Systemic Juvenile Idiopathic Arthritis-Associated Lung Disease: Characterization and Risk Factors

Innovations in the care of childhood interstitial lung disease associated with connective tissue disease and immune-mediated disorders

Childhood interstitial lung disease (chILD) associated with connective tissue and immune mediated disorders is the second most common chILD diagnostic category. As knowledge of the molecular and genetic underpinnings of these rare disorders advances, the recognized clinical spectrum of associated pulmonary manifestations continues to expand. Pulmonary complications of these diseases, including ILD, confer increased risk for morbidity and mortality and contribute to increased complexity for providers tasked with managing the multiple organ systems that can be impacted in these systemic disorders. While pulmonologists play an important role in diagnosis and management of these conditions, thankfully they do not have to work alone. In collaboration with a multidisciplinary team of subspecialists, the pulmonary and other systemic manifestations of these conditions can be managed effectively together. The goal of this review is to familiarize the reader with the classic patterns of chILD and other pulmonary complications associated with primary immune-mediated disorders (monogenic inborn errors of immunity) and acquired systemic autoimmune and autoinflammatory diseases. In addition, this review will highlight current, emerging, and innovative therapeutic strategies and will underscore the important role of multidisciplinary management to improving outcomes for these patients.

Transition to Adult Rheumatology Care: A Disease-Specific Guide

ABSTRACT

Young adults with childhood-onset rheumatic diseases are more frequently establishing and continuing care with adult rheumatologists. The transfer of care can be challenging for both the young adult patients and their adult rheumatologists, in large part due to differences between pediatric-onset rheumatic diseases and their adult-onset counterparts, or due to the rarity of some pediatric-onset rheumatic conditions. Other challenges are due to cultural differences between pediatric and adult medical care and to the young adult needing to increasingly perform self-management skills that were previously managed by parents or other caregivers. In this review, we will provide a summary of strategies for working effectively with young adults as they transition to adult care. We will then discuss a subset of childhood-onset rheumatic diseases-including juvenile idiopathic arthritis, localized scleroderma, autoinflammatory diseases, pediatric-onset systemic lupus erythematosus, juvenile-onset dermatomyositis, and autoimmune encephalitis-for which clinical manifestations, management, and prognosis frequently differ between pediatric onset and adult onset. Our aim is to highlight differences that make caring for this population of transitioning young adults unique, providing tools and knowledge to empower the adult rheumatologist to care for these young adults in ways that are evidence-based, effective, efficient, and rewarding.

Single center clinical analysis of macrophage activation syndrome complicating juvenile rheumatic diseases

BACKGROUND

Macrophage activation syndrome (MAS), an example of secondary hemophagocytic lymphohistiocytosis, is a potentially fatal complication of rheumatic diseases. We aimed to study the clinical and laboratory characteristics, treatment schemes, and outcomes of different rheumatic disorders associated with MAS in children. Early warning indicators of MAS have also been investigated to enable clinicians to make a prompt and accurate diagnosis.

METHODS

Fifty-five patients with rheumatic diseases complicated by MAS were enrolled between January 2017 and December 2022. Clinical and laboratory data were collected before disease onset, at diagnosis, and after treatment with MAS, and data were compared between patients with systemic juvenile idiopathic arthritis (sJIA), Kawasaki disease (KD), and systemic lupus erythematosus (SLE). A random forest model was established to show the importance score of each variable with a significant difference.

RESULTS

Most (81.8%) instances of MAS occurred during the initial diagnosis of the underlying disease. Compared to the active stage of sJIA, the platelet count, erythrocyte sedimentation rate, and fibrinogen level in sJIA-MAS were significantly decreased, whereas ferritin, ferritin/erythrocyte sedimentation rate, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and D-dimer levels were significantly increased. Ferritin level, ferritin/erythrocyte sedimentation rate, and platelet count had the greatest predictive value for sJIA-MAS. The level of IL-18 in the sJIA-MAS group was significantly higher than in the active sJIA group, whereas IL-6 levels were significantly lower. Most patients with MAS were treated with methylprednisolone pulse combined with cyclosporine, and no deaths occurred.

CONCLUSIONS

Thrombocytopenia, ferritin levels, the ferritin/erythrocyte sedimentation rate, and elevated aspartate aminotransferase levels can predict the occurrence of MAS in patients with sJIA. Additionally, our analysis indicates that IL-18 plays an important role in the pathogenesis of MAS in sJIA-MAS.

