Early changes in gene expression and inflammatory proteins in systemic juvenile idiopathic arthritis patients on canakinumab therapy

Efficacy and safety of canakinumab in systemic juvenile idiopathic arthritis, the first Chinese experience

BACKGROUND

Systemic juvenile idiopathic arthritis (sJIA) is a severe form of juvenile arthritis that is characterized by chronic joint inflammation and systemic symptoms such as fever, rash, and organ involvement. Anti-IL-6 receptor monoclonal antibody tocilizumab is an effective treatment. However, some patients still experience persisting or recurrent symptoms and the real-world effectiveness of canakinumab in Chinese patients with sJIA has never been reported. Therefore, this study aimed to assess the efficacy and safety of canakinumab in Chinese patients with sJIA using real-world data.

METHODS

We conducted a retrospective study on children with active sJIA. Clinical features, laboratory data, corticosteroid dosage, and adverse events (AEs) were collected at baseline and at 4, 8, 12, and 24 weeks after initiating canakinumab treatment.

RESULTS

Seven female and four male patients were included in the study. All patients had previously been treated with tocilizumab and were administered canakinumab for 12.4 ± 3.4 months. Notably, significant improvements were observed in both clinical signs and symptoms as well as laboratory indicators. Four children under corticosteroid treatment were able to successfully discontinue their corticosteroid therapy: one at week 4, two at week 12, and one at week 24. Notably, there was a significant reduction in the number of tender and swollen joints (P = 0.0059) as well as the systemic juvenile arthritis disease activity score (P < 0.0001). The most common AE was infection, but no patients experienced serious AEs. No cases of macrophage activation syndrome or death were reported during the follow-up period.

CONCLUSIONS

Canakinumab was found to be potentially efficacious and safe in Chinese patients with sJIA. No new AEs were observed with canakinumab treatment.

Systemic juvenile idiopathic arthritis-associated lung disease: A retrospective cohort study

BACKGROUND

Lung damage in systemic juvenile arthritis (sJIA) is one of the contemporary topics in pediatric rheumatology. Several previous studies showed the severe course and fatal outcomes in some patients. The information about interstitial lung disease (ILD) in the sJIA is scarce and limited to a total of 100 cases.

AIM

To describe the features of sJIA patients with ILD in detail.

METHODS

In the present retrospective cohort study, information about 5 patients less than 18-years-old with sJIA and ILD were included. The diagnosis of sJIA was made according to the current 2004 and new provisional International League of Associations for Rheumatology criteria 2019. ILD was diagnosed with chest computed tomography with the exclusion of other possible reasons for concurrent lung involvement. Macrophage activation syndrome (MAS) was diagnosed with HLH-2004 and 2016 EULAR/ACR/PRINTO Classification Criteria and hScores were calculated during the lung involvement.

RESULTS

The onset age of sJIA ranged from 1 year to 10 years. The time interval before ILD ranged from 1 mo to 3 years. The disease course was characterized by the prevalence of the systemic features above articular involvement, intensive rash (100%), persistent and very active MAS (hScore range: 194-220) with transaminitis (100%), and respiratory symptoms (100%). Only 3 patients (60%) developed a clubbing phenomenon. All patients (100%) had pleural effusion and 4 patients (80%) had pericardial effusion at the disease onset. Two patients (40%) developed pulmonary arterial hypertension. Infusion-related reactions to tocilizumab were observed in 3 (60%) of the patients. One patient with trisomy 21 had a fatal disease course. Half of the remaining patients had sJIA remission and 2 patients had improvement. Lung disease improved in 3 patients (75%), but 1 of them had initial deterioration of lung involvement. One patient who has not achieved the sJIA remission had the progressed course of ILD. No cases of hyper-eosinophilia were noted. Four patients (80%) received canakinumab and one (20%) tocilizumab at the last follow-up visit.

CONCLUSION

ILD is a severe life-threatening complication of sJIA that may affect children of different ages with different time intervals since the disease onset. Extensive rash, serositis (especially pleuritis), full-blown MAS with transaminitis, lymphopenia, trisomy 21, eosinophilia, and biologic infusion reaction are the main predictors of ILD. The following studies are needed to find the predictors, pathogenesis, and treatment options, for preventing and treating the ILD in sJIA patients.

Diagnosing and Treating Systemic Juvenile Idiopathic Arthritis and Adult-Onset Still's Disease as Part of the Still's Disease Continuum

Aim

We have summarised the existing evidence supporting the concept that systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) are part of the same Still's disease spectrum.

Methods

A PubMed/Embase database search was conducted using specific search strings and free text words to screen for relevant articles. The search was limited to studies in humans, published up to June 2023, in English-language.

Summary

sJIA and AOSD are rare autoinflammatory disorders that have similar pathophysiological and clinical features. The clinical presentations of sJIA and AOSD are highly variable, with differential diagnoses that include a broad range of malignancies, infectious diseases, and autoimmune disorders, which contribute to delays in diagnosis. Several sets of classification exist to help diagnose patients in clinical practice; the International League of Associations for Rheumatology criteria for sJIA and the Yamaguchi and Fautrel criteria for AOSD are the most-used criteria. The therapeutic strategy for Still's disease aims to relieve signs and symptoms, prevent irreversible joint damage and potentially life-threatening complications, and avoid deleterious side effects of treatment. Recently, targeted therapies such as interleukin (IL)-1 and IL-6 inhibitors have become available for the treatment of sJIA and AOSD. While these biologics were originally largely reserved for patients in whom non-steroidal anti-inflammatory drugs, corticosteroids and conventional synthetic disease-modifying anti-rheumatic drugs had failed, they are increasingly used earlier in the treatment paradigm. Among IL-1 inhibitors, canakinumab is the only biologic approved in the US for the treatment of both sJIA and AOSD.

Single-cell RNA sequencing in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is one of the most common chronic inflammatory rheumatic diseases in children, with onset before age 16 and lasting for more than 6 weeks. JIA is a highly heterogeneous condition with various consequences for health and quality of life. For some JIA patients, early detection and intervention remain challenging. As a result, further investigation of the complex and unknown mechanisms underlying JIA is required. Advances in technology now allow us to describe the biological heterogeneity and function of individual cell populations in JIA. Through this review, we hope to provide novel ideas and potential targets for the diagnosis and treatment of JIA by summarizing the current findings of single-cell RNA sequencing studies and understanding how the major cell subsets drive JIA pathogenesis.

Recent advances and evolving concepts in Still's disease

Still's disease is a rare inflammatory syndrome that encompasses systemic juvenile idiopathic arthritis and adult-onset Still's disease, both of which can exhibit life-threatening complications, including macrophage activation syndrome (MAS), a secondary form of haemophagocytic lymphohistiocytosis. Genetic insights into Still's disease involve both HLA and non-HLA susceptibility genes, suggesting the involvement of adaptive immune cell-mediated immunity. At the same time, phenotypic evidence indicates the involvement of autoinflammatory processes. Evidence also implicates the type I interferon signature, mechanistic target of rapamycin complex 1 signalling and ferritin in the pathogenesis of Still's disease and MAS. Pathological entities associated with Still's disease include lung disease that could be associated with biologic DMARDs and with the occurrence of MAS. Historically, monophasic, recurrent and persistent Still's disease courses were recognized. Newer proposals of alternative Still's disease clusters could enable better dissection of clinical heterogeneity on the basis of immune cell profiles that could represent diverse endotypes or phases of disease activity. Therapeutically, data on IL-1 and IL-6 antagonism and Janus kinase inhibition suggest the importance of early administration in Still's disease. Furthermore, there is evidence that patients who develop MAS can be treated with IFNγ antagonism. Despite these developments, unmet needs remain that can form the basis for the design of future studies leading to improvement of disease management.

