Understanding inflammation in juvenile idiopathic arthritis: How immune biomarkers guide clinical strategies in the systemic onset subtype

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.

Factors determining resistance to conventional disease-modifying anti-rheumatic drug treatment in oligoarticular juvenile idiopathic arthritis

OBJECTIVE

Our study was designed to investigate the reasons for starting the conventional disease-modifying anti-rheumatic drugs (DMARDs) and the variables that impact the response to DMARD treatment in oligoarticular juvenile idiopathic arthritis (JIA) patients.

METHODS

Oligoarticular JIA patients (n = 187) were categorized into two groups: Group A consisted of patients who achieved remission with DMARD, and Group B comprised those who did not respond to DMARD therapy.

RESULTS

DMARDs were initiated for various reasons: 68 (36.4%) due to active disease despite nonsteroidal anti-inflammatory drugs (± intra-articular corticosteroid) treatment, 59 (31.6%) due to uveitis, 49 (26.2%) due to extended oligoarticular JIA, and 11 (5.9%) due to inflammatory bowel disease. One hundred twenty-three patients (65.8%) achieved remission with DMARDs (Group A), while 64 patients (34.2%) did not respond to DMARD therapy (Group B). In Group B, patients had higher C-reactive protein (CRP) levels as well as higher Juvenile Idiopathic Arthritis Disease Activity Scores-71 (JADAS-71) at diagnosis (both p < 0.001). Moreover, extended oligoarticular JIA subtype (p = 0.017) and involvement of small joints at diagnosis (p = 0.043) were more prevalent among these patients. Group A exhibited a higher frequency of antinuclear antibody positivity (p = 0.014). Elevated CRP levels (> 1.1 mg/dL) (OR 1.308, 95% CI 1.203-3.574; p < 0.001) and high JADAS-71 at diagnosis (> 15.8) (OR 1.659, 95% CI 1.179-2.941; p < 0.001) were associated with DMARD resistance.

CONCLUSION

Elevated CRP and high JADAS-71 at diagnosis were the main factors associated with DMARD resistance in oligoarticular JIA. Prospective long-term studies may help verify the role of these factors associated with DMARD resistance in oligoarticular JIA. Key Points • Conventional DMARDs were most commonly started due to active disease despite NSAID (± intra-articular corticosteroids). • Remission was achieved with DMARD in 65.8% of oligoarticular JIA patients. • Elevated CRP and high JADAS-71 at diagnosis were associated with DMARD resistance.

Bone health and physical activity in adolescents with juvenile idiopathic arthritis: a cross-sectional case-control study

BACKGROUND

Adolescents with juvenile idiopathic arthritis (JIA) tend to engage in less physical activity than their typically developing peers. Physical activity is essential for bone development and reduced physical activity may detrimentally effect bone health. Thus, we examined differences in total body bone mineral content (BMC) and areal bone mineral density (aBMD) between adolescents with JIA and adolescent controls without JIA. We also examined associations between moderate-to-vigorous physical activity (MVPA), lean mass, and bone outcomes.

METHODS

Participants included 21 adolescents with JIA (14 females, 7 males) and 21 sex- and age-matched controls aged 10-20 years. Assessments included: height; weight; triple-single-leg-hop distance (TSLH); MVPA by accelerometry; and total body BMC, aBMD, and lean mass measured using dual X-ray absorptiometry. Height-adjusted z-scores were calculated for BMC and aBMD and used for all analyses. Multiple linear mixed effects models examined group differences in BMC and aBMD, adjusting for sex, maturity, MVPA, TSLH, and lean mass. Participants clusters, based on sex and age (within 18 months), were considered random effects.

RESULTS

Adolescents with JIA had lower total body aBMD z-scores [β (95% CI); -0.58 (-1.10 to -0.07), p = 0.03] and BMC z-scores [-0.47 (-0.91 to -0.03), p = 0.04] compared with controls. Mean daily MVPA was 22.0 min/day lower in adolescents with JIA than controls; however, MVPA was not associated with aBMD [-0.01 (-0.01 to 0.01), p = 0.32] or BMC [0.00 (-0.01 to 0.00), p = 0.39]. Lean mass was positively associated with aBMD [0.05 (0.01 to 0.09) g/cm2, p = 0.03] and BMC [0.06 (0.03 to 0.10) g, p < 0.001].

CONCLUSION

Adolescents with JIA had lower total body aBMD and BMC compared with sex- and age-matched controls without JIA. Group differences in bone outcomes were not associated with the lower MVPA participation of adolescents with JIA. Despite this, physical activity should still be encouraged as it promotes physical well-being.

