Palindromic rheumatism as part of the rheumatoid arthritis continuum

Performance of existing diagnostic criteria for palindromic rheumatism

BACKGROUND

Four criteria have been proposed for the diagnosis of palindromic rheumatism (PR), including those of Hannonen et al., Passero and Barbieri, Guerne and Weisman, and Gonzalez-López. But none of these criteria has been validated. In this research, we investigated the performance of these diagnostic criteria for diagnosing PR.

METHODS

In this study, PR and control groups were consecutively recruited from a prospective cohort of intermittent arthritis. Inclusion criteria for PR group were diagnosing PR by an expert rheumatologist, age ≥ 18, having at least 6 months follow-up, and ruling out of other causes of intermittent arthritis. These criteria were applied to both groups. Sensitivity, specificity, positive predictive value, negative predictive value, diagnostic odds ratio (DOR), and Youden's index were calculated for each criteria.

RESULTS

This study included 197 consecutive subjects diagnosed with PR and 208 subjects with a diagnosis other than PR. The sensitivity of Hannonen et al. criteria was higher than the Gonzalez-Lopez, Guerne and Weisman, and Pasero and Barbieri criteria (96.4% versus 95.4%, 79.2%, and 35.5%, respectively). The specificity of the Pasero and Barbieri criteria was higher than the other criteria. Hannonen al. criteria with a DOR of 325.7, had the highest DOR. In descending order, the best accuracy belonged to Hannonen et al., Gonzalez-Lopez, Guerne and Weisman, and Pasero and Barbieri criteria (94.3%, 94.1%, 86.4%, and 66.9% respectively).

CONCLUSION

This study showed that the Hannonen et al. and Gonzalez-Lopez criteria have a better performance in diagnosing PR. Key Points • The sensitivity of Hannonen et al. criteria and the specifity of Passero and Barbieri criteria are higher than other proposed criteria for diagnosis of palindromic rheumatism. • Hannonen et al. criteria with a sensitivity of 96.4%, specifity of 92.3% and accuracy of 94.3% has the best performance in diagnosis of palindromic rheumatism between existing diagnostic criteria for palindromic rheumatism.

A Distinct Instance of Palindromic Rheumatism Disguised as Polymyalgia Rheumatica

In this case report, we highlight a rare case of palindromic rheumatism (PR) presenting as polymyalgia rheumatica (PMR). Many challenges and complexities are associated with diagnosing and treating PR. Literature reviews showed only a few case reports of this unique presentation. PR has a distinct presentation that often goes unnoticed and is misinterpreted by medical professionals. A more thorough clinical approach is required to identify and treat this condition. We hope sharing such uncommon cases will help the medical community better understand PR and develop improved diagnostic and therapeutic options. This case also demonstrates the need for further research to better understand the pathogenesis of this uncommon condition.

Rheumatoid arthritis: prediction of future clinically-apparent disease, and prevention

PURPOSE OF REVIEW

This review discusses updates in the prediction and prevention of future rheumatoid arthritis (RA).

RECENT FINDINGS

In individuals with musculoskeletal symptoms and elevated antibodies to citrullinated proteins (ACPA) without clinical inflammatory arthritis (IA), a 'simple' score has a positive predictive value (PPV) of ∼28% for clinical IA/RA within 1 year, and a comprehensive score (including ultrasound) has a PPV of ∼71% for clinical RA within 5 years. Controlled clinical trials in individuals at-risk for future RA have been performed using corticosteroids, rituximab, atorvastatin, methotrexate, hydroxychloroquine and abatacept. Abatacept modestly reduced rates of incident clinical RA and imaging inflammation within the trials, rituximab delayed clinical IA, and methotrexate improved function, symptoms and imaging inflammation. Vitamin D with or without omega 3 fatty acids reduced incidence of autoimmune diseases, including RA. While not proven in controlled clinical trials, observational studies suggest exercise, weight loss and smoking cessation may reduce progression to clinical RA.

SUMMARY

Prediction and prevention of RA is advancing although there are no currently approved interventions for prevention. Future studies should include deeper evaluation of the pathophysiology of RA development to improve prediction and identify key pathways to target in future clinical trials, as well as develop infrastructure to support prevention-related research.

Lycocasine A, a Lycopodium Alkaloid from Lycopodiastrum casuarinoides and Its Acid-Sensing Ion Channel 1a Inhibitory Activity

A novel Lycopodium alkaloid, lycocasine A (1), and seven known Lycopodium alkaloids (2-8), were isolated from Lycopodiastrum casuarinoides. Their structures were determined through NMR, HRESIMS, and X-ray diffraction analysis. Compound 1 features an unprecedented 5/6/6 tricyclic skeleton, highlighted by a 5-aza-tricyclic[6,3,1,02,6]dodecane motif. In bioactivity assays, compound 1 demonstrated weak inhibitory activity against acid-sensing ion channel 1a.

