Therapeutic interception in individuals at risk of rheumatoid arthritis to prevent clinically impactful disease.

Multiple clinical trials for rheumatoid arthritis (RA) prevention have been completed. Here, we set out to report on the lessons learnt from these studies. Researchers who conducted RA prevention trials shared the background, rationale, approach and outcomes and evaluated the lessons learnt to inform the next generation of RA prevention trials. Individuals at risk of RA can be identified through population screening, referrals to musculoskeletal programmes and by recognition of arthralgia suspicious for RA. Clinical trials in individuals at risk for future clinical RA have demonstrated that limited courses of corticosteroids, atorvastatin and hydroxychloroquine do not alter incidence rates of clinical RA; however, rituximab delays clinical RA onset, and methotrexate has transient effects in individuals who are anticitrullinated protein antibody-positive with subclinical joint inflammation identified by imaging. Abatacept delays clinical RA onset but does not fully prevent onset of RA after treatment cessation. Additionally, subclinical joint inflammation and symptoms appear responsive to interventions such as methotrexate and abatacept. To advance prevention, next steps include building networks of individuals at risk for RA, to improve risk stratification for future RA and to understand the biological mechanisms of RA development, including potential endotypes of disease, which can be targeted for prevention, thus adopting a more precision-based approach. Future trials should focus on interceptions aimed at preventing clinical RA onset and which treat existing symptoms and imaging-defined subclinical inflammation. These trials may include advanced designs (eg, adaptive) and should be combined with mechanistic studies to further define pathophysiological drivers of disease development.

Elevated Serum Levels of Zonulin Family Peptides in Anticitrullinated Protein Antibody-Positive At-Risk Individuals Without Arthritis.

OBJECTIVE: Recent advances imply that early events triggering rheumatoid arthritis (RA) occur at mucosal surfaces. We aimed to evaluate whether intestinal permeability is altered in patients at increased risk of RA, and/or predicts the development of clinical arthritis, by measuring serum zonulin family peptides (ZFP) levels, which are shown to reflect intestinal barrier integrity. METHODS: Two independent prospective observational cohorts were studied, including subjects with musculoskeletal symptoms and anticitrullinated protein antibodies (ACPA), but without clinical arthritis at baseline. In Sweden, 82 such at-risk patients were compared to 100 age-matched healthy blood donors. In the UK, 307 at-risk patients were compared to 100 ACPA-negative symptomatic controls. ZFP was measured in baseline sera by enzyme-linked immunoassays. RESULTS: In the Swedish at-risk cohort, ZFP levels were significantly increased in patients compared to controls (mean 41.4 vs 33.6 ng/mL, P < 0.001) and Cox regression analysis showed prognostic value of ZFP for arthritis development (hazard ratio [HZ] 1.04 per ng/mL ZFP increase, 95% CI 1.01-1.07, P = 0.02). Elevated ZFP levels among ACPA-positive at-risk patients compared to symptomatic ACPA-negative controls were confirmed in the UK at-risk cohort (mean 69.7 vs 36.0 ng/mL, P < 0.001), but baseline ZFP were not associated with arthritis development (HR 1.00 per ng/mL ZFP increase, 95% CI 1.00-1.01, P = 0.30). CONCLUSION: Serum ZFP levels are elevated in ACPA-positive at-risk patients when compared to both healthy blood donors and symptomatic ACPA-negative controls. Thus, gut barrier function may be of importance in RA-associated autoimmunity. A possible prognostic value of serum ZFP merits further investigation, preferably in larger prospective cohorts.

Predicting Inflammatory Arthritis in At-Risk Persons: Development of Scores for Risk Stratification.