Deep Immunophenotyping of Circulating T and B Cells in Relapsing Adult-Onset Still's Disease

Adult-onset Still's disease (AOSD) is a complex systemic inflammatory disorder, categorized as an 'IL-1 driven' inflammasomapathy. Despite this, the interaction between T and B cells remains poorly understood. We conducted a study, enrolling 7 patients with relapsing AOSD and 15 healthy control subjects, utilizing deep flow cytometry analysis to examine peripheral blood T- and B-cell subsets. T-cell and B-cell subsets were significantly altered in patients with AOSD. Within CD4+ T cells, Th2 cells were decreased. Additionally, Th17 cell and follicular Th cell subsets were altered within CD45RA-CD62L+ and CD45RA-CD62L- Th cells in patients with AOSD compared to healthy controls. We identified changes in CD8+ T cell maturation and 'polarization' in AOSD patients, with an elevated presence of the TEMRA CD8+ T cell subset. Furthermore, the percentage of Tc1 cells was decreased, while the frequency of CCR6-CXCR3- Tc2 cells was elevated. Finally, we determined that the frequency of CD5+CD27- B cells was dramatically decreased in patients with AOSD compared to healthy controls. Further investigations on a large group of patients with AOSD are required to evaluate these adaptive immunity cells in the disease pathogenesis.

Tmem178 Negatively Regulates IL-1β Production Through Inhibition of the NLRP3 Inflammasome

OBJECTIVE

Inflammasomes modulate the release of bioactive interleukin (IL)-1β. Excessive IL-1β levels are detected in patients with systemic juvenile idiopathic arthritis (sJIA) and cytokine storm syndrome (CSS) with mutated and unmutated inflammasome components, raising questions on the mechanisms of IL-1β regulation in these disorders.

METHODS

To investigate how the NLRP3 inflammasome is modulated in sJIA, we focused on Transmembrane protein 178 (Tmem178), a negative regulator of calcium levels in macrophages, and measured IL-1β and caspase-1 activation in wild-type (WT) and Tmem178-/- macrophages after calcium chelators, silencing of Stim1, a component of store-operated calcium entry (SOCE), or by expressing a Tmem178 mutant lacking the Stromal Interaction Molecule 1 (Stim1) binding site. Mitochondrial function in both genotypes was assessed by measuring oxidative respiration, mitochondrial reactive oxygen species (mtROS), and mitochondrial damage. CSS development was analyzed in Perforin-/- /Tmem178-/- mice infected with lymphocytic choriomeningitis virus (LCMV) in which inflammasome or IL-1β signaling was pharmacologically inhibited. Human TMEM178 and IL1B transcripts were analyzed in data sets of whole blood and peripheral blood monocytes from healthy controls and patients with active sJIA.

RESULTS

TMEM178 levels are reduced in whole blood and monocytes from patients with sJIA while IL1B levels are increased. Accordingly, Tmem178-/- macrophages produce elevated IL-1β compared with WT cells. The elevated intracellular calcium levels after SOCE activation in Tmem178-/- macrophages induce mitochondrial damage, release mtROS, and ultimately promote NLRP3 inflammasome activation. In vivo, inhibition of inflammasome or IL-1β neutralization prolongs Tmem178-/- mouse survival in LCMV-induced CSS.

CONCLUSION

Down-regulation of TMEM178 levels may represent a marker of disease activity and help identify patients who could benefit from inflammasome targeting.

The latest advances in the use of biological DMARDs to treat Still's disease

INTRODUCTION

Currently, the therapeutic management of Still's disease, a multisystemic inflammatory rare disorder, is directed to target the inflammatory symptoms and signs of patients. The treatment varies from glucocorticoids to disease-modifying antirheumatic drugs (DMARDs), both conventional synthetic and biological (bDMARDs). Usually, in refractory patients, bDMARDs are administered.

AREAS COVERED

Among bDMARDs, IL-1 and IL-6 inhibitors are frequently used, as data reported from both clinical trials and 'real-life' experiences. Recently, innovative therapeutic strategies have suggested an early administration of bDMARDs to increase the rate of clinical response and drug-free remission. Some new targets have been also proposed targeting IL-18, IFN-γ, and JAK/STAT pathway, which could be applied to Still's disease and its life-threatening evolution.

EXPERT OPINION

Many lines of evidence improved the knowledge about the therapeutic management of Still's disease with bDMARDs. However, many unmet needs may be still highlighted which could provide the basis to arrange further specific research in increasing the rate of clinical response. In fact, Still's disease remains a highly heterogeneous disease suggesting possible diverse underlying pathogenic mechanisms, at least partially, and consequent different therapeutic strategies. A better patient stratification may help in arranging specific studies to improve the long-term outcome of Still's disease.

Population-level single-cell genomics reveals conserved gene programs in systemic juvenile idiopathic arthritis

Systemic autoimmune and autoinflammatory diseases are characterized by genetic and cellular heterogeneity. While current single-cell genomics methods provide insights into known disease subtypes, these analysis methods do not readily reveal novel cell-type perturbation programs shared among distinct patient subsets. Here, we performed single-cell RNA-Seq of PBMCs of patients with systemic juvenile idiopathic arthritis (SJIA) with diverse clinical manifestations, including macrophage activation syndrome (MAS) and lung disease (LD). We introduced two new computational frameworks called UDON and SATAY-UDON, which define patient subtypes based on their underlying disrupted cellular programs as well as associated biomarkers or clinical features. Among twelve independently identified subtypes, this analysis uncovered what we believe to be a novel complement and interferon activation program identified in SJIA-LD monocytes. Extending these analyses to adult and pediatric lupus patients found new but also shared disease programs with SJIA, including interferon and complement activation. Finally, supervised comparison of these programs in a compiled single-cell pan-immune atlas of over 1,000 healthy donors found a handful of normal healthy donors with evidence of early inflammatory activation in subsets of monocytes and platelets, nominating possible biomarkers for early disease detection. Thus, integrative pan-immune single-cell analysis resolved what we believe to be new conserved gene programs underlying inflammatory disease pathogenesis and associated complications.

Efficacy and safety of canakinumab as a second line biologic after tocilizumab treatment failure in children with systemic juvenile idiopathic arthritis: A single-centre cohort study using routinely collected health data

Background

A significant number of systemic juvenile idiopathic arthritis (sJIA) patients discontinue biologic disease-modifying antirheumatic drugs (bDMARDs) due to lack of efficacy or safety concerns. Studies of biologic therapy switch regimens in sJIA are required.

Methods

Patients with sJIA who switched from tocilizumab (due to lack of efficacy or safety) to canakinumab (4 mg/kg every 4 weeks) and were hospitalized at the rheumatology department from August 2012 to July 2020 were included. Primary efficacy outcomes were 30% or greater improvement based on the paediatric criteria of the American College of Rheumatology (ACR30), achievement of inactive disease (JADAS-71 = 0) and clinical remission (ACR sJIA clinical inactive disease criteria). Follow-up from time first canakinumab dose administered was 12 months or the closest time point (not less than 6 and not more than 18 months). Data were extracted from electronic outpatient medical records.

