Oligoarticular and polyarticular JIA: epidemiology and pathogenesis

Dynamics of serum levels of TNF-α in a longitudinal follow-up study in 98 patients with juvenile idiopathic arthritis treated with anti-TNF-α biological drugs

OBJECTIVE

To determine the dynamics of serum levels of TNF-α in patients with juvenile idiopathic arthritis (JIA) treated with anti-TNF-α biological drugs and investigate their association with the disease activity.

METHODS

We conducted a single-centre, observational cohort study in 98 patients with JIA (30 boys, 68 girls, mean age 11.3 years) treated with anti-TNF-α biological drugs. Clinical examinations and laboratory assessments of serum levels of TNF-α were performed before starting therapy with biological drug and at 6-month intervals afterwards up to 2.5 years.

RESULTS

The analysis of serum levels of TNF-α in relation to the disease activity states showed the highest mean serum levels of TNF-α in patients on etanercept who had low disease activity states and in patients on adalimumab who had inactive disease. The correlation analysis in patients with JIA treated with etanercept or adalimumab showed a weak negative correlation between the serum levels of TNF-α and JADAS10 scores (p = 0.007), (r =  - 0.177).

CONCLUSION

The assessment of serum levels of TNF-α in children with JIA during treatment with etanercept or adalimumab is not a reliable biomarker of disease activity or immunological remission. Longitudinal measurement of TNF-α has no added clinical value in patients with JIA treated with anti-TNF-α biological drugs. Key Points • There is limited evidence regarding the effect of anti-TNF therapy on serum concentrations of TNF-α in patients with juvenile idiopathic arthritis • Our study showed an increase in the serum level of TNF-α after the initiation of therapy with either etanercept or adalimumab, which was more significant in patients with inactive or low disease activity • Serum TNF-α is most likely not biologically active during therapy with TNF-α inhibitors and therefore not a reliable biomarker of disease activity or immunological remission in patients with juvenile idiopathic arthritis.

Pre-Rheumatology Referral Consultation and Investigation Pattern in Children with Joint Complaints: Focus on Juvenile Idiopathic Arthritis

The diagnosis of juvenile idiopathic arthritis (JIA) is often entrusted to the pediatric rheumatologist specialist. Timely referral to a specialized center is crucial. This study aims to assess the consultation and investigation patterns of patients with joint complaints before rheumatology referral. This longitudinal cohort study included patients with joint complaints who were referred to the Pediatric Rheumatology Unit. The cohort included 301 patients (58% female), 50 of them (17%) diagnosed with JIA. Compared to patients with orthopedic conditions or functional diseases, JIA patients had seen more specialists (p < 0.01) and received a quicker diagnosis (p < 0.01). Patients with early JIA diagnosis (within 3 months from symptoms onset) were younger (8.46 vs. 11.5 years old; p = 0.04), more frequently female (78% vs. 47%, p = 0.03), and with higher erythrocyte sedimentation rate (ESR) values (37 vs. 9 mm/h; p = 0.02) than those diagnosed later. Patients with a late diagnosis of JIA had a significantly longer median time between the first healthcare visit and the PR referral (25 vs. 101 days; p < 0.01). The main contributor to diagnostic delay in JIA was the time required for PR referral after the first healthcare consult. Younger age, female sex, and higher ESR values were associated with earlier diagnosis of JIA.

Gene association analysis to determine the causal relationship between immune cells and juvenile idiopathic arthritis

BACKGROUND

Juvenile idiopathic arthritis (JIA) is a type of chronic childhood arthritis with complex pathogenesis. Immunological studies have shown that JIA is an acquired self-inflammatory disease, involving a variety of immune cells, and it is also affected by genetic and environmental susceptibility. However, the precise causative relationship between the phenotype of immune cells and JIA remains unclear to date. The objective of our study is to approach this inquiry from a genetic perspective, employing a method of genetic association analysis to ascertain the causal relationship between immune phenotypes and the onset of JIA.

METHODS

In this study, a two-sample Mendelian randomization (MR) analysis was used to select single nucleotide polymorphisms (SNPs) significantly associated with immune cells as instrumental variables to analyze the bidirectional causal relationship between 731 immune cells and JIA. There were four types of immune features (median fluorescence intensity (MFI), relative cellular (RC), absolute cellular (AC), and morphological parameters (MP)). Finally, the heterogeneity and horizontal reproducibility of the results were verified by sensitivity analysis, which ensured more robust results.

RESULTS

We found that CD3 on CM CD8br was causally associated with JIA at the level of 0.05 significant difference (95% CI = 0.630 ~ 0.847, P = 3.33 × 10-5, PFDR = 0.024). At the significance level of 0.20, two immunophenotypes were causally associated with JIA, namely: HLA DR on CD14+ CD16- monocyte (95% CI = 0.633 ~ 0.884, P = 6.83 × 10-4, PFDR = 0.16) and HLA DR on CD14+ monocyte (95% CI = 0.627 ~ 0.882, P = 6.9 × 10-4, PFDR = 0.16).

CONCLUSION

Our study assessed the causal effect of immune cells on JIA from a genetic perspective. These findings emphasize the complex and important role of immune cells in the pathogenesis of JIA and lay a foundation for further study of the pathogenesis of JIA.

Prevalence of temporomandibular disorders in juvenile idiopathic arthritis evaluated with diagnostic criteria for temporomandibular disorders: A systematic review with meta-analysis

BACKGROUND

Juvenile idiopathic arthritis (JIA) is a very common systemic inflammatory rheumatic disorder affecting the musculoskeletal system in children below 16 years of age. Joint inflammation and tissue destruction is the prime characteristic of the disease. Along with the systemic involvement in the long joints, several studies are mentioning the increased association of temporomandibular disorders (TMDs) in JIA. This current systematic review intends to find the prevalence rate of TMD in JIA-affected individuals as compared to healthy controls.

METHODS

We have searched in PubMed, Scopus and Ovid SP for articles published between the timeframe 1 January 1990 and 1 June 2023. All the searched articles were subjected to the Population, Exposure, Comparison, and Outcome model (PECO) based on which inclusion or exclusion is carried out. Participants (P) are children below 18 years of age, Exposure (E) is children or adolescents with a diagnosis of JIA, Comparator is age and gender-matched healthy controls who has no JIA or any systemic disorder, Outcome (O) is the prevalence of TMD. Only the studies that evaluated TMD using diagnostic criteria for evaluation of TMD (DC/TMD) were included in the analysis. We have set the exclusion to the following reasons- diagnostic sensitivity studies, case reports, and systematic reviews. The software Review Manager Version 5.4 (Cochrane Collaboration) was used to perform the pooled analysis. We measured the risk ratio (RR) between the two groups (JIA and no JIA) for the outcome TMD.

RESULTS

The pooled total included subjects were 366 in this review with an established diagnosis of JIA as evaluated by DC/TMD. The overall effect of the pooled data suggests that there is a significant difference in the TMD prevalence in the JIA group when compared to the control, results suggest that TMD is more prevalent in the JIA group RR 3.86; 95% CI [2.59, 5.76].

CONCLUSION

Overall, based on the data we can suggest a positive relationship between JIA and TMD, hence presence of JIA can be a risk factor for the development of TMD. The sensitivity of DC/TMD is low when compared to magnetic resonance imaging.

Pathways of sleep disturbances in juvenile idiopathic arthritis and recommendations for clinical management approaches: A critical review

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease affecting young people. It has a profound impact on their physical, mental and social lives, leading to long-term disability. With the growing awareness of the importance of sleep in all areas of functioning in young people, an emerging literature has drawn attention to the role of sleep in the pathogenesis of JIA. Sleep disturbances in children and adolescents with JIA arise from a wide range of symptoms and pathways, leading to a vicious cycle that exacerbates subclinical inflammation, symptoms and disease progression. Putative factors contributing to sleep disturbances include chronic inflammation, JIA-associated sleep disorders, JIA symptoms (e.g. pain), psychological comorbidities and potential circadian disruption, which may be exacerbated by the transition to adolescence. Here, we review these pathways and advocate key strategies and alternatives for sleep management in young people with JIA in clinical settings. We identify gaps in knowledge and suggest future directions to improve our understanding of JIA sleep disorders, including clinical trials investigating potential strategies to improve sleep health in this young population.

