Juvenile idiopathic arthritis

Identification and validation of susceptibility modules and hub genes in polyarticular juvenile idiopathic arthritis using WGCNA and machine learning

BACKGROUND

Juvenile idiopathic arthritis (JIA), superseding juvenile rheumatoid arthritis (JRA), is a chronic autoimmune disease affecting children and characterized by various types of childhood arthritis. JIA manifests clinically with joint inflammation, swelling, pain, and limited mobility, potentially leading to long-term joint damage if untreated. This study aimed to identify genes associated with the progression and prognosis of JIA polyarticular to enhance clinical diagnosis and treatment.

METHODS

We analyzed the gene expression omnibus (GEO) dataset GSE1402 to screen for differentially expressed genes (DEGs) in peripheral blood single nucleated cells (PBMCs) of JIA polyarticular patients. Weighted gene co-expression network analysis (WGCNA) was applied to identify key gene modules, and protein-protein interaction networks (PPIs) were constructed to select hub genes. The random forest model was employed for biomarker gene screening. Functional enrichment analysis was conducted using David's online database, gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis to annotate and identify potential JIA pathways. Hub genes were validated using the receiver operating characteristic (ROC) curve.

RESULTS

PHLDA1, EGR3, CXCL2, and PF4V1 were identified as significantly associated with the progression and prognosis of JIA polyarticular phenotype, demonstrating high diagnostic and prognostic assessment value.

CONCLUSION

These genes can be utilized as potential molecular biomarkers, offering valuable insights for the early diagnosis and personalized treatment of JIA polyarticular patients.

Immunomodulatory mechanism of Huangqi-Guizhi-Wuwu Decoction in alleviating autoimmune arthritis based on network pharmacology and experimental validation

BACKGROUND

Juvenile idiopathic arthritis (JIA) is the most common type of childhood autoimmune arthritis. Huangqi Guizhi Wuwu decoction (HGWD), a traditional Chinese herbal formula, is widely used in China to treat patients with autoimmune arthritis. However, the bioactive ingredients and their complex regulatory mechanisms remain unclear.

PURPOSE

To investigate the active components of HGWD using a novel comprehensive strategy and clarify the mechanism underlying immunomodulation.

METHODS

The main active components of HGWD were determined using ultra-high-performance liquid chromatography-high resolution mass spectrometry (UPLCHRMS). The core target and biological immune regulation mechanism of HGWD in alleviating JIA were predicted using combined network pharmacology and molecular docking analyses, followed by in vitro and in vivo experiments.

RESULTS

A total of 1387 active components were identified by UPLC-MS, of which eight were the main active ingredients. Network pharmacology showed that HGWD acted on core targets, such as STAT3. Further combined analysis revealed that regulation of the Th17 differentiation pathway may be an important mechanism by which HGWD relieves JIA. Molecular docking verification showed that the key component of HGWD can stably bind JAK/STAT-related proteins. The induced differentiation of Th17 and Treg in vitro experiment confirmed the immunoregulatory effects of HGWD. in vivo experiments, HGWD significantly alleviated symptoms of arthritis in a mouse model of collagen-induced arthritis (CIA) and was closely associated with restoring the Th17/Treg balance.

CONCLUSION

Taken together, serum components/UPLC-MS, network pharmacology, and molecular biology analyses are feasible strategies for exploring the active ingredients in HGWD. This study highlights the clinical potential of HGWD in alleviating JIA and provides evidence of its therapeutic potential through immune regulation.

Vitamin D as a Modifiable Risk Factor for Juvenile Idiopathic Arthritis: A Systematic Review and Meta-analysis of Observational Studies Comparing Baseline Vitamin D in Children with JIA to Individuals Without

CONTEXT

The varying interactions contributing to the development of juvenile idiopathic arthritis (JIA) drive the struggle to understand its etiology. Among the environmental risk factors, vitamin D has been posited to have a component in disease progression, acting as an inflammatory mediator.

OBJECTIVE

To investigate the correlation between serum 25-hydroxyvitamin D [25(OH)D] levels, indicative of vitamin D, among patients diagnosed with JIA compared with control participants. The aim was to elucidate potential therapeutic implications of vitamin D in the management of JIA.

DATA SOURCES

A systematic search of 6 electronic databases (MEDLINE, Embase, Scopus, CINAHL, Web of Science, and Cochrane Library) was performed until February 2023. Inclusion criteria required participants to be <16 years old (either clinically diagnosed with JIA or a matched control participant), with vitamin D levels measured through serum laboratory methods. Exclusion criteria omitted studies in which participants used vitamin D supplementation or medications affecting vitamin D levels without corresponding statistical analyses on their association with vitamin D levels.

DATA EXTRACTION

Each article was reviewed by at least 2 independent reviewers to assess eligibility for analysis.

DATA ANALYSIS

Data were qualitatively analyzed to compare means of serum 25(OH)D levels (ng/mL) between patients with JIA and control participants, followed by a meta-analysis to obtain effect size.

RESULTS

Ten eligible studies were included qualitatively, and eight were included in the meta-analysis. Seven studies found a statistically significant difference in vitamin D levels between control participants and patients with JIA, with five of these reporting a lower mean vitamin D level in patients with JIA. A random-effects model using standardized mean difference found a statistically significant difference in vitamin D levels between control participants and patients with JIA (-0.49; 95% CI, -0.92 to -0.06).

CONCLUSIONS

The findings from the analysis indicate vitamin D levels were lower in patients with JIA as compared with healthy control participants at baseline. It is recommended that research into vitamin D supplementation and JIA should be conducted.

Population-Based Big Data Analysis on Disease Patterns in Patients Identified With Juvenile Idiopathic Arthritis Using National Claims Data

BACKGROUND

This study aimed to identify epidemiologic data, including prevalence and incidence, of patients with juvenile idiopathic arthritis (JIA) in accordance with the diseases diagnostic code and Rare Intractable Disease Registration (RIDR) code from the claims data of the Health Insurance Review and Assessment Service (HIRA), the representative secondary data in Korea.

METHODS

We conducted a retrospective analysis of the national claims data of the HIRA. The study population included 1,728 patients with JIA who 1) had records with diagnostic codes in the format prescribed by the International Classification of Diseases, 10th Revision M08 and the RIDR code V133 between January 1, 2010, and December 31, 2019, and 2) were aged < 16 years as per the definition of JIA. We categorized the patients by age at diagnosis, annual prevalence, and incidence per 100,000 individuals for the study period. Moreover, the study population was stratified by age and gender for subgroup analysis.

RESULTS

The overall prevalence rate for the total, male, and female population was 15.9 (14.5-16.8), 15.4 (13.1-17.0), and 16.4 (15.9-16.9) per 100,000 individuals, respectively. Additionally, the overall incidence rate for the same populations was 2.2 (1.8-2.8), 2.3 (1.7-2.9), and 2.1 (1.8-2.6) per 100,000 individuals, respectively.

CONCLUSION

To the best of our knowledge, this is the first study presenting the epidemiologic data, including prevalence and incidence, of patients with JIA using population-based claims big data in Korea. The results of this study will aid in understanding the current status of JIA in Korea and Asia and in health care planning.

Immunosenescence in autoimmune diseases

Autoimmune diseases (AIDs) are a group of disorders in which the immune system mistakenly attacks the body's own tissues, characterized by the loss of tolerance to self-antigens and destruction of tissues. Aging is a natural process of physiological decline that also alters the immune system, a condition known as immunosenescence. During immunosenescence, the immune system undergoes various changes, including modifications and antigenicity of self-antigens, abnormalities in the quantity, phenotype, and function of lymphocytes and antibodies, as well as a narrowing of the B and T cell receptor repertoire, changes that may increase susceptibility to AIDs. Additionally, senescent immune cells and the senescence-associated secretory phenotype (SASP) contribute to target organ involvement in AIDs, exacerbating chronic inflammation and tissue damage. Mitochondrial dysfunction and metabolic imbalances in AIDs lead to the accumulation of senescent cells, which act as upstream drivers of immunosenescence. In this review, we summarize the bidirectional relationship between AIDs and immunosenescence, as well as its potential mechanisms. Therapeutic approaches targeting immunosenescence in AIDs remain at an early stage. Strategies aimed at resetting or reversing the aging immune system are expected to become a novel direction in the future.

TMT-based quantitative proteomics analysis of serum-derived exosomes in patients with juvenile gout

Objectives

The purpose of this study was to compare the proteomics of serum-derived exosomes in juvenile gout (J-Gout), juvenile hyperuricemia (J-HUA) and oligoarticular juvenile idiopathic arthritis (oJIA).

Methods

Serum-derived exosomes were isolated from patients using a qEV column combined with the ExoQuick-TC kit. The proteomics of serum-derived exosomes was analyzed by tandem mass tag (TMT)-labeled liquid chromatography-mass spectrometry (LC-MS/MS) technology. Proteins differentially expressed in J-Gout and the other two groups were identified. This was followed by volcano plot, hierarchical cluster, Venn diagram, gene ontology (GO), and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analyses.

Results

A total of 838 credible proteins were identified in serum-derived exosomes from the three groups. Eighty-eight differentially expressed proteins (13 upregulated and 75 downregulated) were identified in J-Gout when compared with J-HUA. One hundred twenty-one differentially expressed proteins (20 upregulated and 101 downregulated) were identified in J-Gout when compared with oJIA. A total of 166 differentially expressed proteins were identified in J-Gout, compared with J-HUA and oJIA respectively. Bioinformatic analysis indicated that the 166 differentially expressed proteins were significantly involved in "immune response", "Fc epsilon RI signaling pathway" and "B cell receptor signaling pathway". A total of 43 differentially expressed proteins were identified in J-Gout, compared with J-HUA and oJIA simultaneously. Six proteins were found highly expressed in J-Gout uniquely. ELISA results showed that dipeptidyl peptidase 4 (DPP4) and heparin cofactor 2 (SERPIND1) were the highest in J-Gout, which was consistent with the proteomic results. Correlation analysis revealed that exosome-derived DPP4 and SERPIND1 were positively correlated with C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

Conclusion

The protein composition of serum-derived exosomes in J-Gout was significantly differed from that in J-HUA and oJIA. DPP4 and SERPIND1 were uniquely highly expressed in J-Gout. Some possible mechanisms regarding the inflammatory response and coagulation complement system were proposed, which may provide helpful diagnostic and therapeutic insights for J-Gout.