Results

During the study period, 46 patients with sJIA switched from tocilizumab to canakinumab. Median age at baseline was 8.2 [interquartile range (IQR) 4.0-12.9] years, with the median sJIA duration being 1.8 (IQR 0.8-5.8) years; 37 (80%) patients received at least one conventional DMARD (cDMARD; oral corticosteroids, methotrexate and/or cyclosporine A). Study outcomes were followed up in 45 patients (one patient did not attend the follow-up for an unknown reason); median follow-up was 359 (IQR 282-404) days. During the follow-up, 1 patient discontinued canakinumab due to tuberculosis detection and the dose was reduced or the injection interval increased in 4 (9%) patients. In total, 27 (60%) patients continued to receive at least one cDMARD. Improvement according to the ACR30 criteria was achieved in 43 patients [96%; 95% confidence interval (CI) 85-99], inactive disease in 42 (93%; 95%CI 82-98), and remission in 37 (82%; 95% CI 69-91); after adjustment for actual time-at-risk, the rates were 83, 85 and 73 events per 100 person-years, respectively. During follow-up, 23 AEs (most frequently infections) were reported in 19/45 (42%) patients; 5/45 (11%) patients developed macrophage activation syndrome, with a favorable outcome in all cases.

Conclusions

One-year canakinumab therapy was found to be potentially effective as second-line biologic therapy after discontinuation of tocilizumab in patients with sJIA.

Biomarkers in Systemic Juvenile Idiopathic Arthritis, Macrophage Activation Syndrome and Their Importance in COVID Era

Systemic juvenile idiopathic arthritis (sJIA) and its complication, macrophage activation syndrome (sJIA-MAS), are rare but sometimes very serious or even critical diseases of childhood that can occasionally be characterized by nonspecific clinical signs and symptoms at onset-such as non-remitting high fever, headache, rash, or arthralgia-and are biologically accompanied by an increase in acute-phase reactants. For a correct positive diagnosis, it is necessary to rule out bacterial or viral infections, neoplasia, and other immune-mediated inflammatory diseases. Delays in diagnosis will result in late initiation of targeted therapy. A set of biomarkers is useful to distinguish sJIA or sJIA-MAS from similar clinical entities, especially when arthritis is absent. Biomarkers should be accessible to many patients, with convenient production and acquisition prices for pediatric medical laboratories, as well as being easy to determine, having high sensitivity and specificity, and correlating with pathophysiological disease pathways. The aim of this review was to identify the newest and most powerful biomarkers and their synergistic interaction for easy and accurate recognition of sJIA and sJIA-MAS, so as to immediately guide clinicians in correct diagnosis and in predicting disease outcomes, the response to treatment, and the risk of relapses. Biomarkers constitute an exciting field of research, especially due to the heterogeneous nature of cytokine storm syndromes (CSSs) in the COVID era. They must be selected with utmost care-a fact supported by the increasingly improved genetic and pathophysiological comprehension of sJIA, but also of CSS-so that new classification systems may soon be developed to define homogeneous groups of patients, although each with a distinct disease.

Anakinra in Patients With Systemic Juvenile Idiopathic Arthritis: Long-term Safety From the Pharmachild Registry

OBJECTIVE

To evaluate the long-term safety profile of anakinra in patients with systemic juvenile idiopathic arthritis (sJIA).

METHODS

Data from patients with sJIA enrolled in the Pharmachild registry (ClinicalTrials.gov: NCT03932344) prior to September 30, 2018, and treated with anakinra were analyzed. The study endpoints were the occurrence of non-serious adverse events (SAEs) of at least moderate severity and SAEs, including macrophage activation syndrome (MAS), and the duration of anakinra treatment with reasons for discontinuation. All endpoints were analyzed overall by 6-month time windows, and in different treatment sets represented by those patients treated continuously with anakinra for at least 12, 18, and 24 months (set-12, -18, and -24, respectively).

RESULTS

Three hundred six patients were enrolled. Of these patients, 46%, 34%, and 28% had been treated for at least 12, 18, and 24 months, respectively. Two hundred and one AEs, mostly represented by infections, were reported for 509.3 patient-years (PY) with an overall incidence rate (IR) of 39.5 per 100 PY. Among 56 SAEs (IR 11.0/100 PY), 23.2% were infections and 19.6% MAS episodes. The IR of AEs was higher during the first 6 months of anakinra treatment, followed by decreasing IRs in the long-term treatment sets. Treatment discontinuation occurred in 76% of patients, most frequently in the first 6 months, because of inefficacy (43%), remission (31%), or AEs/intolerance (15%). No deaths or malignancies occurred during anakinra treatment.

CONCLUSION

The results of the present study confirm the long-term safety profile of anakinra in patients with sJIA and demonstrate an overall decreasing incidence of AEs over time. [ClinicalTrials.gov: NCT01399281 and NCT03932344].

Systematic investigation of cytokine signaling activity at the tissue and single-cell levels

Cytokines are critical for intercellular communication in human health and disease, but the investigation of cytokine signaling activity has remained challenging due to the short half-lives of cytokines and the complexity/redundancy of cytokine functions. To address these challenges, we developed the Cytokine Signaling Analyzer (CytoSig; https://cytosig.ccr.cancer.gov/ ), providing both a database of target genes modulated by cytokines and a predictive model of cytokine signaling cascades from transcriptomic profiles. We collected 20,591 transcriptome profiles for human cytokine, chemokine and growth factor responses. This atlas of transcriptional patterns induced by cytokines enabled the reliable prediction of signaling activities in distinct cell populations in infectious diseases, chronic inflammation and cancer using bulk and single-cell transcriptomic data. CytoSig revealed previously unidentified roles of many cytokines, such as BMP6 as an anti-inflammatory factor, and identified candidate therapeutic targets in human inflammatory diseases, such as CXCL8 for severe coronavirus disease 2019.

Identification of Key Biomarkers and Immune Infiltration in Systemic Juvenile Idiopathic Arthritis by Integrated Bioinformatic Analysis

Systemic juvenile idiopathic arthritis (sJIA) is a rare and serious type of JIA characterized by an unknown etiology and atypical manifestations in the early stage, and early diagnosis and effective treatment are needed. We aimed to identify diagnostic biomarkers, immune cells and pathways involved in sJIA pathogenesis as well as potential treatment targets. The GSE17590, GSE80060, and GSE112057 gene expression profiles from the Gene Expression Omnibus (GEO) database were screened to obtain differentially expressed genes (DEGs) between sJIA and healthy controls. Common DEGs were subjected to pathway enrichment analysis; a protein-protein interaction network was constructed, and hub genes were identified. In addition, functional annotation of hub genes was performed with GenCLiP2. Immune infiltration analysis was then conducted with xCell, and correlation analysis between immune cells and the enriched pathways identified from gene set variation analysis was performed. The Connectivity Map database was used to identify candidate molecules for treating sJIA patients. Finally, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was carried out, and the GEO dataset GSE8361 was applied for validation of hub gene expression levels in blood samples from healthy individuals with sJIA. A total of 73 common DEGs were identified, and analysis indicated enrichment of neutrophil and platelet functions and the MAPK pathway in sJIA. Six hub genes were identified, of which three had high diagnostic sensitivity and specificity; ARG1 and PGLYRP1 were validated by qRT-PCR and microarray data of the GSE8361 dataset. We found that increased megakaryocytes and decreased Th1 cells correlated positively and negatively with the MAPK pathway, respectively. Furthermore, MEK inhibitors and some kinase inhibitors of the MAPK family were identified as candidate agents for sJIA treatment. Our results indicate two candidate markers for sJIA diagnosis and reveal the important roles of platelets and the MAPK pathway in the pathogenesis of sJIA, providing a new perspective for exploring potential molecular targets for sJIA treatment.