Expanded population of low-density neutrophils in juvenile idiopathic arthritis

Introduction

Juvenile idiopathic arthritis (JIA), a clinically variable disease characterized by autoimmune arthritis, affects children, and its immunopathology remains elusive. Alterations in neutrophil biology play an important role in this disease. In the present study, we aimed to explore the features of low-density neutrophils (LDNs) in patients with JIA.

Methods

Gene expression of peripheral blood mononuclear cells (PBMCs) from children with distinct subtypes of JIA was analyzed by NanoString Immunology panel. Presence of LDNs was ascertained by flow cytometry and the release of neutrophil-associated products were analyzed by LUMINEX.

Results

LDNs were detected in patients' peripheral blood mononuclear cells (PBMCs) after density gradient centrifugation. Transcriptomic analysis of JIA PBMCs revealed that genes related to neutrophil degranulation were markedly upregulated. The number of LDNs and level of their degranulation products increased in patients' PBMCs and correlated with serum calprotectin, but not with disease activity, sedimentation rate and C-reactive protein (CRP) levels. The phenotypes of LDNs varied from those of normal-density neutrophils and healthy donor LDNs. Phenotypical analysis revealed LDNs are immature and primed population with decreased suppressive capacity. A negative correlation between surface proteins CD62L, CD66b, and CD11b and the number of inflamed joints/JADAS was established.

Conclusion

Our results describe LDNs as primed, degranulated, immature cells with impaired suppressive activities. This work thus contributes to the increasing body of evidence that LDNs in JIA are altered and their role in the disease immunopathogenesis and possible clinical associations should be investigated further.

Children with extended oligoarticular and polyarticular juvenile idiopathic arthritis have alterations in B and T follicular cell subsets in peripheral blood and a cytokine profile sustaining B cell activation

OBJECTIVES

The main goal of this study was to characterise the frequency and phenotype of B, T follicular helper (Tfh) and T follicular regulatory (Tfr) cells in peripheral blood and the cytokine environment present in circulation in children with extended oligoarticular juvenile idiopathic arthritis (extended oligo JIA) and polyarticular JIA (poly JIA) when compared with healthy controls, children with persistent oligoarticular JIA (persistent oligo JIA) and adult JIA patients.

METHODS

Blood samples were collected from 105 JIA patients (children and adults) and 50 age-matched healthy individuals. The frequency and phenotype of B, Tfh and Tfr cells were evaluated by flow cytometry. Serum levels of APRIL, BAFF, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-17A, IL-21, IL-22, IFN-γ, PD-1, PD-L1, sCD40L, CXCL13 and TNF were measured by multiplex bead-based immunoassay and/or ELISA in all groups included.

RESULTS

The frequency of B, Tfh and Tfr cells was similar between JIA patients and controls. Children with extended oligo JIA and poly JIA, but not persistent oligo JIA, had significantly lower frequencies of plasmablasts, regulatory T cells and higher levels of Th17-like Tfh cells in circulation when compared with controls. Furthermore, APRIL, BAFF, IL-6 and IL-17A serum levels were significantly higher in paediatric extended oligo JIA and poly JIA patients when compared with controls. These immunological alterations were not found in adult JIA patients in comparison to controls.

CONCLUSIONS

Our results suggest a potential role and/or activation profile of B and Th17-like Tfh cells in the pathogenesis of extended oligo JIA and poly JIA, but not persistent oligo JIA.

MicroRNAs in Juvenile Idiopathic Arthritis: State of the Art and Future Perspectives

Juvenile Idiopathic Arthritis (JIA) represents the most common chronic pediatric arthritis in Western countries and a leading cause of disability in children. Despite recent clinical achievements, patient management is still hindered by a lack of diagnostic/prognostic biomarkers and targeted treatment protocols. MicroRNAs (miRNAs) are short non-coding RNAs playing a key role in gene regulation, and their involvement in many pathologies has been widely reported in the literature. In recent decades, miRNA's contribution to the regulation of the immune system and the pathogenesis of autoimmune diseases has been demonstrated. Furthermore, miRNAs isolated from patients' biological samples are currently under investigation for their potential as novel biomarkers. This review aims to provide an overview of the state of the art on miRNA investigation in JIA. The literature addressing the expression of miRNAs in different types of biological samples isolated from JIA patients was reviewed, focusing in particular on their potential application as diagnostic/prognostic biomarkers. The role of miRNAs in the regulation of immune responses in affected joints will also be discussed along with their potential utility as markers of patients' responses to therapeutic approaches. This information will be of value to investigators in the field of pediatric rheumatology, encouraging further research to increase our knowledge of miRNAs' potential for future clinical applications in JIA.

Risk stratification using anti-citrullinated peptide antibodies (ACPA) in polyarticular subtypes of juvenile idiopathic arthritis in adulthood

OBJECTIVES

Polyarticular juvenile idiopathic arthritis (pJIA) is a subset of juvenile idiopathic arthritis (JIA), divided into two subtypes according to the presence of rheumatoid factor: pJIA without rheumatoid factor (pJIA RF-) and pJIA with positive rheumatoid factor (pJIA RF+), this latter is characterised with more structural damage. Anti-citrullinated peptide antibodies (ACPA) are often associated with RF. The respective performance of ACPA versus RF in structural outcome in pJIA, and in particular in adulthood pJIA remains unknown. Therefore, the aim of this study was to determine whether ACPA could be of value to assess structural damage in pJIA persisting in adulthood.

METHODS

Patients with pJIA and available data for ACPA, RF and X-ray were included retrospectively. Structural damage was assessed by two independent blinded investigators using Sharp Van Der Heijde scores.

RESULTS

56 pJIA adult patients were included: 62% (35/56) had pJIA RF+ and 38% (21/56) pJIA RF-. ACPA positivity in pJIA was significantly associated with presence of RF (96% vs 26%, P<0.001). RF positivity was significantly associated with higher Sharp van Der Heijde erosion and total scores (respectively P<0.01 and P<0.05). There were higher Sharp Van Der Heijde erosion, joint space narrowing and total scores in the pJIA ACPA+ subgroup than in the pJIA ACPA- subgroup, although there was no statistical significance. However, when adjusted on disease duration, pJIA ACPA+ patients had significantly higher erosion and total scores than pJIA ACPA- patients (P<0.05), and pJIA ACPA+ patients required more bDMARDs than pJIA ACPA- patients (P<0.05). Moreover, pJIA patients with high Sharp van Der Heijde joint space narrowing and total scores had significantly higher ACPA levels (P<0.01). A correlation was identified between ACPA levels and Sharp van Der Heijde total score (r=0.54, P<0.05). In the pJIA RF+ subgroup the presence of ACPA was associated with additional structural damage compared to no ACPA: sharp Van Der Heijde erosion, joint space narrowing and total scores were higher in the pJIA RF+ ACPA+ subgroup than in the pJIA RF+ ACPA- subgroup although these results did not reach significance.

CONCLUSION

Our results suggest that pJIA RF+ ACPA+ adult patients may have a more severe articular phenotype than pJIA RF+ ACPA- patients. ACPA could bring an additional value to RF for pJIA patients regarding structural damage. Altogether our results show that RF and ACPA are associated with structural damage measured by Sharp Van Der Heijde score in pJIA persisting in adulthood.