Vitamin D Status in Palindromic Rheumatism: A Propensity Score Matching Analysis

OBJECTIVE

To determine whether there is a correlation between vitamin D levels and palindromic rheumatism (PR) as an at-risk phenotype of rheumatoid arthritis (RA).

METHODS

A total of 308 participants were enrolled in this cross-sectional study. We recorded their clinical characteristics and performed propensity-score matching (PSM). Serum 25(OH)D3 levels were determined via enzyme-linked immunosorbent assay.

RESULTS

Our PSM resulted in 48 patients with PR and 96 matched control individuals. The multivariate regression analysis we performed after the PSM did not show a significant increase in PR risk in patients with vitamin D deficiency/insufficiency. There was no significant correlation between levels of 25(OH)D3 and frequency/duration of attacks, number of joints affected, and duration of symptoms before diagnosis (P ≥ .05). Mean (SD) serum levels of 25(OH)D3 in patients with and without progression to RA were 28.7 (15.9) ng/mL and 25.1 (11.4) ng/mL, respectively.

CONCLUSION

Based on the results, we found no clear association between vitamin D serum levels and the risk, severity, and rate of PR progressing into RA.

Palindromic Rheumatism Improved After Bariatric Surgery: A Case Report

Palindromic rheumatism (PR) is a unique syndrome considered a prelude to rheumatoid arthritis (RA). It is characterized by recurrent, unpredictable episodes of joint inflammation and distinct clinical features. Unlike RA, PR episodes are brief and reversible, involving sudden-onset joint pain, swelling, and erythema. The exact etiology and diagnostic criteria of PR remain elusive, but it often shares autoantibodies with RA, leading patients to transition from PR to RA. The management of PR is multifaceted and empirical, involving various treatment modalities such as non-steroidal anti-inflammatory drugs (NSAIDs), colchicine, and disease-modifying anti-rheumatic drugs (DMARDs). However, the relationship between obesity and PR remains underexplored. This case presents a 52-year-old woman, who presented to our hospital with recurrent and debilitating arthritis episodes since 2016. Initially affecting her wrists and later extending to her knees, shoulders, and back, these episodes severely impaired her daily activities. Despite a diagnosis of RA in 2019, supported by a positive rheumatoid factor (RF) test, and subsequent DMARD treatment, her symptoms persisted. In 2022, during her examinations at our hospital, the distinctive pattern of intermittent symptoms accompanied by damage-free joints was unveiled, suggesting a potential diagnosis of palindromic rheumatism. Notably, this case highlights the potential association between obesity and PR, as the patient's decision to undergo bariatric surgery in 2022 led to substantial weight loss of over 36 kg. This weight reduction yielded remarkable improvements in her condition, resulting in reduced frequency and severity of PR attacks. As a consequence, her medication regimen was simplified, emphasizing the therapeutic role of weight management in PR. This case paves the way for further research into the relationship between obesity, PR, and non-pharmacological interventions in PR management.

Importance of tenosynovitis in preventing the progression through rheumatoid arthritis continuum

Rheumatoid arthritis (RA) has long been characterized by synovitis and bone erosions typically developing symmetrically in small joints. However, recent advances in imaging modalities have indicated frequent association of tenosynovitis with RA, and some consider tenosynovitis to be not just a complication but a major trait of RA. Furthermore, as there are cases with tenosynovitis preceding the clinical detection of inflammatory arthritis in predisposed individuals, tenosynovitis may constitute an important biomarker in defining the pre-RA phase of disease development. Tenosynovitis itself must be treated as it causes functional impairment and physical as well as socioeconomic burden, and its treatment may result in effective prevention of RA development at a pre-arthritic stage. Thus, further efforts need to be taken in detecting and treating tenosynovitis in the pre-RA stage, which can be facilitated by ultrasonography and magnetic resonance imaging.

Iguratimod efficacy in palindromic rheumatism treatment

BACKGROUND

As a new immunomodulator for rheumatoid arthritis, iguratimod (IGU) also has therapeutic potential in other immune diseases. In this study, we determined the effects of IGU on disease control in patients with palindromic rheumatism (PR).

METHODS

Patients with PR were divided into Control group (Ctrl group) and an IGU treatment (IGU group) groups. Drug efficacy was evaluated according to the frequency of PR attacks (monthly), the visual analog scale (VAS) score of patient pain, and clinical symptoms.