Evaluating the Diagnostic Performance of Systemic Immune-Inflammation Index in Childhood Inflammatory Arthritis: A Focus on Differentiating Juvenile Idiopathic Arthritis from Reactive Arthritis

In pediatric care, the range of potential diagnoses for arthritis can be relatively extensive, primarily involving infectious and inflammatory causes and, to a lesser extent, oncological conditions. Specifically, when addressing inflammatory causes, differentiating between Juvenile Idiopathic Arthritis (JIA) and Reactive Arthritis (ReA) can prove to be challenging during the first weeks, owing to the lack of specific antibodies in several JIA subtypes. This single-center retrospective study of 108 children with arthritis aimed to evaluate in greater detail the complete blood count (CBC) profiles of children with JIA and ReA in greater detail. The most significant differences were noted in terms of the Systemic Immune-Inflammation Index (SII), with higher values in the JIA group. Moreover, within the JIA group, SII displayed a significant positive correlation with conventional inflammatory biomarkers, specifically C-reactive protein (ρ = 0.579) and Erythrocyte Sedimentation Rate (ρ = 0.430). It was the only independent factor associated with the presence of JIA after adjusting for age (p = 0.030). Also, even with the moderate diagnostic value, the discriminating capacity of SII was superior to those of each of its component CBC parameters according to receiver operating characteristic (ROC) analysis. In summary, this study identified elevated SII values in the JIA group compared to the ReA group, indicating the potential utility of SII as an adjuvant discriminatory marker between these two arthritis forms.

Patients with Systemic Juvenile Idiopathic Arthritis (SJIA) Show Differences in Autoantibody Signatures Based on Disease Activity

Systemic juvenile idiopathic arthritis (SJIA) is a severe rheumatic disease in children. It is a subgroup of juvenile idiopathic arthritis (JIA; MIM #604302), which is the most common rheumatic disease in children. The diagnosis of SJIA often comes with a significant delay, and the classification between autoinflammatory and autoimmune disease is still discussed. In this study, we analyzed the immunological responses of patients with SJIA, using human proteome arrays presenting immobilized recombinantly expressed human proteins, to analyze the involvement of autoantibodies in SJIA. Results from group comparisons show several differentially reactive antigens involved in inflammatory processes. Intriguingly, many of the identified antigens had a high reactivity against proteins involved in the NF-κB pathway, and it is also notable that many of the detected DIRAGs are described as dysregulated in rheumatoid arthritis. Our data highlight novel proteins and pathways potentially dysregulated in SJIA and offer a unique approach to unraveling the underlying disease pathogenesis in this chronic arthropathy.

Uric acid could be a marker of cardiometabolic risk and disease severity in children with juvenile idiopathic arthritis

In addition to disease-specific complications, juvenile idiopathic arthritis (JIA) has been linked to metabolic impairments in adults. Recent data supported the usefulness of uric acid (UA) as risk factor for cardiometabolic derangements. Given the lack of pediatric evidence in this field, we aimed to explore this association in a cohort of children diagnosed with JIA. We retrospectively evaluated 113 children diagnosed with JIA classified according to the International League of Association for Rheumatology (ILAR) criteria attending our Rheumatology Clinic. Both clinical and biochemical assessments were performed. Participants were stratified in four groups according to quartiles of serum UA. Disease activity was calculated by the Juvenile Arthritis Disease Activity Score 10 (JADAS-10) joint reduced count, and cut-offs for disease states were applied. Patients belonging to the highest UA quartile showed higher serum triglycerides, total cholesterol, creatinine, and glucose levels (p = 0.01, p = 0.025, p = 0.04, and p = 0.005, respectively) and lower HDL cholesterol values (p < 0.0001) than subjects belonging to the lowest quartiles. Ferritin, erythrocyte sedimentation rate levels, and age at disease onset did not significantly differ across UA quartiles (all p > 0.05). As activity disease index, JADAS-10 score significantly increased across UA quartiles (p = 0.009).

CONCLUSION

Children with JIA presented with a worse cardiometabolic profile and a greater disease severity across UA quartiles. Our findings suggest that in clinical practice, UA might represent a useful marker of cardiometabolic risk and disease severity in children with JIA.

WHAT IS KNOWN

• JIA has been linked to metabolic derangements in adulthood. • UA has been recognized as a marker of cardiometabolic risk both in adults and children.

WHAT IS NEW

• Children with JIA belonging to the highest UA quartile showed a worse cardiometabolic profile and a greater disease severity. • UA might represent a helpful marker not only of cardiometabolic risk but also of disease severity in children with JIA.