BACKGROUND: Inflammatory arthritis (IA) is an immune-related condition defined by the presence of clinical synovitis. Its most common form is rheumatoid arthritis. OBJECTIVE: To develop scores for predicting IA in at-risk persons using multidimensional biomarkers. DESIGN: Prospective observational cohort study. SETTING: Single-center, Leeds, United Kingdom. PARTICIPANTS: Persons with new musculoskeletal symptoms, a positive test result for anticitrullinated protein antibodies, and no clinical synovitis and followed for 48 weeks or more or until IA occurred. MEASUREMENTS: A simple score was developed using logistic regression, and a comprehensive score was developed using the least absolute shrinkage and selection operator Cox proportional hazards regression. Internal validation with bootstrapping was estimated, and a decision curve analysis was done. RESULTS: Of 455 participants, 32.5% (148 of 455) developed IA, and 15.4% (70 of 455) developed it within 1 year. The simple score identified 249 low-risk participants with a false negative rate of 5% (and 206 high-risk participants with a false-positive rate of 72%). The comprehensive score identified 119 high-risk participants with a false-positive rate of 29% (and 336 low-risk participants with a false-negative rate of 19%); 40% of high-risk participants developed IA within 1 year and 71% within 5 years. LIMITATIONS: External validation is required. Recruitment occurred over 13 years, with lower rates of IA in later years. There was geographic variation in laboratory testing and recruitment availability. CONCLUSION: The simple score identified persons at low risk for IA who were less likely to need secondary care. The comprehensive score identified high-risk persons who could benefit from risk stratification and preventive measures. Both scores may be useful in clinical care and should also be useful in clinical trials. PRIMARY FUNDING SOURCE: National Institute for Health and Care Research Leeds Biomedical Research Centre.

Lymphocyte subset phenotyping for the prediction of progression to inflammatory arthritis in anti-citrullinated-peptide antibody-positive at-risk individuals.

OBJECTIVES: Inflammatory arthritis (IA) is considered the last stage of a disease continuum, where features of systemic autoimmunity can appear years before clinical synovitis. Time to progression to IA varies considerably between at-risk individuals, therefore the identification of biomarkers predictive of progression is of major importance. We previously reported on the value of three CD4+T-cell subsets as biomarkers of progression. Here, we aim to establish the value of 18 lymphocyte subsets (LS) for predicting progression to IA. METHODS: Participants were recruited based on a new musculoskeletal complaint and being positive for anti-citrullinated-peptide Antibody. Progression (over 10 years) was defined as the development of clinical synovitis. LS analysis was performed for lymphocyte lineages, naïve/memory subsets, inflammation-related cells (IRC), and regulatory cells (Treg/B-reg). Modelling used Logistic/Cox regressions. RESULTS: Of 210 patients included, 93 (44%) progressed to IA, 41/93 (44%) within 12 months (rapid progressors). 5/18 LS were associated with progression (Treg/CD4-naïve/IRC (adjusted p < 0.0001), CD8 (p = 0.021), B-reg (p = 0.015)) and 3 trends (NK-cells/memory-B-cells/plasmablasts).Unsupervised hierarchical clustering using these 8 subsets segregated 3 clusters of patients, one cluster being enriched (63/109(58%)) and one poor (10/45(22%)) in progressors.Combining all clinical and LS variables, forward logistic regression predicted progression with accuracy=85.7% and AUC=0.911, selecting smoking/Rheumatoid-Factor/HLA-Shared-Epitope/Tender-Joint-Count-78 and Treg/CD4-naive/CD8/NK-cells/B-reg/plasmablasts.To predict rapid progression, a Cox regression was performed resulting in a model combining smoking/rheumatoid factor and IRC/CD4-naïve/Treg/NK-cells/CD8+T-cells (AUC=0.794). CONCLUSION: Overall, progression was predicted by specific LS, suggesting potential triggers for events leading to the development of IA, while rapid progression was associated with a different set of subsets.

Ultrasound in anti-CCP+ at-risk individuals without clinical synovitis: development of a novel 6-joint protocol for feasible risk prediction.