Cytokine profiles associated with disease severity and prognosis of autoimmune pulmonary alveolar proteinosis

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is characterized by an abnormal accumulation of surfactants in the alveoli. Most cases are classified as autoimmune PAP (APAP) because they are associated with autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF). However, GM-CSF autoantibody levels are unlikely to correlate with the disease severity or prognosis of APAP.

METHODS

We collected clinical records and measured 38 serum cytokine concentrations for consecutive patients with APAP. After exclusion of 21 cytokines because of undetectable levels, 17 cytokine levels were compared between low and high disease severity scores (DSSs). We also compared whole lung lavage (WLL)-free survival with cut-off values defined by receiver operating characteristic (ROC) curves of cytokine levels and WLL administration at 11 months.

RESULTS

Nineteen patients with APAP were enrolled in the study. Five were classified as DSS 1 or 2, while the others were classified as DSS 4 or 5. Comparison between DSS 1-2 and 4-5 revealed that the concentrations of IP-10 and GRO increased in the latter groups (p < 0.05). Fifteen patients underwent WLL. Comparison between those who underwent WLL within 11 months and the others showed that IP-10 and TNF-α were tended to be elevated in the former group (p = 0.082 and 0.057, respectively). The cut-off values of IP-10, 308.8 pg/mL and TNF-α, 19.1 pg/mL, defined by the ROC curves, significantly separated WLL-free survivals with log-rank analyses (p = 0.005).

CONCLUSIONS

The concentrations of IP-10 and GRO may reflect the DSSs of APAP. A combination of IP-10 and TNF-α levels could be a biomarker to predict WLL-free survival.

New discoveries in the genetics and genomics of systemic juvenile idiopathic arthritis

INTRODUCTION

Systemic juvenile idiopathic arthritis (sJIA) is a severe inflammatory condition with onset in childhood. It is sporadic, but elements of its stereotypical innate immune responses are likely genetically encoded by both common variants with small effect sizes and rare variants with larger effects.

AREAS COVERED

Genomic investigations have defined the unique genetic architecture of sJIA. Identification of the class II HLA locus as the strongest sJIA risk factor for the first time brought attention to T lymphocytes and adaptive immune mechanisms in sJIA. The importance of the human leukocyte antigen (HLA) locus was reinforced by recognition that HLA-DRB1*15 alleles are strongly associated with development of drug reactions and sJIA-associated lung disease (sJIA-LD). At the IL1RN locus, genetic variation relates to both risk of sJIA and may also predict non-response to anakinra. Finally, rare genetic variants may have critical roles in disease complications, such as homozygous LACC1 mutations in families with an sJIA-like illness, and hemophagocytic lymphohistiocytosis (HLH) gene variants in some children with macrophage activation syndrome (MAS).

EXPERT OPINION

Genetic and genomic analysis of sJIA holds great promise for both basic discovery of the course and complications of sJIA, and may help guide personalized medicine and therapeutic decision-making.

The Systemic Score May Identify Life-Threatening Evolution in Still Disease: Data from the GIRRCS AOSD-Study Group and the AIDA Network Still Disease Registry

OBJECTIVE

We aimed to evaluate the clinical usefulness of the systemic score in the prediction of life-threatening evolution in Still disease. We also aimed to assess the clinical relevance of each component of the systemic score in predicting life-threatening evolution and to derive patient subsets accordingly.

METHODS

A multicenter, observational, prospective study was designed including patients included in the Gruppo Italiano Di Ricerca in Reumatologia Clinica e Sperimentale Adult-Onset Still Disease Study Group and the Autoinflammatory Disease Alliance Network Still Disease Registry. Patients were assessed to see if the variables to derive the systemic score were available. The life-threatening evolution was defined as mortality, whatever the clinical course, and/or macrophage activation syndrome, a secondary hemophagocytic lymphohistiocytosis associated with a poor prognosis.

RESULTS

A total of 597 patients with Still disease were assessed (mean ± SD age 36.6 ± 17.3 years; male 44.4%). The systemic score, assessed as a continuous variable, significantly predicted the life-threatening evolution (odds ratio [OR] 1.24; 95% confidence interval [CI] 1.07-1.42; P = 0.004). A systemic score ≥7 also significantly predicted the likelihood of a patient experiencing life-threatening evolution (OR 3.36; 95% CI 1.81-6.25; P < 0.001). Assessing the clinical relevance of each component of the systemic score, liver involvement (OR 1.68; 95% CI 1.48-2.67; P = 0.031) and lung disease (OR 2.12; 95% CI 1.14-4.49; P = 0.042) both significantly predicted life-threatening evolution. The clinical characteristics of patients with liver involvement and lung disease were derived, highlighting their relevance in multiorgan disease manifestations.