Physical activity as a promising alternative for young people with juvenile idiopathic arthritis: Towards an evidence-based prescription

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in young people. Although biologics now enable most children and adolescents with JIA to enjoy clinical remission, patients present lower physical activity and spend more time in sedentary behavior than their healthy counterparts. This impairment probably results from a physical deconditioning spiral initiated by joint pain, sustained by apprehension on the part of both the child and the child's parents, and entrenched by lowered physical capacities. This in turn may exacerbate disease activity and lead to unfavorable health outcomes including increased risks of metabolic and mental comorbidities. Over the past few decades, there has been growing interest in the health benefits of increased overall physical activity as well as exercise interventions in young people with JIA. However, we are still far from evidence-based physical activity and / or exercise prescription for this population. In this review, we give an overview of the available data supporting physical activity and / or exercise as a behavioral, non-pharmacological alternative to attenuate inflammation while also improving metabolism, disease symptoms, poor sleep, synchronization of circadian rhythms, mental health, and quality of life in JIA. Finally, we discuss clinical implications, identify gaps in knowledge, and outline a future research agenda.

Proteomic profiling of extracellular vesicles in synovial fluid and plasma from Oligoarticular Juvenile Idiopathic Arthritis patients reveals novel immunopathogenic biomarkers

Introduction

New early low-invasive biomarkers are demanded for the management of Oligoarticular Juvenile Idiopathic Arthritis (OJIA), the most common chronic pediatric rheumatic disease in Western countries and a leading cause of disability. A deeper understanding of the molecular basis of OJIA pathophysiology is essential for identifying new biomarkers for earlier disease diagnosis and patient stratification and to guide targeted therapeutic intervention. Proteomic profiling of extracellular vesicles (EVs) released in biological fluids has recently emerged as a minimally invasive approach to elucidate adult arthritis pathogenic mechanisms and identify new biomarkers. However, EV-prot expression and potential as biomarkers in OJIA have not been explored. This study represents the first detailed longitudinal characterization of the EV-proteome in OJIA patients.

Methods

Fourty-five OJIA patients were recruited at disease onset and followed up for 24 months, and protein expression profiling was carried out by liquid chromatography-tandem mass spectrometry in EVs isolated from plasma (PL) and synovial fluid (SF) samples.

Results

We first compared the EV-proteome of SF vs paired PL and identified a panel of EV-prots whose expression was significantly deregulated in SF. Interaction network and GO enrichment analyses performed on deregulated EV-prots through STRING database and ShinyGO webserver revealed enrichment in processes related to cartilage/bone metabolism and inflammation, suggesting their role in OJIA pathogenesis and potential value as early molecular indicators of OJIA development. Comparative analysis of the EV-proteome in PL and SF from OJIA patients vs PL from age/gender-matched control children was then carried out. We detected altered expression of a panel of EV-prots able to differentiate new-onset OJIA patients from control children, potentially representing a disease-associated signature measurable at both the systemic and local levels with diagnostic potential. Deregulated EV-prots were significantly associated with biological processes related to innate immunity, antigen processing and presentation, and cytoskeleton organization. Finally, we ran WGCNA on the SF- and PL-derived EV-prot datasets and identified a few EV-prot modules associated with different clinical parameters stratifying OJIA patients in distinct subgroups.

Discussion

These data provide novel mechanistic insights into OJIA pathophysiology and an important contribution in the search of new candidate molecular biomarkers for the disease.

Incidence, prevalence, and comorbidities of juvenile idiopathic arthritis in Germany: a retrospective observational cohort health claims database study

BACKGROUND

Juvenile idiopathic arthritis (JIA) describes heterogenous categories of chronic inflammatory rheumatic conditions of unknown origin in children and adolescents. Epidemiological data in the literature vary, depending on geographic location, ethnicity and the case definition used. We evaluated epidemiology, especially that of the categories defined by the International League of Associations for Rheumatology (ILAR).

METHODS

Using data from two different longitudinal health claims databases (WIG2 and InGef) from January 1^st, 2013 to December 31^st, 2019, we looked at patients aged 2 to 15 years old with at least one main inpatient or two secondary inpatient/verified outpatient ICD-10 diagnoses in at least two different quarters within one calendar year. We calculated prevalence and incidence (per 100,000 patients) and extrapolated data to the entire German population, looking at differences in gender and age groups. Additionally, we collected data on "other" not necessary comorbidities in our JIA patient population.

RESULTS

Of the 3-4 million patients in the databases (respectively) in 2018, we found a total of 546 (WIG2) and 849 (InGef) patients that met our JIA case definition, with an incidence of 34 (29-41) and 60 (53-67) and prevalence of 133 (122-145) and 168 (157-179). Both incidence and prevalence throughout the age range were mostly higher in females than males, however the difference between females and males increased with increasing age. Of the ILAR categories, oligoarthritis was the most prevalent (70 and 91 per 100,000), with about half of our JIA patients in this category, followed by undifferentiated arthritis (49 and 56 cases per 100,000) and rheumatoid factor negative (RF-) (31 and 39 per 100,000). Incidence in 2018 was the highest in these three categories. Atopic dermatitis, vasomotor and allergic rhinitis, and uveitis were the pre-defined comorbidities seen most often in both databases.

CONCLUSION

This study provides current incidence and prevalence JIA data in Germany, contributing to knowledge on burden of disease and tools for healthcare planning.

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.

A comparison of Juvenile Idiopathic Arthritis classification systems with the Research in Arthritis in Canadian Children, Emphasizing Outcomes (ReACCh-Out) cohort

OBJECTIVE

To compare International League of Associations for Rheumatology (ILAR) and Paediatric Rheumatology INternational Trials Organisation (PRINTO) classifications for juvenile idiopathic arthritis (JIA) using data from the Research in Arthritis in Canadian Children emphasizing Outcomes cohort (ReACCh-Out). The aim of the PRINTO classification, still in development, is to identify homogeneous groups of patients with JIA.

METHODS

We used data recorded within 7 months of diagnosis in 1228 patients to assign patients according to the two classification systems by computation. We compared the proportions of patient classified and the alignment of classified categories with clinical-biological subtypes and adult types of arthritis.

RESULTS

The PRINTO system classified 244 patients (19.9%) as Early-onset ANA-positive (EOANA), 157 (12.8%) as Enthesitis/Spondylitis-related, 38 (3.1%) as Systemic, and 10 (0.8%) as RF-positive JIA. Twelve percent of patients were unclassifiable using ILAR while 63.3% were unclassifiable using PRINTO criteria (777 Other JIA and 2 Unclassified JIA). In sensitivity analyses, >50% remained unclassifiable by PRINTO. ILAR categories aligned better with clinical-biological subtypes in 131 patients (χ² =44, p=0.005 versus χ² =15, p=0.07 for PRINTO), and with adult types of arthritis in 389 evaluable patients.

CONCLUSION

Current identified PRINTO disorders classify a minority of patients with JIA, leaving a large proportion with Other disorders requiring further characterization. Current PRINTO classifications do not appear to improve alignment with clinical-biological subtypes or adult forms of arthritis relative to the older ILAR system.

Juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is an umbrella term for arthritis of unknown origin, lasting for >6 weeks with onset before 16 years of age. JIA is the most common chronic inflammatory rheumatic condition of childhood. According to the International League Against Rheumatism (ILAR) classification, seven mutually exclusive categories of JIA exist based on disease manifestations during the first 6 months of disease. Although the ILAR classification has been useful to foster research, it has been criticized mainly as it does not distinguish those forms of chronic arthritis observed in adults and in children from those that may be unique to childhood. Hence, efforts to provide a new evidence-based classification are ongoing. Similar to arthritis observed in adults, pathogenesis involves autoimmune and autoinflammatory mechanisms. The field has witnessed a remarkable improvement in therapeutic possibilities of JIA owing to the availability of new potent drugs and the possibility to perform controlled trials with support from legislative interventions and large networks availability. The goal of drug therapy in JIA is to rapidly reduce disease activity to inactive disease or clinical remission, minimize drug side effects and achieve a quality of life comparable to that of healthy peers. As JIA can influence all aspects of a child's and their family's life, researchers increasingly recognize improvement of health-related quality of life as a key treatment goal.

