Inflammation In Juvenile Idiopathic Arthritis Research Articles

Serum and salivary inflammatory biomarkers in juvenile idiopathic arthritis—an explorative cross-sectional study

BackgroundBiomarkers may be useful in monitoring disease activity in juvenile idiopathic arthritis (JIA). With new treatment options and treatment goals in JIA, there is an urgent need for more sensitive and responsive biomarkers.ObjectiveWe aimed to investigate the patterns of 92 inflammation-related biomarkers in serum and saliva in a group of Norwegian children and adolescents with JIA and controls and in active and inactive JIA. In addition, we explored whether treatment with tumor necrosis factor inhibitors (TNFi) affected the biomarker levels.MethodsThis explorative, cross-sectional study comprised a subset of children and adolescents with non-systemic JIA and matched controls from the Norwegian juvenile idiopathic arthritis study (NorJIA Study). The JIA group included individuals with clinically active or inactive JIA. Serum and unstimulated saliva were analyzed using a multiplex assay of 92 inflammation-related biomarkers. Welch’s t-test and Mann–Whitney U-test were used to analyze the differences in biomarker levels between JIA and controls and between active and inactive disease.ResultsWe included 42 participants with JIA and 30 controls, predominantly females, with a median age of 14 years. Of the 92 biomarkers, 87 were detected in serum, 73 in saliva, and 71 in both biofluids. A pronounced difference between serum and salivary biomarker patterns was found. Most biomarkers had higher levels in serum and lower levels in saliva in JIA versus controls, and in active versus inactive disease. In serum, TNF and S100A12 levels were notably higher in JIA and active disease. The TNF increase was less pronounced when excluding TNFi-treated individuals. In saliva, several biomarkers from the chemokine family were distinctly lower in the JIA group, and levels were even lower in active disease.ConclusionIn this explorative study, the serum and salivary biomarker patterns differed markedly, suggesting that saliva may not be a suitable substitute for serum when assessing systemic inflammation in JIA. Increased TNF levels in serum may not be a reliable biomarker for inflammatory activity in TNFi-treated children and adolescents with JIA. The lower levels of chemokines in saliva in JIA compared to controls and in active compared to inactive disease, warrant further investigation.

Evaluation of synovial inflammation in juvenile idiopathic arthritis using superb microvascular imaging compared with power Doppler ultrasound.

This study aimed to investigate the diagnostic and prognostic performance of superb microvascular imaging (SMI) in evaluation of synovial inflammation in patients with juvenile idiopathic arthritis (JIA) compared with power Doppler ultrasound (PDUS). Fifty-nine patients with active disease and 62 patients with inactive disease were enrolled. The synovial inflammation was evaluated via vascularity index (VI) of SMI and PDUS. The correlations between VIs and the inflammatory biomarkers were analysed by Spearman's coefficient. Receiver operating characteristics curves were plotted to examine the prognostic value of SMI and PDUS. The VI of SMI was significantly higher than that of PDUS in JIA patients regardless of the disease activity. The SMI and PDUS VI were significantly correlated with levels of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum amyloid A (SAA). The SMI VI was significantly higher in patients with relapse than in those with remission, and showed superior performance in predicting relapse in JIA patients with inactive disease. SMI may detect the synovial inflammation with greater sensitivity than PDUS in patients with JIA, and correlate well with the inflammatory biomarkers. SMI signal in the knees might play an important role in prediction of relapse in clinically inactive patients, thus allowing personalised treatment strategies for JIA patients.

EULAR 2023 Abstract Highlights

The following selected highlights spotlight several interesting and timely abstracts presented at the European Alliance of Associations for Rheumatology (EULAR) Congress 2023, covering topics such as recurring joint inflammation in juvenile idiopathic arthritis, systemic lupus erythematosus, and the importance of a healthy lifestyle in patients with osteoarthritis.