[Rheumatic shoulder joints in childhood]

Although the knee joint in children and adolescents is most frequently affected in cases of juvenile idiopathic arthritis (JIA), shoulder joint arthritis is only present in a small proportion of JIA patients at disease onset. Shoulder joint involvement is more frequently seen in polyarthritis or chronic JIA, which if not considered and left untreated can lead to substantial joint immobility and with a destructive course. In addition to the clinical examination, imaging methods help to verify an early involvement of the shoulder joint and imaging can also provide important information in a treat to target concept. The treatment of pediatric omarthritis is very often guided by the treatment algorithm for the appropriate JIA category. In this respect, in addition to local steroid injections, medications such as methotrexate, biologicals and also Janus kinase (JAK) inhibitors are used. In addition to the pharmacotherapy, physiotherapy also plays an important role.

Single cell RNA-sequencing identified CCR7+/RELB+/IRF1+ T cell responding for juvenile idiopathic arthritis pathogenesis

Background

To further explore the disease heterogeneity of different subtypes of Juvenile idiopathic arthritis (JIA) and analyze their pathogenesis mechanisms.

Method

The single-cell RNA sequencing (scRNA-seq) analysis of peripheral blood mononuclear cells (PBMCs) was carried out to investigate the disease heterogeneity and molecular mechanisms of immune responses in immune cells in JIA.

Result

In our study, we provided a immunological landscape of HLA-B27-positive JIA and HLA-B27-negative JIA immune cells at single cell RNA-Seq resolution. We found a higher proportion of CCR7+/RELB+/IRF1+ triple positive T cells in the peripheral blood of patients with JIA, and such T cells were predominantly present in HLA-B27+ JIA patients. Furthermore, we hypothesized that CCR7+/RELB+/IRF1+ triple positive T cells were highly activated T cells capable of promoting the differentiation of osteoclasts by producing IL-17, thus causing damage to cartilage in HLA-B27+ JIA patients. Unlike JIA patients, CCR7+/RELB+/IRF1+ triple positive T cells were not found in the peripheral blood of pSS patients and SLE patients, moreover, T cells from pSS patients and SLE patients were less able to produce IL-17 than those from JIA patients.

Conclusion

Our study provided evidence of cellular and molecular levels of involvement in JIA pathogenesis and identified the critical roles for T cells in JIA pathogenesis. Furthermore, our results suggested that there were significant differences in T cell composition and gene expression between HLA-B27+ JIA patients and HLA-B27- JIA patients. Our findings indicated that CCR7+/RELB+/IRF1+ positive T cells could damage the cartilage of HLA-B27+ JIA by producing cytokines such as IL-17.

The efficacy and safety of biologic or targeted synthetic DMARDs in rheumatoid arthritis treatment: one year of review 2024

BACKGROUND

Both articular and extra-articular structures are affected by rheumatoid arthritis (RA), a chronic inflammatory rheumatic illness that results in severe joint destruction, disability, and death. To increase the response rate and provide RA patients more options, there is an unmet need for the development of innovative treatment drugs. Evaluation of cellular, cytokine, genomic, and transcriptome profiles that would predict therapeutic response to biologic or targeted disease-modifying anti-rheumatic drugs (DMARDs) with various action modes is necessary for a customized therapy plan in RA. Owing to the development of new biologic medicines that target distinct mechanisms of action, the treatment algorithm for RA has undergone significant modification during the last one to two decades. More patients are now able to undergo biologic therapy early in the progression of their illness, thanks to the availability of less expensive biosimilars.

OBJECTIVE

To summarize the efficacy and safety of biologic or targeted syntheticb/ts DMARDs in RA treatment based on the publications in the past year.

MATERIAL AND METHODS

We compiled the most recent findings from original research publications of 2024 about the effects of b/tsDMARDs on the treatment of RA. In addition, this review article also concluded the recent findings from original research publications of the year 2024 about the effects of b/tsDMARDs biosimilars for treating RA.

CONCLUSION

This article summarizes the evidence and safety of biologic DMARDs (bDMARDs) or targeted synthetic DMARDs (tsDMARDs) in the management of RA, including those that target tumor necrosis factor alpha, interleukin (IL)-6, B cells, T-cell co-stimulation, and Janus kinase (JAK) from original research articles published in 2024.

The interplay between pain and disease activity: personal models of pain beliefs and emotional representations in children and young people with juvenile idiopathic arthritis in a UK nationwide prospective inception cohort

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is a group of childhood-onset inflammatory rheumatic conditions characterized by pain as one of the most common and distressing symptoms. This cross-sectional study aimed to investigate whether relationships between reported pain and disease activity in JIA affected beliefs about pain, known as "personal models."

METHODS

187 out of a possible 363 participants with JIA who completed questionnaires about function and pain perception were recruited through the Childhood Arthritis Prospective Study (CAPS). A pre-selected pain score threshold and validated disease activity score cut-offs were used to assign the participants into four groups: low pain/low disease, low pain/high disease, high pain/low disease, and high pain/high disease. Multivariable linear regressions examined associations between the groups and their "personal models."

RESULTS

Compared to participants with low pain/low disease, those with high pain/high disease and those with high pain/low disease were more likely to sense greater threat, have more negative emotional representations, and perceive less control over their pain. Participants with low pain/high disease had similar pain beliefs compared to those with low pain/low disease.

CONCLUSION

This is the first study to compare "personal models" of pain in JIA. Children and young people who experience high pain severity regardless of disease activity perceived high pain threat, low controllability, and negative emotional representations. This highlights the importance of considering and addressing personal models of pain at diagnosis, especially those who present high levels of pain.

Efficacy and safety of ibuprofen and naproxen in the treatment of oligoarticular juvenile idiopathic arthritis: bi-national cohort study

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in children. Nonsteroidal anti-inflammatory drugs (NSAIDs) and intra-articular corticosteroid injections are first-line therapy for oligoarticular JIA. NSAIDs Adverse events (AEs) include gastrointestinal ulcers/bleeding and impaired renal function. The most prescribed NSAIDs for oligoarticular JIA are ibuprofen and naproxen. However, direct comparison between these drugs is lacking. We aimed to compare the efficacy and safety of ibuprofen versus naproxen for oligoarticular JIA.

METHODS

This is a bi-national retrospective study of oligoarticular JIA patients treated with either ibuprofen or naproxen as first-line therapy. Efficacy was defined as patients that achieved complete response (no evidence for arthritis). Safety was assessed by the occurrence of adverse events during follow-up.

RESULTS

Of 164 patients, 103 were treated in the Israeli group and 61 in the US group. The study population had a mean age of 4.49 ± 3.55 years, with F:M ratio of ∼2.5:1. No significant difference was found in drug efficacy [Complete response was observed in 15% of the ibuprofen group vs. 17.3% in naproxen group (p = 0.7)]. Treatment duration > 28 days was associated with significantly higher odds for complete response (p = 0.021). For safety, 12 AEs were associated with naproxen, whereas no AEs were associated with ibuprofen (p = 0.004). Treatment was discontinued in all AEs cases.

CONCLUSIONS

Ibuprofen and naproxen showed similar albeit low efficacy which emphasizes their role as bridging therapy until IACI is achieved. However, ibuprofen showed better safety profile naproxen and therefore should be considered as first-line therapy.

Comparative efficacy and safety of etanercept and adalimumab in the treatment of polyarticular juvenile idiopathic arthritis

OBJECTIVE

This study aims to evaluate the efficacy and safety of Etanercept and Adalimumab in the treatment of polyarticular juvenile idiopathic arthritis (pJIA).

METHODS

From Jan 2021 to Oct 2023, 66 pJIA patients were prospectively randomized into Etanercept (n = 33) and Adalimumab (n = 33) groups at our hospital. Efficacy, via Juvenile Arthritis Disease Activity Score 10 (JADAS-10), and anti-cyclic citrullinated peptide (CCP), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell count (WBC) were assessed pre-treatment and at 1-, 3-, 6-month intervals post-treatment. Adverse reactions were monitored.

RESULTS

Two groups showed comparable efficacy (P > 0.05) at baseline in anti-CCP, TNF-α, CRP, ESR, WBC, and JADAS-10 score. Treatment for a period of 1 to 3 months led to statistically significant reductions in these markers over time (P < 0.05). Adalimumab group was found significantly lower levels of mentioned markers than Etanercept group at 1-3 months (P < 0.05), but after 6 months, statistical differences vanished (P > 0.05). Normal total bilirubin, alanine transaminase, aspartate aminotransferase, serum creatinine levels were detected post-3 months in both groups; with similar adverse reaction rates (P > 0.05).

CONCLUSION

Both Etanercept and Adalimumab are effective and safe for managing pJIA, demonstrating significant reductions in inflammatory markers and disease activity with no significant difference in efficacy or safety profiles.

CLINICAL TRIAL NUMBER

Not applicable.

Digital Interventions for Patients With Juvenile Idiopathic Arthritis: Systematic Review and Meta-Analysis

Background

Juvenile idiopathic arthritis (JIA) is a chronic rheumatic condition requiring long-term, multidisciplinary treatment, which consumes significant health care resources and family energy. This study aims to analyze the effectiveness of digital interventions on patient outcomes in individuals with JIA.

Objective

This meta-analysis aimed to evaluate the impact of digital interventions on alleviating symptoms and improving overall well-being in children and adolescents with JIA.

Methods

A systematic search of 5 databases identified randomized controlled trials assessing the impact of digital interventions on physiological and psychological outcomes in adolescents and children (average age ≤19 y). Outcomes included pain, physical activity, health-related quality of life, self-efficacy, and disease-related issues. A total of 2 reviewers independently screened papers and extracted data on intervention functionalities and outcomes, assessing the risk of bias. A meta-analysis using a random-effects model synthesized the results.