RESULTS

The drug positivity and disease control rates of the IGU group (100.00% and 90.91%, respectively) were significantly higher than those of the Ctrl group (61.11% and 5.56%; p = .002 and p < .001, respectively). The median number of PR flares and the VAS score of patients in the Ctrl group decreased from 3.00 (1.00-15.00) to 0.83 (0.00-12.00) and from 5 (4-6) to 4 (1-6), respectively. In the IGU group, the median number of PR attacks decreased from 4.50 (2.00-15.00) to 0.00 (0.00-0.33), and the VAS score decreased from 5 (4-6) to 0 (0-2). The IGU group exhibited a significant reduction in PR flare frequency and improvement in the VAS value (p < .001 and p < .001, respectively).

CONCLUSION

Our study is the first to describe the efficacy of IGU in PR treatment. IGU can significantly reduce the number of PR flares and improve the clinical symptoms of patients with PR.

Assessing the Immune Cell Subset and Genetic Mutations in Patients With Palindromic Rheumatism Seronegative for Rheumatoid Factor and Anti-Cyclic Citrullinated Peptide

OBJECTIVE

The etiology underlying cases of palindromic rheumatism (PR) not associated with other rheumatic diseases in patients who are seronegative for rheumatoid factor and anti-cyclic citrullinated peptide (seronegative PR) is unclear. We aimed to investigate the immune cells and genes involved.

METHODS

This was a single-center comparative study of 48 patients with seronegative PR and 48 healthy controls. Mass cytometry and RNA sequencing were used to identify distinct immune cell subsets in blood. Among the 48 seronegative PR patients, plasma samples from 40 patients were evaluated by enzyme-linked immunosorbent assay for cytokine levels, and peripheral blood samples from 25 patients were evaluated by flow cytometry for mononuclear cell subsets. Plasma samples from 21 patients were evaluated by real-time polymerase chain reaction for differential gene and protein expression, and samples from 3 patients were analyzed with whole-exome sequencing for gene mutations.

RESULTS

Immunophenotyping revealed a markedly increased frequency of CD14+CD11b+CD36+ and CD4+CD25-CD69+ cells in seronegative PR patients with active flares compared with healthy controls (P < 0.0001 for both cell subset comparisons). Gene enrichment analyses of RNA-sequencing data from sorted CD14+CD11b+CD36+ and CD4+CD25-CD69+ cells showed involvement of the inflammatory/stress response, phagocytosis, and regulation of apoptosis functional pathways. Up-regulated expression of CXCL16 and IL10RA was observed in monocytes from PR patients. Up-regulation of PFKFB3, DDIT4, and TGFB1, and down-regulation of PDIA6 were found in monocytes and lymphocytes from PR patients with active flares and PR patients in intercritical periods. Plasma levels of S100A8/A9 and interleukin-1β were elevated in PR patients. Whole-exome sequencing revealed novel polygenic mutations in HACL1, KDM5A, RASAL1, HAVCR2, PRDM9, MBOAT4, and JRKL.

CONCLUSION

In seronegative PR patients, we identified a distinct CD14+CD11b+CD36+ cell subset that can induce an inflammatory response under stress and exert antiinflammatory effects after phagocytosis of apoptotic cells, and a CD4+CD25-CD69+ T cell subset with pro- and antiinflammatory properties. Individuals with genetic mutations involving epigenetic modification, potentiation and resolution of stress-induced inflammation/apoptosis, and a dysregulated endoplasmic reticulum stress response could be predisposed to seronegative PR.

Autoimmune inflammatory rheumatic diseases post-COVID-19 vaccination

Vaccination against COVID-19 is one of the critical tools to provide herd immunity, reduce mortality, and control the pandemic worldwide. Despite the safety of vaccination against SARS-CoV-2 in the healthy population, a minority of people may develop rare post-vaccine adverse reactions such as autoimmune syndromes. The current study aimed to identify and present a series of patients with de-novo autoimmune rheumatic diseases (ARDs) associated with COVID-19 vaccines. Inclusion criteria were the onset of ARDs symptoms at ∼3-4 weeks post-vaccination, age ≥ 16, no previous history of ARDs, meeting the classification criteria for one of the ARDs, and staying in the follow-up. The most commonly used vaccines in patients were Sinopharm [7 cases (50%)] and AstraZeneca [6 cases (42.9%)]. ARDs were significantly more common in subjects who received the AstraZeneca vaccine than in those who received other vaccines. Based on the results, patients were diagnosed with rheumatoid arthritis or one of its subtypes (5 cases), vasculitis (4 cases), systemic lupus erythematosus (3 cases), and peripheral seronegative spondyloarthritis (2 cases). Except for one patient with self-limitation of ARD, others were treated with disease-modifying antirheumatic drugs, and one case developed irreversible neurological complications. Indeed, our data can warn physicians about the possibility of ARDs post-vaccination, lead to faster diagnosis, prevent loss of window of opportunity for treatment, and prevent irreversible organ damage. Based on the published literature, autoimmune phenomena post-COVID-19 vaccination may be related to the overstimulation of mediators and cytokines due to complicated antigen-specific/non-specific immunological responses and mechanisms.