Patterns of clinical joint inflammation in juvenile idiopathic arthritis

ObjectivesWe studied patterns of joint inflammation in juvenile idiopathic arthritis (JIA) to assess whether joint activity recurs locally in the same joints.MethodsJoints of 91 patients of the BeSt for Kids...

The reliability of Juvenile Arthritis Magnetic Resonance Imaging Scoring system in the evaluation of the shoulder joint in juvenile idiopathic arthritis.

We aimed to evaluate shoulder joint by magnetic resonance imaging (MRI) using the Juvenile Arthritis Magnetic Resonance Imaging Scoring (JAMRIS) system in children with juvenile idiopathic arthritis (JIA) and to compare clinical, laboratory parameters and disease activity scores with MRI parameters. A total of 32 shoulder joints of 20 patients (16 males, 4 females; mean age: 8.9±3.5 years; range, 2.5 to 14 years) with a known diagnosis of JIA and a clinical suspicion of shoulder joint involvement and underwent MRI were included. Reliability was determined by inter- and intra-observer correlation coefficients. Correlation of the clinical and laboratory parameters with JAMRIS scores was done using the non-parametric tests. Sensitivity of clinical examination to detect shoulder joint arthritis was also determined. Of the 32 joints, 27 joints in 17 patients showed MRI changes. Seven joints in five patients fulfilled the definition of clinical arthritis, all revealed MRI changes. In 25 joints without clinical arthritis, early and late MRI changes were seen in 19 (67%) and 12 (48%) joints, respectively. The inter- and intra-observer correlation coefficients for JAMRIS system were excellent. No correlation was found between MRI parameters, clinical, laboratory, and disease activity scores. The sensitivity of clinical examination to detect shoulder joint arthritis was 25.9%. The JAMRIS system is reliable and reproducible to determine shoulder joint inflammation in JIA. Detection of shoulder joint arthritis by clinical examination has a poor sensitivity.

B Cells on the Stage of Inflammation in Juvenile Idiopathic Arthritis: Leading or Supporting Actors in Disease Pathogenesis?

Juvenile idiopathic arthritis (JIA) is a term that collectively refers to a group of chronic childhood arthritides, which together constitute the most common rheumatic condition in children. The International League of Associations for Rheumatology (ILAR) criteria define seven categories of JIA: oligoarticular, polyarticular rheumatoid factor (RF) negative (RF-), polyarticular RF positive (RF+), systemic, enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. The ILAR classification includes persistent and extended oligoarthritis as subcategories of oligoarticular JIA, but not as distinct categories. JIA is characterized by a chronic inflammatory process affecting the synovia that begins before the age of 16 and persists at least 6 weeks. If not treated, JIA can cause significant disability and loss of quality of life. Treatment of JIA is adjusted according to the severity of the disease as combinations of non-steroidal anti-inflammatory drugs (NSAIDs), synthetic and/ or biological disease modifying anti-rheumatic drugs (DMARDs). Although the disease etiology is unknown, disturbances in innate and adaptive immune responses have been implicated in JIA development. B cells may have important roles in JIA pathogenesis through autoantibody production, antigen presentation, cytokine release and/ or T cell activation. The study of B cells has not been extensively explored in JIA, but evidence from the literature suggests that B cells might have indeed a relevant role in JIA pathophysiology. The detection of autoantibodies such as antinuclear antibodies (ANA), RF and anti-citrullinated protein antibodies (ACPA) in JIA patients supports a breakdown in B cell tolerance. Furthermore, alterations in B cell subpopulations have been documented in peripheral blood and synovial fluid from JIA patients. In fact, altered B cell homeostasis, B cell differentiation and B cell hyperactivity have been described in JIA. Of note, B cell depletion therapy with rituximab has been shown to be an effective and well-tolerated treatment in children with JIA, which further supports B cell intervention in disease development.

Human regulatory T cells locally differentiate and are functionally heterogeneous within the inflamed arthritic joint.