Results

The review included 11 studies involving 885 patients with JIA. Digital interventions included educational (eg, self-management training), therapeutic (eg, pain management), and behavioral (eg, promoting physical activity) approaches. These were delivered through websites, telephone consultations, video conferences, apps, and interactive games, with durations ranging from 8 to 24 weeks and no clear link observed between intervention length and outcomes. Compared with conventional control groups, digital interventions were significantly effective in alleviating pain (standardized mean difference [SMD] -0.19, 95% CI -0.35 to -0.04) and enhancing physical activity levels (SMD 0.37, 95% CI 0.06-0.69). Marginal improvements in health-related quality of life, self-efficacy, and disease-related issues were observed, but these did not reach statistical significance (SMD -0.04, 95% CI -0.19 to 0.11; SMD 0.05, 95% CI -0.11 to 0.20; and SMD 0.09, 95% CI -0.11 to 0.29, respectively). The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach rated the quality of evidence for pain, health-related quality of life, self-efficacy, and disease-related issues as moderate, while the evidence quality for physical activity was assessed as low.

Conclusions

Digital interventions can alleviate pain and enhance physical activity in patients with JIA. However, given the limited sample size and high risk of bias in some studies, further high-quality research is needed to improve the treatment and management of JIA.

African guidelines for diagnosis and management of polyarticular juvenile idiopathic arthritis: PAFLAR initiative

BACKGROUND

Juvenile idiopathic arthritis (JIA) is the most common rheumatologic disease of childhood. The Existing guidelines for polyarticular JIA are typically based on data from non-African populations and may not fully address the unique challenges faced in African settings. We aimed to produce updated African guidelines for the diagnosis and treatment of children and adolescents with polyarticular juvenile idiopathic arthritis (poly-JIA).

METHODS

This study was conducted with the aim of reaching a consensus among African experts on the diagnosis and treatment of poly-JIA using the Delphi technique. The first scientific committee identified a total of 15 key clinical questions according to the PICO (Patient/Population, Intervention, Comparison, Outcome) approach. A systematic review of the evidence-based literature was conducted for this work. The core steering group identified researchers and clinicians with expertise in pediatric rheumatology. A Delphi process was used to reach consensus.

RESULTS

An online questionnaire was sent to the expert panel that participated in the survey (100% response rate). A total of 15 recommendation points were identified, divided into two parts: five recommendations for diagnosis and ten recommendations for management. The percentage of those who agreed with the recommendations (fourth and fifth place) ranged from 80 to 100%. All 15 clinical recommendation statements that the scientific committee had identified had been agreed upon in wording (i.e., 75% of respondents agreed or strongly agreed).

CONCLUSIONS

We successfully developed guidelines for children with polyarticular JIA, taking into consideration the African specific nature of limited resources and low income, also on the same time incorporating newly released data and using a treat to target approach.

Evaluation of ILAR and PRINTO classifications for juvenile idiopathic arthritis: oligoarticular JIA vs early-onset ANA-positive JIA

OBJECTIVES

The International League of Associations for Rheumatology (ILAR) juvenile idiopathic arthritis (JIA) classification was revisited by the Pediatric Rheumatology International Trials Organization (PRINTO) in 2018. Classifications should establish uniform groups to assist physicians in providing optimal care. Therefore, we evaluated changes proposed by PRINTO to highlight their impact on forming consistent groups regarding uveitis and treatment responses, particularly focusing on early-onset anti-nuclear antibody (ANA)-positive JIA.

METHODS

Pediatric patients diagnosed with JIA according to ILAR and PRINTO classification, with a minimum of 1-year of follow-up, were enrolled, excluding those meeting the exclusion criteria for both the oligoarticular JIA and the early-onset ANA-positive JIA groups.

RESULTS

Among the 139 enrolled patients, 110 (79.1%) had oligoarticular JIA, while 15 (10.8%) had early-onset ANA-positive JIA. The below-age-5 criterion demonstrated the strongest association with uveitis, while the below-age-7 provided similar associations without substantial exclusions (odds ratio (OR) 8.62 [2.50-29.81] vs 7.45 [2.37-26.66]). Patients with a single ANA positivity at a titer ≥ 1/160 and age of onset below 7 had a notably higher risk of new-onset uveitis and biologic DMARD requirement (OR 7.95 [2.37-26.66] and 3.6 [1.42-9.09], respectively).

CONCLUSION

The inclusion of age of disease onset and ANA positivity with a titer ≥ 1/160 has enhanced uniformity in uveitis risk and treatment response, including failure of conventional synthetic DMARDs. Additionally, a single ANA positivity at a ≥ 1/160 titer rather than requiring two instances yields similar consistency. However, the joint count criteria failed to form consistent groups. PRINTO's classification places a significant proportion of patients into the "other JIA" group, necessitating further classification for improved clinical utility. Key Points •Inclusion of age and ANA positivity criteria increased uniformity among the subgroups. •Single ANA positivity at a ≥ 1/160 titer can be sufficient instead of twice. •Early utilization of bDMARDs may be beneficial for early-onset ANA-positive JIA group. •PRINTO classification must further classify the "other JIA" before being implemented in clinical practice.

Transition-related outcomes among a cohort of patients with juvenile idiopathic arthritis

A major goal in juvenile idiopathic arthritis (JIA) long-term management is to ensure a successful transition to adult age. This study aims to assess transition outcomes in a group of JIA patients during their passage from pediatric to adult healthcare assistance at a single center. This is a cross-sectional study. All patients with JIA undergoing a transition from the Pediatric Rheumatology Service of the IRCCS "Burlo Garofolo" Hospital, Trieste, to the adult Rheumatology Service of "Santa Maria della Misericordia" Hospital, Udine, between 2017 and 2022, were enrolled. Clinical and laboratory data were collected. A semi-structured survey exploring patients' satisfaction was distributed through email. Numerical variables were compared using Student's t-test or Mann-Whitney test. Categorical variables were compared with Fisher's exact test. We recruited 36 patients (26 female, 72.2%): 9 with polyarticular course JIA, 13 oligoarticular, 8 psoriatic arthritis, 3 systemic JIA, and 3 enthesitis-related arthritis. The mean age at transition was 18.6 (Q1-Q3, 18.3-19.1). JADAS-27 score significantly decreased after the transition, with a mean difference of 2.6 (p = 0.014). No patients were lost to follow-up, and in 8 out of 36 (22.2%), a step-up therapy was needed within the first 12 months. Among these, no correlation was found with the JIA subtype, age at onset, type of involved joints, and other variables explored. Finally, the 15 patients who answered the survey (response rate 50%) were satisfied about the transition process. This study described a real-life transition experience from pediatric to adult rheumatology care, showing good transition outcome measures, with no patients lost to follow-up and a reduction of JADAS-27 score after completing the process.

Lifetime clinical presentation of Still's disease in the Afro-descendant population of the French West Indies

INTRODUCTION

The continuum in Still's disease has never been addressed in Afro-descendant (AD) populations. The aim of this study was to compare the features of Still's disease between children and adults in the AD population of French West Indies (FWI).

METHODS

Retrospective longitudinal study from January 2000-2022. We included children and adults with systemic juvenile idiopathic arthritis and Still's disease. Clinical data were obtained from computerized hospital archives, registries of clinicians and the national registry for rare diseases. The main outcome was similarity in cardinal and non-cardinal symptoms.

RESULTS

Fifty-eight patients were included (57% adults). Sex distribution between children and adults was significantly different (Female respectively 36% vs 70.6%, P=0.03). Diagnostic criteria overlapped in most cases (80%), regardless of age. The children had significantly more typical skin rashes (100% vs 29.4%, P<0.001), coronary artery dilation (16% vs 0%, P=0.03), and macrophage activation syndrome (52% vs 9%, P<0.001). The adults had significantly more inflammatory polyarthalgia without arthritis (91% vs 32% P<0.001) and pulmonary involvement (51.5% vs 4% P<0.001). The phenotypes were 86% systemic (43% monophasic, 43% polycyclic) and 14% chronic polyarticular. No difference was found in the number of relapses, use of biologics and mortality.

CONCLUSIONS

There is a rationale for considering Still's disease as a single entity in our AD population, focusing on the cardinal symptoms, but particular attention should be paid to the non-cardinal symptoms depending on the age of onset.

Polyarticular juvenile idiopathic arthritis has a distinct co-inhibitor receptor profile

OBJECTIVES

JIA is the most common rheumatic disease of childhood; the pathogenesis is associated with T-cell activation. T-cell activation can be counterbalanced by signals generated by inhibitory receptors (IRs) such as CTLA-4, PD-1, LAG-3 and TIM-3. Here, we identify the role of IRs in the pathogenesis of different JIA subtypes.

METHODS

In total, we included 67 oligoarticular JIA, 12 IgM-RF negative polyarticular JIA, 17 enthesitis-related arthritis, 11 systemic JIA patients and 10 healthy controls. We collected plasma (and SF) samples from the patients either at the onset or during a flare of their disease. We measured the soluble levels of co-IRs (IL-2Rα, 4-1BB, CD86, TGF-β1, CTLA-4, PD-L1, PD-1, TIM-3, LAG- 3, Galectin-9) by cytometric bead array kits and their cellular expression (PD-1, CTLA-4, TIM-3, LAG-3) by flow cytometry. We compared the plasma levels and cellular expressions of different co-IRs within different JIA subgroups.

RESULTS

The polyarticular JIA group was different from the three other examined JIA subgroups, having higher levels of plasma sCTLA-4 (P < 0.001), sPD-1 (P < 0.05) and s4-1BB (P < 0.05) when compared with the other JIA subgroups and healthy controls. We analysed the cellular surface expression of different co-IRs on the peripheral blood mononuclear cells of different JIA subtypes. Similar to plasma levels, both the percentage (P < 0.05) and the mean fluorescence intensity (P < 0.01) of CTLA4 expression were higher in the polyarticular JIA subgroup.

CONCLUSION

This is the first report studying the expression profile of different co-IRs in different subtypes of JIA. Polyarticular JIA patients had a different co-IR profile, having more CTLA-4, PD-1 and 4-1BB in their plasma than the other subtypes of JIA.