Cross-Tissue Transcriptomic Analysis Leveraging Machine Learning Approaches Identifies New Biomarkers for Rheumatoid Arthritis

There is an urgent need to identify biomarkers for diagnosis and disease activity monitoring in rheumatoid arthritis (RA). We leveraged publicly available microarray gene expression data in the NCBI GEO database for whole blood (N=1,885) and synovial (N=284) tissues from RA patients and healthy controls. We developed a robust machine learning feature selection pipeline with validation on five independent datasets culminating in 13 genes: TNFAIP6, S100A8, TNFSF10, DRAM1, LY96, QPCT, KYNU, ENTPD1, CLIC1, ATP6V0E1, HSP90AB1, NCL and CIRBP which define the RA score and demonstrate its clinical utility: the score tracks the disease activity DAS28 (p = 7e-9), distinguishes osteoarthritis (OA) from RA (OR 0.57, p = 8e-10) and polyJIA from healthy controls (OR 1.15, p = 2e-4) and monitors treatment effect in RA (p = 2e-4). Finally, the immunoblotting analysis of six proteins on an independent cohort confirmed two proteins, TNFAIP6/TSG6 and HSP90AB1/HSP90.

A computational workflow for the detection of candidate diagnostic biomarkers of Kawasaki disease using time-series gene expression data

Unlike autoimmune diseases, there is no known constitutive and disease-defining biomarker for systemic autoinflammatory diseases (SAIDs). Kawasaki disease (KD) is one of the "undiagnosed" types of SAIDs whose pathogenic mechanism and gene mutation still remain unknown. To address this issue, we have developed a sequential computational workflow which clusters KD patients with similar gene expression profiles across the three different KD phases (Acute, Subacute and Convalescent) and utilizes the resulting clustermap to detect prominent genes that can be used as diagnostic biomarkers for KD. Self-Organizing Maps (SOMs) were employed to cluster patients with similar gene expressions across the three phases through inter-phase and intra-phase clustering. Then, false discovery rate (FDR)-based feature selection was applied to detect genes that significantly deviate across the per-phase clusters. Our results revealed five genes as candidate biomarkers for KD diagnosis, namely, the HLA-DQB1, HLA-DRA, ZBTB48, TNFRSF13C, and CASD1. To our knowledge, these five genes are reported for the first time in the literature. The impact of the discovered genes for KD diagnosis against the known ones was demonstrated by training boosting ensembles (AdaBoost and XGBoost) for KD classification on common platform and cross-platform datasets. The classifiers which were trained on the proposed genes from the common platform data yielded an average increase by 4.40% in accuracy, 5.52% in sensitivity, and 3.57% in specificity than the known genes in the Acute and Subacute phases, followed by a notable increase by 2.30% in accuracy, 2.20% in sensitivity, and 4.70% in specificity in the cross-platform analysis.

Severe COVID-19 in pediatric age: an update on the role of the anti-rheumatic agents

BACKGROUND

SARS-CoV-2 can induce an immune impairment and dysregulation, finally resulting in the massive release of inflammatory mediators (cytokine storm), strongly contributing to the pulmonary and systemic manifestations in severe coronavirus disease 2019 (COVID-19). As a consequence, different drugs active on the immune system have been proposed for the treatment of the disease in adults.

ROLE OF THE ANTI-RHEUMATIC AGENTS IN CHILDREN

Children are more likely to develop a mild disease course, as the severe form of COVID-19 is identified in less than 5% of the pediatric patients. Moreover, in children a peculiar disease phenotype, defined as multisystem inflammatory syndrome in children (MIS-C) is observed, representing the most severe expression of the inflammatory dysregulation caused by SARS-CoV-2. The limited experience with the severe pediatric COVID-19 and MIS-C does not allow conclusions about the role of the immune pharmacological approach, and therefore the treatment of these conditions represents a considerable clinical challenge. The use of chloroquine, hydroxychloroquine, and colchicine in the early disease stages is not sufficiently supported by evidence, and there is an increasing interest in the role of biologic agents, including anti-IL-1 and anti-IL-6 agents, in the prevention and treatment of the severe manifestations of COVID-19.

CONCLUSION

The therapeutic approach to pediatric COVID-19 is multidisciplinary, and anti-rheumatic agents have a prominent role in severe disease. This paper reviews the rationale for the use of anti-rheumatic agents in pediatric COVID-19 and MIS-C and the clinical experience with the single drugs. Finally, the areas of potential improvement in the use of anti-rheumatic agents, including the optimization of the drug choice and the timing of administration, are discussed.

Application of systems biology-based in silico tools to optimize treatment strategy identification in Still's disease

Background

Systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still’s disease (AOSD) are manifestations of an autoinflammatory disorder with complex pathophysiology and significant morbidity, together also termed Still’s disease. The objective of the current study is to set in silico models based on systems biology and investigate the optimal treat-to-target strategy for Still’s disease as a proof-of-concept of the modeling approach.

Methods

Molecular characteristics of Still’s disease and data on biological inhibitors of interleukin (IL)-1 (anakinra, canakinumab), IL-6 (tocilizumab, sarilumab), and glucocorticoids as well as conventional disease-modifying anti-rheumatic drugs (DMARDs, methotrexate) were used to construct in silico mechanisms of action (MoA) models by means of Therapeutic Performance Mapping System (TPMS) technology. TPMS combines artificial neuronal networks, sampling-based methods, and artificial intelligence. Model outcomes were validated with published expression data from sJIA patients.

Results

Biologicals demonstrated more pathophysiology-directed efficiency than non-biological drugs. IL-1 blockade mainly acts on proteins implicated in the innate immune system, while IL-6 signaling blockade has a weaker effect on innate immunity and rather affects adaptive immune mechanisms. The MoA models showed that in the autoinflammatory/systemic phases of Still’s disease, in which the innate immunity plays a pivotal role, the IL-1β-neutralizing antibody canakinumab is more efficient than the IL-6 receptor-inhibiting antibody tocilizumab. MoA models reproduced 67% of the information obtained from expression data.

Conclusions

Systems biology-based modeling supported the preferred use of biologics as an immunomodulatory treatment strategy for Still’s disease. Our results reinforce the role for IL-1 blockade on innate immunity regulation, which is critical in systemic autoinflammatory diseases. This further encourages early use on Still’s disease IL-1 blockade to prevent the development of disease or drug-related complications. Further analysis at the clinical level will validate the findings and help determining the timeframe of the window of opportunity for canakinumab treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02507-w.

Advancing the treatment of juvenile idiopathic arthritis

Treatment for juvenile idiopathic arthritis has undergone substantial changes in recent decades. These changes are partly due to the availability of new treatments, mainly biological agents, as well as developments in treatment strategies, including a focus on concepts such as treat-to-target. In addition, the creation of large paediatric research networks has improved patient access to, and design of, clinical trials for rare paediatric diseases. Although these advances have resulted in improvements in care for most patients with juvenile idiopathic arthritis, certain subgroups of patients continue to have a poor prognosis. Further research aims to identify patients in these subgroups early, to personalise their care, improve functional outcomes, and minimise long-term damage and harm. Optimising the duration of therapy for those individuals who require systemic immunosuppression is also of importance. Incorporation of novel biomarkers in combination with validated clinical measures in an effort to predict outcomes and target therapy accordingly is an exciting development.