ObjectiveTregs are crucial for immune regulation, and environment‐driven adaptation of effector (e)Tregs is essential for local functioning. However, the extent of human Treg heterogeneity in inflammatory settings is unclear.MethodsWe combined single‐cell RNA‐ and TCR‐sequencing on Tregs derived from three to six patients with juvenile idiopathic arthritis (JIA) to investigate the functional heterogeneity of human synovial fluid (SF)‐derived Tregs from inflamed joints. Confirmation and suppressive function of the identified Treg clusters was assessed by flow cytometry.ResultsFour Treg clusters were identified; incoming, activated eTregs with either a dominant suppressive or cytotoxic profile, and GPR56+CD161+CXCL13+ Tregs. Pseudotime analysis showed differentiation towards either classical eTreg profiles or GPR56+CD161+CXCL13+ Tregs supported by TCR data. Despite its most differentiated phenotype, GPR56+CD161+CXCL13+ Tregs were shown to be suppressive. Furthermore, BATF was identified as an overarching eTreg regulator, with the novel Treg‐associated regulon BHLHE40 driving differentiation towards GPR56+CD161+CXCL13+ Tregs, and JAZF1 towards classical eTregs.ConclusionOur study reveals a heterogeneous population of Tregs at the site of inflammation in JIA. SF Treg differentiate to a classical eTreg profile with a more dominant suppressive or cytotoxic profile that share a similar TCR repertoire, or towards GPR56+CD161+CXCL13+ Tregs with a more distinct TCR repertoire. Genes characterising GPR56+CD161+CXCL13+ Tregs were also mirrored in other T‐cell subsets in both the tumor and the autoimmune setting. Finally, the identified key regulators driving SF Treg adaptation may be interesting targets for autoimmunity or tumor interventions.

Assessment of systemic and ocular inflammation in juvenile idiopathic arthritis via choroidal vascularity index.

We aimed to evaluate the retina and the choroid in children with juvenile idiopathic arthritis (JIA) employing optical coherence tomography (OCT). This cross-sectional study, carried out between June 2017-December 2019, included JIA patients with (JIAU; n = 28) and without (JIAN; n = 65) uveitis and age-matched healthy controls (HC) (n = 102). Laboratory and demographic information of the children were obtained from hospital records. Activity of the disease was evaluated by the Juvenile Arthritis Disease Activity Score-71 (JADAS-71). Choroidal scans were obtained with spectral domain-OCT in enhanced-depth imaging (EDI)-OCT mode to assess choroidal thickness (ChT) at five locations (under the fovea, at 750 and 1500μm nasal and temporal sections), luminal area (LA), stromal area (SA), total subfoveal choroidal area (TCA) and CVI (choroidal vascularity index). Central foveal thickness (CFT) and 1-mm diameter foveal thickness (FT) were calculated automatically through macular volume scan analysis. The choroid was significantly thicker in JIAU and JIAN patients than in HC at the subfoveal and at the 750N, 750T, 1500T points (p < 0.001, p = 0.009, p < 0.001, and p < 0.001, respectively). The CVI was lower in JIAU patients than in JIAN patients and HC (p = 0.02). Conversely, CFT was greater in JIAU patients as compared to the JIAN patients and HC (p = 0.02). Changes in chorioretinal OCT parameters in the absence of uveitis in JIA patients may reflect subclinical choroidal inflammation in these patients. Ophthalmologic examination, including choroidal imaging in a larger cohort, may clarify this aspect.

Tryptophan is Linking Metabolism to Inflammation in Juvenile Idiopathic Arthritis

Tryptophan is Linking Metabolism to Inflammation in Juvenile Idiopathic Arthritis

Synovial fluid neutrophils in oligoarticular juvenile idiopathic arthritis have an altered phenotype and impaired effector functions