Clinical Impact of HLA-B27 on Juvenile Idiopathic Arthritis: Eighteen Years of Follow-up in the Population-Based Nordic Juvenile Idiopathic Arthritis Cohort

OBJECTIVE

We have previously shown that HLA-B27 was negatively associated with remission status eight years after the onset of juvenile idiopathic arthritis (JIA). We now aimed to study the associations of HLA-B27 with clinical features and disease outcomes 18 years after the onset of JIA.

METHODS

We studied 434 patients from the population-based Nordic JIA cohort. Demographic and clinical data, including remission status, were collected consecutively at baseline, eight years after disease onset, and 18 years after disease onset and presented in relation to HLA-B27 status.

RESULTS

The HLA-B27 status was available for 416 of the 434 participants (96%) and was positive for 93 participants (22.4%), more often in men (P = 0.01). The sacroiliac, hips, and subtalar joints were more frequently involved in individuals who were HLA-B27 positive than in individuals who were HLA-B27 negative. In almost half of the individuals with HLA-B27 positivity and uveitis, the uveitis was asymptomatic. Uveitis, inflammatory back pain, sacroiliitis, arthritis in hip, tarsal, and subtalar joints, and enthesitis during the disease course were all associated with a lower rate of remission off medication. HLA-B27 positivity was significantly associated with a higher risk of not being in remission off medication after 18 years (odds ratio [OR] 2.6), especially in men (OR 5.6).

CONCLUSION

Clinical features related to spondylarthropathies were more common in patients who were HLA-B27 positive and associated with worse outcomes and nonremission 18 years after disease onset, particularly in men. Our results underline the adverse impact of having HLA-B27 positivity on long-term outcomes in individuals with JIA.

Glycolytic reprogramming shapes the histone acetylation profile of activated CD4+ T cells in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is an autoimmune disease characterized by accumulation of activated CD4+ T cells in the synovial fluid (SF) of affected joints. JIA CD4+ T cells exhibit a unique inflammation-associated epigenomic signature, but the underlying mechanisms remain unclear. We demonstrate that CD4+ T cells from JIA SF display heightened glycolysis upon activation and JIA-specific H3K27 acetylation, driving transcriptional reprogramming. Pharmacological inhibition of glycolysis altered the expression of genes associated with these acetylated regions. Healthy CD4+ T cells exposed to JIA SF exhibited increased glycolytic activity and transcriptomic changes marked by heightened histone 3 lysine 27 acetylation (H3K27ac) at JIA-specific genes. Elevated H3K27ac was dependent on glycolytic flux, while inhibiting glycolysis or pyruvate dehydrogenase (PDH) impaired transcription of SF-driven genes. These findings demonstrate a key role of glycolysis in JIA-specific gene expression, offering potential therapeutic targets for modulating inflammation in JIA.

Active Vibrational Achilles Tendon Sensing for Identifying and Characterizing Inflammatory Symptomatology in Enthesitis Related Arthritis

OBJECTIVE

This study explores the potential of active vibrational sensing as a digital biomarker to identify and characterize inflammatory symptomatology in the Achilles tendon and its entheses in juvenile idiopathic arthritis (JIA), particularly enthesitis related arthritis (ERA), a subcategory of JIA.

METHODS

Active vibrational data were non-invasively recorded using a miniature coin vibration motor and accelerometer. Twenty active vibration recordings from children diagnosed with JIA were used in the analysis. Machine learning algorithms were leveraged to classify the vibrational signatures according to the corresponding subject groups. Subjects were classified into symptomatic ERA (sxERA), asymptomatic ERA (asxERA), and asymptomatic JIA (non-ERA) (asxNERA) groups based on clinical evaluations and ILAR criteria.

RESULTS

Distinct vibrational signatures were observed during tiptoe standing, providing differentiation between subject groups. Feature-based and waveform-based approaches effectively classified the sxERA group against asxNERA and asxERA groups using leave-one-subject-out (LOSO-CV) and 3-fold cross-validation. For the 3-fold cross-validation, the mean accuracies for distinguishing sxERA from asxNERA were 81% (feature-based) and 81% (waveform-based), while the accuracies for discriminating sxERA against asxERA were 73% (feature-based) and 74% (waveform-based).

CONCLUSION

Active vibrational sensing demonstrates promise as a tool for identifying Achilles tendon inflammation in JIA, potentially aiding in early diagnosis and disease monitoring.

SIGNIFICANCE

Developing active vibrational sensing as a diagnostic modality could address challenges in diagnosing ERA and facilitate timely intervention and personalized care for JIA, potentially enhancing long-term patient outcomes.

Assessment of choroidal vascularity index in juvenile idiopathic arthritis: implications for disease monitoring

PURPOSE

Juvenile Idiopathic Arthritis (JIA) can affect ocular structures, but choroidal involvement is not well understood. This study investigates the Choroidal Vascularity Index (CVI) in JIA patients compared to healthy controls and explores its relationship with disease activity.

METHODS

In this cross-sectional study, 35 JIA patients and 40 healthy controls underwent comprehensive ophthalmic examination and swept-source optical coherence tomography (SS-OCT). CVI, central macular thickness (CMT), and subfoveal choroidal thickness (SFCT) were measured. The Juvenile Arthritis Disease Activity Score (JADAS) was calculated for JIA patients. Statistical analysis included comparison between groups and correlation analysis.

RESULTS

JIA patients showed significantly lower CVI compared to controls (68.3 ± 2.5% vs. 72 ± 4.6%, p < 0.001). No significant difference was found in SFCT. CVI demonstrated a moderate negative correlation with JADAS (r = -0.368, p < 0.05). However, receiver operating characteristic (ROC) analysis revealed poor diagnostic performance of CVI for detecting JIA (AUC = 0.25).

CONCLUSION

The study reveals reduced choroidal vascularity in JIA patients and a correlation between CVI and disease activity. While CVI shows limited diagnostic utility, it may serve as a potential marker for monitoring inflammatory burden and treatment response in JIA. Further research is needed to establish its clinical utility fully.

Treatment of Juvenile Idiopathic Arthritis

This review outlines the natural history, diagnosis, and management of juvenile idiopathic arthritis involving the hand and wrist. The discussion of management considers both nonoperative and surgical management to preserve functionality and mitigate long-term articular damage in children and adolescents. The review describes the current literature and identifies areas for further study.

Early Anti-Drug Antibodies Predict Adalimumab Response in Juvenile Idiopathic Arthritis

Adalimumab, a TNF-alpha inhibitor, is approved to treat juvenile idiopathic arthritis (JIA), helping control disease activity and reduce flare frequency. This study aims to investigate predictors of treatment response, including anti-drug antibodies. We reviewed 65 JIA patients (mean age 10.47 ± 3.90 years; 61.5% male) receiving adalimumab for an average of 2.64 ± 0.56 years, with demographics, laboratory parameters, therapeutic regimens, and treatment outcomes recorded. Disease status was evaluated using the Wallace criteria up to 36 months post-treatment initiation, and anti-adalimumab antibody levels were measured after 6 months of treatment. Enthesitis-related arthritis was the most common subtype (64.6%). Inactive disease status was achieved by 83.1% of patients, with 59.3% experiencing relapse. Detectable anti-adalimumab antibody at six months (p = 0.023) and temporomandibular joint (TMJ) involvement (p = 0.038) identified those less likely to achieve inactive disease. An antibody level cutoff of 7.426 ng/mL best predicted response (AUC = 0.808; p = 0.008), while high anti-adalimumab antibody levels after treatment (p = 0.032) and an injection intervals over two weeks (p = 0.042) were predictors of future flares. Our results highlight that the presence of anti-adalimumab antibodies six months after treatment is a risk factor for poor response to adalimumab therapy.

Metabolomics in juvenile idiopathic arthritis: A distinct profile in patients under methotrexate

The objective of the present study was to evaluate biochemical quantitative metabolites in peripheral blood serum samples of Juvenile Idiopathic Arthritis (JIA) patients and healthy controls. A cross-sectional study included 33 post-pubertal JIA (21 without and 12 with Methotrexate (MTX) women and 28 age-matched healthy controls. Metabolomic analyses based on targeted electrospray ionization tandem mass spectrometry were used to identify possible biochemical pathway modifications in serum from JIA patients. The mean current age (p = 0.065) was similar in JIA patients and healthy controls. Current MTX use in all subtypes of JIA patients was associated with an increase in concentrations of free carnitine [21.74 (12.7‒35.2) vs. 27.49 (14.5‒41.3) µM/L, p = 0.02], suggesting an enhanced mitochondrial metabolism and intestinal absorptive function. In contrast, a decreased mitochondrial metabolism was observed in polyarticular and systemic JIA subtypes, with a decrease of several acylcarnitines' concentrations (p < 0.05). In conclusion, the present study identified a distinctive pattern of serum metabolic signatures in JIA patients under MTX therapy. Our findings indicate that MTX use is associated with a more efficient mitochondrial function.

Biologics promote catch-up growth in young Juvenile idiopathic arthritis patients with lower body height

BACKGROUND

Juvenile idiopathic arthritis (JIA) is accompanied by growth retardation especially in severe cases. While the use of biologics has shown efficacy in restoring growth impairment, data from Asia are limited. We aim to investigate the growth of JIA patients and identify those who can benefit from the use of biologics in Taiwan.

METHODS

JIA patients who received regular follow-up and treatment at a tertiary medical center in Taiwan between January 2011 and June 2023 were retrospectively reviewed. General demographics and growth parameters, including body height, body weight, and body mass index (BMI), were collected at the time of biologics initiation, then at 6 and 12 months into treatment and they were transformed into z-scores for further analysis.

RESULTS

A total of 104 JIA patients, including 52 biologics-free controls, were enrolled. Enthesitis-related arthritis (ERA) accounted for 51% all cases. The initial z-scores for body height, body weight and BMI were -0.33, -0.35, -0.45, respectively. A significantly higher proportion of biologics-treated patients achieved catch-up growth, defined as a continuous increase in height z-scores 1 year following biologics treatment, compared to the biologics-free controls (38% vs. 12%; p = 0.002) 12 months into treatment. In subgroup analysis, JIA patients with lower initial z-scores for height (p = 0.021), a shorter period between symptom onset and diagnosis (p = 0.026), younger ages at the time of biologics initiation (p < 0.001) and higher accumulative dose of steroid before biologics (p = 0.048) are more likely to achieve catch-up growth. Combining the age at the time of biologics initiation and patients' initial z-score for height may be sufficient to predict catch-up growth following treatment with biologics (AUC = 0.804; p < 0.0001).