CONCLUSION

The clinical utility of the systemic score was shown in identifying Still disease at a higher risk of life-threatening evolution in a large cohort. Furthermore, the clinical relevance of liver involvement and lung disease was highlighted.

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.

Pediatric systemic juvenile idiopathic arthritis-related lung disease: Description of clinical cohort and review of management

CONTEXT

Since the early 2010s, there has been an increased awareness of interstitial lung disease in systemic juvenile idiopathic arthritis (sJIA-LD) in pediatric patients. Despite the increase in prevalence of sJIA-LD, little is known about this disease process and effective therapeutic management.

OBJECTIVES

To identify and characterize the disease process and management of interstitial lung disease related to systemic juvenile idiopathic arthritis.

STUDY DESIGN

In this single-center, retrospective case series of 9 patients, we analyze demographic, clinical, radiographic, and laboratory data to corroborate common clinical characteristics and describe an approach for diagnosis and monitoring of sJIA-LD.

DATA EXTRACTION

All data was extracted through electronic medical records and individually reviewed by two pediatric pulmonologists and two pediatric rheumatologists.

RESULTS

Our results were similar to other described cases of sJIA-LD as patients in our cohort were more likely to be younger, have a history of macrophage activation syndrome and prior use of biologic therapies. In contrast to prior studies, they did not present with peripheral lymphadenopathy and hepatosplenomegaly.

LIMITATIONS

The cohort size was small and data is reflective of one center's approach to management of a rare lung disease process.

CONCLUSION

Interstitial lung disease due to sJIA is rare and management can be difficult in these complex patients.More research is necessary to understand the increased incidence and treatment of sJIA-LD in pediatric population.

Disease Course, Treatments, and Outcomes of Children With Systemic Juvenile Idiopathic Arthritis-Associated Lung Disease

OBJECTIVE

Systemic juvenile idiopathic arthritis-associated lung disease (SJIA-LD) is a life-threatening disease complication. Key questions remain regarding clinical course and optimal treatment approaches. The objectives of the study were to detail management strategies after SJIA-LD detection, characterize overall disease courses, and measure long-term outcomes.

METHODS

This was a prospective cohort study. Clinical data were abstracted from the electronic medical record, including current clinical status and changes since diagnosis. Serum biomarkers were determined and correlated with presence of LD.

RESULTS

We enrolled 41 patients with SJIA-LD, 85% with at least one episode of macrophage activation syndrome and 41% with adverse reactions to a biologic. Although 93% of patients were alive at last follow-up (median 2.9 years), 37% progressed to requiring chronic oxygen or other ventilator support, and 65% of patients had abnormal overnight oximetry studies, which changed over time. Eighty-four percent of patients carried the HLA-DRB1*15 haplotype, significantly more than patients without LD. Patients with SJIA-LD also showed markedly elevated serum interleukin-18 (IL-18), variable C-X-C motif chemokine ligand 9 (CXCL9), and significantly elevated matrix metalloproteinase 7. Treatment strategies showed variable use of anti-IL-1/6 biologics and addition of other immunomodulatory treatments and lung-directed therapies. We found a broad range of current clinical status independent of time from diagnosis or continued biologic treatment. Multidomain measures of change showed imaging features were the least likely to improve with time.

CONCLUSION

Patients with SJIA-LD had highly varied courses, with lower mortality than previously reported but frequent hypoxia and requirement for respiratory support. Treatment strategies were highly varied, highlighting an urgent need for focused clinical trials.

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.

Part 5: Allogeneic HSCT in refractory SJIA with lung disease; recent cases from centers in North America & Europe

It has been increasingly recognized that there is a subset of patients with refractory systemic JIA, who have failed all available medications and may benefit from HSCT. The increasing experience with HSCT in SJIA, suggests that despite the complicated post-HSCT course, short-term, the transplanted patients either achieved SJIA remission or reduced burden of disease. Longer follow-up, however, is needed to better define the long-term outcomes. The discussion at the NextGen 2022 conference was focused on the optimal timing for the procedure, the need for a good control of inflammatory SJIA activity prior to HSCT, and the role of the reduced intensity conditioning regimens as there was a remote concern that such regimens might increase the risk of SJIA relapse after the transplantation. There was unanimous agreement about the importance of long-term registries to address these questions.