Novel biomarkers for prediction of outcome and therapeutic response in juvenile idiopathic arthritis

INTRODUCTION

The search for biomarkers in juvenile idiopathic arthritis (JIA) is a promising and rapidly expanding field of investigation. The biomarkers identified so far may help to dissect the clinical heterogeneity of the illness, measure the level of disease activity, predict clinical remission, relapse, response to medications, course over time, complications, and forestall disease flares.

AREAS COVERED

We provide a summary of the most recent advances in the development and application of biomarkers in JIA. We performed a PubMed search for significant articles combining predetermined keywords related to biomarkers in non-systemic and systemic JIA, chronic uveitis, and macrophage activation syndrome (MAS). The biomarkers available or under study are presented and discussed separately for non-systemic and systemic subtypes and for the two main disease complications, uveitis and MAS.

EXPERT OPINION

The incorporation of valid and reliable biomarkers in standard clinical care may help to design better patient-tailored treatment regimens and to improve the therapeutic strategies based on the treat-to-target approach. The establishment of biomarkers that predict the risk of disease flare may lead to define the optimal modalities for treatment discontinuation after the achievement of clinical remission.

Juvenile idiopathic arthritis of the temporomandibular joint - no longer the forgotten joint

Juvenile idiopathic arthritis (JIA) of the temporomandibular joint (TMJ) is common in children, with an increasing awareness of the condition in all healthcare professionals. TMJ involvement presents a challenge in both diagnosis and treatment, as late presentation can still occur as the disease often develops asymptomatically. This can result in facial deformity and/or functional difficulties including obstructive sleep apnoea. Early diagnosis is therefore essential, requiring a high index of clinical suspicion coupled with the judicious use of gadolinium contrast magnetic resonance imaging (MRI). Long-term management is best provided by a multidisciplinary team as patients often need a combination of pharmacological management, surgical interventions, orthodontics, and psychological support. End stage deformity can be treated by different surgical options, each with their own risks and benefits, however recently there is increasing recognition for the role of total alloplastic TMJ replacement. This review focuses on the diagnosis and management of TMJ arthritis and aims to highlight the important role of maxillofacial surgeons in JIA treatment.

Efficacy and Safety of Abatacept, Adalimumab, and Etanercept in Pediatric Patients With Juvenile Idiopathic Arthritis

OBJECTIVE

The lack of randomized controlled trials comparing biologics for the treatment of juvenile idiopathic arthritis (JIA) has led to wide variation in treatment approaches. The objective of this study is to compare the efficacy and safety of abatacept, adalimumab, and etanercept in JIA patients treated at a tertiary pediatric institution.

METHODS

This was a single-center, retrospective chart review of patients initiated on abatacept, adalimumab, or etanercept from December 1, 2015, to August 31, 2018, at Monroe Carell Jr. Children's Hospital at Vanderbilt (VCH). The primary outcome was the change in the Physician Global Assessment (PGA) score after 4 to 6 months of biologic therapy. Secondary outcomes included change in laboratory markers of JIA disease activity, change in the number of joints with active disease or limitation of motion, reduction in corticosteroid dose, adverse effects, adherence among patients who have their medications filled at the institution's specialty pharmacy, and reason for discontinuation of therapy.

RESULTS

A total of 139 patients were included, with a median age of 13 years. Most patients, 80.6%, experienced a reduction in their PGA score after starting biologic therapy. There was not a statistically significant difference among the agents (p = 0.64). Adverse effects were reported in only 26.6% of patients, with the most frequent being injection site reactions or pain (n = 35). Ultimately, 32% of patients discontinued biologic therapy with a lack of efficacy being the most common reason.

CONCLUSIONS

Abatacept, adalimumab, and etanercept were not significantly different in efficacy and safety for the treatment of JIA at this single institution.

Suppression of lncRNA MALAT1 reduces pro-inflammatory cytokines production by regulating miR-150-5p/ZBTB4 axis through JAK/STAT signal pathway in systemic juvenile idiopathic arthritis

Systemic juvenile idiopathic arthritis (sJIA) is a common chronic disease occurring in children. Increasing studies have demonstrated that long noncoding RNAs (lncRNAs) play important roles in the pathogenesis of diverse human diseases. This study aimed to explore the role of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and its mechanism in sJIA. We found that the expression of MALAT1, the plasma level of pro-inflammatory cytokines (IL-6, IL-17, IL-1β, and TNF-α) as well as MMP-8 and MMP-9 production were significantly elevated in sJIA patients. Moreover, we observed that the production of these cytokines in peripheral blood mononuclear cells (PBMCs) from sJIA patients were reduced after MALAT1 knockdown. Furthermore, bioinformatics analysis predicted that MALAT1 might bind to miR-150-5p and ZBTB4 was a downstream target gene of miR-150-5p. Besides, rescue assays revealed that MALAT1 knockdown-mediated suppressive effects on cytokine production could be reversed by ZBTB4 overexpression. In addition, MALAT1 activated the JAK/STAT signaling by upregulating ZBTB4 expression. In summary, our findings demonstrated that MALAT1 promoted pro-inflammatory cytokine and MMP production by targeting the miR-150-5p/ZBTB4 axis through JAK/STAT signaling pathway in sJIA, suggesting that MALAT1 may have a potential diagnostic biomarker for the pathogenesis and therapy of sJIA.