OBJECTIVES: To investigate, in anti-cyclic citrullinated peptide antibody positive individuals with musculoskeletal symptoms but no clinical synovitis (CCP+ at-risk), the additional value of ultrasound (US) for the prediction of inflammatory arthritis (IA). Furthermore, to define a concise US protocol for feasible risk prediction. METHODS: Demographic and clinical data were collected in 417 CCP+ at-risk (Leeds CCP cohort) with a baseline US scan assessing synovitis and bone erosions in 36 joints, and a follow-up duration ≥24 months. Multivariable binary regression models for IA development at 24 months evaluated routine clinical variables associated with IA alone ("clinical" model) and combined with a 36-joint US scanning protocol ("clinical-US extended" model). A "clinical-US short" model was developed. RESULTS: At 24 months, 92/417 (22.1%) CCP+ at-risk developed IA (median time: 7 months, IQR : 3-12). The "clinical-US extended" model performed better than the "clinical" model (AUC 0.788 vs AUC 0.731 respectively, p< 0.001) with an odds ratio for IA development of 3.18 (95% IC 1.80-5.63) for US synovitis and 2.54 (95% IC 1.21-5.37) for bone erosions. The "clinical-US short" model, which retained the wrists, knees and MTP5 joints, performed better (AUC 0.782) than the "clinical" model (p< 0.001) and similarly (difference in Akaike information criteria <2) to the "clinical-US extended" model. CONCLUSIONS: US provides valuable information for predicting progression to IA in CCP+ individuals both alone and in addition to clinical variables. US synovitis was associated with a threefold increase risk of IA development. A concise US protocol of 6 joints provides clinically feasible risk prediction in CCP+ at-risk.

Can biomarkers predict successful tapering of conventional disease-modifying therapy in rheumatoid arthritis patients in stable remission?

OBJECTIVES: Specific guidelines for managing RA patients in clinical remission for ≥6 months on cs-DMARDs are lacking. Tapering of treatment is encouraged, however, without validated biomarkers for success. We aimed to assess the rate of sustained remission after 12 months in patients who either (i) followed structured cs-DMARD tapering or (ii) continued therapy, focusing on the added value of biomarkers as predictors of outcome. METHODS: RA patients fulfilling 3v-DAS28CRP<2.6 for ≥6 months on stable cs-DMARD therapy were included. Patients were offered structured tapering, with 117 accepting tapering and 83 continuing therapy. Clinical, ultrasound, immunological (T-cell subsets) and patient-reported outcome (PRO) data were collected. The primary endpoint was the proportion of patients in sustained remission without relapse after 12 months. Regression analyses were used to identify predictors of sustained remission. RESULTS: Of those who tapered, 64% remained in clinical remission after 12 months compared with 80% (p=0.018) of patients on stable treatment. In the tapering group, higher levels of CRP, TJC, % inflammation-related T-cell (IRC) and PROs were associated with flare (all p<0.05), with a trend for total PD (p=0.066). A model predicting sustained remission retained RAQoL, total PD and IRC (85% accuracy, AUROC=0.893, p<0.0001). In the non-tapering group, higher CRP, ESR, SJC and shorter disease duration (all p<0.05) were associated with flare, with no parameter able to predict sustained remission. CONCLUSIONS: In the tapering group, the combination of clinical, PRO, US and T-cell parameters demonstrated added value for predicting sustained remission compared with clinical parameters alone. These data may inform best tapering practice.

Perceptions and experiences of individuals at-risk of rheumatoid arthritis (RA) knowing about their risk of developing RA and being offered preventive treatment: systematic review and thematic synthesis of qualitative studies.

OBJECTIVES: There is increasing interest in identifying individuals at-risk of rheumatoid arthritis (RA) and initiating early treatment to prevent or delay the onset of arthritis. We aimed to describe the perceptions and experiences of at-risk individuals and to inform the conduct of clinical trials and studies, and clinical practice. METHODS: A systematic review and thematic synthesis of qualitative studies was conducted. Two review authors independently screened studies for inclusion, appraised their methodological quality using the Critical Appraisal Skills Programme checklist and assessed confidence in the findings using the Grading of Recommendations Assessment, Development and Evaluation-Confidence in Evidence from Reviews of Qualitative Research approach. RESULTS: Seven studies involving 115 individuals at-risk of developing RA were included. Three major themes (seven subthemes) were identified: understanding the risk of developing RA (knowledge of RA and identification of potential risk factors); preventive interventions to reduce the risk of developing RA (understanding the value and role of preventive interventions, and engagement with preventive interventions); and perceptions of predictive testing for RA (benefits of predictive testing, decision to undertake predictive testing and concerns about predictive testing). Moderate confidence in most review findings was evident. CONCLUSION: While there are clear benefits in informing individuals at-risk of RA about their risk following predictive testing and offering preventive treatment, there are potential barriers to engagement, intensified by the burden of uncertainty. Identification of the optimum approaches for presenting risk information, including the risks and benefits of engaging with preventive interventions, is urgently needed to support individuals at-risk of RA in their decision making. PROSPERO REGISTRATION NUMBER: CRD42021236034.