CONCLUSIONS

Growth retardation appears limited among JIA patients in Taiwan. Initiation of biologics at a younger age may improve linear growth, especially for patients initially shorter for their age.

Juvenile Idiopathic Arthritis Associated Uveitis. Current Status: Epidemiology, Pathogenesis, and Clinical Issues

Uveitis is the most common extraarticular manifestation of juvenile idiopathic arthritis (JIA) and with no adequate management results in serious eye complications such as cataracts, secondary glaucoma, retinal detachment, and linear corneal dystrophy. This pathology reduces patients’ quality of life and can lead to significant social and economic losses, both due to direct health costs and due to disability (total loss of sight). Childhood uveitis accounts for approximately 5–10% of all uveitis in global population, however their prevalence has been increasing in recent years. The etiology and pathogenesis of JIA-associated uveitis remains poorly studied despite the well-known correlation of uveitis with JIA. Uveitis in children is difficult to diagnose in routine pediatric practice, both due to its course (asymptomatic/mild), and due to challenging verbal communication and examination (young children), which poses significant clinical problem. This article presents current data on the epidemiology, pathogenesis, clinical manifestations, and terminology of JIA-associated uveitis.

Histopathology of Idiopathic Condylar Resorption Differs From Temporomandibular Joint-Only Juvenile Idiopathic Arthritis

BACKGROUND

Idiopathic condylar resorption (ICR) is a rare condition of unknown etiology characterized by progressive decrease in volume and pathologic remodeling of a previously normal mandibular condyle. Juvenile idiopathic arthritis (JIA) affecting only the temporomandibular joint (TMJ-only JIA) is characterized by synovitis and destruction of TMJ tissues without involvement of other joints. It is often difficult to differentiate the 2 conditions because they exhibit similar phenotypes.

PURPOSE

To compare histology of resected condylar specimens from patients with ICR and TMJ-only JIA. Specific aims were as follows: 1) to correlate longitudinal clinical data with histopathology of resected condyle specimens and 2) to compare resorption patterns between the 2 disease processes.

STUDY DESIGN, SETTING, SAMPLE

This was a retrospective cohort study of patients treated at the Massachusetts General Hospital from 1999 through 2023.

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE

Primary predictor variable was the diagnosis (ICR or JIA). Secondary predictor variables included age, gender, race, putative contributing factors, and laboratory studies.

MAIN OUTCOME VARIABLE(S)

Primary outcome variable was presence or absence of inflammatory infiltrates in bone and synovial specimens. Secondary outcome variables were structural integrity and morphologic characteristics of the condylar cartilage and bone.

ANALYSES

Spearman correlation was used to assess the relationship between histological scores and age, gender, and possible associated contributing factors. A P value < .05 was considered statistically significant.

RESULTS

Thirty-five subjects (67 specimens) were included in group 1 (ICR). Eight subjects (15 specimens) were included in group 2 (TMJ-only JIA). The histopathologic findings in ICR consisted of severe and irregular cartilage surface disruption, fibrocartilage degeneration, and subchondral bone with no inflammatory infiltrate. Degeneration was observed to begin at the anterior pole of the condyle and progress eventually to total resorption to the sigmoid notch. TMJ-only JIA was notable for more severe condylar degeneration and inflammation in the bone and synovia. There was no specific pattern of degeneration. For both groups, the subject's age, gender, or putative contributing factors did not correlate with the histopathologic scores.

CONCLUSION AND RELEVANCE

These results support the hypothesis that ICR and TMJ-only JIA are distinct clinical entities and can be distinguished by histopathologic findings in the mandibular condyles and synovia.

The validity and reliability of the Turkish version of the Fear of Pain Questionnaire for Children-Short Form (FOPQC-SF) in children and adolescents with juvenile idiopathic arthritis

OBJECTIVE

The aim of this study was to investigate the validity and reliability of the Turkish version of the Fear of Pain Questionnaire for Children-Short Form (FOPQC-SF) in children/adolescents with juvenile idiopathic arthritis (JIA).

METHODS

To evaluate validity of FOPQC-SF, 70 children/adolescents with JIA were included. Data were collected using Pediatric Quality Of Life Inventory 3.0. Module Arthritis (PedsQL), Childhood Health Assessment Questionnaire (CHAQ) and Juvenile Arthritis Disease Activity Score (JADAS).To determine the reliability of the FOPQC-SF, test-retest was performed at one-week intervals on participants who had not made any changes to their pharmacological treatment and had not received any additional treatment.

RESULTS

With factor restrictions, items of Turkish version of FOPQC-SF were found acceptable for a 2-factor structure (fear:4 items; avoidance:6 items)(RMSEA = 0.058, GFI = 0.890, X2 = 40.667 X2/df = 1.196). With no restrictions, items of Turkish version of FOPQC-SF were found to be excellent for a 3-factor structure (fear:3 items; avoidance:4 items; other:3 items) (RMSEA = 0.036, GFI = 0.909, X2 = 34.465, X2/df = 1.077).The Cronbach's alpha value of Turkish version of FOPQC-SF total was 0.865 (good). The intraclass correlation coefficient (ICC2,1) was 0.865 (very high). Fear and avoidance subscales and total score of Turkish version of FOPQC-SF had low to moderate correlation with CHAQ-disability index, CHAQ-pain, CHAQ-global evaluation, JADAS, PedsQL-child total, PedsQL-parent total (r:-0.283/-0.452)(p < 0.05). Other subscale of Turkish version of FOPQC-SF had low to moderate correlation with CHAQ-disability index, CHAQ-pain, PedsQL-parent total (r:0.286/0.318) (p < 0.05).

CONCLUSION

The Turkish version of FOPQC-SF was found to be clinically valid and reliable in children and adolescents with JIA.

The plasma metabolome of juvenile idiopathic arthritis varies according to subtype and underlying inflammatory status

BACKGROUND

Juvenile idiopathic arthritis (JIA) is challenging to classify and effectively monitor due to the lack of disease- and subtype-specific biomarkers. A robust molecular signature that tracks with specific JIA features over time is urgently required, and targeted plasma metabolomics may reveal such a signature. The primary aim of this study was to characterise the differences in the plasma metabolome between JIA patients and non-JIA controls and identify specific markers of JIA subtype. We also assessed the extent to which these signatures are due to underlying inflammation as assessed by glycoprotein acetyls (GlycA) and high-sensitivity C-Reactive Protein (hsCRP) levels.

METHODS

Targeted nuclear magnetic resonance (NMR) metabolomic profiles of plasma of 72 children with JIA and 18 controls were assessed cross-sectionally. Associations between 71 metabolomic biomarkers and JIA, JIA subtype, disease activity status, and inflammation markers (GlycA and hsCRP) were assessed using multivariable linear regression models.

RESULTS

JIA was associated with higher GlycA (mean difference = 0.93 standard deviations, 95% confidence interval = [0.370, 1.494], Padj = 0.039) and docosahexaenoic acid (1.06, [0.51, 1.60], Padj = 0.021), and lower acetate (-0.92, [-1.43, -0.41], Padj = 0.024) relative to controls. This variation was largely driven by systemic JIA (sJIA), with 24 of 71 total biomarkers significantly different (Padj <0.05) relative to controls. There were no specific differences identified in oligoarticular (oJIA) or polyarticular (rheumatoid factor positive or negative) JIA relative to controls. Despite being generally highly correlated with hsCRP (r > 0.70), GlycA, but not hsCRP, was positively associated with active disease in sJIA (0.22, [-0.40, -0.04], Padj = 0.018), and 6 of 24 sJIA-associated markers were associated with GlycA levels. Only 1 sJIA-associated biomarker, histidine, was associated with hsCRP levels.

CONCLUSION

Differences in the plasma NMR metabolomic profiles are apparent in children with sJIA, but not other JIA subtypes, relative to non-JIA controls. These findings suggest a potential utility for classifying and monitoring JIA through metabolomic profiling, with chronic inflammation, measured by GlycA, potentially playing a role in at least some of these metabolomic differences.

Histological synovitis score in juvenile idiopathic arthritis and other pediatric synovial inflammatory conditions

OBJECTIVE

The Krenn's scoring is a system for histopathological grading of synovial inflammation, and in adults, useful in etiological grouping. The score has only rarely been used in pediatric samples. We aimed to assess the performance of the score in juvenile idiopathic arthritis and other pediatric synovial inflammatory processes in categorization of the disease and in finding characteristic pathological features.

DESIGN

We collected an unselected series of pediatric (age < 16 years) routine synovial biopsy samples to represent normal synovium and inflammatory conditions. The final diagnosis based on clinical follow-up was determined and classified as normal synovium, and different groups according to etiology. Total of 142 patients were analyzed. According to the score, case was classified to normal, low- or high-grade synovitis.

RESULTS

The synovitis scores in clinically normal synovium were low with 48 % of cases with scores of low-grade synovitis. In structural joint disorders scores varied from normal to low grade synovitis with occasional cases of high grade synovitis. In transient/reactive arthritis scores showed increase, majority clustering to low grade synovitis. In JIA and in bacterial synovitis the scores were higher than in the other groups high grade synovitis being the dominant grade. Extended oligoarthritis showed higher score than persistent oligoarthritis. ROC analysis indicated that JIA could be differentiated from other conditions.

CONCLUSIONS

The Krenn's synovitis score is useful in the etiological classification of pediatric synovial samples, high Krenn's score suggesting JIA. Observed differences between the subcategories of oligoarthritis may be useful in subclassifying these types of JIA.