Inflammasomes and Childhood Autoimmune Diseases: A Review of Current Knowledge

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

Roles of Interactions Between Toll-Like Receptors and Their Endogenous Ligands in the Pathogenesis of Systemic Juvenile Idiopathic Arthritis and Adult-Onset Still's Disease

Systemic juvenile idiopathic arthritis (JIA) and adult-onset Still’s disease (AOSD) are systemic inflammatory disorders that manifest as high-spiking fever, joint pain, evanescent skin rash, and organomegaly. Their pathogenesis is unclear, but inflammation is triggered by activation of the innate immune system with aberrant production of proinflammatory cytokines. Along with extrinsic factors, intrinsic pathways can trigger an unexpected immune response. Damage-associated molecular patterns (DAMPs) induce the activation of innate immune cells, leading to sterile inflammation in systemic JIA and AOSD. These endogenous proteins interact with Toll-like receptors (TLRs), which are pattern recognition receptors, and mediate immune signaling following stimulation by pathogen-associated molecular patterns and DAMPs. Several DAMPs, such as S100 proteins, play a role in the development or severity of systemic JIA and AOSD, in which their interactions with TLRs are altered. Also, the expression levels of genes encoding DAMPs contribute to the susceptibility to systemic JIA and AOSD. Herein, we review reports that TLR and DAMP signaling initiates and/or maintains the inflammatory response in systemic JIA and AOSD, and their correlations with the clinical characteristics of those diseases. In addition, we assess their utility as biomarkers or therapeutics for systemic JIA and AOSD.

Immature neutrophil signature associated with the sexual dimorphism of systemic juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is a group of inflammatory conditions of unknown etiology whose incidence is sex dependent. Although several studies have attempted to identify JIA-related gene signatures, none have systematically assessed the impact of sex on the whole blood transcriptomes of JIA patients. By analyzing over 400 unique pediatric gene expression profiles, we characterized the sexual differences in leukocyte composition of systemic JIA patients and identified sex-specific gene signatures that were related to immature neutrophils. Female systemic JIA patients presented higher activation of immature neutrophil-related genes compared to males, and these genes were associated with the response to IL-1 receptor blockade treatment. Also, we found that this immature neutrophil signature is sexually dimorphic across human lifespan and in adults with rheumatoid arthritis and asthma. These results suggest that neutrophil maturation is sexually dimorphic in rheumatic inflammation, and that this may impact disease progression and treatment.

Functional Ability and Health-Related Quality of Life in Randomized Controlled Trials of Tocilizumab in Patients With Juvenile Idiopathic Arthritis

OBJECTIVE

To evaluate changes in health-related quality of life (HRQoL) and disability in children with systemic juvenile idiopathic arthritis (JIA) or polyarticular JIA treated with tocilizumab.

METHODS

Secondary analyses of two double-blind, placebo-controlled trials of intravenous tocilizumab in children with active systemic JIA or polyarticular JIA were conducted. Patient-reported outcomes of disability (Childhood Health Assessment Questionnaire [C-HAQ]), HRQoL (Child Health Questionnaire Parent Form 50 [CHQ-P50], health concepts, physical summary score [CHQ-P50-PhS], psychosocial summary score [CHQ-P50-PsS]), pain, and well-being (100-mm visual analog scale [VAS]) were measured at weeks 0 and 12 for systemic JIA, weeks 16 and 40 for polyarticular JIA, and week 104 for both JIA subgroups.