Determining in which pre-arthritis stage HLA-shared epitope alleles and smoking exert their effect on the development of rheumatoid arthritis.

OBJECTIVES: The human leukocyte antigen-shared epitope (HLA-SE) alleles and smoking are the most prominent genetic and environmental risk factors for rheumatoid arthritis (RA). However, at which pre-arthritis stage (asymptomatic/symptomatic) they exert their effect is unknown. We aimed to determine whether HLA-SE and smoking are involved in the onset of autoantibody positivity, symptoms (clinically suspect arthralgia (CSA)) and/or progression to clinical arthritis. METHODS: We performed meta-analyses on results from the literature on associations of HLA-SE and smoking with anti-citrullinated protein antibodies (ACPAs) in the asymptomatic population. Next, we studied associations of HLA-SE and smoking with autoantibody positivity at CSA onset and with progression to clinical inflammatory arthritis (IA) during follow-up. Associations in ACPA-positive patients with CSA were validated in meta-analyses with other arthralgia cohorts. Analyses were repeated for rheumatoid factor (RF), anti-carbamylated protein antibodies (anti-CarP) and anti-acetylated protein antibodies (AAPA). RESULTS: Meta-analyses showed that HLA-SE is not associated with ACPA positivity in the asymptomatic population (OR 1.06 (95% CI:0.69 to 1.64)), whereas smoking was associated (OR 1.37 (95% CI: 1.15 to 1.63)). At CSA onset, both HLA-SE and smoking associated with ACPA positivity (OR 2.08 (95% CI: 1.24 to 3.49), OR 2.41 (95% CI: 1.31 to 4.43)). During follow-up, HLA-SE associated with IA development (HR 1.86 (95% CI: 1.23 to 2.82)), in contrast to smoking. This was confirmed in meta-analyses in ACPA-positive arthralgia (HR 1.52 (95% CI: 1.08 to 2.15)). HLA-SE and smoking were not associated with RF, anti-CarP or AAPA-positivity at CSA onset. Longitudinally, AAPA associated with IA development independent from ACPA and RF (HR 1.79 (95% CI: 1.02 to 3.16)), anti-CarP did not. CONCLUSIONS: HLA-SE and smoking act at different stages: smoking confers risk for ACPA and symptom development, whereas HLA-SE mediates symptom and IA development. These data enhance the understanding of the timing of the key risk factors in the development of RA.

Ultrasound subclinical synovitis in anti-CCP-positive at-risk individuals with musculoskeletal symptoms: an important and predictable stage in the rheumatoid arthritis continuum.

OBJECTIVES: To investigate whether anti-CCP2-positive at-risk individuals with musculoskeletal (MSK) symptoms but without clinical synovitis (CCP2+ at-risk) develop US subclinical synovitis before inflammatory arthritis and if US subclinical synovitis can be predicted. METHODS: First, US scans of CCP2+ at-risk individuals who developed inflammatory arthritis ('progressors') were reviewed for subclinical synovitis prior to inflammatory arthritis development. Patients in whom the pre-progression US scan was negative but the scan was conducted >6 months before progression were excluded. Subsequently, regression analyses were performed to identify predictors of US synovitis in CCP2+ at-risk individuals without baseline US abnormalities who had one or more longitudinal US scan and a complete dataset. RESULTS: US subclinical synovitis was detected in one or more scan in 75 of 97 progressors (77.3%) {median time to inflammatory arthritis development from first evidence of US synovitis 26.5 weeks [interquartile range (IQR) 7-60]}, in whom one or more scan was available, excluding those with a negative scan >6 months from inflammatory arthritis development (n = 38). In 220 CCP2+ at-risk individuals with normal baseline US scans, who had one or more longitudinal US scan and a complete dataset, US synovitis was detected in 69/220 (31.4%) [median time to first developing US synovitis 56.4 weeks (IQR 33.0-112.0)]. In the multivariable analysis, only anti-CCP3 antibodies were predictive for the development of US synovitis [odds ratio 4.75 (95% CI 1.97, 11.46); P < 0.01]. CONCLUSIONS: In anti-CCP2+ at-risk individuals, a stage of subclinical synovitis usually precedes the development of inflammatory arthritis. Anti-CCP2+/CCP3+ individuals without clinical or US subclinical synovitis may represent the optimal window of opportunity for intervention to prevent joint disease.