Therapeutic Potential of Bee and Wasp Venom in Anti-Arthritic Treatment: A Review

Arthritis has a high global prevalence. During the early ancient human era, bee (Apis) venom therapy was employed in Egypt, Greece, and China to alleviate ailments such as arthritis and neuralgia. In addition, bee venom has long been used as a traditional medicine for immune-related diseases in Korea. Wasp (Vespa) venom is a folk medicine of the Jingpo people in Yunnan, China, and has been widely used to treat rheumatoid arthritis. In spite of this, the underlying mechanisms of bee and wasp venoms for the treatment of arthritis are yet to be fully understood. In recent years, researchers have investigated the potential anti-arthritic properties of bee and wasp venoms. Studies have shown that both bee and wasp venom can improve swelling, pain, and inflammation caused by arthritis. The difference is that bee venom reduces arthritis damage to bone and cartilage by inhibiting the IRAK2/TAK1/NF-κB signaling pathway, NF-κB signaling pathway, and JAK/STAT signaling pathway, as well as decreasing osteoclastogenesis by inhibiting the RANKL/RANK signaling pathway. Wasp venom, on the other hand, regulates synovial cell apoptosis via the Bax/Bcl-2 signaling pathway, inhibits the JAK/STAT signaling pathway to reduce inflammation production, and also ameliorates joint inflammation by regulating redox balance and iron death in synovial cells. This review provides a detailed overview of the various types of arthritis and their current therapeutic approaches; additionally, it comprehensively analyzes the therapeutic properties of bee venom, wasp venom, or venom components used as anti-arthritic drugs and explores their mechanisms of action in anti-arthritic therapy.

Causal effect of gut microbiota on juvenile idiopathic arthritis: A two-sample Mendelian a randomization study

There is increasing evidence of a significant association between the gut microbiome and juvenile idiopathic arthritis (JIA). However, whether this association is causal remains to be determined. This study was a two-sample Mendelian randomization (MR) study using publicly available genome-wide association study (GWAS) summary data to investigate the causal relationship between the gut microbiome and JIA. We used summary data on gut flora and JIA obtained from genome-wide association studies (GWAS) from MiBioGen and NHGRI-EBI, using inverse variance weighting as the main method to analyse causality in the TSMR causality analysis. To check the stability of the TSMR results, we performed several sensitivity analyses and assessed the presence of reverse causality through a reverse TSMR analysis. We calculated the degree of sample overlap where applicable. The current TSMR analyses identified four bacterial taxa associated with JIA. Specifically, two bacteria, Catenibacterium (p = 2 × 10-2) and Holdemania (p = 4 × 10-2), were negatively associated with the risk of developing JIA, suggesting a protective effect, while Olsenella (p = 1 × 10-2) and Rikenellaceae (RC9gutgroup) (p = 1 × 10-2) were positively associated with the risk of JIA, suggesting that these two bacteria may be risk factors for JIA. However, the results for Catenibacterium and Holdemania should be interpreted with caution due to instability observed in 'leave-one-out' sensitivity analyses. Reverse TSMR analyses found no evidence of reverse causality between JIA and gut flora. Our confirmation of a causal relationship between gut flora and JIA provides an innovative perspective for the study of JIA: targeting and modulating dysregulation of specific bacterial taxa to prevent and treat JIA.

Validation of the EQ-5D-Y-5L parent-proxy version among children with juvenile idiopathic arthritis

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is the most common type of arthritis among children. It can cause joint pain and permanent physical damage, which affects mobility and daily activities. The EQ-5D-Y-3L self-report version has been validated in JIA, but the validity of EQ-5D-Y-5L remains unknown. We examined the psychometric properties of the EQ-5D-Y-5L parent-proxy version among children with JIA.

METHODS

We used data from the Understanding Childhood Arthritis Network Canadian-Dutch collaboration study cohort, including patients with new-onset JIA, and those starting or stopping biologics. Clinical data and the parent-proxy version of the childhood health assessment questionnaire (CHAQ) and EQ-5D-Y-5L were collected. We evaluated the ceiling and floor effect; convergent and divergent validity using Spearman's rank correlation; known-group validity using one-way ANOVA (Analysis of Variance) and effect size; and informativity using Shannon's evenness index.

RESULTS

467 patient visits representing 407 patients were analyzed. The EQ-5D-Y-5L had no ceiling/floor effect. The EQ-5D-Y-5L showed good convergent (e.g., EQ-5D-Y-5L pain/discomfort dimension vs. CHAQ pain index (Spearman's r = 0.74, 95% confidence interval (C.I.): 0.69-0.79)), divergent (e.g., EQ-5D-Y-5L pain/discomfort dimension vs. CHAQ eating dimension (Spearman's r = 0.19, 95% C.I.: 0.09-0.29)) and known-group validity (e.g., mean EQ-5D-Y-5L level summary score for patients with inactive versus active disease status, 6.34 vs. 10.52 (p < 0.001, effect size = 1.20 (95% C.I.: 0.95-1.45)). Shannon's evenness index ranged from 0.52 to 0.88, suggesting most dimensions had relatively even distributions.

CONCLUSIONS

In this patient sample, EQ-5D-Y-5L parent-proxy version exhibited construct validity and informativity, suggesting the EQ-5D-Y-5L can be used to measure the quality of life of children with JIA.

Parotid saliva and blood biomarkers in juvenile idiopathic arthritis in relation to temporomandibular joint magnetic resonance imaging findings

BACKGROUND

Juvenile idiopathic arthritis (JIA) often affects the temporomandibular joint (TMJ) caused by an abnormal immune system that includes overactive inflammatory processes. Salivary biomarkers may be a powerful tool that can help establishing diagnosis, prognosis and monitor disease progress.

OBJECTIVE

The objective was to investigate biomarkers in parotid saliva and blood plasma in relation to temporomandibular joint (TMJ) magnetic resonance imaging (MRI) findings in patients with JIA and healthy individuals.

METHODS

Forty-five children aged 6 to 16 years with JIA and 16 healthy age- and sex-matched controls were included. Unstimulated parotid saliva samples and venous blood were collected. Biochemical analyses were performed for the cytokine biomarkers. The participants underwent MR imaging of the TMJs, where changes in the inflammatory and the damage domains were assessed.

RESULTS

In the JIA patients, lower concentrations of IL-6R and gp130 were found in parotid saliva than in plasma. Higher concentrations of IL-6 were found in parotid saliva than in plasma. IL-6, IL-6R and gp130 in parotid saliva explained the presence of bone marrow oedema and effusion in the JIA patients.

CONCLUSIONS

This study suggests that the IL-6 family in parotid saliva is associated with TMJ bone marrow oedema and effusion in patients with JIA, suggesting that IL-6 has promising properties as a parotid saliva biomarker for TMJ inflammatory activity.

The importance of ultrasound examination in care of juvenile idiopathic arthritis patients: 9 months follow-up study

Introduction

Juvenile idiopathic arthritis (JIA) is a group of rare musculoskeletal disorders with chronic inflammation of joints, typically manifesting before the age of 16 years. The assessment of disease activity remains pivotal in JIA treatment decisions, particularly during clinical remission. While musculoskeletal ultrasound (MSUS) has shown promise in detecting subclinical synovitis, longitudinal data on MSUS features in JIA remains limited. The aim of this study was to evaluate the prevalence of subclinical synovitis observed in MSUS over a follow-up period in JIA patients. Additionally, it sought to assess the consistency and correlation between clinical findings, standardized composite clinical score (JADAS10), and MSUS-detected synovitis during 9 months follow-up.

Patients and methods

a prospective single-center study was conducted, enrolling all consecutive JIA patients (excluding systemic JIA) seen at the study center in one year period. At three-months intervals over a 9 months period (M0, M3, M6 and M9), patients underwent clinical examination, laboratory tests, and MSUS assessment. Data on demographic characteristics, disease profile, and treatment were collected. Patients were categorized into active disease (ACT) or remission (REM) groups based on Wallace criteria and JADAS10 scores using previously validated thresholds. The ultrasound assessments adhered to the Outcome Measures in Rheumatology Clinical Trials (OMERACT) pediatric group, covering 40 joints, were performed by two ultrasonographers at every visit. Subclinical synovitis was defined as synovitis detected exclusively by MSUS. Spearman's correlation coefficients (rs) were used to evaluate the association between MSUS, clinical data, and outcome measures, such as active joint count (ACJ), patient's/parent's global assessment of disease activity (PaGA), physician's global assessment of disease activity (PhGA) and JADAS10.

Results

subclinical synovitis was evident in 5.2% of all joints and in 80.6% of the patients at baseline. During the follow-up period, signs of subclinical synovitis decreased to 3.8% of joints, however, the proportion of affected patients remained high (67.7%), with the majority in REM group. Despite the consistent strong correlation between PaGA and PhGA throughout the study (rs > 0.895; p < 0.001), both measures displayed moderate (rs = 0.647; p < 0.001) to weak (rs = 0.377; p = 0.04) correlations with MSUS findings. Notably, PaGA remained significantly correlated with MSUS at the M9 visit (rs = 0.377, p = 0.04), while PhGA showed no correlation (p = 0.094).

Conclusions

The study results indicate the persistence of subclinical inflammation detected by MSUS in a significant proportion of JIA patients, even during clinical remission. Moreover, the findings suggest that conventional measurements of JIA activity may be insufficient for assessing patients in clinical remission.

Quantifying hospital-associated costs, and accompanying travel costs and productivity losses, before and after withdrawing TNF-α inhibitors in juvenile idiopathic arthritis

OBJECTIVE

To quantify differences in hospital-associated costs, and accompanying travel costs and productivity losses, before and after withdrawing TNF-α inhibitors (TNFi) in JIA patients.

METHODS

This was a retrospective analysis of prospectively collected data from electronic medical records of paediatric JIA patients treated with TNFi, which were immediately discontinued, spaced (increased treatment interval) or tapered (reduced subsequent doses). Costs of hospital-associated resource use (consultations, medication, radiology procedures, laboratory testing, procedures under general anaesthesia, hospitalization) and associated travel costs and productivity losses were quantified during clinically inactive disease until TNFi withdrawal (pre-withdrawal period) and compared with costs during the first and second year after withdrawal initiation (first and second year post-withdrawal).

RESULTS

Fifty-six patients were included of whom 26 immediately discontinued TNFi, 30 spaced and zero tapered. Mean annual costs were €9165/patient on active treatment (pre-withdrawal) and decreased significantly to €5063/patient (-44.8%) and €6569/patient (-28.3%) in the first and second year post-withdrawal, respectively (P < 0.05). Of these total annual costs, travel costs plus productivity losses were €834/patient, €1180/patient, and €1320/patient in the three periods respectively. Medication comprised 80.7%, 61.5% and 72.4% of total annual costs in the pre-withdrawal, first and second year post-withdrawal period, respectively.