Efficacy of leflunomide in the treatment of palindromic rheumatism

OBJECTIVE

The goal of treatment in palindromic rheumatism (PR) is to control the attacks and prevent disease evolution to chronic arthritis. Conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) including antimalarial and methotrexate cannot control attacks in all patients.

METHODS

In this retrospective study, we assessed the efficacy of leflunomide in patients with PR who had an inadequate response to DMARDs. In this study, patients who had a diagnosis of PR and were treated with leflunomide because of active disease despite treatment with csDMARDs for at least 6 months were included. Remission was defined as no attacks for 3 months and prednisolone dose ≤5 mg/d. Leflunomide treatment failure was defined as failure to achieve remission, the need to add other DMARDs for controlling attacks and disease progression to chronic arthritis during treatment with leflunomide.

RESULTS

Ten cases with active disease despite treatment with hydroxychloroquine and methotrexate and low-dose prednisolone treated with leflunomide were included in the study. During the 12.6 ± 7.5 months of treatment with leflunomide, the frequency of attacks significantly decreased. Complete and partial remission were achieved in 90% of patients.

CONCLUSION

Our results indicate that leflunomide controls PR attacks and it might be a new option for patients with PR.

Long-term outcome of patients with palindromic rheumatism treated with methotrexate

OBJECTIVE

Palindromic rheumatism (PR) is characterized by self-resolving and short duration attacks of arthritis/periarthritis. The present study was performed to report the results of PR treatment with methotrexate (MTX).

METHODS

We reviewed the charts of 152 patients with diagnosis of PR. Inclusion criteria were diagnosis of PR according to the criteria of Weismann, age ≥16, active disease and treatment with MTX for at least 6 months. Disease outcome was assessed by reaching remission and prevention of disease evolution to chronic arthritis. Remission was defined as stopping the attacks for 12 weeks and prednisolone dose ≤5 mg/d. MTX treatment failure was defined as failure to achieve remission, the need to add other disease-modifying antirheumatic drugs and disease progression to chronic arthritis.

RESULTS

Fifty-nine patients were included in the study. Median duration of follow-up was 43 months. Attacks were controlled in 89.8% of patients. In 80% of the patients remission occurred during 12 months after starting treatment with MTX. Treatment failed in 20.3% of patients. Wrist joint involvement and positive rheumatoid factor (RF) were significantly more common in the MTX treatment-failed group. In RF positive patients evolution to rheumatoid arthritis was more common than in RF negative patients. No significant differences were observed in remission rate and evolution to rheumatoid arthritis in anticitrullinated C peptide positive and negative patients.

CONCLUSIONS

The present study, demonstrated the efficacy of MTX in controlling PR in seropositive and seronegative patients over a median of 43 months of treatment.

Pre-RA: Can early diagnosis lead to prevention?

Rheumatoid arthritis (RA) is currently diagnosed and treated once an individual displays the clinical findings of inflammatory arthritis (IA). However, growing evidence supports that there is a 'pre-RA' stage that can be identified through factors such as autoantibodies in absence of clinically apparent IA. In particular, biomarkers, including antibodies to citrullinated protein antigens (ACPA), demonstrate a high risk for future IA/RA, and multiple clinical trials have been developed to intervene in individuals in pre-RA to prevent or delay clinically apparent disease. Herein, we will discuss in more depth what is currently known about the natural history of RA, and the emerging possibility that early 'diagnosis' of RA-related autoimmunity followed by an intervention can lead to the delay or prevention of the first onset of clinically apparent RA.

Cigarette smoking and risk of palindromic rheumatism: A propensity score matching analysis

Present study was conducted to investigate smoking status in palindromic rheumatism (PR) patients compared to healthy individuals as well as to assess the effect of smoking on clinical features and outcomes of PR. One hundred and forty-six patients with diagnosis of PR and 346 healthy controls were included in this study. Demographic, clinical, and laboratory characteristics and the smoking history of PR patients at the cohort entry were obtained from patients' records. Demographic and smoking history of the control group were obtained by direct interview. In order to reduce heterogeneity between the studied groups, propensity score matching (PSM) analyses was performed. Matching was achieved by considering age, gender, educational status, and marital status. After PSM, we carried out a multivariate analysis with PR as the main outcome variable, ever smoking as the main predictor variable and age, gender, educational status, and marital status as covariates. PSM resulted in 123 PR patients and 246 matched controls. Multivariate analysis did not show a significant increase in the risk of PR in ever smokers. Seventy-six patients were anti-citrullinated protein/peptide antibody positive (ACPA-positive). Multivariate logistic regression showed a significant increase in the risk of PR in ACPA-positive ever smokers. Except lower sustained remission rate in ever smokers, no significant differences were observed in clinical manifestations and outcomes of PR between ever and never smokers. In conclusion, smoking is a risk factor for ACPA-positive PR.

