Associations of clinical and inflammatory biomarker clusters with juvenile idiopathic arthritis categories

Peripheral blood regulatory T cells and disease activity, quality of life, and outcomes in children with juvenile idiopathic arthritis

OBJECTIVES

To measure regulatory T cell (Treg) levels in the peripheral blood of children with juvenile idiopathic arthritis (JIA) and analyse the association of this measure with disease activity, quality of life, adjustment of treatment, and hospitalisation.

METHODS

We conducted a two-phase study (cross-sectional and prospective), including consecutive children with a JIA diagnosis according to ILAR criteria. Our independent variables were Tregs, Th1, Th2, and cytokines in peripheral blood, and our dependent variables in the cross-sectional phase were arthritis category, JIA activity, and patient-reported outcomes. To test associations, we used Spearman's correlation coefficient and the Mann-Whitney U test. In the prospective phase, we explored the probability of treatment adjustment and hospitalisation for JIA during follow-up according to Tregs levels at baseline, using Cox proportional regression.

RESULTS

Our sample included 87 participants (median age 11 years, 63.2% girls). Tregs were not associated with most variables of interest. However, we found that higher Tregs concentration was associated with lower erythrocyte sedimentation rate (ESR) and better subjective disease status and course, while higher IL-10 and TGF-β levels were associated with lower ESR, less pain, and better subjective disease status We found no association between Tregs and treatment adjustments or hospitalisation.

CONCLUSIONS

Higher baseline Treg levels in the peripheral blood of children with JIA may be associated with reduced disease activity and better quality of life, though were not informative on the inflammatory progression on the follow-up.

Association of IL-17A and IL-10 Polymorphisms with Juvenile Idiopathic Arthritis in Finnish Children

To analyze the role of interleukin IL-17A and IL-10 polymorphisms in susceptibility to juvenile idiopathic arthritis (JIA), 98 Finnish children and adolescents with JIA were studied. Data from the 1000 Genomes Project, consisting of 99 healthy Finns, served as the controls. The patients were analyzed for four IL-17A and three IL-10 gene-promoter polymorphisms, and the serum IL-17A, IL-17F, IL-10, and IL-6 levels were determined. The IL-17A rs8193036 variant genotypes (CT/CC) were more common among the patients than controls, especially in those with polyarthritis (OR 1.93, 95% CI 1.11-3.36; p = 0.020). IL-17A rs2275913 minor allele A was more common in patients (OR 1.45, 95% Cl 1.08-1.94; p = 0.014) and especially among patients with oligoarthritis and polyarthritis than the controls (OR 1.61, 95%CI 1.06-2.43; p = 0.024). Carriers of the IL-17A rs4711998 variant genotype (AG/AA) had higher serum IL-17A levels than those with genotype GG. However, carriers of the variant genotypes of IL-17A rs9395767 and rs4711998 appeared to have higher IL-17F levels than those carrying wildtype. IL-10 rs1800896 variant genotypes (TC/CC) were more abundant in patients than in the controls (OR 1.97, 95%CI 1.06-3.70; p = 0.042). Carriers of the IL-10 rs1800896 variant genotypes had lower serum levels of IL-17F than those with wildtype. These data provide preliminary evidence of the roles of IL-17 and IL-10 in the pathogenesis of JIA and its subtypes in the Finnish population. However, the results should be interpreted with caution, as the number of subjects included in this study was limited.

Transcriptomic signatures of classical monocytes reveal pro-inflammatory modules and heterogeneity in polyarticular juvenile idiopathic arthritis

Introduction

Polyarticular juvenile idiopathic arthritis (pJIA) is a childhood-onset autoimmune disease. Immune cells contribute to persistent inflammation observed in pJIA. Despite the crucial role of monocytes in arthritis, the precise involvement of classical monocytes in the pathogenesis of pJIA remains uncertain. Here, we aimed to uncover the transcriptomic patterns of classical monocytes in pJIA, focusing on their involvement in disease mechanism and heterogeneity.