Identification of novel autoantigens as potential biomarkers in juvenile idiopathic arthritis associated uveitis

BACKGROUND

Many children with juvenile idiopathic arthritis (JIA) have autoantibodies, targeting nuclear components (anti-nuclear antibodies, ANA). ANA in JIA is associated with uveitis, an eye inflammation which may cause permanent vision impairment if not detected and treated. However, ANA-testing is neither specific nor sensitive enough to be a clinically reliable predictor of uveitis risk, and the precise autoantigens targeted by ANA in JIA are largely unknown. If identified, specific autoantibodies highly associated with uveitis could be used as biomarkers to facilitate identification of JIA patients at risk.

METHODS

Antibodies from six ANA-positive, oligoarticular JIA patients, with and without uveitis, were explored by two large-scale methods: (1) screening against 42,100 peptides on an autoimmunity profiling planar array, and (2) immunoprecipitations from cell lysates with antigen identification by mass spectrometry. Three hundred thirty-five peptide antigens, selected from proteins identified in the large-scale methods and the scientific literature were investigated using a bead-based array in a cohort of 56 patients with oligoarticular- or RF-negative polyarticular JIA, eight of which were having current or previous uveitis.

RESULTS

In the planar array, reactivity was detected against 332 peptide antigens. The immunoprecipitations identified reactivity towards 131 proteins. Only two proteins were identified by both methods. In the bead-based array of selected peptide antigens, patients with uveitis had a generally higher autoreactivity, seen as higher median fluorescence intensity (MFI) across all antigens, compared to patients without uveitis. Reactivity towards 17 specific antigens was significantly higher in patients with uveitis compared to patients without uveitis. Hierarchical clustering revealed that patients with uveitis clustered together.

CONCLUSION

This study investigated autoantigens in JIA and uveitis, by combining two exploratory methods and confirmation in a targeted array. JIA patients with current or a history of uveitis had significantly higher reactivity towards 17 autoantigens and a generally higher autoreactivity compared to JIA patients without uveitis. Hierarchical clustering suggests that a combination of certain autoantibodies, rather than reactivity towards one specific antigen, is associated with uveitis. Our analysis of autoantibodies associated with uveitis in JIA could be a starting point for identification of prognostic biomarkers useful in JIA clinical care.

Evaluation of pediatric patients with јuvenile idiopathic arthritis treated with biological therapy Tocilizumab (Actemra)

Juvenile idiopathic arthritis (JIA) is the most common chronic disease in childhood. It manifests a heterogenic group of symptoms of arthritis, lasting at least 6 weeks and it appears before the age of 16. Patients who had no good therapeutic response to conventional therapy with Methotrexate were treated with biological therapy. The aim of this paper was to evaluate 9 patients who were receiving Tocilizumab at the Department of Rheumocardiology, University Clinic of Pediatric Diseases in Skopje. Materials and methods: Our study included 9 patients treated at our Department with biological therapy with Tocilizumab. Prior to initiation of the biological therapy, all patients underwent laboratory investigations, purified protein derivative (PPD) skin test for tuberculosis, X ray of the lungs and heart, and analysis of hepatitis markers. All patients were treated with amp. Actemra (tocilizumab) 8 mg/kg/tt i.v. Two of the patients had a severe form of the disease (one with severe systemic form and one with severe oligoarticular form of JIA). All presented patients had clinical remission of the disease. Conclusion: Therapy with tocilizumab in patients with juvenile idiopathic arthritis is a good therapeutic choice. The results obtained in our study have shown a significant therapeutic effect of tocilizumab even in severe forms of the disease.  

miR-23a contributes to T cellular redox metabolism in juvenile idiopathic oligoarthritis

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease of unknown origin. The regulation of inflammatory processes involves multiple cellular steps including mRNA transcription and translation. Different miRNAs tightly control these processes. We aimed to determine the roles of specific miRNAs within JIA pathogenesis.

METHODS

We performed a global miRNA expression analysis in parallel in cells from the arthritic joint and peripheral blood of oligoarticular JIA patients and healthy controls. QRT-PCR analysis was used to verify expression of miRNA in T cells. Ex vivo experiments and flow cytometric analyses were used to analyze proliferation and redox metabolism.

RESULTS

Global miRNA expression analysis demonstrated a different composition of miRNA expression at the site of inflammation compared with peripheral blood. Bioinformatic analysis of predicted miRNA target genes suggest a huge overrepresentation of genes involved in metabolic and oxidative stress pathways in the inflamed joint. Despite enhanced ROS levels within the local inflammatory milieu, JIA T cells are hyperproliferative and reveal an overexpression of miR-23a, which is an inhibitor of PPIF, the regulator of mitochondrial ROS escape. Mitochondrial ROS escape is diminished in JIA T cells resulting in their prolonged survival.

CONCLUSION

Our data suggest that miRNA dependent mitochondrial ROS shuttling might be a mechanism that contributes to T cell regulation in JIA at the site of inflammation.

Children hospitalized for juvenile arthritis in the United States

Juvenile arthritis (JA) is an autoimmune condition affecting children. We used the 2017 National Inpatient Sample (NIS) to evaluate the impact of JA in the United States. The admission data were converted to weighted form and patients between the ages of 0 and 18 (inclusive) were used in our study. 560 weighted cases were found in 2017. It was more common in females than males (340 females, 220 males), Whites (235 cases), and Medicaid covered 61.6% of all patients with JA (345 cases). The total hospital charges were $25,147,389 while the mean length of stay (LOS) was 4.55 days. The highest number of cases was reported in April 2017.

Sleep in children and adolescents with juvenile idiopathic arthritis: a systematic review and meta-analysis of case-control studies

STUDY OBJECTIVES

Juvenile idiopathic arthritis (JIA) is one of the most common pediatric rheumatic disease. However, sleep alteration associated with this auto-immune disease remain unclear. We aimed in this systematic review and meta-analysis to compare sleep duration, quality, and architecture in JIA subjects with those in their healthy peers.

METHODS

Systematic search performed in PubMed, EMBase, Cochrane, and PsycINFO databases included 19 studies in the qualitative synthesis of which 10 met the inclusion criteria for the meta-analysis.

RESULTS

Pooled results from subjective methods indicated pronounced sleep disturbances and complaints in youth with JIA compared with their healthy counterparts. This was further confirmed by Increased difficulty maintaining sleep (wake after sleep onset; SMD: -0.69; CI: -1.29; -0.09, p =0.02) and a tendency to increased difficulty initiating sleep (sleep onset latency; SMD: -0.29; CI: -0.60; 0.03, p =0.07). There were no remarkable differences in sleep duration or sleep architecture between JIA patients and healthy controls. High heterogeneity was found for several outcomes. This could be explained by the different methods used as well as associated sleep disorders, medication and comorbidities.

CONCLUSIONS

Although included studies were methodologically diverse, the summarized results of our review and meta-analysis bring evidence that children with JIA present more fragmented sleep compared to healthy peers. Thereby, the implementation of strategies to manage and improve sleep in this population are needed and might have a beneficial effect on the symptoms and functions of JIA.

Salivary glands involvement: a new indicator of juvenile idiopathic oligoarticular arthritis (preliminary results)

OBJECTIVE

Early diagnosis is critical to reduce long-term disability in patients with JIA by ensuring prompt treatment. The aim of this cross-sectional study was to evaluate the salivary gland function in JIA, addressing specifically oligoarticular (JIA1) and polyarticular (JIA2) subtypes, compared with healthy controls. This may contribute to the identification of salivary risk indicators of the disease that may help diagnosis at an early stage or even before the onset of other clinical evidence.

METHODS

Twenty-eight patients with JIA1, 28 patients with JIA2, according to the ILAR criteria, and 28 healthy controls (C) were included in the study. Exclusion criteria were any concurrent medical condition. Data on medication, dietary and oral hygiene habits were collected using a questionnaire. All patients underwent oral examination and saliva measurement.

