Impaired lymph node stromal cell function during the earliest phases of rheumatoid arthritis.

BACKGROUND: Systemic autoimmunity can be present years before clinical onset of rheumatoid arthritis (RA). Adaptive immunity is initiated in lymphoid tissue where lymph node stromal cells (LNSCs) regulate immune responses through their intimate connection with leucocytes. We postulate that malfunctioning of LNSCs creates a microenvironment in which normal immune responses are not properly controlled, possibly leading to autoimmune disease. In this study we established an experimental model for studying the functional capacities of human LNSCs during RA development. METHODS: Twenty-four patients with RA, 23 individuals positive for autoantibodies but without clinical disease (RA risk group) and 14 seronegative healthy control subjects underwent ultrasound-guided inguinal lymph node (LN) biopsy. Human LNSCs were isolated and expanded in vitro for functional analyses. In analogous co-cultures consisting of LNSCs and peripheral blood mononuclear cells, αCD3/αCD28-induced T-cell proliferation was measured using carboxyfluorescein diacetate succinimidyl ester dilution. RESULTS: Fibroblast-like cells expanded from the LN biopsy comprised of fibroblastic reticular cells (gp38+CD31-) and double-negative (gp38-CD31-) cells. Cultured LNSCs stably expressed characteristic adhesion molecules and cytokines. Basal expression of C-X-C motif chemokine ligand 12 (CXCL12) was lower in LNSCs from RA risk individuals than in those from healthy control subjects. Key LN chemokines C-C motif chemokine ligand (CCL19), CCL21 and CXCL13 were induced in LNSCs upon stimulation with tumour necrosis factor-α and lymphotoxin α1ß2, but to a lesser extent in LNSCs from patients with RA. The effect of human LNSCs on T-cell proliferation was ratio-dependent and altered in RA LNSCs. CONCLUSIONS: Overall, we developed an experimental model to facilitate research on the role of LNSCs during the earliest phases of RA. Using this innovative model, we show, for the first time to our knowledge, that the LN stromal environment is changed during the earliest phases of RA, probably contributing to deregulated immune responses early in disease pathogenesis.

Distinctive expression of T cell guiding molecules in human autoimmune lymph node stromal cells upon TLR3 triggering.

Infections are implicated in autoimmunity. Autoantibodies are produced in lymphoid tissue where lymph node stromal cells (LNSCs) regulate lymphocyte function. Infections can alter the interaction between LNSCs and lymphocytes resulting in defective immune responses. In rheumatoid arthritis (RA) autoantibody production precedes clinical disease allowing identification of at risk individuals. We investigated the ability of human LNSCs derived from RA, RA-risk and healthy individuals to sense and respond to pathogens. Human LNSCs cultured directly from freshly collected lymph node biopsies expressed TLR1-9 with exception of TLR7. In all donors TLR3 triggering induced expression of ISGs, IL-6 and adhesion molecules like VCAM-1 and ICAM-1. Strikingly, T cell guiding chemokines CCL19 and IL-8 as well as the antiviral gene MxA were less induced upon TLR3 triggering in autoimmune LNSCs. This observed decrease, found already in LNSCs of RA-risk individuals, may lead to incorrect positioning of lymphocytes and aberrant immune responses during viral infections.

Corrigendum: Synovial tissue research: a state-of-the-art review.

This corrects the article DOI: 10.1038/nrrheum.2017.115.

Synovial tissue research: a state-of-the-art review.

This corrects the article DOI: 10.1038/nrrheum.2017.115.

Stromal cell markers are differentially expressed in the synovial tissue of patients with early arthritis.

INTRODUCTION: Previous studies have shown increased expression of stromal markers in synovial tissue (ST) of patients with established rheumatoid arthritis (RA). Here, ST expression of stromal markers in early arthritis in relationship to diagnosis and prognostic outcome was studied. METHODS: ST from 56 patients included in two different early arthritis cohorts and 7 non-inflammatory controls was analysed using immunofluorescence to detect stromal markers CD55, CD248, fibroblast activation protein (FAP) and podoplanin. Diagnostic classification (gout, psoriatic arthritis, unclassified arthritis (UA), parvovirus associated arthritis, reactive arthritis and RA), disease outcome (resolving vs persistent) and clinical variables were determined at baseline and after follow-up, and related to the expression of stromal markers. RESULTS: We observed expression of all stromal markers in ST of early arthritis patients, independent of diagnosis or prognostic outcome. Synovial expression of FAP was significantly higher in patients developing early RA compared to other diagnostic groups and non-inflammatory controls. In RA FAP protein was expressed in both lining and sublining layers. Podoplanin expression was higher in all early inflammatory arthritis patients than controls, but did not differentiate diagnostic outcomes. Stromal marker expression was not associated with prognostic outcomes of disease persistence or resolution. There was no association with clinical or sonographic variables. CONCLUSIONS: Stromal cell markers CD55, CD248, FAP and podoplanin are expressed in ST in the earliest stage of arthritis. Baseline expression of FAP is higher in early synovitis patients who fulfil classification criteria for RA over time. These results suggest that significant fibroblast activation occurs in RA in the early window of disease.

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.