Treatment of palindromic rheumatism: A systematic review

OBJECTIVES

Palindromic rheumatism (PR) characterised by self-resolving attacks of arthritis and peri-arthritis that may progress to other autoimmune connective tissue diseases (CTDs). The aim of this systematic review was to analyse the effectiveness of different treatments on PR.

METHODS

Articles were collected from Cochrane, PubMed, Science Direct, Scopus, ProQuest, Ebsco, Google Scholar, MEDLINE and EMBASE. Search keywords were "palindromic rheumatism," "palindromic rheumatism and remission," "palindromic rheumatism and course," "palindromic rheumatism and prognosis," "palindromic rheumatism and treatment" and "palindromic rheumatism and therapy." The studies that were included met the following criteria: (a) adult patients aged ≥16 with PR; (b) being on treatment with medications defined as those that were developed for the treatment of inflammatory arthritis and (c) including outcome measures to evaluate the efficacy of the treatment including remission rate and progression to other diseases.

RESULTS

Twenty-four studies met the inclusion criteria. Although case series and retrospective studies showed that conventional disease-modifying antirheumatic drugs (DMARDs) can control attacks of the disease, 15%-70% of patients with PR evolve to autoimmune CTDs during several years, despite treatment with DMARDs. A retrospective study showed that tight control strategy could control attacks of the disease and prevent its progression to RA. The evidence provided from available studies is insufficient to determine that DMARDs can prevent the progression of PR to autoimmune CTDs.

CONCLUSION

Although case series and retrospective studies showed that DMARDs can control attacks of the disease, our review suggests that randomised clinical trials and prospective studies with adequate sample size are needed to prove that DMARDs can prevent progression of PR to autoimmune CTDs and which DMARDs are preferred for the treatment of PR.

T-cell responses to hybrid insulin peptides prior to type 1 diabetes development

T-cell responses to posttranslationally modified self-antigens are associated with many autoimmune disorders. In type 1 diabetes, hybrid insulin peptides (HIPs) are implicated in the T-cell-mediated destruction of insulin-producing β-cells within pancreatic islets. The natural history of the disease is such that it allows for the study of T-cell reactivity prior to the onset of clinical symptoms. We hypothesized that CD4 T-cell responses to posttranslationally modified islet peptides precedes diabetes onset. In a cohort of genetically at-risk individuals, we measured longitudinal T-cell responses to native insulin and hybrid insulin peptides. Both proinflammatory (interferon-γ) and antiinflammatory (interluekin-10) cytokine responses to HIPs were more robust than those to native peptides, and the ratio of such responses oscillated between pro- and antiinflammatory over time. However, individuals who developed islet autoantibodies or progressed to clinical type 1 diabetes had predominantly inflammatory T-cell responses to HIPs. Additionally, several HIP T-cell responses correlated to worsening measurements of blood glucose, highlighting the relevance of T-cell responses to posttranslationally modified peptides prior to autoimmune disease development.

Palindromic rheumatism: Evidence of four subtypes of palindromic-like arthritis based in either MEFV or rheumatoid factor/ACPA status

INTRODUCTION

MEFV mutations have been documented in patients with palindromic rheumatism (PR) who do not meet FMF criteria, and RF and ACPA positive RA may start with PR.

OBJECTIVE

To analyze the clinical phenotype and disease evolution of patients with intermittent, palindromic-like (PL) arthritis seen in our Arthritis Unit according to the RF, ACPA and MEFV mutation status.

METHODS

MEFV genotyping was done in 76 patients with PL arthritis as defined by predominantly short attacks (≤7days) and a relapsing course. Characteristics of arthritic episodes, RF and ACPA positivity, and the colchicine response were retrospectively collected. Patients were stratified and evaluated according to MEFV mutations and/or positive autoantibodies (ACPA and/or RF).

RESULTS

Among the patients, 26.3% (20/76) had a MEFV mutation and 23 (30%) were ACPA and/or RF positive. MEFV mutations and/or autoantibody status allowed four PL arthritis patients to be distinguished: group I (MEFV+), with younger age of onset, short duration attacks (<3days), mainly located in the knee, more frequent non-articular manifestations (fever, pericarditis or abdominal pain) and good response to colchicine; group II (autoantibody+) is older than group I, with the same frequency of short attacks, but the most affected joints were the wrists and small joints of hands: 48% met RA classification criteria during follow-up and were taking DMARDs; group III (MEFV- and autoantibody-) was the most frequent (48%) and clinically heterogeneous group; 51% had attacks lasting>3days, and 15 patients developed criteria of immune-mediated inflammatory, autoinflammatory or infectious diseases. Group IV (MEFV+ associated with preexisting immune-inflammatory disease), was associated with very short attacks, like groups I and II, superimposed or coincident with definite immune-inflammatory disease, including seropositive RA, with good response to colchicine.