Biomarkers of Response to Biologic Therapy in Juvenile Idiopathic Arthritis

Background: Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory arthritis of childhood, characterized by various clinical phenotypes associated with variable prognosis. Significant progress has been achieved with the use of biologic treatments, which specifically block pro-inflammatory molecules involved in the disease pathogenesis. The most commonly used biologics in JIA are monoclonal antibodies and recombinant proteins targeting interleukins 1 (IL-1) and 6 (IL-6), and tumor necrosis factor α (TNF-α). Several biomarkers have been investigated in JIA. Aims: To assess the level of evidence available regarding the role of biomarkers in JIA related to guiding clinical and therapeutic decisions, providing disease prognostic information, facilitating disease activity monitoring and assessing biologic treatment response in JIA, as well as propose new strategies for biologic therapy-related biomarker use in JIA. Methods: We searched PubMed for relevant literature using predefined key words corresponding to several categories of biomarkers to assess their role in predicting and assessing biologic treatment response and clinical remission in JIA. Results: We reviewed serological, cellular, genetic, transcriptomic and imaging biomarkers, to identify candidates that are both well-established and widely used, as well as newly investigated in JIA on biologic therapy. We evaluated their role in management of JIA as well as identified the unmet needs for new biomarker discovery and better clinical applications. Conclusion: Although there are no ideal biomarkers in JIA, we identified serological biomarkers with potential clinical utility. We propose strategies of combining biomarkers of response to biologics in JIA, as well as routine implementation of clinically acceptable imaging biomarkers for improved disease assessment performance.

Transcriptional response modules characterize IL-1β and IL-6 activity in COVID-19

Dysregulated IL-1β and IL-6 responses have been implicated in the pathogenesis of severe Coronavirus Disease 2019 (COVID-19). Innovative approaches for evaluating the biological activity of these cytokines in vivo are urgently needed to complement clinical trials of therapeutic targeting of IL-1β and IL-6 in COVID-19. We show that the expression of IL-1β or IL-6 inducible transcriptional signatures (modules) reflects the bioactivity of these cytokines in immunopathology modelled by juvenile idiopathic arthritis (JIA) and rheumatoid arthritis. In COVID-19, elevated expression of IL-1β and IL-6 response modules, but not the cytokine transcripts themselves, is a feature of infection in the nasopharynx and blood but is not associated with severity of COVID-19 disease, length of stay, or mortality. We propose that IL-1β and IL-6 transcriptional response modules provide a dynamic readout of functional cytokine activity in vivo, aiding quantification of the biological effects of immunomodulatory therapies in COVID-19.

Distinct Gene Expression Signatures Characterize Strong Clinical Responders Versus Nonresponders to Canakinumab in Children With Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

Canakinumab is a human anti-interleukin-1β (anti-IL-1β) blocking agent that effectively neutralizes IL-1β-mediated signaling for treatment of systemic juvenile idiopathic arthritis (JIA). While many patients have dramatic clinical response to IL-1 blockade, approximately one-third fail to respond, but there are currently no validated clinical or immunologic predictors of response. We undertook this study to characterize distinct gene signatures for treatment response and nonresponse to canakinumab in systemic JIA patients.

METHODS

We performed a secondary analysis of whole-blood gene expression microarrays using blood samples obtained from healthy controls and systemic JIA patients at baseline and on day 3 after canakinumab treatment (GEO accession no. GSE80060). Patients were considered strong clinical responders if they met the ACR90 response (exhibited ≥90% improvement in the American College of Rheumatology [ACR] JIA response criteria; nonresponders were those who met ACR30 [exhibiting ≤30% improvement in the ACR JIA response criteria]). A random-effects model with patient identity as the random variable was used for differential expression analysis.

RESULTS

We identified a distinct gene expression signature in patients with a strong clinical response to canakinumab treatment as compared to nonresponders, mediated by up-regulation of neutrophil- and IL-1-associated genes and characterized by increasing divergence from control transcriptomes with increasing clinical response. We also identified a signature including up-regulated CD163 expression that was associated with canakinumab nonresponse. Intriguingly, canakinumab treatment induced either up- or down-regulation of type I interferon (IFN) genes, independent of clinical response.

CONCLUSION

Here, we identify a gene signature in systemic JIA patients prior to receiving treatment that distinguishes strong responders to canakinumab from nonresponders. Further prospective studies are needed to assess the utility of these insights for treatment decisions in systemic JIA and to track the association of up-regulated type I IFN signatures with systemic JIA complications.

An Integrative Transcriptomic Analysis of Systemic Juvenile Idiopathic Arthritis for Identifying Potential Genetic Markers and Drug Candidates

Systemic juvenile idiopathic arthritis (sJIA) is a rare subtype of juvenile idiopathic arthritis, whose clinical features are systemic fever and rash accompanied by painful joints and inflammation. Even though sJIA has been reported to be an autoinflammatory disorder, its exact pathogenesis remains unclear. In this study, we integrated a meta-analysis with a weighted gene co-expression network analysis (WGCNA) using 5 microarray datasets and an RNA sequencing dataset to understand the interconnection of susceptibility genes for sJIA. Using the integrative analysis, we identified a robust sJIA signature that consisted of 2 co-expressed gene sets comprising 103 up-regulated genes and 25 down-regulated genes in sJIA patients compared with healthy controls. Among the 128 sJIA signature genes, we identified an up-regulated cluster of 11 genes and a down-regulated cluster of 4 genes, which may play key roles in the pathogenesis of sJIA. We then detected 10 bioactive molecules targeting the significant gene clusters as potential novel drug candidates for sJIA using an in silico drug repositioning analysis. These findings suggest that the gene clusters may be potential genetic markers of sJIA and 10 drug candidates can contribute to the development of new therapeutic options for sJIA.

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.

Monocyte and bone marrow macrophage transcriptional phenotypes in systemic juvenile idiopathic arthritis reveal TRIM8 as a mediator of IFN-γ hyper-responsiveness and risk for macrophage activation syndrome

OBJECTIVES

Systemic juvenile idiopathic arthritis (SJIA) confers high risk for macrophage activation syndrome (MAS), a life-threatening cytokine storm driven by interferon (IFN)-γ. SJIA monocytes display IFN-γ hyper-responsiveness, but the molecular basis of this remains unclear. The objective of this study is to identify circulating monocyte and bone marrow macrophage (BMM) polarisation phenotypes in SJIA including molecular features contributing to IFN response.

METHODS

Bulk RNA-seq was performed on peripheral blood monocytes (n=26 SJIA patients) and single cell (sc) RNA-seq was performed on BMM (n=1). Cultured macrophages were used to define consequences of tripartite motif containing 8 (TRIM8) knockdown on IFN-γ signalling.

RESULTS

Bulk RNA-seq of SJIA monocytes revealed marked transcriptional changes in patients with elevated ferritin levels. We identified substantial overlap with multiple polarisation states but little evidence of IFN-induced signature. Interestingly, among the most highly upregulated genes was TRIM8, a positive regulator of IFN-γ signalling. In contrast to PBMC from SJIA patients without MAS, scRNA-seq of BMM from a patient with SJIA and MAS identified distinct subpopulations of BMM with altered transcriptomes, including upregulated IFN-γ response pathways. These BMM also showed significantly increased expression of TRIM8. In vitro knockdown of TRIM8 in macrophages significantly reduced IFN-γ responsiveness.

CONCLUSIONS

Macrophages with an 'IFN-γ response' phenotype and TRIM8 overexpression were expanded in the bone marrow from an MAS patient. TRIM8 is also upregulated in SJIA monocytes, and augments macrophage IFN-γ response in vitro, providing both a candidate molecular mechanism and potential therapeutic target for monocyte hyper-responsiveness to IFNγ in cytokine storms including MAS.