BackgroundNeutrophils are the most prevalent immune cells in the synovial fluid in inflamed joints of children with oligoarticular juvenile idiopathic arthritis (JIA). Despite this, little is known about neutrophil function at the site of inflammation in JIA and how local neutrophils contribute to disease pathogenesis. This study aimed to characterize the phenotype and function of synovial fluid neutrophils in oligoarticular JIA.MethodsNeutrophils obtained from paired blood and synovial fluid from patients with active oligoarticular JIA were investigated phenotypically (n = 17) and functionally (phagocytosis and oxidative burst, n = 13) by flow cytometry. In a subset of patients (n = 6), blood samples were also obtained during inactive disease at a follow-up visit. The presence of CD206-expressing neutrophils was investigated in synovial biopsies from four patients by immunofluorescence.ResultsNeutrophils in synovial fluid had an activated phenotype, characterized by increased CD66b and CD11b levels, and most neutrophils had a CD16hi CD62Llowaged phenotype. A large proportion of the synovial fluid neutrophils expressed CD206, a mannose receptor not commonly expressed by neutrophils but by monocytes, macrophages, and dendritic cells. CD206-expressing neutrophils were also found in synovial tissue biopsies. The synovial fluid neutrophil phenotype was not dependent on transmigration alone. Functionally, synovial fluid neutrophils had reduced phagocytic capacity and a trend towards impaired oxidative burst compared to blood neutrophils. In addition, the effector functions of the synovial fluid neutrophils correlated negatively with the proportion of CD206+ neutrophils.ConclusionsNeutrophils in the inflamed joint in oligoarticular JIA were altered, both regarding phenotype and function. Neutrophils in the synovial fluid were activated, had an aged phenotype, had gained monocyte-like features, and had impaired phagocytic capacity. The impairment in phagocytosis and oxidative burst was associated with the phenotype shift. We speculate that these neutrophil alterations might play a role in the sustained joint inflammation seen in JIA.

Oral health and plaque microbial profile in juvenile idiopathic arthritis

BackgroundThe oral microbiota has been implicated in the pathogenesis of rheumatoid arthritis through activation of mucosal immunity. This study tested for associations between oral health, microbial communities and juvenile idiopathic arthritis (JIA).MethodsA cross-sectional exploratory study of subjects aged 10–18 years with oligoarticular, extended oligoarticular and polyarticular JIA was conducted. Control groups included pediatric dental clinic patients and healthy volunteers. The primary aim was to test for an association between dental health indices and JIA; the secondary aim was to characterize the microbial profile of supragingival plaque using 16S rRNA gene sequencing.ResultsThe study included 85 patients with JIA, 62 dental patients and 11 healthy child controls. JIA patients overall had significantly more gingival inflammation compared to dental patients, as evidenced by bleeding on probing of the gingiva, the most specific sign of active inflammation (p = 0.02). Overall, however, there was a trend towards better dental hygiene in the JIA patients compared to dental patients, based on indices for plaque, decay, and periodontitis. In the JIA patients, plaque microbiota analysis revealed bacteria belonging to genera Haemophilus or Kingella elevated, and Corynebacterium underrepresented. In poly JIA, bacteria belonging to the genus Porphyromonas was overrepresented and Prevotella was underrepresented.ConclusionIncreased gingival inflammation in JIA was independent of general oral health, and thus cannot be attributed to poor dental hygiene secondary to disability. The variation of microbial profile in JIA patients could indicate a possible link between gingivitis and synovial inflammation.

Serologic Evidence of Gut-driven Systemic Inflammation in Juvenile Idiopathic Arthritis.