RESULTS

While stimulated salivary flow rate (SFR) was significantly lower in JIA1 compared with JIA2 and C (P < 0.001), both salivary buffer capacity and pH were similar in the two JIA groups but statistically different from C (P = 0.002 and P = 0.010, respectively). Children with very low SFR (<3.5 ml) exhibited a 16-fold higher likelihood of being affected by JIA1 rather than JIA2 (P = 0.003), while no association was observed between low flow rate and JIA subtype (P = 0.744).

CONCLUSION

These preliminary data suggest impairment of salivary gland function as a risk indicator for JIA1 with no association with dietary habits and drug intake.

Juvenile idiopathic arthritis: from aetiopathogenesis to therapeutic approaches

Juvenile idiopathic arthritis (JIA) is the most common paediatric rheumatological disorder and is classified by subtype according to International League of Associations for Rheumatology criteria. Depending on the number of joints affected, presence of extra-articular manifestations, systemic symptoms, serology and genetic factors, JIA is divided into oligoarticular, polyarticular, systemic, psoriatic, enthesitis-related and undifferentiated arthritis. This review provides an overview of advances in understanding of JIA pathogenesis focusing on aetiology, histopathology, immunological changes associated with disease activity, and best treatment options. Greater understanding of JIA as a collective of complex inflammatory diseases is discussed within the context of therapeutic interventions, including traditional non-biologic and up-to-date biologic disease-modifying anti-rheumatic drugs. Whilst the advent of advanced therapeutics has improved clinical outcomes, a considerable number of patients remain unresponsive to treatment, emphasising the need for further understanding of disease progression and remission to support stratification of patients to treatment pathways.

A peptide-based anti-Adalimumab antibody assay to monitor immune response to biologics treatment in juvenile idiopathic arthritis and childhood chronic non-infectious uveitis

Immune response to biologics treatment, while widely reported, yet fails to correlate with clinical outcomes and assay to assay comparison is often not possible. Hence, we developed a new peptide based-detection assay to stratify pediatric patients with juvenile idiopathic arthritis (JIA) or chronic non-infectious uveitis (CNU) and monitor anti-drug antibodies (ADAbs) formed as part of an immune response to treatment with the fully human monoclonal therapeutic antibody Adalimumab. Adalimumab derived synthetic peptides were optimized for maximum immunogenicity and were tested by SP-ELISA on a development cohort of 18 JIA and CNU treated patients. The two best performing peptides able to differentiate patient groups were selected for evaluation with a larger scale ELISA testing on a total of 29 sera from pediatric patients with JIA or CNU. The results of this peptide-based assay were compared to an in-house developed SPR biosensor ADAbs assay and a commercially available bridging ELISA. The first peptide, termed HC3, was able to positively detect ADAbs in 7 out of the 29 sera, while the second peptide, called LC3, was able to detect ADAbs in 11 out of 29 sera in the evaluation group. Following statistical data evaluation, it has been found that the detection of ADAbs using the peptide-based ELISA assay positively correlates with disease progression and remission. Two synthetic peptides derived from Adalimumab may provide a beneficial tool to clinicians for monitoring patient response to such treatment and taking informed decisions for treatment alternatives.

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

Background

Neutrophils 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.

Methods

Neutrophils 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.

Results

Neutrophils in synovial fluid had an activated phenotype, characterized by increased CD66b and CD11b levels, and most neutrophils had a CD16^hi CD62L^lowaged 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.

Conclusions

Neutrophils 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.

Synovial Fluid Neutrophils From Patients With Juvenile Idiopathic Arthritis Display a Hyperactivated Phenotype

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood. The predominant subtypes, oligoarticular and polyarticular JIA, are traditionally considered to be autoimmune diseases with a central role for T cells and autoantibodies. Mounting evidence suggests an important role for neutrophils in JIA pathogenesis. We undertook this study to investigate the phenotypic features of neutrophils present in the blood and inflamed joints of patients.

METHODS

JIA synovial fluid (SF) and parallel blood samples from JIA patients and healthy children were collected. SF-treated neutrophils from healthy donors and pleural neutrophils from patients with pleural effusion were investigated as controls for SF exposure and extravasation. Multicolor flow cytometry panels allowed for in-depth phenotypic analysis of neutrophils, focusing on the expression of adhesion molecules, activation, and maturation markers and chemoattractant receptors. Multiplex technology was used to quantify cytokines in plasma and SF.

RESULTS

SF neutrophils displayed an activated, hypersegmented phenotype with decreased CD62L expression, up-regulation of adhesion molecules CD66b, CD11b, and CD15, and down-regulation of CXCR1/2. An elevated percentage of CXCR4-positive neutrophils was detected in SF from patients. Pleural neutrophils showed less pronounced maturation differences. Strikingly, significant percentages of SF neutrophils showed a profound up-regulation of atypical neutrophil markers, including CXCR3, intercellular adhesion molecule 1, and HLA-DR.

CONCLUSION

Our data show that neutrophils in inflamed joints of JIA patients have an activated phenotype. This detailed molecular analysis supports the notion that a complex intertwining between these innate immune cells and adaptive immune events drives JIA.

Abatacept: A Review of the Treatment of Polyarticular-Course Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) encompasses several forms of chronic inflammatory arthritis of unknown etiology presenting in children < 16 years of age, with a minimum symptom duration of 6 weeks. Approximately half of affected children have polyarticular-course JIA (pJIA), a functional concept related to several clinically and genetically heterogeneous JIA categories (systemic, extended oligoarthritis, polyarticular rheumatoid factor-positive or rheumatoid factor-negative, enthesitis-related arthritis, and psoriatic arthritis), which has as its defining feature the involvement of five or more joints during the disease course. Chronic inflammation and joint damage lead to the manifestations of JIA such as pain, limitation of motion, and loss of physical function, all of which negatively impact patients' quality of life. The American College of Rheumatology recommends initial treatment with a conventional synthetic disease-modifying antirheumatic drug (csDMARD), such as methotrexate (MTX) and, in patients with pJIA who have an inadequate response or intolerance to MTX, the use of a biologic DMARD (bDMARD) such as a tumor necrosis factor inhibitor, abatacept, or tocilizumab. Abatacept selectively modulates the CD80/CD86:CD28 co-stimulatory signal required for full T cell activation, and thus has a distinct mechanism of action upstream of that of other currently available bDMARD treatments for rheumatic diseases. To enable physicians to make informed treatment decisions, it is important to review available data for the existing therapeutic agents. Here, we summarize the current evidence from phase III pivotal trials of intravenous (IV) and subcutaneous (SC) abatacept and from an ongoing registry of patients with JIA treated with abatacept. In the pivotal trials for IV and SC abatacept, either with or without MTX, both formulations demonstrated clinical efficacy, with a high proportion of patients achieving stringent clinical responses, as well as improvements in patient-reported outcomes and a favorable safety profile, particularly with regard to infections.

Inflammasomes and Childhood Autoimmune Diseases: A Review of Current Knowledge

Inflammasomes are multiprotein complexes capable of sensing pathogen-associated molecular patterns (PAMPs), danger-associated molecular patterns (DAMPs), and cellular perturbations. Upon stimulation, the inflammasomes activate the production of the pro-inflammatory cytokines IL-1β and IL-18 and induce gasdermin D-mediated pyroptosis. Dysregulated inflammasome signaling could lead to hyperinflammation in response to environmental triggers, thus contributing to the pathogenesis of childhood autoimmune/autoinflammatory diseases. In this review, we group childhood rheumatic diseases into the autoinflammation to autoimmunity spectrum and discuss about the involvement of inflammasomes in disease mechanisms. Genetic mutations in inflammasome components cause monogenic autoinflammatory diseases, while inflammasome-related genetic variants have been implicated in polygenic childhood rheumatic diseases. We highlight the reported associations of inflammasome signaling-related genetic polymorphisms/protein levels with pediatric autoimmune disease susceptibility and disease course. Furthermore, we discuss about the use of IL-1 receptor antagonist as an adjunctive therapy in several childhood autoimmune diseases, including macrophage activation syndrome (MAS) and multisystem inflammatory syndrome in children (MIS-C) related to COVID-19. A comprehensive multi-cohort comparison on inflammasome gene expression profile in different pediatric rheumatic diseases is needed to identify patient subsets that might benefit from the adjunctive therapy of IL-1β inhibitors.