Dysbiosis in the oral microbiomes of anti-CCP positive individuals at risk of developing rheumatoid arthritis.

OBJECTIVES: An increased prevalence of periodontitis and perturbation of the oral microbiome has been identified in patients with rheumatoid arthritis (RA). The periodontal pathogen Porphyromonas gingivalis may cause local citrullination of proteins, potentially triggering anti-citrullinated protein antibody production. However, it is not known if oral dysbiosis precedes the onset of clinical arthritis. This study comprehensively characterised the oral microbiome in anti-cyclic citrullinated peptide (anti-CCP) positive at-risk individuals without clinical synovitis (CCP+at risk). METHODS: Subgingival plaque was collected from periodontally healthy and diseased sites in 48 CCP+at risk, 26 early RA and 32 asymptomatic healthy control (HC) individuals. DNA libraries were sequenced on the Illumina HiSeq 3000 platform. Taxonomic profile and functional capability of the subgingival microbiome were compared between groups. RESULTS: At periodontally healthy sites, CCP+at risk individuals had significantly lower microbial richness compared with HC and early RA groups (p=0.004 and 0.021). Microbial community alterations were found at phylum, genus and species levels. A large proportion of the community differed significantly in membership (523 species; 35.6%) and structure (575 species; 39.1%) comparing CCP+at risk and HC groups. Certain core species, including P. gingivalis, had higher relative abundance in the CCP+at risk group. Seventeen clusters of orthologous gene functional units were significantly over-represented in the CCP+at risk group compared with HC (adjusted p value <0.05). CONCLUSION: Anti-CCP positive at-risk individuals have dysbiotic subgingival microbiomes and increased abundance of P. gingivalis compared with controls. This supports the hypothesis that the oral microbiome and specifically P. gingivalis are important in RA initiation.

EULAR points to consider for conducting clinical trials and observational studies in individuals at risk of rheumatoid arthritis.

BACKGROUND: Despite growing interest, there is no guidance or consensus on how to conduct clinical trials and observational studies in populations at risk of rheumatoid arthritis (RA). METHODS: An European League Against Rheumatism (EULAR) task force formulated four research questions to be addressed by systematic literature review (SLR). The SLR results informed consensus statements. One overarching principle, 10 points to consider (PTC) and a research agenda were proposed. Task force members rated their level of agreement (1-10) for each PTC. RESULTS: Epidemiological and demographic characteristics should be measured in all clinical trials and studies in at-risk individuals. Different at-risk populations, identified according to clinical presentation, were defined: asymptomatic, musculoskeletal symptoms without arthritis and early clinical arthritis. Study end-points should include the development of subclinical inflammation on imaging, clinical arthritis, RA and subsequent achievement of arthritis remission. Risk factors should be assessed at baseline and re-evaluated where appropriate; they include genetic markers and autoantibody profiling and additionally clinical symptoms and subclinical inflammation on imaging in those with symptoms and/or clinical arthritis. Trials should address the effect of the intervention on risk factors, as well as progression to clinical arthritis or RA. In patients with early clinical arthritis, pharmacological intervention has the potential to prevent RA development. Participants' knowledge of their RA risk may inform their decision to participate; information should be provided using an individually tailored approach. CONCLUSION: These consensus statements provide data-driven guidance for rheumatologists, health professionals and investigators conducting clinical trials and observational studies in individuals at risk of RA.

Perturbations of the gut microbiome in anti-CCP positive individuals at risk of developing rheumatoid arthritis.