Transcriptional response modules characterise IL-1β and IL-6 activity in COVID-19

Dysregulated IL-1β and IL-6 responses have been implicated in the pathogenesis of severe Coronavirus Disease 2019 (COVID-19). Innovative approaches for evaluating the biological activity of these cytokines in vivo are urgently needed to complement clinical trials of therapeutic targeting of IL-1β and IL-6 in COVID-19. We show that the expression of IL-1β or IL-6 inducible transcriptional signatures (modules) reflects the bioactivity of these cytokines in immunopathology modelled by juvenile idiopathic arthritis (JIA) and rheumatoid arthritis. In COVID-19, elevated expression of IL-1β and IL-6 response modules, but not the cytokine transcripts themselves, is a feature of infection in the nasopharynx and blood, but is not associated with severity of COVID-19 disease, length of stay or mortality. We propose that IL-1β and IL-6 transcriptional response modules provide a dynamic readout of functional cytokine activity in vivo, aiding quantification of the biological effects of immunomodulatory therapies in COVID-19.

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.

IL-18 as a biomarker linking systemic juvenile idiopathic arthritis and macrophage activation syndrome

OBJECTIVES

Systemic juvenile idiopathic arthritis (sJIA) is a childhood arthritis with features of autoinflammation and high risk of macrophage activation syndrome (MAS). IL-18 has been shown to have key roles in sJIA and MAS. We aimed to examine IL-18 levels in sJIA in relation to disease activity and history of MAS and other disease biomarkers namely S100 proteins and CXCL9.

METHODS

Total IL-18, CXCL9 and S100 proteins levels were determined in 40 sJIA patients, and IL-18 levels were compared between patients with regards to disease activity, history of MAS, and other biomarkers.

RESULTS

Total IL-18 levels were significantly higher in patients with active sJIA (median 16 499 pg/ml; interquartile range (IQR) 4816-61 839), and remained persistently elevated even in the majority of patients with inactive disease (1164 pg/ml; IQR 587-3444). Patients with history of MAS had significantly higher IL-18 levels (13 380 pg/ml; IQR 4212-62 628) as compared with those without MAS history (956.5 pg/ml; IQR 276.3-4262.5). Total IL-18 performed well with area under the curve of 0.8145 and 0.84 in predicting disease activity and history of MAS, respectively. We observed moderate correlation between IL-18 and CXCL9 (R = 0.56), S100A8/A9 (R = 0.47) and S100A12 (R = 0.46). The correlation was stronger for ferritin (R = 0.74) and overall for those with active disease.

CONCLUSION

Total IL-18 levels were elevated in the majority of sJIA patients regardless of clinical features, but were higher in patients with active disease and history of MAS. Change in IL-18 may reflect increased disease activity or development of MAS.

Systemic juvenile idiopathic arthritis and macrophage activation syndrome: update on pathogenesis and treatment

PURPOSE OF REVIEW

The past decade has seen substantial progress in defining the cause and pathogenesis of the chronic childhood arthropathy systemic juvenile idiopathic arthritis (SJIA) and its related complication macrophage activation syndrome (MAS). The purpose of this review is to describe and synthesize advances in this field, particularly since 2016, with the potential to transform clinical practice.

RECENT FINDINGS

Newly developed MAS classification criteria have been further studied and validated in other diseases and populations, as well as a recently proposed score to distinguish MAS from familial hemophagocytic lymphohistiocytosis. There has also been substantial progress toward understanding the genetic underpinnings of SJIA and MAS, both through targeted study of specific genes and the results of a large genome-wide association study. The immunopathogenesis of SJIA has been further elucidated through several studies regarding the proinflammatory cytokines interleukin-18, interferon (IFN)γ, and how their interplay impacts emergence of MAS. Finally, big data studies integrating genomic information with immunophenotypes have potential to provide novel insights into disease mechanisms in SJIA.

SUMMARY

Collectively, these research advances have significant implications regarding the classification and diagnosis of SJIA and MAS, and support a next generation of biologic treatments including kinase inhibitors and targeted interleukin-18 or IFNγ blockade.

Interleukin-6 in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is a chronic childhood arthritis. Its pathogenesis is very complicated, with the involvement of not only immune cells but various types of parenchymal cells, and is affected by both genetic and environmental predispositions. The clinical spectrum from inflammation to related conditions is largely mediated by cytokines including interleukin (IL)-6. Fluctuations in IL-6 and its related molecules can modulate the pathogenesis and the clinical presentation positively or negatively. The recent clinical impact of IL-6 blockade on JIA has begun a therapeutic paradigm shift. This review describes the characteristics of JIA, mainly focused on IL-6 with the current therapeutic perspective.

Molecular signature characterisation of different inflammatory phenotypes of systemic juvenile idiopathic arthritis

Objectives

The International League of Associations for Rheumatology classification criteria define systemic juvenile idiopathic arthritis (SJIA) by the presence of fever, rash and chronic arthritis. Recent initiatives to revise current criteria recognise that a lack of arthritis complicates making the diagnosis early, while later a subgroup of patients develops aggressive joint disease. The proposed biphasic model of SJIA also implies a ‘window of opportunity’ to abrogate the development of chronic arthritis. We aimed to identify novel SJIA biomarkers during different disease phases.

Methods

Children with active SJIA were subgrouped clinically as systemic autoinflammatory disease with fever (SJIAsyst) or polyarticular disease (SJIApoly). A discovery cohort of n=10 patients per SJIA group, plus n=10 with infection, was subjected to unbiased label-free liquid chromatography mass spectrometry (LC-MS/MS) and immunoassay screens. In a separate verification cohort (SJIAsyst, n=45; SJIApoly, n=29; infection, n=32), candidate biomarkers were measured by multiple reaction monitoring MS (MRM-MS) and targeted immunoassays.

Results

Signatures differentiating the two phenotypes of SJIA could be identified. LC-MS/MS in the discovery cohort differentiated SJIAsyst from SJIApoly well, but less effectively from infection. Targeted MRM verified the discovery data and, combined with targeted immunoassays, correctly identified 91% (SJIAsyst vs SJIApoly) and 77% (SJIAsyst vs infection) of all cases.

Conclusions

Molecular signatures differentiating two phenotypes of SJIA were identified suggesting shifts in underlying immunological processes in this biphasic disease. Biomarker signatures separating SJIA in its initial autoinflammatory phase from the main differential diagnosis (ie, infection) could aid early-stage diagnostic decisions, while markers of a phenotype switch could inform treat-to-target strategies.

Unveiling the Efficacy, Safety, and Tolerability of Anti-Interleukin-1 Treatment in Monogenic and Multifactorial Autoinflammatory Diseases

Autoinflammatory diseases (AIDs) are heterogeneous disorders characterized by dysregulation in the inflammasome, a large intracellular multiprotein platform, leading to overproduction of interleukin-1(IL-1)β that plays a predominant pathogenic role in such diseases. Appropriate treatment is crucial, also considering that AIDs may persist into adulthood with negative consequences on patients' quality of life. IL-1β blockade results in a sustained reduction of disease severity in most AIDs. A growing experience with the human IL-1 receptor antagonist, Anakinra (ANA), and the monoclonal anti IL-1β antibody, Canakinumab (CANA), has also been engendered, highlighting their efficacy upon protean clinical manifestations of AIDs. Safety and tolerability have been confirmed by several clinical trials and observational studies on both large and small cohorts of AID patients. The same treatment has been proposed in refractory Kawasaki disease, an acute inflammatory vasculitis occurring in children before 5 years, which has been postulated to be autoinflammatory for its phenotypical and immunological similarity with systemic juvenile idiopathic arthritis. Nevertheless, minor concerns about IL-1 antagonists have been raised regarding their employment in children, and the development of novel pharmacological formulations is aimed at minimizing side effects that may affect adherence to treatment. The present review summarizes current findings on the efficacy, safety, and tolerability of ANA and CANA for treatment of AIDs and Kawasaki vasculitis with a specific focus on the pediatric setting.