Methods

A total of 17 healthy subjects and 18 premenopausal women with pJIA according to ILAR criteria were included. Classical monocytes were isolated, and RNA sequencing was performed. Differential expression analysis was used to compare pJIA patients and healthy control group. Differentially expressed genes (DEGs) were identified, and gene set enrichment analysis (GSEA) was performed. Using unsupervised learning approach, patients were clustered in two groups based on their similarities at transcriptomic level. Subsequently, these clusters underwent a comparative analysis to reveal differences at the transcriptomic level.

Results

We identified 440 DEGs in pJIA patients of which 360 were upregulated and 80 downregulated. GSEA highlighted TNF-α and IFN-γ response. Importantly, this analysis not only detected genes targeted by pJIA therapy but also identified new modulators of immuno-inflammation. PLAUR, IL1B, IL6, CDKN1A, PIM1, and ICAM1 were pointed as drivers of chronic hyperinflammation. Unsupervised learning approach revealed two clusters within pJIA, each exhibiting varying inflammation levels.

Conclusion

These findings indicate the pivotal role of immuno-inflammation driven by classical monocytes in pJIA and reveals the existence of two subclusters within pJIA, regardless the positivity of rheumatoid factor and anti-CCP, paving the way to precision medicine.

Understanding the role and adoption of artificial intelligence techniques in rheumatology research: An in-depth review of the literature

The major and upward trend in the number of published research related to rheumatic and musculoskeletal diseases, in which artificial intelligence plays a key role, has exhibited the interest of rheumatology researchers in using these techniques to answer their research questions. In this review, we analyse the original research articles that combine both worlds in a five- year period (2017-2021). In contrast to other published papers on the same topic, we first studied the review and recommendation articles that were published during that period, including up to October 2022, as well as the publication trends. Secondly, we review the published research articles and classify them into one of the following categories: disease identification and prediction, disease classification, patient stratification and disease subtype identification, disease progression and activity, treatment response, and predictors of outcomes. Thirdly, we provide a table with illustrative studies in which artificial intelligence techniques have played a central role in more than twenty rheumatic and musculoskeletal diseases. Finally, the findings of the research articles, in terms of disease and/or data science techniques employed, are highlighted in a discussion. Therefore, the present review aims to characterise how researchers are applying data science techniques in the rheumatology medical field. The most immediate conclusions that can be drawn from this work are: multiple and novel data science techniques have been used in a wide range of rheumatic and musculoskeletal diseases including rare diseases; the sample size and the data type used are heterogeneous, and new technical approaches are expected to arrive in the short-middle term.

Evidence of persistent glial cell dysfunction in the anterior cingulate cortex of juvenile idiopathic arthritis children: a proton MRS study

BACKGROUND

This study aims to investigate whether the neurometabolites of the anterior cingulate cortex (ACC) were distinct in patients with active and inactive juvenile idiopathic arthritis (JIA) using the proton magnetic resonance spectroscopy.

METHODS

We measured the levels of total N-acetylaspartate (tNAA), choline (Cho), myo-inositol (ml), glutamate (Glu) and the complex of glutamate and glutamine (Glx) relative to total creatine (tCr) in ACC of each participant.

RESULTS

Compared with the healthy controls, a significant decrease of total Cho/tCr and Glx/tCr ratio in ACC occurred in active and inactive JIA group. The tCho/Cr level was negatively associated with the serum level of ESR in active JIA patients. There was no difference in NAA/tCr ratio among the three groups, which may imply that no neuron and axonal losses occurred in either active or inactive JIA patients.

CONCLUSIONS

The abnormal neurometabolites in tCho/tCr and Glx/tCr in ACC may indicate that persistent dysfunction of glial cell, while neither neuron nor axonal losses occurred in active and inactive JIA patients.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Association between high mobility group box 1 protein and juvenile idiopathic arthritis: a prospective longitudinal study

OBJECTIVE

To analyze the levels of high mobility group box 1 (HMGB1) protein on different courses of juvenile idiopathic arthritis (JIA).

METHODS

In our prospective longitudinal study, children with JIA were included with their blood samples collected at the first visit, 1-month, 3-month, and 6-month follow-up, respectively. Samples were also collected from healthy controls and children with reactive arthritis at the first visit. Levels of HMGB1 were determined using enzyme-linked immunosorbent assays. Clinical disease characteristics and routine laboratory findings were analyzed as well.