The 4th NextGen therapies for SJIA and MAS: part 2 phenotypes of refractory SJIA and the landscape for clinical trials in refractory SJIA

Although the introduction of the IL-1 and IL-6 inhibiting biologics in 2012 has revolutionized the treatment and markedly improved outcomes for many patients with SJIA, about 20% of these patients continue to have active disease, have markedly decreased quality of life and high disease activity as well as treatment-related morbidity and mortality. There is a clear need to define these disease states, and then use these definitions as the basis for further studies into the prevalence, clinical features, and pathophysiologic mechanisms. While such patients are most likely to benefit from novel therapies, they are very difficult to enroll in the ongoing clinical trials given the unique features of their disease and large numbers of background medications. The discussions at the NextGen 2022 conference focused on strategies to overcome these obstacles and accelerate studies in refractory SJIA.

The 4th NextGen therapies of SJIA and MAS, part 4: it is time for IL-18 based trials in systemic juvenile idiopathic arthritis?

Since IL-18 has recently emerged as a biomarker associated with refractory disease course in SJIA, the focus of the discussion was the feasibility of the biomarker-driven drug development to SJIA. Overall, there was broad agreement on the conclusion that IL-18 is a uniquely specific biomarker for many of the subsets of SJIA most in need of new therapies, and it may define a class of diseases mediated by IL-18 excess. The consensus was that leveraging IL-18 remains our most promising "lead" for use in refractory SJIA as it may mechanistically explain the disease pathophysiology and lead to more targeted therapies.

The 4th NextGen therapies for SJIA and MAS: part 3 clinical trials in refractory SJIA: historic controls as an alternative to a withdrawal design study

The substantial morbidity and mortality associated with refractory systemic JIA underlies the need for new treatment approaches. However, progress in this area has been limited by the difficulty of enrolling these patients in clinical trials with traditional designs, particularly in patients presenting with the life-threatening macrophage activation syndrome. At the NextGen 2022 conference, there was group consensus that using historical cohorts as a control group to avoid the need for a placebo-arm or drug withdrawal was highly desirable and might be acceptable for clinical trials in MAS to support medication efficacy and safety. However, if historic controls were used in a trial, it would be important to ensure that the historic cohort matches the study group in terms of clinical characteristics (such as disease severity and exposure to other medications), and that disease outcome in both groups is assessed using the same outcome measures. The discussions at the NextGen 2022 conference focused on the potential strategies to achieve these goals.

[Lung involvement in autoinflammatory diseases]

Genetic autoinflammatory diseases are now a recognized and rapidly expanding group. The lung involvement historically associated with autoinflammatory diseases is inflammatory seritis, primarily seen in familial Mediterranean fever and other interleukin-1 mediated diseases. Over the last ten years, pulmonary involvement has been the core presentation of two autoinflammatory diseases associated with constitutive type I interferon activation, i.e. SAVI and COPA syndrome. Most patients with these diseases usually develop early progression to pulmonary fibrosis, which is responsible for high rates of morbidity and mortality. Other rare autoinflammatory diseases are associated with alveolar proteinosis, particularly when related to MARS mutations. Additionally, in adults, VEXAS is frequently associated with pulmonary involvement, albeit without prognosis effect. A molecular approach to autoinflammatory diseases enables not only the definition of biomarkers for diagnosis, but also the identification of targeted treatments. Examples include JAK inhibitors in SAVI and COPA syndrome, even though this therapy does not prevent progression to pulmonary fibrosis. Another illustrative example is the efficacy of methionine supplementation in alveolar proteinosis linked to MARS mutations. Overall, in autoinflammatory diseases the lung is now emerging as a possible affected organ. Continuing discovery of new autoinflammatory diseases is likely to uncover further pathologies involving the lung. Such advances are expected to lead to the development of novel therapeutic perspectives.

Recombinant Interleukin-1 Receptor Antagonist Is an Effective First-Line Treatment Strategy in New-Onset Systemic Juvenile Idiopathic Arthritis, Irrespective of HLA-DRB1 Background and IL1RN Variants

OBJECTIVE

Human leukocyte antigen (HLA)-DRB1*15:01 has been recently associated with interstitial lung disease (LD), eosinophilia, and drug reactions in systemic juvenile idiopathic arthritis (sJIA). Additionally, genetic variants in IL1RN have been linked to poor response to anakinra. We sought to reproduce these findings in a prospective cohort study of patients with new-onset sJIA treated with anakinra as first-line therapy.

METHODS

HLA and IL1RN risk alleles were identified via whole-genome sequencing. Treatment responses and complications were compared between carriers versus noncarriers.