Decreased frequency of allergy in juvenile idiopathic arthritis: Results of a case-control study

OBJECTIVES

To determine the frequency of Th2-mediated allergic diseases (AD) in mainly Th1-driven juvenile idiopathic arthritis (JIA) subtypes.

METHODS

Ninety-nine JIA patients and 128 control subjects were enrolled in a prospective case-control study. All subjects were assessed with standard allergy questionnaire, complete blood cell count, and total serum immunoglobulin (sIg) E. sIgs G, A, M, Juvenile Arthritis Disease Activity Score-27 (JADAS27), and serum acute phase reactants (sAPR) were obtained in JIA. In the presence of allergic symptoms, skin prick (SPT) and pulmonary function tests (PFT) were performed.

RESULTS

Despite similar allergy risk factors, the frequencies of asthma and allergic rhinitis were lower in JIA group (all p ≤ .02). Allergic patients with JIA performed lower FEV₁/FVC ratio, PEF, and FEF25-75 compared to the control group (all p ≤ .04). JADAS27 and sAPR were similar among JIA patients with and without AD. Two JIA patients were found to have hypogammaglobulinemia.

CONCLUSION

The frequencies of AD, asthma, and allergic rhinitis may decrease in Th1-mediated JIA subtypes although the coexistence does not appear to affect the severity of arthritis whereas allergic symptoms may resolve after immunosuppressive treatment. PFTs should be obtained periodically in JIA. JIA patients may have an underlying primary immunodeficiency (ID) or immunosuppressive drugs may cause secondary ID.KEY POINTSCompared to the population, the frequency of Th2-mediated allergic diseases is lower in oligoarthritis and RF-negative polyarthritis that are primarily driven by a Th1 activity.The coexistence of allergic diseases in juvenile idiopathic arthritis does not affect the severity of arthritis.Pulmonary function tests can be thought to be obtained periodically in juvenile idiopathic arthritis.Immunological workup should be considered in atypically or severely presented patients with juvenile idiopathic arthritis before the initiation of immunosuppressive therapy to differentiate primary and secondary immunodeficiency.

Assessment and treatment of Down syndrome-associated arthritis: a survey of pediatric rheumatologists

BACKGROUND

Inflammatory arthritis in children with Down syndrome (DS) was first described in 1984 and is now termed Down syndrome-associated arthritis (DA). Studies have shown that DA is under-recognized with a 19-month average delay in diagnosis. Additionally, most patients present with polyarticular, rheumatoid factor (RF) and anti-nuclear antibody (ANA) negative disease. Current therapies for juvenile idiopathic arthritis (JIA) have been used, but appear to be poorly tolerated, more toxic and less effective in patients with DA. There is currently no standardized approach to the assessment or management of DA. The objective of this study was to describe provider perspectives toward diagnostic and treatment approach of DA, to provide baseline information upon which to design future studies.

METHODS

An electronic survey, organized into sections regarding individual practices of assessment and treatment approach of DA, was sent to the Pediatric Rheumatology electronic list-serv. Survey responses were voluntary and results were analyzed by descriptive statistics.

RESULTS

Of 90 survey responses received, 89 were included in the analysis (one was a duplicate response). The respondents were mostly pediatric rheumatologist (94%), with greater than 10 years of experience (55%). The majority (64%) currently see 1-3 patients with DA. Most view DA as the same disease as JIA (73%), and the majority (63%) use a combination of history, exam and imaging to diagnose DA. The most ordered diagnostic tests are CBC (97%) and ESR (96%). The most used treatments include NSAIDs (94%) and methotrexate (91%) followed by anti-TNF agents (90%). Methotrexate is most administered by subcutaneous route (84%) at a dose of 15 mg/m² (56%). Oral corticosteroids were only used in 19% of the patients with DA.

CONCLUSION

This is the first study to evaluate provider perspectives towards the diagnostic and treatment approach of DA. Most pediatric rheumatologists feel that DA and JIA are synonymous, and similar approaches to diagnosis are employed, utilizing history, physical exam, laboratory tests, and imaging modalities. DA is treated similarly to JIA with initiation of NSAIDs, disease-modifying anti-rheumatic drugs and biologic therapy. More research is needed to determine optimal screening and therapeutic approach specific to DA.

Pediatrician Beliefs about Juvenile Idiopathic Arthritis May Result in Referral Delays: A Spanish National Survey

We explored, through a national survey, pediatrician beliefs and misconceptions that could interfere with early referral of patients with juvenile idiopathic arthritis. A total of 831 pediatricians participated. Approximately one-half of the respondents underestimated the incidence of the disease and thought that pain was the leading symptom of oligoarticular forms.

Impaired Muscular Fat Metabolism in Juvenile Idiopathic Arthritis in Inactive Disease

Objectives: The objective of this study was to evaluate muscular metabolic function in children with inactive juvenile idiopathic arthritis (JIA).

Methods: Fifteen children with inactive JIA and fifteen healthy controls were matched by sex, biological age, and Tanner stage. Participants completed a submaximal incremental exercise test to determine their fat and carbohydrate oxidation rates.

Results: Between the two groups, heart rate values and carbohydrate oxidation rates were the same, regardless of the relative intensity of exercise. Lipid oxidation rates were lower in JIA patients, regardless of the percentage of VO₂ peak (p < 0.05). Respiratory exchange ratios beyond 50% of VO₂ peak were higher in patients with JIA (p < 0.05). Respective maximal fat oxidation rates (MFO) for controls and children with JIA were 218.7 ± 92.2 vs. 157.5 ± 65.9 mg ⋅ min^-1 (p = 0.03) and 4.9 ± 1.9 vs. 3.4 ± 1.2 mg ⋅ min^-1 ⋅ kg^-1 (p = 0.04). There was no difference between the two groups in heart rate, percentage of VO₂ peak, or power of exercise to achieve MFO. Controls reached their MFO at an exercise power significantly higher than did JIA subjects (42.8 ± 16.8 and 31.9 ± 9.8 W, p = 0.004).

Conclusion: Children with JIA show metabolic disturbance during exercise, even when the disease is considered inactive. This disturbance is seen in a lower lipid oxidation rate during submaximal exercise.

Bilateral Destructive Hip Disease from Untreated Juvenile Idiopathic Arthritis

We report a novel case of a pediatric patient with bilateral hip destruction from untreated Juvenile idiopathic arthritis (JIA). She was presented at the age of 9 with hip pain associated with bilateral acetabular dysplasia and a dislocated left femoral head. Only 1.5 years later, the patient developed complete destruction of the left femoral head and dislocated right femoral head. The authors have not identified literature describing a similar case report of bilateral femoral head destruction resulting from Persistent Oligoarticular JIA. Pediatric patients presenting with rapidly evolving destructive process should be evaluated for rheumatologic, infectious, and spinal etiologies.

B Cells as a Therapeutic Target in Paediatric Rheumatic Disease

B cells carry out a central role in the pathogenesis of autoimmune disease. In addition to the production of autoantibodies, B cells can contribute to disease development by presenting autoantigens to autoreactive T cells and by secreting pro-inflammatory cytokines and chemokines which leads to the amplification of the inflammatory response. Targeting both the antibody-dependent and antibody-independent function of B cells in adult rheumatic disease has led to the advent of B cell targeted therapies in clinical practice. To date, whether B cell depletion could also be utilized for the treatment of pediatric disease is relatively under explored. In this review, we will discuss the role of B cells in the pathogenesis of the pediatric rheumatic diseases Juvenile Idiopathic Arthritis (JIA), Juvenile Systemic Lupus Erythematosus (JSLE) and Juvenile Dermatomyositis (JDM). We will also explore the rationale behind the use of B cell-targeted therapies in pediatric rheumatic disease by highlighting new case studies that points to their efficacy in JIA, JSLE, and JDM.