OBJECTIVE: Individuals with newly diagnosed RA have a distinct microbiome when compared with healthy controls. However, little is known as to when these microbiome perturbations begin. Using a prospective at-risk cohort of individuals positive for anti-citrullinated protein (anti-CCP) antibody with new onset musculoskeletal symptoms, but without clinical arthritis, we investigated for the presence of a gut dysbiosis before the onset of RA. METHODS: The gut microbiota of 25 anti-CCP positive individuals without clinical synovitis were sequenced targeting the V4 region of the 16S rRNA gene. Using a publicly available database, a control population of 44 individuals, approximately matched in age, gender, diet and ethnicity was selected for comparison, using the same sequencing methodology. Median interval between sample collection and progression to RA was 188 days. Taxonomic analysis was performed using QIIME and MEGAN, and statistical analysis using R software. RESULTS: There were significant differences (P =0.01) at family level in gut microbiomes of anti-CCP positive individuals vs controls. The anti-CCP positive population had an overabundance of Lachnospiraceae, Helicobacteraceae, Ruminococcaceae, Erysipelotrichaceae and Bifidobacteriaceae, among others. Five individuals progressed to RA between sample collection and analysis. Clustering of the progressor population was observed on a phylogenetic network created using a probabilistic similarity index (Goodall's index). CONCLUSIONS: Anti-CCP positive at-risk individuals without clinical synovitis appear to have a distinct gut microbiome compared with healthy controls. Phylogenetic clustering was observed in individuals who progressed to RA, suggesting that distinct taxa are associated with the development of RA many months before its onset.

In anti-CCP+ at-risk individuals, radiographic bone erosions are uncommon and are not associated with the development of clinical arthritis.

OBJECTIVES: To investigate the prevalence, distribution and predictive value for the development of inflammatory arthritis (IA) of conventional radiography (CR) bone erosions (BE) in anti-CCP positive (CCP+) at-risk individuals with musculoskeletal (MSK) symptoms but without clinical synovitis. METHODS: Baseline CR of the hands and feet of 418 CCP+ at-risk individuals were analysed. The presence of US-BE was explored in the anatomical areas in which CR-BE were reported. Hands and feet CR at the time of progression were analysed in a subset of individuals who developed IA (73/123, 59.3%). Logistic regression analyses were performed to calculate the predictive value of baseline CR-BE for the development of IA in 394 CCP+ individuals with ≥1 follow-up visit. RESULTS: BE were detected in 17/418 (4.1%) CCP+ at-risk individuals (median Simple Erosions Narrowing Score-BE = 2.0, IQR: 1.0-2.0; median Sharp van der Heijde score-BE = 4.0, IQR: 3.0-8.5), most frequently in the foot joints (11/17, 64.7% individuals). A total of 123/394 (31.2%) CCP+ at-risk individuals developed IA; 7/17 (41.2%) with, and 116/377 (30.8%) without BE on CR (P = 0.37). US-BE were found in 4/7 (57.1%) individuals with CR-BE who developed IA, but only in 1/10 (10.0%) who did not. At the time of progression, new BE were detected in 4/73 (5.5%) CCP+ individuals on repeated CR. In the regression analyses, baseline CR-BE were not predictive for the development of IA. CONCLUSIONS: In CCP+ at-risk individuals with MSK symptoms, CR-detected BE are uncommon and do not predict the development of IA.

Ultrasound erosions in the feet best predict progression to inflammatory arthritis in anti-CCP positive at-risk individuals without clinical synovitis.

OBJECTIVES: To investigate, in anti-cyclic citrullinated peptide antibody positive (CCP+) at-risk individuals without clinical synovitis, the prevalence and distribution of ultrasound (US) bone erosions (BE), their correlation with subclinical synovitis and their association with the development of inflammatory arthritis (IA). METHODS: Baseline US scans of 419 CCP+ at-risk individuals were analysed. BE were evaluated in the classical sites for rheumatoid arthritis damage: the second and fifth metacarpophalangeal (MCP2 and MCP5) joints, and the fifth metatarsophalangeal (MTP5) joints. US synovitis was defined as synovial hypertrophy (SH) ≥2 or SH ≥1+power Doppler signal ≥1. Subjects with ≥1 follow-up visit were included in the progression analysis (n=400). RESULTS: BE were found in ≥1 joint in 41/419 subjects (9.8%), and in 55/2514 joints (2.2%). The prevalence of BE was significantly higher in the MTP5 joints than in the MCP joints (p<0.01). A significant correlation between BE and US synovitis in the MTP5 joints was detected (Cramer's V=0.37, p<0.01). The OR for the development of IA (ever) was highest for the following: BE in >1 joint 10.6 (95% CI 1.9 to 60.4, p<0.01) and BE and synovitis in ≥1 MTP5 joint 5.1 (95% CI 1.4 to 18.9, p=0.02). In high titre CCP+ at-risk individuals, with positive rheumatoid factor and BE in ≥1 joint, the OR increased to 16.9 (95% CI 2.1-132.8, p<0.01). CONCLUSIONS: In CCP+ at-risk individuals, BE in the feet appear to precede the onset of clinical synovitis. BE in >1 joint, and BE in combination with US synovitis in the MTP5 joints, are the most predictive for the development of clinical arthritis.