CONCLUSIONS

Patients with PL arthritis can be classified in four groups according to the presence or not of MEFV mutations and ACPA/RF antibodies with a different clinical evolution and therapeutic response.

Palindromic Rheumatism: Just a Pre-rheumatoid Stage or Something Else?

Palindromic rheumatism (PR), a unique clinical entity, has a characteristic clinical presentation with a relapsing/remitting course. It is established that most patients with PR evolve to chronic disease, of which rheumatoid arthritis (RA) is by far the most common. The relationship between PR and RA is unclear, with similarities and differences between the two, and not all patients evolve to RA in the long-term. Therefore, PR is clearly a pre-RA stage for most, but not all, patients. Autoimmunity plays a substantial role in PR, with the same characteristic autoantibody profile observed in RA, although with some differences in the immune response repertoire. Autoinflammation may also be relevant in some cases of PR. Prognostic factors for RA progression are identified but their exact predictive value is not clear. There are several unmet needs in PR, such as the diagnostic criteria and clinical case definition, the pathogenic mechanisms involved in the unusual clinical course, and the evolution to RA, and our understanding of the therapeutic strategy that could best avoid progression to persistent and potentially destructive arthritis.

Palindromic rheumatism: a unique and enigmatic entity with a complex relationship with rheumatoid arthritis

INTRODUCTION

Palindromic rheumatism (PR) is a form of relapsing/remitting arthritis that may evolve to chronic rheumatic disease, mainly rheumatoid arthritis (RA). The exact nature of PR is unclear, as it may be considered a disease in itself, an abortive form of RA or just a pre-RA stage.

AREAS COVERED

The authors review the most relevant epidemiological and clinical aspects of PR, especially the pathogenetic role of autoimmunity in PR, with most patients having a characteristic autoantibody profile similar to that observed in RA. The role of autoinflammation is also discussed. A literature review on the rate of RA progression and its prognostic factors was analyzed. Data on the efficacy of drug therapies used to treat PR are presented. PubMed was searched using the terms 'palindromic rheumatism' OR 'palindromic arthritis'.

EXPERT OPINION

PR is a disease entity with a close but unclear relationship with RA. In PR there is an unmet need, which is to clarify the clinical spectrum and elucidate the risk factors for evolution to RA. The role of autoimmunity and the autoinflammatory component should be investigated. Since most patients evolve to RA, PR may display a unique therapeutic opportunity to avoid this evolution.

Incidence and risk of developing rheumatic diseases in 19,724 patients with palindromic rheumatism in South Korea: A nationwide population-based study

OBJECTIVES

The spectrum of progression of palindromic rheumatism (PR) to chronic diseases is quite variable. Hence, this study aimed to investigate the incidence and risk of developing rheumatic diseases in PR using nationwide, population-based medical claims data from Korea.

METHODS

We assessed the incidence rate (IR) of PR in the population in the given year. After matching individuals with PR with those without PR (1:10) for age, gender, and the index year, we calculated the hazard ratios (HRs) with 95% confidence intervals (CIs) using the Cox proportional hazard model.

RESULTS

A total of 19,724 newly diagnosed incident PR cases were identified from 2010 to 2016. The mean age was 50.2±14.9 years. The incidence of PR was 7.02 (95% CI 6.92-7.12) per 100,000 person-years (6.22 and 7.80 in men and women, respectively). During observation, 8.79% patients with PR and 0.30% individuals without PR developed various outcome diseases. Patients with PR had an increased risk of seropositive rheumatoid arthritis (HR 46.51, 95% CI [41.05-52.69]), psoriatic arthritis (44.79 [15.16-132.35]), systemic lupus erythematosus (24.53 [16.15-37.24]), mixed connective tissue disease (22.01 [7.65-63.34]), Behçet's disease (21.04 [13.81-32.06]), Sjögren's syndrome (12.36 [8.54-17.88]), ankylosing spondylitis (9.00 [6.67-12.15]), dermatomyositis/polymyositis (6.14 [2.55-14.82]), and systemic sclerosis (3.75 [1.47-9.58]) compared with individuals without PR.

CONCLUSIONS

This nationwide, population-based cohort study demonstrated that about one-eleventh of patients with PR eventually develop systemic rheumatic diseases and that patients with PR have an increased risk of developing various rheumatic diseases including seropositive rheumatoid arthritis.