RESULTS

The trial included 112 patients with systemic JIA and 188 patients with polyarticular JIA. In patients with polyarticular JIA, the mean ± SD C-HAQ score decreased from 1.39 ± 0.74 at baseline to 0.67 ± 0.65 at week 16 (P < 0.001). In patients with systemic JIA, the mean ± SD CHQ-P50-PhS improved more with tocilizumab therapy than with placebo at week 12 (7.3 ± 10.2 versus 2.4 ± 10.6) (P < 0.05). Almost all mean CHQ-P50 health concept scores, CHQ-P50-PsS, and CHQ-P50-PhS improved (P ≤ 0.002) by week 104 for patients with systemic JIA. Patients with polyarticular JIA and patients with systemic JIA showed significant reductions in disability (mean ± SD C-HAQ scores of -1.09 ± 0.71 and -1.17 ± 0.80, respectively), improvements in well-being (mean ± SD well-being VAS scores of -43.76 ± 26.61 and -51.53 ± 23.57, respectively), and decreases in pain (mean ± SD pain VAS scores of -41.56 ± 31.06 and -51.26 ± 26.79, respectively) (P < 0.001); in patients with polyarticular JIA and patients with systemic JIA who were treated with tocilizumab, 92.9% of polyarticular JIA patients and 96.8% of systemic JIA patients reported no more than minimal pain (a score of ≤35 mm on the VAS) at week 104.

CONCLUSION

Tocilizumab treatment was associated with significantly reduced disability and pain and improved HRQoL in patients with systemic JIA and polyarticular JIA.

Systemic autoinflammatory diseases

Systemic autoinflammatory diseases (SAIDs) are a growing group of disorders caused by a dysregulation of the innate immune system leading to episodes of systemic inflammation. In 1997, MEFV was the first gene identified as disease causing for Familial Mediterranean Fever, the most common hereditary SAID. In most cases, autoinflammatory diseases have a strong genetic background with mutations in single genes. Since 1997 more than 30 new genes associated with autoinflammatory diseases have been identified, affecting different parts of the innate immune system. Nevertheless, for at least 40-60% of patients with phenotypes typical for SAIDs, a distinct diagnosis cannot be met, leading to undefined SAIDs (uSAIDs). However, SAIDs can also be of polygenic or multifactorial origin, with environmental influence modulating the phenotype. The implementation of a disease continuum model combining the adaptive and the innate immune system with autoinflammatory and autoimmune diseases shows the complexity of SAIDs and the importance of new methods to elucidate molecular changes and causative factors in SAIDs. Diagnosis is often based on clinical presentation and genetic testing. The timeline from onset to diagnosis takes up to 7.3 years, highlighting the indisputable need to identify new treatment and diagnostic targets. Recently, other factors are under investigation as additional contributors to the pathogenesis of SAIDs. This review gives an overview of pathogenesis and etiology of SAIDs, and summarizes recent diagnosis and treatment options.

Investigations of cellular immunity in juvenile idiopathic arthritis

The following was emphasised in an informative, educational issued on the American College of Rheumatology website in April 2017: “About one child in every 1000 develops some type of chronic arthritis. These disorders can affect children at any age, although rarely in the first six months of life. It is estimated that around 300,000 children in the United States have been diagnosed with the condition”. Therefore, knowledge of immunological investigations in patients with juvenile idiopathic arthritis is important for finding new treatment pathways. Our aim was to assess the immunological investigations and immune system implications in juvenile idiopathic arthritis. We will discuss: a) the specifically targeted proteins – the citrullinated peptide antibodies; b) non-specifically targeted proteins – heat-shock proteins (anti-HSP60, -65, and -70 antibodies), CLEC16A, inflammasomes, and phagocyte-derived S100; c) interleukins – IL-1, IL-6, IL-10, IL-17, and IL-18; d) innate immunity – macrophage activation syndrome, natural killer cells, complement activity, and immune complexes; and e) therapeutic targets – monoclonal antibodies, JAK inhibitors, and intravenous immune globulin.

Allogeneic hematopoietic stem cell transplantation for severe, refractory juvenile idiopathic arthritis

Patients with juvenile idiopathic arthritis (JIA) can experience a severe disease course, with progressive destructive polyarthritis refractory to conventional therapy with disease-modifying antirheumatic drugs including biologics, as well as life-threatening complications including macrophage activation syndrome (MAS). Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative immunomodulatory strategy for patients with such refractory disease. We treated 16 patients in 5 transplant centers between 2007 and 2016: 11 children with systemic JIA and 5 with rheumatoid factor-negative polyarticular JIA; all were either refractory to standard therapy, had developed secondary hemophagocytic lymphohistiocytosis/MAS poorly responsive to treatment, or had failed autologous HSCT. All children received reduced toxicity fludarabine-based conditioning regimens and serotherapy with alemtuzumab. Fourteen of 16 patients are alive with a median follow-up of 29 months (range, 2.8-96 months). All patients had hematological recovery. Three patients had grade II-IV acute graft-versus-host disease. The incidence of viral infections after HSCT was high, likely due to the use of alemtuzumab in already heavily immunosuppressed patients. All patients had significant improvement of arthritis, resolution of MAS, and improved quality of life early following allo-HSCT; most importantly, 11 children achieved complete drug-free remission at the last follow-up. Allo-HSCT using alemtuzumab and reduced toxicity conditioning is a promising therapeutic option for patients with JIA refractory to conventional therapy and/or complicated by MAS. Long-term follow-up is required to ascertain whether disease control following HSCT continues indefinitely.