Prevention and cure: The major unmet needs in the management of rheumatoid arthritis.

The outcome of treatment of patients with rheumatoid arthritis (RA) has qualitatively improved in recent years due to better and earlier treatment approaches, and new drugs. It is now generally accepted that the phenotype of RA is the end-point of a disease continuum. Large retrospective studies have identified anti-citrullinated protein antibodies (ACPAs) and rheumatoid factor in the stored serum of patients, years before the development of clinical RA. Recent data suggest mucosal sites such as the oral mucosa (in particular the periodontium), lung and gut may be the sites where auto-immunity is initiated. The role of bacteria at these sites is reviewed. Much recent work has focussed on the role of high resolution imaging namely ultrasound and magnetic resonance imaging in identifying subclinical inflammation in at-risk individuals with early musculoskeletal symptoms (e.g. arthralgia) but without clinical synovitis. Importantly, the first musculoskeletal site involved is usually not the joint (synovium). Sub-clinical disease predicts the onset of clinical arthritis, and its timing, in symptomatic at-risk individuals. These and other predictive markers will be described. The ability to identify patients at-risk of RA before joint involvement has led to interventions aimed at preventing/delaying disease. Once arthritis occurs, rapid remission is the target of therapy. The percentage of patients with RA achieving clinical remission has improved markedly compared with a few decades ago. The optimum outcome is to induce remission sufficiently profound so that therapy can be stopped, without flare, that is drug-free remission, which is effectively cure. Limitations of the tools used to measure remission, the outcome of tapering therapy, and new approaches to achieve successful drug cessation are described. Overall, this article reviews progress towards meeting the unmet needs of prevention/cure.

The Role of Musculoskeletal Ultrasound in the Rheumatoid Arthritis Continuum.

PURPOSE OF REVIEW: Rheumatoid arthritis (RA) is no longer considered a fixed phenotype but rather a disease continuum. This review outlines the current and potential value of applying ultrasound (US) along this continuum: from the prediction of progression to RA in at-risk individuals, to confirmation of the early diagnosis of RA, as well as the consideration of differential diagnoses, and the use in disease monitoring and defining remission. RECENT FINDINGS: In individuals at-risk of RA (i.e., positive autoantibodies with symptoms but without synovitis), US has shown a promising predictive value for the development of clinical arthritis, providing the opportunity to improve risk stratification (and disease prevention) of these individuals. The detection of inflammation on US in patients with early undifferentiated arthritis, in which a definite diagnosis cannot be reached, could predict evolution to persistent arthritis, mostly RA. This, in addition to the US potential ability to identify disease specific patterns for different rheumatic conditions, might facilitate early diagnosis and, therefore, improve the management of patients with RA, or other types of inflammatory arthritides. US has also demonstrated the capability to predict radiographic progression, and relapse risk after treatment discontinuation, in RA patients in remission according to the clinical instruments, raising implications in the management, including therapy discontinuation, of these patients. US has an undeniable value in the management of patients at different stages along the RA continuum. Further research is needed to identify which groups of patients benefit the most from US imaging.

Identification of a distinct imaging phenotype may improve the management of palindromic rheumatism.