RESULTS

A total of 64 children were enrolled, of whom 31 (48.4%) were female. The median age at the first visit for participants with JIA was 9.25 years (range, 1.42-15.42) and the median duration of disease was 2.38 months (range, 1.53-49.31). Serum HMGB1 levels at the first visit were significantly elevated in children with systemic JIA compared with other groups, and so were in enthesitis-related arthritis versus healthy controls. Significant correlations were established at the first visit between HMGB1 levels and duration of disease, C-reactive protein, percentage of neutrophils, and ferritin. Data from all samples revealed that serum HMGB1 levels in JIA were significantly associated with erythrocyte sedimentation rates, C-reactive protein, percentage of neutrophils, and disease activity scores.

CONCLUSIONS

Serum HMGB1 may be associated with clinical disease activity of JIA and specifically increased at the first visit in children with systemic JIA, suggesting its function as a sensitive inflammatory marker. Further large-scale studies are warranted to explore its spectrum in JIA.

Clinical and psychosocial stress factors are associated with decline in physical activity over time in children with juvenile idiopathic arthritis

BACKGROUND

Physical activity (PA) patterns in children with juvenile idiopathic arthritis (JIA) over time are not well described. The aim of this study was to describe associations of physical activity (PA) with disease activity, function, pain, and psychosocial stress in the 2 years following diagnosis in an inception cohort of children with juvenile idiopathic arthritis (JIA).

METHODS

In 82 children with newly diagnosed JIA, PA levels, prospectively determined at enrollment, 12 and 24 months using the Physical Activity Questionnaire for Children (PAQ-C) and Adolescents (PAQ-A) raw scores, were evaluated in relation to disease activity as reflected by arthritis activity (Juvenile Arthritis Disease Activity Score (JADAS-71)), function, pain, and psychosocial stresses using a linear mixed model approach. Results in the JIA cohort were compared to normative Pediatric Bone Mineral Accrual Study data derived from healthy children using z-scores.

RESULTS

At enrollment, PA z-score levels of study participants were lower than those in the normative population (median z-score - 0.356; p = 0.005). At enrollment, PA raw scores were negatively associated with the psychosocial domain of the Juvenile Arthritis Quality of Life Questionnaire (r = - 0.251; p = 0.023). There was a significant decline in PAQ-C/A raw scores from baseline (median and IQR: 2.6, 1.4-3.1) to 24 months (median and IQR: 2.1, 1.4-2.7; p = 0.003). The linear mixed-effect model showed that PAQ-C/A raw scores in children with JIA decreased as age, disease duration, and ESR increased. The PAQ-C/A raw scores of the participants was also negatively influenced by an increase in disease activity as measured by the JADAS-71 (p <  0.001).

CONCLUSION

Canadian children with newly diagnosed JIA have lower PA levels than healthy children. The decline in PA levels over time was associated with disease activity and higher disease-specific psychosocial stress.

Biological classification of childhood arthritis: roadmap to a molecular nomenclature

Chronic inflammatory arthritis in childhood is heterogeneous in presentation and course. Most forms exhibit clinical and genetic similarity to arthritis of adult onset, although at least one phenotype might be restricted to children. Nevertheless, paediatric and adult rheumatologists have historically addressed disease classification separately, yielding a juvenile idiopathic arthritis (JIA) nomenclature that exhibits no terminological overlap with adult-onset arthritis. Accumulating clinical, genetic and mechanistic data reveal the critical limitations of this strategy, necessitating a new approach to defining biological categories within JIA. In this Review, we provide an overview of the current evidence for biological subgroups of arthritis in children, delineate forms that seem contiguous with adult-onset arthritis, and consider integrative genetic and bioinformatic strategies to identify discrete entities within inflammatory arthritis across all ages.

Recent progress in the treatment of non-systemic juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease affecting the joints and other organs that occurs in 1 in 1,000 children in the United States. Given the various categories of JIA, interpretation of the literature can be difficult. In this review, new developments in understanding non-systemic JIA and its treatment will be covered. Recent advances in the journey toward personalized treatment in JIA will be highlighted, including a review of currently available biologic modifiers. Uveitis and the temporomandibular joint will be discussed as particularly challenging treatment issues. Recent guideline updates and literature-guided treatment decisions will be reviewed.