Association between interleukin-10 polymorphisms and juvenile idiopathic arthritis: a meta-analysis

INTRODUCTION

The aim of this review is to investigate IL-10 polymorphisms (-1082 G/A, -819 C/T, and -592 C/A) and their association with susceptibility to JIA.

EVIDENCE ACQUISITION

A meta-analysis was conducted after database search for relevant articles (MEDLINE and EMBASE).

EVIDENCE SYNTHESIS

A total of seven studies involving 1495 patients and 1670 controls were considered in the meta-analysis. There was no association between the IL-10 -1082 G/A, -819 C/T, and -592 C/A polymorphisms and JIA in allele contrast and any of the genetic models (allele contrast: odds ratio [OR] 0.90, 95% confidence interval [CI] 0.79-1.02, P=0.09; OR=0.97, 95% CI 0.83-1.13, P=0.68; OR=0.92, 95% CI 0.81-1.06, P=0.24, respectively). In subgroup analysis, none of the subtypes of JIA including systemic, rheumatoid factor (RF)-positive polyarticular, RF-negative polyarticular, and oligoarticular was not significantly associated with IL-10 polymorphism. Meta-analysis of the IL-10 haplotype revealed no association between GCC, ACC, and ATA haplotypes and JIA.

CONCLUSIONS

This meta-analysis showed that IL-10 polymorphisms were not associated with risk of JIA.

The role of IL-1 inhibition in systemic juvenile idiopathic arthritis: current status and future perspectives

The pathogenesis, clinical course, and response to treatment in systemic juvenile idiopathic arthritis (SJIA) differ from other types of juvenile idiopathic arthritis and are similar to other interleukin-1 (IL-1)-mediated diseases. The main cytokine involved in the pathogenesis of SJIA is IL-1β, which can be neutralized by targeted anti-IL-1 therapy. In SJIA, no antibodies have been found and there is growing evidence that it is mainly an autoinflammatory and not an autoimmune disease. Before the era of biologic therapy, treatment of SJIA was primarily based on long-term treatment with high doses of glucocorticosteroids (GCS). The side effects of GCS could have a significant impact on the outcome of the disease and could cause long-term damage. Treatment with anti-IL-1 agents early in the disease course has revolutionized the management principles of SJIA. However, not all SJIA patients respond equally well to anti-IL-1 therapy, and it has been shown that age at the onset of disease, duration of the disease, number of affected joints, neutrophil count, and ferritin level can predict the response to anti-IL-1 therapy. In particular, an elevated ferritin level should prompt testing for macrophage activation syndrome (MAS), the most severe complication of SJIA. Anti-IL-1 therapy has been shown to be effective also in patients with MAS. Although anti-IL-1 agents are currently not recommended as first-line treatment, there is growing evidence that anti-IL-1 agents introduced at the beginning of SJIA could enable lower doses and a shorter duration of GCS therapy, change the long-term disease outcome, and even influence molecular disease patterns. There are currently three anti-IL-1 agents available: anakinra, canakinumab, and rilonacept. In this review, we present the current knowledge on the pathogenesis of SJIA, the rational for anti-IL-1 treatment, and future perspectives on the treatment of SJIA.

Serum profile of transferrin isoforms in juvenile idiopathic arthritis: a preliminary study

It is reported that alterations in protein glycosylation are present in adult rheumatic diseases; however, the data related to pediatric rheumatic conditions are very scarce. The aim of this study was to assess the effect of juvenile idiopathic arthritis (JIA) on the serum glycosylation profile of transferrin isoforms. Twenty-five patients with different clinical forms of an active JIA and 22 healthy controls were studied. Serum samples were analyzed by capillary electrophoresis on MINICAP electrophoretic system (Sebia, France) to determine the levels of transferrin isoforms. In patients with JIA, tetrasialotransferrin (median 82.6%; range 68.8–99.5) concentration was lower (P = 0.032), and pentasialotransferrin (median 14%; range 0.5–31.2) was higher (P = 0.020) in comparison to controls (median 84.45; range 79.8–87.4; median 11.55; range 9.7–16.1, respectively). No significant correlations between concentration of transferrin isoforms and disease activity score (JADAS 27) or the degree of disability (VAS and CHAQ) were found. Erythrocyte sedimentation rate and CRP levels correlated positively with disialotransferrin (R = 0.493, P = 0.017; R = 0.850, P < 0.001, respectively) and pentasialotransferrin (R = 0.533, P = 0.006; R = 0.491, P = 0.045, respectively), and negatively with trisialotransferrin (R = − 0.546, P = 0.007; R = − 0.515, P = 0.049, respectively) and tetrasialotransferrin (R = − 0.436, P = 0.029; R = − 0.504, P = 0.039, respectively). This preliminary study shows the shifts in transferrin isoforms profile among patients with JIA. Our data indicate a potential clinical utility of the transferrin isoforms measurement, especially tetrasialotransferrin and pentasialotransferrin. Further prospective studies on larger groups of patients should be conducted to validate the results.