OBJECTIVES: To use high-resolution imaging to characterise palindromic rheumatism (PR) and to compare the imaging pattern observed to that seen in new-onset rheumatoid arthritis (NORA). METHODS: Ultrasound (US) assessment of synovitis, tenosynovitis and non-synovial extracapsular inflammation (ECI) was performed during and between flares in a prospective treatment-naive PR cohort. MRI of the flaring region was performed where possible. For comparison, the same US assessment was also performed in anticyclic citrullinated peptide (CCP) positive individuals with musculoskeletal symptoms (CCP+ at risk) and patients with NORA. RESULTS: Thirty-one of 79 patients with PR recruited were assessed during a flare. A high frequency of ECI was identified on US; 19/31 (61%) of patients had ECI including 12/19 (63%) in whom ECI was identified in the absence of synovitis. Only 7/31 (23%) patients with PR had synovitis (greyscale ≥1 and power Doppler ≥1) during flare. In the hands/wrists, ECI was more prevalent in PR compared with NORA and CCP+ at risk (65% vs 29 % vs 6%, p<0.05). Furthermore, ECI without synovitis was specific for PR (42% PR vs 4% NORA (p=0.003) and 6% CCP+ at risk (p=0.0012)). Eleven PR flares were captured by MRI, which was more sensitive than US for synovitis and ECI. 8/31 (26%) patients with PR developed RA and had a similar US phenotype to NORA at progression. CONCLUSION: PR has a distinct US pattern characterised by reversible ECI, often without synovitis. In patients presenting with new joint swelling, US may refine management by distinguishing relapsing from persistent arthritis.

MRI inflammation of the hand interosseous tendons occurs in anti-CCP-positive at-risk individuals and may precede the development of clinical synovitis.

Interosseous tendon inflammation (ITI) has been described in rheumatoid arthritis (RA). Whether ITI occurs in at-risk individuals before the onset of clinical synovitis is unknown. OBJECTIVES: To investigate, by MRI, ITI in anti-cyclic citrullinated peptide (CCP)-positive at-risk individuals (CCP +at risk) and to describe the anatomy, prevalence and clinical associations across the RA continuum. METHODS: Hand MRI was performed in 93 CCP + at risk, 47 early RA (ERA), 28 established 'late' RA (LRA) and 20 healthy controls (HC) and scored for ITI, flexor tenosynovitis (TSV) and RA MRI scoring at the metacarpophalangeal joints (MCPJs). Cadaveric and histological studies were performed to explore the anatomical basis for MRI ITI. RESULTS: The proportion of subjects with ITI and the number of inflamed interosseous tendons (ITs) increased along the disease continuum (p<0.001): 19% of CCP +at risk, 49% of ERA and 57% of LRA had ≥1 IT inflamed . ITI was not found in any HC. ITI was more frequently identified in tender MCPJs compared with nontender MCPJs (28% vs 12%, respectively). No IT tenosynovial sheath was identified in cadavers on dissection or histological studies suggesting MRI findings represent peritendonitis. Dye studies indicated no communication between the IT and the joint. CONCLUSIONS: ITI occurs in CCP + at-risk individuals and can precede the onset of clinical synovitis. The ITs may be important nonsynovial extracapsular targets in the development and progression of RA.

A new window of opportunity in rheumatoid arthritis: targeting at-risk individuals.

PURPOSE OF REVIEW: Progress in our understanding of the preclinical events in rheumatoid arthritis (RA) has provided important insights into disease pathogenesis. Studying prospective cohorts of individuals at risk for RA development offers the opportunity to accurately characterize the sequence of events in preclinical disease as well as quantify the risk of different preclinical phenotypes. These data may provide the basis for preventive strategies in RA. RECENT FINDINGS: RA-related systemic autoimmunity and inflammation occur long before clinical arthritis. There is growing evidence that initiating events may occur at mucosal surfaces including the periodontium, lung and gut and may be influenced by the local microbiome. For potential preventive strategies to be feasible, it is important that individuals at high risk for RA development can be readily identified from the general population. To this end, studying multiple biomarkers in prospective cohorts of at-risk individuals enables risk prediction in different at-risk phenotypes. RA prevention using immunomodulation is currently being investigated in individuals at high risk of RA development. SUMMARY: The prospective study of at-risk individuals can provide invaluable aetiological insights as well as facilitating accurate risk prediction data. In this way, high-risk individuals may be identified for preventive interventions.