Accumulating evidence links juvenile idiopathic arthritis (JIA) to nonhost factors such as gut microbes. We hypothesize that children with new-onset JIA have increased intestinal bacterial translocation and circulating lipopolysaccharide (LPS). We studied systemic treatment-naive patients with JIA [polyarticular JIA, n = 22, oligoarticular JIA, n = 31, and spondyloarthropathies (SpA), n = 16], patients with established inflammatory bowel disease-related arthritis (IBD-RA, n = 11), and 34 healthy controls. We determined circulating IgG reactivity against LPS, LPS-binding protein (LBP), α-1-acid glycoprotein (α-1AGP), and C-reactive protein (CRP) in plasma or serum from these patients and controls. Juvenile Arthritis Disease Activity Score (JADAS-27) was calculated for patients with JIA. Circulating anticore LPS antibody concentrations in patients with polyarticular JIA (p = 0.001), oligoarticular JIA (p = 0.024), and SpA (p = 0.001) were significantly greater than in controls, but there were no significant intergroup differences. Circulating LBP concentrations were also significantly greater in patients with polyarticular JIA (p = 0.001), oligoarticular JIA (p = 0.002), and SpA (p = 0.006) than controls, as were α-1AGP concentrations (p = 0.001, 0.001, and 0.003, respectively). No differences were observed between controls and patients with IBD-RA in any of the assays. Circulating concentrations of LBP and α-1AGP correlated strongly with CRP concentrations (r = 0.78 and r = 0.66, respectively). Anticore LPS antibody levels and CRP (r = 0.26), LBP (r = 0.24), and α-AGP (r = 0.22) concentrations had weaker correlations. JADAS-27 scores correlated with LBP (r = 0.66) and α-1AGP concentrations (r = 0.58). Children with polyarticular JIA, oligoarticular JIA, and SpA have evidence of increased exposure to gut bacterial products. These data reinforce the concept that the intestine is a source of immune stimulation in JIA.

Ultrasound imaging of synovial inflammation in juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic entity of childhood. The hallmark feature of all subtypes is joint inflammation. Imaging is used to evaluate the extent and severity of inflammation, degree of joint damage and response to treatment, which in turn impacts patient management. Ultrasound has become a useful adjunct to clinical examination because it shows promise in evaluating clinical and subclinical inflammation (synovitis, enthesitis) as well as cartilage and bone erosive changes. However more collaborative research is needed to help define the normal appearance of the growing skeleton, clarify the significance of subclinical findings and develop useful definitions, imaging protocols and scoring systems of disease.

Update on research and clinical translation on specific clinical areas from biology to bedside: Unpacking the mysteries of juvenile idiopathic arthritis pathogenesis.

In the past decades, we have gained important insights into the mechanisms of disease and therapy underlying chronic inflammation in juvenile idiopathic arthritis (JIA). These insights have resulted in several game-changing therapeutic modalities for many patients. However, additional progress still has to be made with regard to efficacy, cost reduction, minimization of side effects, and dose-tapering and stop strategies of maintenance drugs. Moreover, to really transform the current therapeutic strategies into personalized medicine, we need validated biomarkers to translate increased insights into clinical practice. In this article, we describe recent developments in JIA research and outline how clinical innovations need to go hand in hand with basic discoveries to really effect care for patients. Facilitating the transition from bench to bedside is crucial for addressing the major current challenges in JIA management. When successful, it will set new standards for a safe, targeted, and personalized medicine in JIA.

Diffusion-weighted imaging for assessment of synovial inflammation in juvenile idiopathic arthritis: a promising imaging biomarker as an alternative to gadolinium-based contrast agents

ObjectivesTo compare dynamic-contrast-enhanced MRI (DCE) and diffusion-weighted imaging (DWI) in quantifying synovial inflammation in juvenile idiopathic arthritis (JIA).MethodsRegions of interest (ROI) were drawn in the synovium of JIA patients on T1 DCE and T2 DWI, followed by extraction of the maximum enhancement (ME), maximum initial slope (MIS), time to peak (TTP), % of different time intensity curve shapes (TIC) and apparent diffusion coefficient (ADC) of the ROIs. Mann-Whitney-U test was used for comparing parameters between MRI-active and -inactive patients (defined by the juvenile arthritis MRI scoring system). Spearman’s rank was used to analyse the correlation between DCE and DWI.ResultsThirty-five JIA patients (18 MRI active and 17 MRI inactive) were included. Median age was 13.1 years and 71% were female. ME, MIS, TTP, % TIC 5 and ADC were significantly different in MRI-active versus MRI-inactive JIA with median ADC 1.49 × 10-3mm2/s in MRI-active and 1.25 × 10-3mm2/s in MRI-inactive JIA, p = 0.001, 95% confidence interval of difference in medians =0.11-0.53 × 10-3mm2/s. ADC correlated to ME, MIS and TIC 5 shapes (r = 0.62, r = 0.45, r = -0.51, respectively, all p < 0.05).ConclusionsSimilar to DCE parameters, DWI-derived ADC is significantly different in MRI-active JIA as compared to MRI-inactive JIA. The non-invasiveness of DWI combined with its possibility to detect synovial inflammation shows the potential of DWI.Key Points• MRI can quantify: dynamic contrast-enhanced and diffusion-weighted MRI can quantify synovitis• Both DWI and DCE can differentiate active from inactive JIA• The DWI-derived apparent diffusion coefficient (ADC) is higher in active JIA• DWI is non-invasive and thus safer and more patient-friendly• DWI is a potentially powerful and non-invasive imaging biomarker for JIA