Anti-carbamylated protein antibody isotype pattern differs between palindromic rheumatism and rheumatoid arthritis

Background

A restricted response against citrullinated peptides/proteins, with less isotype usage, has been found in palindromic rheumatism (PR) in comparison with rheumatoid arthritis (RA). We hypothesized that this different antibody response may be observed for other post-translational modified proteins. We compared the prevalence and isotype usage of two specificities of anti-carbamylated peptide/protein antibodies (Anti-CarP) in patients with PR and RA.

Methods

Cross-sectional study including 54 patients with pure PR and 53 patients with RA, matched by sex, age, disease duration and ACPA. Anti-CarP specificities were determined by home-made enzyme-linked immunosorbent assay tests using a synthetic chimeric fibrin/filaggrin homocitrullinated peptide (CFFHP) and fetal calf serum (FCS) homocitrullinated protein as antigens. IgG, IgA and IgM isotypes were measured.

Results

Anti-CarP were positive (CFFHP or FCS) in 24% and 64% of patients with PR and RA, respectively (p < 0.005). All Anti-CarP isotype proportions were significantly lower in PR than in RA: Anti-CarP-IgG (24% versus 51%), Anti-CarP-IgA (7% versus 34%) and Anti-CarP-IgM (7% versus 36%). Mean titers of Anti-CarP isotypes were also lower in PR. In Anti-CarP positive patients, the isotype distribution differed between PR and RA: IgG Anti-CarP was used in all PR patients and in 79% of RA patients. By contrast, a significantly lower isotype usage of both IgA (31% versus 53%) and IgM (31% versus 56%) was observed in PR patients. No significant differences in clinical or demographic characteristics were observed according to Anti-CarP status in PR patients, except for a higher prevalence of ACPA and higher mean titers of ACPA and rheumatoid factor in Anti-CarP positive patients.

Conclusion

Anti-CarP are found in patients with PR but in a lower proportion and with a different isotype usage from in RA, suggesting a distinct B cell response to homocitrullinated antigens in PR.

Persistent inflammatory and non-inflammatory mechanisms in refractory rheumatoid arthritis

Despite nearly three decades of advances in the management of rheumatoid arthritis (RA), a substantial minority of patients are exposed to multiple DMARDs without necessarily benefitting from them; a group of patients variously designated as having 'difficult to treat', 'treatment-resistant' or 'refractory' RA. This Review of refractory RA focuses on two types of patients: those for whom multiple targeted therapies lack efficacy and who have persistent inflammatory pathology, which we designate as persistent inflammatory refractory RA (PIRRA); and those with supposed refractory RA who have continued disease activity that is predominantly independent of objective evidence of inflammation, which we designate as non-inflammatory refractory RA (NIRRA). These two types of disease are not mutually exclusive, but identifying those individuals with predominant PIRRA or NIRRA is important, as it informs distinct treatment and management approaches. This Review outlines the clinical differences between PIRRA and NIRRA, the genetic and epigenetic mechanisms and immune pathways that might contribute to the immunopathogenesis of recalcitrant synovitis in PIRRA, and a possible basis for non-inflammatory symptomatology in NIRRA. Future approaches towards the definition of refractory RA and the application of single-cell and integrated omics technologies to the identification of refractory RA endotypes are also discussed.

Clinical Significance of Anti-Modified Citrullinated Vimentin Antibodies in Palindromic Rheumatism

OBJECTIVE

This study evaluated anti-modified citrullinated vimentin (anti-MCV) performance in determining the clinical picture and outcomes of palindromic rheumatism (PR).

METHODS

In a retrospective study, patients with PR with at least 1 year of follow-up diagnosed according to clinical criteria were enrolled. Anti-MCV antibodies were measured, and levels >20 IU/mL were considered positive. Disease prognosis was assessed according to patients acquiring remission and preventing PR from developing into rheumatoid arthritis (RA) or other diseases.

RESULTS

Seventy-six patients with PR with a mean follow-up of 30.57 months (median = 21 months; minimum = 12 months; maximum = 48 months) were included in the study. Anti-MCV antibodies were positive in 69.7% of patients. Metacarpophalangeal (MCP) joint involvement and positive anti-cyclic citrullinated peptides were significantly higher in patients who were anti-MCV-positive, whereas ankle joint involvement was significantly lower. No significant correlation was observed between the anti-MCV titer and the severity of attacks. Remission in patients who were anti-MCV-positive and negative was 75.5% and 78.3%, respectively, with no significant difference. Evolution to RA was observed in only 3.8% of patients who were anti-MCV-positive. No patients who were anti-MCV-negative developed RA.

CONCLUSION

Except for MCP and ankle joint involvement, anti-MCV was not helpful in determining the clinical picture and outcome of PR.