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

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

Decreased PD-1 expression on circulating CD4+T cell and PD-L1 expression on myeloid dendritic cell correlate with clinical manifestations in systemic juvenile idiopathic arthritis

OBJECTIVES

Programmed cell death-1 (PD-1) and its ligand (PD-L1) mediate negative signal in autoimmune diseases. While little is known about its role in juvenile idiopathic arthritis (JIA). The study aimed to reveal the circulating cell profile and the relative PD-1/PD-L1 expression of JIA subsets, elucidating their underlying immunomodulatory mechanisms.

METHODS

We detected the circulating cells and the relative PD-1/PD-L1 signaling in 101 JIA patients and 50 controls by flow cytometry and analyzed their association with disease activity and clinical manifestations.

RESULTS

Different from other JIA types, active systemic JIA (sJIA) patients had lower percentage and count of CD4⁺T cells and lower PD-1 expression on them compared with healthy controls (P<0.05), active polyarthritis (P<0.05) and enthesitis-related arthritis (ERA) patients (P<0.05). Also, they had higher percentage and count of myeloid dendritic cell (mDC) and lower PD-L1 expression on mDC compared with healthy controls (P<0.05). Both PD-1 on CD4⁺T cell and PD-L1 on mDC were negatively correlated with JADAS-27 in sJIA patients (P<0.05). In addition, PD-1 expression on CD4⁺T cell was negatively associated with the number of involved joints (P<0.05) and PD-L1 on mDC was lower in patients with fever (P<0.01), which could further divide patients into two groups of different manifestations.

CONCLUSIONS

Our finding displayed decreased CD4⁺T cell, increased mDC and reduced PD-1/PD-L1 signal in sJIA PBMC comparing with other JIA subsets, which might be helpful in JIA differential diagnosis and responsible for distinct clinical manifestations via different mechanisms.

Clinical Juvenile Arthritis Disease Activity Score proves to be a useful tool in treat-to-target therapy in juvenile idiopathic arthritis

OBJECTIVES

To assess if the Juvenile Arthritis Disease Activity Score (JADAS71) could be used to correctly identify patients with juvenile idiopathic arthritis (JIA) in need of antitumour necrosis factor therapy (anti-TNF) therapy 3 and 6 months after start of methotrexate (MTX).

METHODS

Monocentric retrospective cohort study from 2011 to 2015 analysing all patients with oligoarticular JIA (OJIA) (n=39) and polyarticular course JIA (PJIA) (n=74) first starting MTX. Three and 6 months after MTX start, clinical and laboratory features and the 2011 American College of Rheumatology (ACR) JIA treatment recommendations (ACR clinical practice guideline (ACR-CPG)) were compared between groups starting and not starting anti-TNF therapy. The sensitivity and specificity of the ACR-CPG, JADAS71 and the clinical JADAS to identify non-responders after 12 months were calculated.

RESULTS

Physicians escalated patients with significantly higher physician global assessment, clinical JADAS (cJADAS) and patient Visual Analogue Scale (VAS). The decision not to escalate was correct in 70%-75% as shown by MTX response. The implementation of the ACR-CPG would increase the current anti-TNF use from 12% to 65%. The use of (c)JADAS in identifying patients in need of anti-TNF therapy outperformed the ACR-CPG with a much higher sensitivity, specificity and accuracy. The cJADAS threshold for treatment escalation at month 3 and 6 was >5 and >3 for OJIA and >7 and >4 for PJIA, respectively. The performance of the cJADAS decreased when the patient VAS contribution to the total score was restricted and overall did not improve by adding the erythrocyte sedimentation rate.

CONCLUSIONS

The cJADAS identifies patients in need of anti-TNF and is a user-friendly tool ready to be used for treat to target in JIA. The patient VAS is a critical item in the cJADAS for the decision to escalate to anti-TNF.