Secretion of pro-inflammatory cytokines and chemokines and loss of regulatory signals by fibroblast-like synoviocytes in juvenile idiopathic arthritis.

PurposeThe goal is to investigate the specific contribution of fibroblast‐like synoviocytes (FLS) to the inflammatory milieu of the synovium in juvenile idiopathic arthritis (JIA) through detection of secreted proteins.Experimental designExpression of 89 cytokines and chemokines is determined on unprocessed synovial fluid from controls and JIA patients using antibody arrays. Supernatants from pure cell cultures of FLS grown from synovial fluids or tissues from JIA and controls are also examined for protein expression. Ingenuity Pathway Analysis (IPA) is revealed top pathways and upstream regulators of significant proteins.ResultsProtein studies is revealed that JIA FLS release pro‐inflammatory cytokines and chemokines, including IL‐4, IL‐6, IL‐17, CXCL1, and CXCL6, and lose expression of important regulator signals, such as IL‐10 and TIMP2. Of the 84 proteins differentially expressed between controls and JIA in the synovial fluid, 1/3 (29 proteins) are differentially expressed in the cell culture supernatants of JIA and control FLS. ELISA of cell culture supernatants and synovial fluid confirmed seven key proteins.Conclusion and clinical relevanceJIA FLS are central to perpetuation of inflammation in JIA, including trafficking of inflammatory cells and effects on the extracellular matrix. These cells express key disease‐specific chemokines that, with further refinement, may allow us to tailor therapy appropriately.

Lipoprotein cholesterol fractions are related to markers of inflammation in children and adolescents with juvenile idiopathic arthritis: a cross sectional study.

BackgroundThe purpose of the study is to determine levels of total cholesterol (TC), low-density, and high-density lipoprotein fractions of cholesterol (LDLc and HDLc), in patients with juvenile idiopathic arthritis (JIA), and relate those to disease activity, overweight, and physical activity (PA), testing the hypothesis that the levels of cholesterol fractions are associated with inflammation as well as with overweight and low PA.MethodsTwo hundred ten patients with JIA were included in this descriptive cross-sectional study. TC, LDLc, HDLc were measured, and associations with clinical disease activity (JADAS27), biomarkers of inflammation (myelo-related protein complex 8/14 (MRP8/14), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR)), body mass index (BMI), waist-to-height ratio (WtH ratio), and PA were explored.ResultsMean values for TC, LDLc, and HDLc in the patients were within the normal range for Danish Children. HDLc was negatively correlated with MRP8/14 (r = −0.343, CI −0.474 to −0.201, p < 0.0005) but was not related to overweight or PA. Neither TC nor LDLc showed any association with inflammation, overweight, or PA. MRP8/14 correlated positively with CRP, JADAS27 and WtH ratio (r = 0.277, CI 0.142 to 0.413, p = 0.001).ConclusionsLevels of cholesterol fractions in patients with JIA were found within the normal range. Nonetheless, the level of HDLc was negatively associated with the level of the inflammatory marker MRP8/14, which is in accordance with the concept of inflammation as an important driver for premature development of atherosclerosis in JIA. WtH ratio (a measure of central fatness) was not associated to HDLc, but to MRP8/14, suggestive of central fatness as an additional driving factor for the chronic inflammation in JIA.