Comparative study of Interleukin-18 (IL-18) serum levels in adult onset Still's disease (AOSD) and systemic onset juvenile idiopathic arthritis (sJIA) and its use as a biomarker for diagnosis and evaluation of disease activity

Background

Signs and symptoms establish the diagnosis of adult onset Still’s disease (AOSD) as well as of systemic onset juvenile idiopathic arthritis (sJIA). The published data regarding the importance of IL-18 as a marker for diagnosis and disease activity so far are conflicting. The aim of this study was to clarify the role of IL-18 as a diagnostic and disease activity marker in AOSD and sJIA.

Methods

Thirty adult patients diagnosed with AOSD and twenty children diagnosed with sJIA were included in the study. Clinical and laboratory data were obtained retrospectively for each patient visit whenever IL-18 serum levels were determined. IL-18 levels were determined by ELISA. Sixty-five adults and twenty-three children presenting with fever and/or arthritis who did not meet the criteria for a diagnosis of AOSD or sJIA served as comparison groups. Rau’s criteria and CRP values were used to evaluate disease activity.

Results

IL-18 levels were significantly elevated in patients with active AOSD compared to AOSD patients in remission and to the comparison group with a median of 16,327 pg/ml, 470 pg/ml, and 368 pg/ml, respectively (p < 0.001). Analogous to AOSD in active sJIA, the median IL-18 serum level was significantly higher with 21,512 pg/ml than in the comparison group with 2580 pg/ml (p < 0.001).

At our cut-off point of 5000 pg/ml, the calculated specificity of IL-18 to establish the diagnosis of AOSD was 96.9%, and the sensitivity 63.3% (AUC = 0.870, p < 0.001). For the diagnosis of sJIA, a cut-off value of 10,000 pg/ml was chosen with a specificity of 100% and a sensitivity of 60% (AUC = 0.774, p = 0.003). At a cut-off value of 5000 pg/ml, the specificity was 62% and the sensitivity 65%.

Conclusions

This study gives further evidence to earlier publications of elevated IL-18 serum levels in active AOSD and sJIA, with up to 1000-fold higher concentrations compared to other rheumatic diseases. A clear association of IL-18 serum levels with disease activity in AOSD was found. The results support the use of IL-18 as an important biomarker in AOSD and sJIA.

Electronic supplementary material

The online version of this article (10.1186/s41927-019-0053-z) contains supplementary material, which is available to authorized users.

Neutrophils From Children With Systemic Juvenile Idiopathic Arthritis Exhibit Persistent Proinflammatory Activation Despite Long-Standing Clinically Inactive Disease

Background: Systemic juvenile idiopathic arthritis (SJIA) is a chronic childhood arthropathy with features of autoinflammation. Early inflammatory SJIA is associated with expansion and activation of neutrophils with a sepsis-like phenotype, but neutrophil phenotypes present in longstanding and clinically inactive disease (CID) are unknown. The objective of this study was to examine activated neutrophil subsets, S100 alarmin release, and gene expression signatures in children with a spectrum of SJIA disease activity.

Methods: Highly-purified neutrophils were isolated using a two-step procedure of density-gradient centrifugation followed by magnetic-bead based negative selection prior to flow cytometry or cell culture to quantify S100 protein release. Whole transcriptome gene expression profiles were compared in neutrophils from children with both active SJIA and CID.

Results: Patients with SJIA and active systemic features demonstrated a higher proportion of CD16⁺CD62L^lo neutrophil population compared to controls. This neutrophil subset was not seen in patients with CID or patients with active arthritis not exhibiting systemic features. Using imaging flow cytometry, CD16⁺CD62L^lo neutrophils from patients with active SJIA and features of macrophage activation syndrome (MAS) had increased nuclear hypersegmentation compared to CD16⁺CD62L⁺ neutrophils. Serum levels of S100A8/A9 and S100A12 were strongly correlated with peripheral blood neutrophil counts. Neutrophils from active SJIA patients did not show enhanced resting S100 protein release; however, regardless of disease activity, neutrophils from SJIA patients did show enhanced S100A8/A9 release upon PMA stimulation compared to control neutrophils. Furthermore, whole transcriptome analysis of highly purified neutrophils from children with active SJIA identified 214 differentially expressed genes (DEG) compared to neutrophils from healthy controls. The most significantly upregulated gene pathway was Immune System Process, including AIM2, IL18RAP, and NLRC4. Interestingly, this gene set showed intermediate levels of expression in neutrophils from patients with long-standing CID yet persistent serum IL-18 elevation. Indeed, all patient samples regardless of disease activity demonstrated elevated inflammatory gene expression, including inflammasome components and S100A8.

Conclusion: We identify features of neutrophil activation in SJIA patients with both active disease and CID, including a proinflammatory gene expression signature, reflecting persistent innate immune activation. Taken together, these studies expand understanding of neutrophil function in chronic autoinflammatory disorders such as SJIA.

NFIL3 mutations alter immune homeostasis and sensitise for arthritis pathology

OBJECTIVES

NFIL3 is a key immunological transcription factor, with knockout mice studies identifying functional roles in multiple immune cell types. Despite the importance of NFIL3, little is known about its function in humans.

METHODS

Here, we characterised a kindred of two monozygotic twin girls with juvenile idiopathic arthritis at the genetic and immunological level, using whole exome sequencing, single cell sequencing and flow cytometry. Parallel studies were performed in a mouse model.

RESULTS

The patients inherited a novel p.M170I in NFIL3 from each of the parents. The mutant form of NFIL3 demonstrated reduced stability in vitro. The potential contribution of this mutation to arthritis susceptibility was demonstrated through a preclinical model, where Nfil3-deficient mice upregulated IL-1β production, with more severe arthritis symptoms on disease induction. Single cell sequencing of patient blood quantified the transcriptional dysfunctions present across the peripheral immune system, converging on IL-1β as a pivotal cytokine.

CONCLUSIONS

NFIL3 mutation can sensitise for arthritis development, in mice and humans, and rewires the innate immune system for IL-1β over-production.

Recent advances in our understanding of the pathogenesis of juvenile idiopathic arthritis and their potential clinical implications

INTRODUCTION

Juvenile idiopathic arthritis (JIA) comprises systemic and non-systemic forms of chronic childhood arthritis diagnosed prior to age 16. Significant improvement in treatment outcomes has been witnessed since the introduction of biologics. In particular, advances in research in the area of multidimensional interrogation and network analysis have facilitated understanding of the complex cacophony of components orchestrating disease immunopathogenesis. Areas covered: In this review, we will examine the scientific advances that have augmented our understanding of JIA pathogenesis, focusing on the progress made in systemic, poly, and oligo JIA in four major aspects: (a) unraveling the pathogenic mechanisms, (b) disease classification, (c) therapeutic selection, and (d) decision for withdrawal of medications after achieving remission. Expert commentary: Dysregulation of innate immune cell physiology and function in sJIA will be highlighted. MicroRNAs contribute to monocyte/macrophage polarization with resulting consequences on macrophage activation syndrome development. The involvement of neutrophils, a major source of S100A8/9/12, in the active inflammatory phase of sJIA is compelling. In non-sJIA, circulating CD4 subsets in T effector and regulatory compartments possessing a strong synovial T-cell receptor coverage and disease activity correlation, acted as an accessible reservoir of pathogenic cells exploitable for clinical management.