The Role of Ultrasound Across the Inflammatory Arthritis Continuum: Focus on "At-Risk" Individuals

In individuals at-risk of developing inflammatory arthritis, the value of an ultrasound (US) scan assessment to predict progression has been demonstrated repeatedly. However, depending on recruitment criteria, these individuals may be at different stages in the arthritis development continuum, therefore representing a heterogeneous population. As a consequence, the predictive value of ultrasound results may differ between cohorts. As other reviews have focused on the challenges in population recruitment or have combined biomarkers predicting value according to one recruitment pathway, we wanted to focus on the sole use of ultrasound assessment and its variation according to population recruitment criteria. In this review, we discuss the use of ultrasound in the different at-risk populations across the inflammatory arthritis disease continuum. This review demonstrates that although some sub-population data is scarce, ultrasound is best predictive in three at-risk populations: those with a positive ACPA test in the context of non-specific MSK symptoms, those with clinically suspect arthralgia and those with palindromic rheumatism. We consider that ultrasound assessment will be a cornerstone in prediction risk modeling and prevention studies of the preclinical phases of IA in the future.

The Prevalence of Autoimmune Diseases in Longstanding Diabetes: Results from the Canadian Study of Longevity in Adults with Type 1 Diabetes

OBJECTIVE

We aimed to determine the prevalence of autoimmune diseases (e.g. thyroid disease, celiac disease, etc) in Canadians with longstanding type 1 diabetes (T1D) and to explore sex-specific differences and the association with complications.

METHODS

Cross-sectional data were analyzed in an exploratory secondary analysis from the Canadian Study of Longevity in Type 1 Diabetes, a nationwide registry of people with T1D of at least 50 years' duration. In total, 374 participants provided self-reported questionnaire data and physician-reported laboratory results. Student's t-test, the Wilcoxon rank-sum test, the χ² test and logistic regression were used to identify associations with autoimmune diseases.

RESULTS

The 374 participants had a median T1D duration of 53 years (interquartile range, 51 to 58) and a median age of onset of 11 years (6 to 16), and 57.1% were females. Females had a greater prevalence of autoimmune diseases (60.6% vs 34.4%, p<0.001). Thyroid disease was most prevalent (41%, 153/374), especially in females (51.6% vs 26.9%), and the prevalence of 1 or more autoimmune disease was 49.3% (184/374). Autoimmune disease was associated with lower odds of cardiovascular disease (CVD)-odds ratio [OR] 0.61, 95% confidence interval [CI] 0.37 to 1.00 for thyroid autoimmune disease and OR 0.34 (95% CI 0.12 to 0.93) for nonthyroid autoimmune disease, both compared to those without autoimmune disease (p=0.033). Autoimmune diseases were not associated with the presence of nephropathy, neuropathy or retinopathy.

CONCLUSIONS

Lifetime risk of autoimmune disease in longstanding T1D approaches 50%, is greater in females and is driven by thyroid disease. The probability of diabetes complications, such as CVD, was lower in those with autoimmune disease, which was driven mostly by nonthyroid autoimmune diseases.

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.

MiR-145-5p mitigates dysregulated Wnt1/β-catenin signaling pathway in rheumatoid arthritis

Fibroblast-like synoviocytes (FLS) lining the arthritic synovial joint region have been implicated to be a key player in bone remodeling. The uncontrolled proliferation of this cell subtype is strictly regulated by various molecular elements including microRNAs (miRNAs). The Wnt1/β-catenin signaling pathway plays a crucial role in the survival of FLS cells. This study explores the underlying mechanism of miR-145-5p towards the Wnt1/β-catenin pathway. MiR-145-5p depicted a strong binding affinity towards frizzled class receptor 4 (FZD4) 3' UTR, a key receptor complex essential for recognizing circulating Wnt1 molecules. Adjuvant induced arthritic fibroblast-like synoviocytes (AA-FLS) isolated from rats stimulated with Wnt1 (10 ng/ml) elicited active Wnt1/β-catenin signaling. Transfection of miR-145-5p mimic (50 pmol) to AA-FLS stimulated with Wnt1 elicited reduced expression levels of various factors of Wnt1/β-catenin signaling including low-density lipoprotein receptor-related protein 5 (LRP5), dishevelled segment polarity protein 1 (Dvl1) and β-catenin transcription factor. Moreover, pro-inflammatory cytokines (TNFα, IL-1β, IL-6 and IL-23) were regulated compared to the diseased groups. Furthermore, miR-145-5p counterbalanced the levels of receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) at the cellular level, essential for bone remodeling. Hence, we suggest that miR-145-5p regulates the survival/proliferation of FLS cells in RA disease condition through attenuation of Wnt1/β-catenin signaling.