A novel subset of fibrocyte-like cells in synovial fluid communicate with CD8 T cells and shape the local inflammatory milieu in Juvenile Idiopathic Arthritis (JIA). (HUM3P.253)

Abstract We reported previously that children with JIA carry senescent CD31+CD8+ T cells disproportionate with age. Such cells are inflammatory effectors via CD31-driven TCR-independent activation pathway. Here, we hypothesized that these T cells interact with non-hematopoietic cells in the synovial space to perpetuate joint inflammation. JIA patients medically indicated to undergo arthrocentesis were recruited. Synovial aspirates were screened by flow cytometry, and short-term cultures were established. Results showed two subsets of plastic-adherent fibrocyte-like cells (FLC). About 75% were procollagen-CD45-CD14- cells that variably expressed CD34. The other ~25% were procollagen+CD45+CD14+IL17RA+ CD34- FLC; a finding unlike similar cells reported for adult-onset rheumatoid arthritis. FLC exposed to rIL-17 and/or rTNFα induced production of MMPs that were reversed with corticosteroid, TNFi, anti-IL6R, or experimental NFkB inhibitors. Co-culture of FLC with autologous CD8 T cells resulted in production of the same array of MMPs and inflammatory cytokines that were partially blocked by neutralizing anti-CD31 antibody. These results suggest a FLC-CD8 T cell communication circuit in the maintenance of joint inflammation in JIA. Further understanding of the regulation and/or the consequences of this local cell-cell interaction could shed light into the systemic complications of this childhood disease that impose lifelong health burden. [Supported by Nancy E Taylor Foundation and NIH].

Joint inflammation assessed by physical examination and MRI of the knee in juvenile idiopathic arthritis: low predictive value for synovitis

The presence of joint inflammation in juvenile idiopathic arthritis (JIA) patients can be made by physical examination and confirmed by imaging. The discrepancy between physical examination and MRI for evaluation of synovitis in a target joint is possibly explained by the fact that clinical measures mostly reflect overall disease activity instead of measures specific for the joint imaged by MRI.

Hypomethylation at the regulatory T cell-specific demethylated region in CD25hi T cells is decoupled from FOXP3 expression at the inflamed site in childhood arthritis.

The maintenance of FOXP3 expression in CD25hi regulatory T cells (Tregs) is crucial to the control of inflammation and essential for successful Treg transfer therapies. Coexpression of CD25 and FOXP3 in combination with a hypomethylated region within the FOXP3 gene, called the Treg-specific demethylated region (TSDR), is considered the hallmark of stable Tregs. The TSDR is an epigenetic motif that is important for stable FOXP3 expression and is used as a biomarker to measure Treg lineage commitment. In this study, we report that, unlike in peripheral blood, CD4+ T cell expression of CD25 and FOXP3 is frequently dissociated at the inflamed site in patients with juvenile idiopathic arthritis, which led us to question the stability of human Tregs in chronic inflammatory environments. We describe a novel CD4+CD127loCD25hi human T cell population that exhibits extensive TSDR and promoter demethylation in the absence of stable FOXP3 expression. This population expresses high levels of CTLA-4 and can suppress T conventional cell proliferation in vitro. These data collectively suggest that this population may represent a chronically activated FOXP3lo Treg population. We show that these cells have defects in IL-2 signaling and reduced expression of a deubiquitinase important for FOXP3 stability. Clinically, the proportions of these cells within the CD25hi T cell subset are increased in patients with the more severe courses of disease. Our study demonstrates, therefore, that hypomethylation at the TSDR can be decoupled from FOXP3 expression in human T cells and that environment-specific breakdown in FOXP3 stability may compromise the resolution of inflammation in juvenile idiopathic arthritis.