Imaging findings of sterile pyogenic arthritis, pyoderma gangrenosum and acne (PAPA) syndrome: differential diagnosis and review of the literature

Pyogenic arthritis, pyoderma gangrenosum and acne (PAPA) syndrome is a rare autosomal-dominant autoinflammatory disease of incomplete penetrance and variable expression. PAPA syndrome is the result of a mutation in the proline serine threonine phosphatase-interacting protein 1 (PSTPIP1/CD2BP1) gene located on chromosome 15, which results in an abnormal overproduction of the pro-inflammatory cytokine interleukin-1β (IL-1). This syndrome clinically manifests as early onset of recurrent episodes of acute aseptic inflammation of the joints, generally occurring in the first two decades of life, followed by manifestation of characteristic skin lesions in the third decade, after an obvious decline in the joint symptoms. Although uncommon, the potential clinical implications of PAPA syndrome warrant an appropriate diagnosis in a timely fashion.

Foxp3 Molecular Dynamics in Treg in Juvenile Idiopathic Arthritis

Since the identification of the regulatory T-cell (Treg)-associated transcription factor Foxp3, there have been intensive research efforts to understand its biology and roles in maintaining immune homeostasis. It is well established that thymic selection of a repertoire of self-reactive Foxp3⁺ T-cells provides an essential mechanism to minimize reactions to self-antigens in the periphery, and thus aid in the prevention of autoimmunity. It is clear from both genetic and immunological analyses of juvenile idiopathic arthritis (JIA) patients that T-cells have a strong role to play in both the initiation and propagation of disease. The current paradigm is to view autoimmunity as a consequence of an imbalance between inflammatory and immunoregulatory mechanisms. This view has led to the assigning of cells and inflammatory mediators to different classes based on their assumed pro- or anti-inflammatory roles. This is typically reported as ratios of effector T-cells to Treg cells. Problematically, many analyses are based on static “snapshots-in-time,” even though both mouse models and human patient studies have highlighted the dynamic nature of Foxp3⁺ T-cells in vivo, which can exhibit plasticity and time-dependent functional states. In this review, we discuss the role of Foxp3 dynamics in the control of T-cell responses in childhood arthritis, by reviewing evidence in humans and relevant mouse models of inflammatory disease. Whilst the cellular dynamics of Treg have been well evaluated—leading to standard data outputs such as frequency, quantity and quality (often assessed by in vitro suppressive capacity)—we discuss how recent insights into the molecular dynamics of Foxp3 transcription and its post-translational control may open up tantalizing new avenues for immunotherapies to treat autoimmune arthritis.

Identification of enhanced IFN-γ signaling in polyarticular juvenile idiopathic arthritis with mass cytometry

Polyarticular juvenile idiopathic arthritis (JIA) is among the most challenging of the JIA subtypes to treat. Even with current biologic therapies, the disease remains difficult to control in a substantial subset of patients, highlighting the need for new therapies. The aim of this study was to use the high dimensionality afforded by mass cytometry with phospho-specific antibodies to delineate signaling abnormalities in immune cells from treatment-naive polyarticular JIA patients. Peripheral blood mononuclear cells were isolated from 17 treatment-naive polyarticular JIA patients, 10 of the patients after achieving clinical remission, and 19 healthy controls. Samples were stimulated for 15 minutes with IL-6 or IFN-γ and analyzed by mass cytometry. Following IFN-γ stimulation, increased STAT1 and/or STAT3 phosphorylation was observed in subsets of CD4 T cells and classical monocytes from treatment-naive patients. The enhanced IFN-γ signaling was associated with increased expression of JAK1 and SOCS1 in CD4 T cells. Furthermore, substantial heterogeneity in surface marker expression was observed among the subsets of CD4 T cells and classical monocytes with increased IFN-γ responsiveness. The identification of enhanced IFN-γ signaling in CD4 T cells and classical monocytes from treatment-naive polyarticular JIA patients provides mechanistic support for investigations into therapies that attenuate IFN-γ signaling in this disease.

T Cell Receptor-Independent, CD31/IL-17A-Driven Inflammatory Axis Shapes Synovitis in Juvenile Idiopathic Arthritis

T cells are considered autoimmune effectors in juvenile idiopathic arthritis (JIA), but the antigenic cause of arthritis remains elusive. Since T cells comprise a significant proportion of joint-infiltrating cells, we examined whether the environment in the joint could be shaped through the inflammatory activation by T cells that is independent of conventional TCR signaling. We focused on the analysis of synovial fluid (SF) collected from children with oligoarticular and rheumatoid factor-negative polyarticular JIA. Cytokine profiling of SF showed dominance of five molecules including IL-17A. Cytometric analysis of the same SF samples showed enrichment of αβT cells that lacked both CD4 and CD8 co-receptors [herein called double negative (DN) T cells] and also lacked the CD28 costimulatory receptor. However, these synovial αβT cells expressed high levels of CD31, an adhesion molecule that is normally employed by granulocytes when they transit to sites of injury. In receptor crosslinking assays, ligation of CD31 alone on synovial CD28^nullCD31⁺ DN αβT cells effectively and sufficiently induced phosphorylation of signaling substrates and increased intracytoplasmic stores of cytokines including IL-17A. CD31 ligation was also sufficient to induce RORγT expression and trans-activation of the IL-17A promoter. In addition to T cells, SF contained fibrocyte-like cells (FLC) expressing IL-17 receptor A (IL-17RA) and CD38, a known ligand for CD31. Stimulation of FLC with IL-17A led to CD38 upregulation, and to production of cytokines and tissue-destructive molecules. Addition of an oxidoreductase analog to the bioassays suppressed the CD31-driven IL-17A production by T cells. It also suppressed the downstream IL-17A-mediated production of effectors by FLC. The levels of suppression of FLC effector activities by the oxidoreductase analog were comparable to those seen with corticosteroid and/or biologic inhibitors to IL-6 and TNFα. Collectively, our data suggest that activation of a CD31-driven, αβTCR-independent, IL-17A-mediated T cell-FLC inflammatory circuit drives and/or perpetuates synovitis. With the notable finding that the oxidoreductase mimic suppresses the effector activities of synovial CD31⁺CD28^null αβT cells and IL-17RA⁺CD38⁺ FLC, this small molecule could be used to probe further the intricacies of this inflammatory circuit. Such bioactivities of this small molecule also provide rationale for new translational avenue(s) to potentially modulate JIA synovitis.

Disease-specific regulation of gene expression in a comparative analysis of juvenile idiopathic arthritis and inflammatory bowel disease

BACKGROUND

The genetic and immunological factors that contribute to differences in susceptibility and progression between sub-types of inflammatory and autoimmune diseases continue to be elucidated. Inflammatory bowel disease and juvenile idiopathic arthritis are both clinically heterogeneous and known to be due in part to abnormal regulation of gene activity in diverse immune cell types. Comparative genomic analysis of these conditions is expected to reveal differences in underlying genetic mechanisms of disease.

METHODS

We performed RNA-Seq on whole blood samples from 202 patients with oligoarticular, polyarticular, or systemic juvenile idiopathic arthritis, or with Crohn's disease or ulcerative colitis, as well as healthy controls, to characterize differences in gene expression. Gene ontology analysis combined with Blood Transcript Module and Blood Informative Transcript analysis was used to infer immunological differences. Comparative expression quantitative trait locus (eQTL) analysis was used to quantify disease-specific regulation of transcript abundance.

RESULTS

A pattern of differentially expressed genes and pathways reveals a gradient of disease spanning from healthy controls to oligoarticular, polyarticular, and systemic juvenile idiopathic arthritis (JIA); Crohn's disease; and ulcerative colitis. Transcriptional risk scores also provide good discrimination of controls, JIA, and IBD. Most eQTL are found to have similar effects across disease sub-types, but we also identify disease-specific eQTL at loci associated with disease by GWAS.