The cargo protein MAP17 (PDZK1IP1) regulates the immune microenvironment

Inflammation is a complex defensive response activated after various harmful stimuli allowing the clearance of damaged cells and initiating healing and regenerative processes. Chronic, or pathological, inflammation is also one of the causes of neoplastic transformation and cancer development. MAP17 is a cargo protein that transports membrane proteins from the endoplasmic reticulum. Therefore, its overexpression may be linked to an excess of membrane proteins that may be recognized as an unwanted signal, triggering local inflammation. Therefore, we analyzed whether its overexpression is related to an inflammatory phenotype. In this work, we found a correlation between MAP17 expression and inflammatory phenotype in tumors and in other inflammatory diseases such as Crohn's disease, Barrett's esophagus, COPD or psoriasis. MAP17 expression correlated also with the markers of inflammation HLAs, BBS10, HERC2, ADNP and PYCARD. Furthermore, we found that MAP17 expression directly regulates NFAT2 and IL-6 activation, inducing the differentiation of monocytes to dendritic cells and suggesting a causal role of MAP17 in inflammation. Immunohistochemistry confirms local inflammation, mainly CD45⁺ cells, at the site of expression of MAP17, at least in tumors, Crohn's and psoriasis. Therefore, our data indicates that the overexpression of the protein MAP17 plays important role in diseases involving chronic inflammation.

Personalized medicine in rheumatology: the paradigm of serum autoantibodies

The sequencing of the human genome is now well recognized as the starting point of personalized medicine. Nonetheless, everyone is unique and can develop different phenotypes of the same disease, despite identical genotypes, as well illustrated by discordant monozygotic twins. To recognize these differences, one of the easiest and most familiar examples of biomarkers capable of identifying and predicting the outcome of patients is represented by serum autoantibodies. In this review, we will describe the concept of personalized medicine and discuss the predictive, prognostic and preventive role of antinuclear antibodies (ANA), anti-citrullinated peptide antibodies (ACPA), rare autoantibodies and anti-drug antibodies (ADA), to evaluate how these can help to identify different disease immune phenotypes and to choose the best option for treating and monitoring rheumatic patients in everyday practice. The importance of ANA resides in the prediction of clinical manifestations in systemic sclerosis and systemic lupus erythematosus and their association with malignancies. ACPA have a predictive role in rheumatoid arthritis, they are associated with the development of a more aggressive disease, extra-articular manifestations and premature mortality in RA patients; moreover, they are capable of predicting therapeutic response. Rare autoantibodies are associated with different disease manifestations and also with a greater incidence of cancer. The determination of ADA levels may be useful in patients where the clinical efficacy of TNF-α inhibitor has dropped, for the assessment of a right management. The resulting scenario supports serum autoantibodies as the cornerstone of personalized medicine in autoimmune diseases.

Measurement of blood calprotectin (MRP-8/MRP-14) levels in patients with juvenile idiopathic arthritis

Objectives

The aim of the investigation was to compare blood calprotectin (MRP8/14, S100A 8/9) levels in patients with systemic-onset, polyarticular, RF-negative and oligoarticular subtypes of juvenile idiopathic arthritis (JIA), and to explore links between blood calprotectin levels and clinical and laboratory markers of JIA activity.

Material and methods

Measurement of calprotectin in blood serum was performed in 160 patients with JIA followed up at Lviv Regional Council Public Institution “Western-Ukrainian Specialised Children’s Medical Centre”. Seventeen patients with systemic-onset JIA (sJIA) and 49 patients with other JIA subtypes (RF-negative polyarthritis and oligoarthritis) in the active phase of the disease were included in this study. Determination of calprotectin levels in blood serum was performed using EK-MRP8/14 Buhlmann Calprotectin reagents (Buhlmann, Switzerland) by the ELISA method.

Results

The results of the investigations showed that blood calprotectin levels were higher in patients with systemic-onset subtype of the disease (median 13,800 ng/ml), and differed significantly from levels in healthy children (median 1,800 ng/ml, p = 0.00002), levels in patients with articular subtypes of JIA (median 2,700 ng/ml, p = 0.000008), and patients with RF-negative polyarthritis (median 3,800 ng/ml, p = 0.003226) and oligoarthritis (median 2,500 ng/ml, p = 0.000009). The highest blood calprotectin levels were found in patients with newly diagnosed sJIA, the median being 32,500 ng/ml (range: 13,800–177,000 ng/ml). Direct correlations were found between blood calprotectin and JADAS 27 activity score (p = 0.000009), ESR (p = 0.000079) and CRP (p = 0.000058).

Conclusions

Blood calprotectin level is one of the measures that can be used to confirm the diagnosis of sJIA and to monitor the disease activity and therapy effectiveness.