Pediatric Rheumatology Collaborative Study Group - over four decades of pivotal clinical drug research in pediatric rheumatology

IMPORTANCE

Specialized research networks are essential to achieve drug approvals for rare pediatric diseases. Such networks help realize the potential of global legislation enacted upon the recognition that most children are treated with drugs whose most beneficial dose and regimen have not been established in pediatric patients. The Pediatric Rheumatology Collaborative Study Group (PRCSG) is a North American clinical trials network that is specialized in the performance of clinical trials of new therapies for pediatric populations with rheumatic diseases. This review provides an overview of the strategies employed by this research network to achieve drug and biologic approvals for children with pediatric rheumatic diseases, particularly juvenile idiopathic arthritis.

OBSERVATIONS

Clinical trial conduct in rare pediatric diseases has required global recruitment. Supported or led by the PRCSG, highly responsive, validated, composite measures have been established to assess drug efficacy. For pediatric orphan diseases with high disease burdens, specialized investigative sites and study designs are needed to complete adequately powered trials at the high standard necessary to enable drug labeling by regulatory agencies. Novel trial designs have been utilized for more efficient testing of innovative drug candidates. All these have been developed or co-developed by the PRCSG research network.

CONCLUSIONS AND RELEVANCE

Specialized research networks in pediatric rheumatology, such as the PRCSG, have changed the landscape of available therapies and improved overall disease outcomes for children with pediatric rheumatic diseases.

Interleukin-1 in monocyte activation phenotypes in systemic juvenile idiopathic arthritis: Observations from a clinical trial of rilonacept, an interleukin-1 inhibitor

Systemic juvenile idiopathic arthritis (sJIA) is a childhood rheumatic disease of unknown origin. Dysregulated innate immunity is implicated in disease pathology. We investigated if IL-1 inhibition affects circulating cytokines and monocyte gene expression. CD14+ monocytes from patients in the RAPPORT trial were analyzed by RT-PCR for expression of IL1B and transcription factors associated with monocyte activation. Serum IL-1ra decreased with treatment, and IL-18BP transiently increased. Serum levels of IL-1β, IL-6, IL-10 and IL-18 were unchanged. IRF5 and STAT6 were decreased, and PPARG was increased, independent of clinical response, and may represent a skew toward a PPARG-driven M2-like phenotype. IL1B expression was decreased in early clinical responders. A transient increase in STAT1, and a decrease in SOCS1 preceded the reduction in IL1B in early clinical responders. Changes in IL1B/STAT1/SOCS1 could be associated with crosstalk between IL-1 and IFN pathways in sJIA. These transcriptional changes might be useful as drug response biomarkers.

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.

Transcription factor motif enrichment in whole transcriptome analysis identifies STAT4 and BCL6 as the most prominent binding motif in systemic juvenile idiopathic arthritis

Background

The term systemic juvenile idiopathic arthritis (sJIA) describes an autoinflammatory condition characterized by arthritis and severe systemic inflammation, which in later stages can transform into interleukin (IL)-17-driven autoimmune arthritis. IL-1 antagonists have been used with good efficacy in the early stages of sJIA.

Methods

A whole transcriptome analysis of peripheral blood RNA samples was performed in six patients with sJIA and active systemic disease, before initiating treatment with the IL-1β receptor antagonist anakinra, and after induction of inactive disease, compared with a single-sample control cohort of 21 patients in several clinical stages of sJIA activity. Whole transcriptomes were compared longitudinally and interindividually including gene ontology and motif enrichment analysis of differentially expressed genes.

Results

There were 741 transcripts were identified using a threshold with a p value <0.01 and a fold change > 2. HLADRB1 and CD74 were identified as the most strongly upregulated genes in inactive compared to active disease; CD177 expression was significantly enhanced in active disease compared to inactive disease. Motif enrichment analysis revealed STAT4, BCL6, and STAT3 as the most prominent transcription factors that were present during active disease. In addition, strong upregulation of the major histocompatability complex II (MHCII) ligand CD74 was found in both active and inactive sJIA compared to healthy controls.

Conclusion

Using transcription factor motif enrichment, this study identifies novel putative pathways in sJIA (STAT4, BCL6) implicating B cell activation at an earlier stage than predicted in refractory disease. The implication of BCL-6 dependent pathways argues for occurrence of autoimmunity early within the process of sJIA chronification. Transcriptional regulation of HLA-DRB1, a recently described independent genetic risk factor, in combination with its cooperating partner CD74 in patients where sJIA is confirmed, supports pathogenic involvement in alterations in antigen presentation during sJIA.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1603-2) contains supplementary material, which is available to authorized users.

Cytokines of the IL-1 family: recognized targets in chronic inflammation underrated in organ transplantations

Interleukin 1 (IL-1) family is a group of cytokines with multiple local and systemic effects, which regulates both innate and adaptive immune responses. Generally, most IL-1 family cytokines express prevailing pro-inflammatory activities (IL-1α, IL-1β, IL-18, IL-33, IL-36 α, β, γ), whereas others are anti-inflammatory (IL-1Ra (IL-1 receptor antagonist), IL-36Ra, IL-38, IL-37). In addition to their immunomodulatory roles, some of them are also involved in the physiological modulation of homeostatic processes and directly affect mRNA transcription. IL-1 family cytokines bind to specific receptors composed of a ligand-binding chain and an accessory chain. The pro-inflammatory effects of IL-1 family cytokines are regulated on the level of transcription, enzymatic processing of precursors, release of soluble antagonists, and expression of decoy receptors. Members of the IL-1 family regulate the recruitment and activation of effector cells involved in innate and adaptive immunity, but they are also involved in the pathogenesis of chronic disorders, including inflammatory bowel disease, rheumatoid arthritis, and various autoimmune and autoinflammatory diseases. There are only limited data regarding the role of IL-1 cytokines in transplantation. In recent years, targeted therapeutics affecting IL-1 have been used in multiple clinical studies. In addition to the recombinant IL-1Ra, anakinra (highly effective in autoinflammatory diseases and tested for other chronic diseases), the monoclonal antibodies canakinumab, gevokizumab, and rilonacept (a long-acting IL-1 receptor fusion protein) provide further options to block IL-1 activity. Furthermore, new inhibitors of IL-18 (GSK 1070806, ABT-325, rIL-18BP (IL-18 binding protein)) and IL-33 (CNTO-7160) are presently under clinical studies and other molecules are being developed to target IL-1 family cytokines.

Gene-expression analysis of adult-onset Still's disease and systemic juvenile idiopathic arthritis is consistent with a continuum of a single disease entity

BACKGROUND

Adult-onset Still's disease (AOSD), a rare autoinflammatory disorder, resembles systemic juvenile idiopathic arthritis (SJIA). The superimposable systemic clinical features of AOSD and SJIA suggest both clinical phenotypes represent the same disease continuum with different ages of onset. To further characterize the similarity between AOSD and SJIA at the molecular level, 2 previously identified response gene sets in SJIA were used to investigate how genes that respond to interleukin (IL)-1β inhibition with canakinumab in SJIA patients behave in AOSD patients with active disease prior to IL-1β targeting therapy, relative to healthy subjects.

FINDINGS

All genes downregulated in SJIA patients following canakinumab treatment were upregulated in most patients with active AOSD prior to canakinumab treatment, relative to healthy subjects. A few patients with milder AOSD had expectedly gene-expression patterns that resembled those in healthy subjects. Comparison of the gene-expression patterns with neutrophil counts showed a correlation between elevated neutrophil numbers and upregulation of canakinumab-responsive genes. Correspondingly, most genes upregulated following canakinumab treatment in patients with SJIA patients were downregulated in the majority of AOSD patients.

CONCLUSIONS

These results further support the concept of a Still's disease continuum that includes both a pediatric/juvenile onset (SJIA) and adult onset (AOSD) form.