CONCLUSION

JIA and IBD are characterized by divergent peripheral blood transcriptomes, the genetic regulation of which displays limited disease specificity, implying that disease-specific genetic influences are largely independent of, or downstream of, eQTL effects.

Next-Generation Sequencing Reveals Restriction and Clonotypic Expansion of Treg Cells in Juvenile Idiopathic Arthritis

OBJECTIVE

Treg cell-mediated suppression of Teff cells is impaired in juvenile idiopathic arthritis (JIA); however, the basis for this dysfunction is incompletely understood. Animal models of autoimmunity and immunodeficiency demonstrate that a diverse Treg cell repertoire is essential to maintain Treg cell function. The present study was undertaken to investigate the Treg and Teff cell repertoires in JIA.

METHODS

Treg cells (CD4+CD25+CD127(low) ) and Teff cells (CD4+CD25-) were isolated from peripheral blood and synovial fluid obtained from JIA patients, healthy controls, and children with Lyme arthritis. Treg cell function was measured in suppressive assays. The T cell receptor β chain (TRB) was amplified by multiplex polymerase chain reaction and next-generation sequencing was performed, with amplicons sequenced using an Illumina HiSeq platform. Data were analyzed using ImmunoSEQ, International ImMunoGeneTics system, and the Immunoglobulin Analysis Tools.

RESULTS

Compared to findings in controls, the JIA peripheral blood Treg cell repertoire was restricted, and clonotypic expansions were found in both blood and synovial fluid Treg cells. Skewed usage and pairing of TRB variable and joining genes, including overuse of gene segments that have been associated with other autoimmune conditions, was observed. JIA patients shared a substantial portion of synovial fluid Treg cell clonotypes that were private to JIA and not identified in Lyme arthritis.

CONCLUSION

We identified restriction and clonotypic expansions in the JIA Treg cell repertoire with sharing of Treg cell clonotypes across patients. These findings suggest that abnormalities in the Treg cell repertoire, possibly engendered by shared antigenic triggers, may contribute to disease pathogenesis in JIA.

Epipolymorphisms associated with the clinical outcome of autoimmune arthritis affect CD4+ T cell activation pathways

Multifactorial diseases, including autoimmune juvenile idiopathic arthritis (JIA), result from a complex interplay between genetics and environment. Epigenetic mechanisms are believed to integrate such gene-environment interactions, fine-tuning gene expression, and possibly contributing to immune system dysregulation. Although anti-TNF therapy has strongly increased JIA remission rates, it is not curative and up to 80% of patients flare upon treatment withdrawal. Thus, a crucial unmet medical and scientific need is to understand the immunological mechanisms associated with remission or flare to inform clinical decisions. Here, we explored the CD4⁺ T-cell DNA methylome of 68 poly-articular and extended oligo-articular JIA patients, before and after anti-TNF therapy withdrawal, to identify features associated with maintenance of inactive disease. Individual CpG sites were clustered in coherent modules without a priori knowledge of their function through network analysis. The methylation level of several CpG modules, specifically those enriched in CpG sites belonging to genes that mediate T-cell activation, uniquely correlated with clinical activity. Differences in DNA methylation were already detectable at the time of therapy discontinuation, suggesting epigenetic predisposition. RNA profiling also detected differences in T-cell activation markers (including HLA-DR) but, overall, its sensitivity was lower than epigenetic profiling. Changes to the T-cell activation signature at the protein level were detectable by flow cytometry, confirming the biological relevance of the observed alterations in methylation. Our work proposes epigenetic discrimination between clinical activity states, and reveals T-cell-related biological functions tied to, and possibly predicting or causing, clinical outcome.

The human microbiome and juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood. The pathogenesis of JIA is thought to be the result of a combination of host genetic and environmental triggers. However, the precise factors that determine one's susceptibility to JIA remain to be unravelled. The microbiome has received increasing attention as a potential contributing factor to the development of a wide array of immune-mediated diseases, including inflammatory bowel disease, type 1 diabetes and rheumatoid arthritis. Also in JIA, there is accumulating evidence that the composition of the microbiome is different from healthy individuals. A growing body of evidence indeed suggests that, among others, the microbiome may influence the development of the immune system, the integrity of the intestinal mucosal barrier, and the differentiation of T cell subsets. In turn, this might lead to dysregulation of the immune system, thereby possibly playing a role in the development of JIA. The potential to manipulate the microbiome, for example by faecal microbial transplantation, might then offer perspectives for future therapeutic interventions. Before we can think of such interventions, we need to first obtain a deeper understanding of the cause and effect relationship between JIA and the microbiome. In this review, we discuss the existing evidence for the involvement of the microbiome in JIA pathogenesis and explore the potential mechanisms through which the microbiome may influence the development of autoimmunity in general and JIA specifically.

Contemporary management of TMJ involvement in JIA patients and its orofacial consequences

Juvenile idiopathic arthritis is the most common chronic rheumatic condition during childhood. Temporomandibular joint arthritis is frequently asymptomatic. When it takes place during childhood, it may affect condylar growth; therefore, these children are at risk of unfavorable long-term outcomes from the associated joint damage. The etiology is not completely understood, but it is considered as multifactorial with both genetic and environmental factors involved.

The standardized examination and imaging protocols serve important purpose to diagnose temporomandibular joint (TMJ) arthritis not only to establish an early interventional strategy but also to assess craniofacial growth and the progression of signs and symptoms in those patients. Although the treatment of juvenile idiopathic arthritis (JIA) has changed dramatically over the last decades due to new therapeutic options, TMJ arthritis still can develop during the course of the disease. In clinical experience, TMJs appear to respond less well to the standard of care used to treat other joints. More individualized approach to the patient’s treatment serves as the main goal of personalized medicine. It could be achieved by adopting new methods of medical imaging such as conebeam computer tomography as well as developing reliable biomarkers which may assist with predicting disease type, course, or severity and predicting response to medication.

This article provides an overview of current information on orofacial complications in JIA and its management. Based on information provided in this review, more precise diagnosis, proper tools for recognizing people at risk, and more efficient treatment approaches could be implemented. This may lead to more personalized treatment management strategies of TMJ complications of JIA patients.

Sustained-release dexamethasone intravitreal implant in juvenile idiopathic arthritis-related uveitis

The purpose of this study is to review the results of treatment of juvenile idiopathic arthritis-related uveitis with the use of intravitreal dexamethasone implant. Sixteen eyes with Juvenile idiopathic arthritis (JIA)-associated uveitis received intravitreal dexamethasone implant to treat recalcitrant anterior segment inflammation (43.7 %), chronic macular edema (6.2 %), or a combination of both (50 %). One month after injection, mean visual acuity had improvement to 39.6 ± 11 ETDRS letters (p < 0.001). Mean AC cells measure at 1 month was 0.79 and 0.75 at 3 months. One month after injection, there was a significant reduction of central retinal thickness (CRT) to 342.4 ± 79.3 µm (p < 0.01). One month after the second implant, 11 eyes (91.6 %) achieved improved activity of the anterior uveitis, and mean best-corrected visual acuity improved to 44.6 ± 8.1 ETDRS letters (p < 0.01). At 1 month after the second injection, 4/5 eyes had resolution of macular edema with CRT of 250.4 ± 13.7 µm (p < 0.01). Of the 16 eyes, 12 eyes received a second injection at mean of 7.5 ± 3.1 months after the first treatment, and 5 eyes received a third Ozurdex injection on average 7 ± 4.6 months after the second injection. Of the 16 eyes, five eyes were pseudophakic prior to injection. Of the remaining 11 eyes, 8 (73 %) developed worsening posterior subcapsular cataract at a mean of 7.3 ± 1.2 months after the first injection. After the first injection, only one eye required topical antiglaucoma therapy with maximum pressure of 25 mmHg. In patients with recalcitrant JIA-associated active uveitis, injection of sustained-release dexamethasone can achieve control of anterior inflammation and resolution of macular edema.