CONCLUSION

In the first two years after initiating withdrawal, the total annual costs were decreased compared with the pre-withdrawal period. However, cost reductions were lower in the second year compared with the first year post-withdrawal, primarily due to restarting or intensifying biologics. To support biologic withdrawal decisions, future research should assess the full long-term societal cost impacts, and include all biologics.

Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in children. The International League of Associations for Rheumatology (ILAR) has defined JIA as "arthritis of unknown etiology persisting for ≥6 wk with an onset at <16 y of age, after excluding other causes of joint inflammation". Synovial inflammation is the result of a complex interplay of aberrant immune systems (both adaptive and innate) in a genetically susceptible individual, with possible external stimuli/triggers. Diagnosis of JIA essentially remains clinical, and laboratory investigations usually help to assess the severity of disease activity. Few investigations like antinuclear antibodies (ANA), human leukocyte antigen (HLA)-B27, and rheumatoid factor (RF) help to categorize or prognosticate a child with JIA. Timely use of effective therapeutic interventions including biological has shown good long-term outcomes of JIA.

Incidence of juvenile idiopathic arthritis in Finland, 2000-2020

OBJECTIVE

Previous epidemiological data of JIA in Finland are from the turn of the millennium. We aimed to determine the recent annual incidence of JIA in several consecutive years in Finland and to explore the differences in incidence between sexes, age groups and regions.

METHODS

We analysed all children <16 years of age who met the ILAR classification criteria for JIA. Cases from 2000-2020 were identified from two national registers: the Care Register for Health Care of the Finnish Institute for Health and Welfare and the Reimbursement Register containing medication data from the Social Insurance Institution of Finland; cases from 2016-2020 were identified from the Finnish Rheumatology Quality Register.

RESULTS

The incidence of JIA was 31.7 per 100 000 (95% CI 30.2, 33.1), according to the Care Register in 2000-2020 and peaked in 2010-2014. No considerable differences in incidence rates were observed among registers. In all age groups, incidence in girls was predominant compared with boys. The incidence in girls peaked at the ages of 2 years and 14-15 years. Decreasing incidence was observed among boys 0-3 years old during the entire study period, whereas increasing incidence was observed among teenage girls and boys 4-7 years old in 2000-2013.

CONCLUSION

The incidence of JIA is not only very high with respect to that in other parts of the world but also higher than previously reported in Finland. The incidence varied by region and year but was not higher at the end than the beginning of the study period.

A lifelong journey: Long-term perspectives on Juvenile Idiopathic Arthritis

Juvenile Idiopathic Arthritis (JIA) represents a diverse group of chronic inflammatory conditions that begin in childhood or adolescence and continue into adulthood, with varying severity and outcomes. This review discusses the complexities of transitioning JIA patients emphasizing that inadequate transition from pediatric to adult care leads to loss of follow-up, treatment discontinuation, and increased disease activity. Furthermore, challenges in disease classification hinder continuity of care across lifespan. It is also pointed out that predicting long-term outcomes in JIA remains complex due to heterogeneity and evolving phenotypes. Factors such as disease category, joint involvement, and treatment influence disease activity, functional disability, and quality of life. Despite advancements in treatment strategies, a substantial proportion of patients experience long-term disability and joint damage. Finally, it is underscored that optimising long-term outcomes in adults with JIA requires a multifaceted approach encompassing structured transition processes, personalised treatment strategies, and comprehensive management of comorbidities. Further research is needed to refine predictive models, enhance disease monitoring tools, and understand the complex interplay between disease activity, treatment response, and long-term outcomes.

Safety and effectiveness of abatacept in juvenile idiopathic arthritis: results from the PRINTO/PRCSG registry

OBJECTIVE

The aim of this study was to report the interim 5-year safety and effectiveness of abatacept in patients with JIA in the PRINTO/PRCSG registry.

METHODS

The Abatacept JIA Registry (NCT01357668) is an ongoing observational study of children with JIA receiving abatacept; enrolment started in January 2013. Clinical sites enrolled patients with JIA starting or currently receiving abatacept. Eligible patients were assessed for safety (primary end point) and effectiveness over 10 years. Effectiveness was measured by clinical 10-joint Juvenile Arthritis Disease Activity Score (cJADAS10) in patients with JIA over 5 years. As-observed analysis is presented according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.

RESULTS

As of 31 March 2020, 587 patients were enrolled; 569 are included in this analysis (including 134 new users) with 1214.6 patient-years of safety data available. Over 5 years, the incidence rate (IR) per 100 patient-years of follow-up of serious adverse events was 5.52 (95% CI: 4.27, 7.01) and of events of special interest was 3.62 (95% CI: 2.63, 4.86), with 18 serious infections [IR 1.48 (95% CI: 0.88, 2.34)]. As early as month 3, 55.9% of patients achieved cJADAS10 low disease activity and inactive disease (20.3%, 72/354 and 35.6%, 126/354, respectively), sustained over 5 years. Disease activity measures improvement over 5 years across JIA categories.

CONCLUSION

Abatacept was well tolerated in patients with JIA, with no new safety signals identified and with well-controlled disease activity, including some patients achieving inactive disease or remission.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT01357668.

Increased neutrophil extracellular trap formation in oligoarticular, polyarticular juvenile idiopathic arthritis and enthesitis-related arthritis: biomarkers for diagnosis and disease activity

Objective

Neutrophil extracellular traps (NETs) are important factors in initiating and perpetuating inflammation. However, the role of NETs in different subtypes of juvenile idiopathic arthritis (JIA) has been rarely studied. Therefore, we aimed to explore the ability of JIA-derived neutrophils to release NETs and the effect of TNF-α (tumor necrosis factor-alpha) inhibitors on NET formation both in vitro and in vivo, and evaluate the associations of NET-derived products with clinical and immune-related parameters.

Methods

The ability of neutrophils to release NETs and the effect of adalimumab on NET formation was assessed via in vitro stimulation and inhibition studies. Plasma NET-derived products were detected to assess the incidence of NET formation in vivo. Furthermore, flow cytometry and western blotting were used to detect NET-associated signaling components in neutrophils.

Results

Compared to those derived from HCs, neutrophils derived from patients with oligoarticular-JIA, polyarticular-JIA and enthesitis-related arthritis were more prone to generate NETs spontaneously and in response to TNF-α or PMA in vitro. Excessive NET formation existed in peripheral circulation of JIA patients, and elevated plasma levels of NET-derived products (cell-free DNA and MPO-DNA complexes) could accurately distinguish JIA patients from HCs and were positively correlated with disease activity. Multiple linear regression analysis showed that erythrocyte sedimentation rate and TNF-α levels were independent variables and were positively correlated with cell-free DNA concentration. Notably, TNF-α inhibitors could effectively prevent NET formation both in vitro and in vivo. Moreover, the phosphorylation levels of NET-associated kinases in JIA-derived neutrophils were markedly increased.

Conclusion

Our data suggest that NETs might play pathogenic roles and may be involved in TNF-α-mediated inflammation in JIA. Circulating NET-derived products possess potential diagnostic and disease monitoring value. Furthermore, the preliminary results related to the molecular mechanisms of NET formation in JIA patients provide a theoretical basis for NET-targeted therapy.

Integrative analysis reveals novel insights into juvenile idiopathic arthritis pathogenesis and shared molecular pathways with associated traits

Background

Juvenile idiopathic arthritis (JIA) is an autoimmune joint disease that frequently co-occurs with other complex phenotypes, including cancers and other autoimmune diseases. Despite the identification of numerous risk variants through genome-wide association studies (GWAS), the affected genes, their connection to JIA pathogenesis, and their role in the development of associated traits remain unclear. This study aims to address these gaps by elucidating the gene-regulatory mechanisms underlying JIA pathogenesis and exploring its potential role in the emergence of associated traits.

Methods

A two-sample Mendelian Randomization (MR) analysis was conducted to identify blood-expressed genes causally linked to JIA. A curated protein interaction network was subsequently used to identify sets of single-nucleotide polymorphisms (i.e., spatial eQTL SNPs) that regulate the expression of JIA causal genes and their protein interaction partners. These SNPs were cross-referenced against the GWAS catalog to identify statistically enriched traits associated with JIA.

Results

The two-sample MR analysis identified 52 genes whose expression changes in the blood are putatively causal for JIA. These genes (e.g., HLA, LTA, LTB, IL6ST) participate in a range of immune-related pathways (e.g., antigen presentation, cytokine signalling) and demonstrate cell type-specific regulatory patterns across different immune cell types (e.g., PPP1R11 in CD4+ T cells). The spatial eQTLs that regulate JIA causal genes and their interaction partners were statistically enriched for GWAS SNPs linked with 95 other traits, including both known and novel JIA-associated traits. This integrative analysis identified genes whose dysregulation may explain the links between JIA and associated traits, such as autoimmune/inflammatory diseases (genes at 6p22.1 locus), Hodgkin lymphoma (genes at 6p21.3 [FKBPL, PBX2, AGER]), and chronic lymphocytic leukemia (BAK1).

Conclusion

Our approach provides a significant advance in understanding the genetic architecture of JIA and associated traits. The results suggest that the burden of associated traits may differ among JIA patients, influenced by their combined genetic risk across different clusters of traits. Future experimental validation of the identified connections could pave the way for refined patient stratification, the discovery of new biomarkers, and shared therapeutic targets.

Glutathione S-Transferase Gene Polymorphisms as Predictors of Methotrexate Efficacy in Juvenile Idiopathic Arthritis

Because of the unpredictable efficacy of methotrexate (MTX) in the treatment of juvenile idiopathic arthritis (JIA), the possibility of a favourable outcome is reduced in more than 30% of patients. To investigate the possible influence of glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) gene deletion polymorphisms on MTX efficacy in patients with JIA, we determined these polymorphisms in 63 patients with JIA who did not achieve remission and 46 patients with JIA who achieved remission during MTX therapy. No significant differences were observed in the distribution of single GSTM1 or GSTT1 deletion polymorphisms or their combination between the two groups: 58.7% to 63.5%; p = 0.567, 17.4% to 22.2%; p = 0.502, and 13% to 12.7%; p = 0.966, respectively. Our results suggest that GSTM1 and GSTT1 deletion polymorphisms do not influence the efficacy of MTX in patients with JIA. Additional studies are required to determine the possible influence of GST deletion polymorphisms on MTX efficacy in patients with JIA.

Causal association of juvenile idiopathic arthritis or JIA-associated uveitis and gut microbiota: a bidirectional two-sample Mendelian randomisation study

Background

The gut microbiota significantly influences the onset and progression of juvenile idiopathic arthritis (JIA) and associated uveitis (JIAU); however, the causality remains unclear. This study aims to establish a causal link between gut microbiota and JIA or JIAU.

Methods

Using publicly available genome-wide association studies (GAWS) summary data, we conducted a two-sample Mendelian randomisation (MR) analysis employing various methods, namely inverse variance weighted (IVW), simple mode, weighted mode, weighted median and MR-Egger regression methods, to assess the causal association between JIA or JIAU and gut microbiota. Sensitivity analyses, including Cochrane's Q test, MR-Egger intercept test, leave-one-out analysis and MR-PRESSO, were performed to evaluate the robustness of the MR results. Subsequently, reverse MR analysis was conducted to determine causality between gene-predicted gut microbiota abundance and JIA or JIAU.

Results

The MR analysis revealed a causal association between gut microbiota abundance variations and JIA or JIAU risk. Specifically, the increased abundance of genus Ruminococcaceae UCG013 (OR: 0.055, 95%CI: 0.006-0.103, p = 0.026) and genus Ruminococcaceae UCG003 (β: 0.06, 95%CI: 0.003-0.117, p = 0.041) correlated with an increased risk of JIA, while genus Lachnospiraceae UCG001 (OR: 0.833, 95%CI: 0.699~0.993, p = 0.042) was associated with a reduced risk of JIA, among others. Sensitivity analysis confirmed MR analysis robustness.

Conclusions

This study provides substantial evidence supporting a causal association between genetically predicted gut microbiota and JIA or JIAU. It highlights the significant role of intestinal flora in JIA or JIAU development, suggesting their potential as novel biomarkers for diagnosis and prevention. These findings offer valuable insights to mitigate the impact of JIA or JIAU.

Research progress of T cell autophagy in autoimmune diseases

T cells, as a major lymphocyte population involved in the adaptive immune response, play an important immunomodulatory role in the early stages of autoimmune diseases. Autophagy is a cellular catabolism mediated by lysosomes. Autophagy maintains cell homeostasis by recycling degraded cytoplasmic components and damaged organelles. Autophagy has a protective effect on cells and plays an important role in regulating T cell development, activation, proliferation and differentiation. Autophagy mediates the participation of T cells in the acquired immune response and plays a key role in antigen processing as well as in the maintenance of T cell homeostasis. In autoimmune diseases, dysregulated autophagy of T cells largely influences the pathological changes. Therefore, it is of great significance to study how T cells play a role in the immune mechanism of autoimmune diseases through autophagy pathway to guide the clinical treatment of diseases.

Population Pharmacokinetics of Adalimumab in Juvenile Idiopathic Arthritis Patients: A Retrospective Cohort Study Using Clinical Care Data

BACKGROUND AND OBJECTIVE

Juvenile idiopathic arthritis (JIA) is a chronic autoimmune disorder that primarily affects the joints in children. Notably, it is known to co-occur with uveitis. Adalimumab, a monoclonal anti-TNF antibody, is effective in treating both conditions. A deeper understanding of the pharmacokinetics (PK) of adalimumab in JIA is crucial to advance in more personalized treatment approaches. The objective of this study is to evaluate the population PK profile of adalimumab in JIA and to explain causes for its variability.

MATERIALS AND METHODS

Adalimumab and antidrug antibody concentrations were retrospectively retrieved from the charts of patients with JIA. Initially, five literature-based population PK models of adalimumab were evaluated to assess their ability to describe the observed concentration-time profiles in the JIA cohort. These models included one specifically for the pediatric Crohn's disease population and four derived from studies in adult populations in healthy subjects and rheumatoid arthritis patients. Subsequently, a novel population PK model tailored to the JIA population was developed using NONMEM software. Monte Carlo simulations were then conducted utilizing the final PK model to visualize the concentration-time profile of adalimumab in patients with JIA and the impact of covariates.

RESULTS

A cohort of 50 patients with JIA with 78 available adalimumab samples was assessed. The mean age was 11.8 ± 3.9 years, with a median body weight of 49 kg (interquartile range 29.4-59.8 kg). All literature models adequately described the concentration-time profiles in JIA. The best model, which was developed in patients with rheumatoid arthritis during the maintenance phase of treatment, served as a basis for estimating clearance in JIA, resulting in a value of 0.37 L per day per 70 kg. Patient body weight, antidrug antibodies, methotrexate use, CRP level, and comorbidity of uveitis were found to have a significant impact on adalimumab clearance, and these reduced the inter-patient variability from 58.6 to 28.0%. On steady state in the simulated patient population, the mean trough level was 7.4 ± 5.5 mg/L. The two dosing regimens of 20 and 40 mg every other week, based on patients' body weight, resulted in comparable simulated overall drug exposure.

CONCLUSIONS

Five literature models effectively described adalimumab PK in this pediatric cohort, highlighting the potential for extrapolating existing models to the pediatric population. The new JIA model confirmed the effect of several known covariates and found a novel association for drug clearance with methotrexate use (lower) and uveitis (higher), which might have clinical relevance for personalized dosing in JIA.

Connective tissue disease-associated lung disease in children

Connective tissue diseases are a heterogeneous group of autoimmune diseases that can affect a variety of organ systems. Lung parenchymal involvement is an important contributor to morbidity and mortality in children with connective tissue disease. Connective tissue disease-associated lung disease in children often manifests as one of several radiologic-pathologic patterns of disease, with certain patterns having a propensity to occur in association with certain connective tissue diseases. In this article, key clinical, histopathologic, and computed tomography (CT) features of typical patterns of connective tissue disease-associated lung disease in children are reviewed, with an emphasis on radiologic-pathologic correlation, to improve recognition of these patterns of lung disease at CT and to empower the pediatric radiologist to more fully contribute to the care of pediatric patients with these conditions.

A population pharmacokinetic model using allometric scaling for baricitinib in patients with juvenile idiopathic arthritis

Baricitinib is approved for the treatment of rheumatoid arthritis (RA) in more than 70 countries, and juvenile idiopathic arthritis (JIA) in the European Union. Population pharmacokinetic (PK) models were developed in a phase 3 trial to characterize PK in pediatric patients with JIA and identify weight-based dosing regimens. The phase 3, randomized, double-blind, placebo-controlled withdrawal, efficacy and safety trial, JUVE-BASIS, enrolled patients (aged 2 to <18 years) with polyarticular course JIA. During a safety/PK period, baricitinib concentration data from age-based dose cohorts were compared to concentrations from adult patients receiving 4-mg QD. PK data were used to develop a population PK model with allometric scaling to determine a weight-based posology in pediatric patients with JIA that matched the adult 4-mg exposure. Baricitinib plasma concentrations from 217 pediatric patients were used to characterize PK. Based on the adult model, pediatric PK was best described using a 2-compartment model with allometric scaling on clearance and volume of distribution and renal function (estimated with glomerular filtration rate [GFR], a known covariate affecting PK of baricitinib) on clearance. The PK modeling suggested the optimal dosing regimen based on weight for pediatric patients as: 2-mg QD for patients 10 to <30 kg and 4-mg QD for patients ≥30 kg. The use of a population PK model of baricitinib treatment in adult patients with RA, with the addition of allometric scaling for weight on clearance and volume terms, was useful to predict exposures and identify weight-based dosing in pediatric patients with JIA.

The Juvenile Arthritis Quality of Life Questionnaire in patients with juvenile idiopathic arthritis: Turkish version, validity, and reliability study

INTRODUCTION

This study aimed to assess the cultural adaptation, validity, and reliability of the Turkish version of the Juvenile Arthritis Quality of Life Questionnaire (JAQQ) in patients with juvenile idiopathic arthritis (JIA).

METHODS

A total of 100 JIA patients (64% female), aged 9 to 18 years, participated in the study conducted at a tertiary care university hospital. The JAQQ was culturally adapted through a rigorous translation process and administered alongside established measures, including the Childhood Health Assessment Questionnaire (CHAQ), Juvenile Arthritis Biopsychosocial Questionnaire (JABQ), and Children's Depression Inventory (CDI). Validity and reliability were evaluated using Spearman's correlation coefficients, Cronbach's alpha, intraclass correlation coefficient (ICC), standard error of the mean (SEM), and minimal detectable change (MDC).

RESULTS

The Turkish version of JAQQ exhibited high convergent validity, correlating significantly with CHAQ, JABQ, and CDI. No floor or ceiling effects were observed in the total JAQQ score, indicating a balanced assessment. Internal consistency was excellent (Cronbach's α = 0.948), and test-retest reliability was satisfactory (ICC = 0.913). SEM and MDC95 values were 0.357 and 0.99, respectively.

CONCLUSIONS

The Turkish adaptation of JAQQ emerges as a valid and reliable instrument for comprehensively assessing the health-related quality of life in children and adolescents diagnosed with JIA. The questionnaire's robust psychometric properties, coupled with distinctive features like individualized assessment, highlight its potential as a valuable tool for both clinical assessment and scientific research in the field of pediatric rheumatology. Key Points • The Juvenile Arthritis Quality of Life Questionnaire (JAQQ) is an important scale that evaluates the quality of life of children with Juvenile Idiopathic Arthritis (JIA). • JAQQ is known and used in the field of pediatric rheumatology in Turkey, but its Turkish adaptation has not been made before. • Our study includes 100 JIA patients aged between 9 and 18 years and shows that the Turkish version of JAQQ is valid and reliable in measuring the quality of life of these children. • This research contributes to the accurate assessment of the quality of life in Turkish children diagnosed with JIA, providing valuable insights for both clinical and scientific studies.