RESULTS

Seventeen of 65 patients (26%) carried HLA-DRB1*15:01, comparable with the general population, and there was enrichment for HLA-DRB1*11:01, a known risk locus for sJIA. The rates of clinical inactive disease (CID) at 6 months, 1 year, and 2 years were generally high, irrespective of HLA-DRB1 or IL1RN variants, but significantly lower in carriers of an HLA-DRB1*11:01 allele. One patient, an HLA-DRB1*15:01 carrier, developed sJIA-LD. Of the three patients with severe drug reactions to biologics, one carried HLA-DRB1*15:01. The prevalence of eosinophilia did not significantly differ between HLA-DRB1*15:01 carriers and noncarriers at disease onset (6.2% vs 14.9%, P = 0.67) nor after the start of anakinra (35.3% vs 37.5% in the first 2 years of disease).

CONCLUSION

We observed high rates of CID using anakinra as first-line treatment irrespective of HLA-DRB1 or IL1RN variants. Only one of the 17 HLA-DRB1*15:01 carriers developed sJIA-LD, and of the three patients with drug reactions to biologics, only one carried HLA-DRB1*15:01. Although thorough monitoring for the development of drug hypersensitivity and refractory disease courses in sJIA, including sJIA-LD, remains important, our data support the early start of biologic therapy in patients with new-onset sJIA irrespective of HLA-DRB1 background or IL1RN variants.

Biological and clinical roles of IL-18 in inflammatory diseases

Several new discoveries have revived interest in the pathogenic potential and possible clinical roles of IL-18. IL-18 is an IL-1 family cytokine with potent ability to induce IFNγ production. However, basic investigations and now clinical observations suggest a more complex picture. Unique aspects of IL-18 biology at the levels of transcription, activation, secretion, neutralization, receptor distribution and signalling help to explain its pleiotropic roles in mucosal and systemic inflammation. Blood biomarker studies reveal a cytokine for which profound elevation, associated with detectable 'free IL-18', defines a group of autoinflammatory diseases in which IL-18 dysregulation can be a primary driving feature, the so-called 'IL-18opathies'. This impressive specificity might accelerate diagnoses and identify patients amenable to therapeutic IL-18 blockade. Pathogenically, human and animal studies identify a preferential activation of CD8+ T cells over other IL-18-responsive lymphocytes. IL-18 agonist treatments that leverage the site of production or subversion of endogenous IL-18 inhibition show promise in augmenting immune responses to cancer. Thus, the unique aspects of IL-18 biology are finally beginning to have clinical impact in precision diagnostics, disease monitoring and targeted treatment of inflammatory and malignant diseases.

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.

Janus Kinase Inhibitors and Interstitial Lung Disease Associated With Pediatric Rheumatic Diseases: An Unexplored Field

Rheumatic diseases are often complicated by lung disease, commonly presenting as interstitial lung disease (ILD), with potentially detrimental consequences for patient survival. Although less frequent in pediatric patients, pulmonary involvement may be observed in almost all childhood-onset rheumatic conditions. The development of biological disease-modifying anti-rheumatic drugs has significantly improved clinical outcomes. However, disease remission is not always complete or long-lasting, and treatment may need to be discontinued due to adverse effects. A novel class of drugs, namely Janus kinase inhibitors (JAKis), has been proposed to provide a significant survival benefit for patients with rheumatic diseases. Despite the ample literature on the efficacy and safety of JAKis in rheumatic disease, only a few studies have investigated the effectiveness of these drugs in patients with pulmonary involvement, and only two case reports have presented results in pediatric patients. We provide an overview of the rationale for using JAKis in ILDs associated with rheumatic disease and summarize the main studies evaluating their efficacy in both adult and pediatric patients. The present review highlights the need for controlled long-term studies to assess the efficacy and safety of JAKis in pediatric rheumatic disease complicated by lung disease.

Treatment of systemic juvenile idiopathic arthritis

Systemic juvenile idiopathic arthritis (sJIA) is an inflammatory disease with hallmarks of severe systemic inflammation, which can be accompanied by arthritis. Contemporary scientific insights set this paediatric disorder on a continuum with its counterpart, adult-onset Still disease (AOSD). Patients with sJIA are prone to complications, including life-threatening hyperinflammation (macrophage activation syndrome (sJIA-MAS)) and sJIA-associated lung disease (sJIA-LD). Meanwhile, the treatment arsenal in sJIA has expanded markedly. State-of-the-art therapeutic approaches include biologic agents that target the IL-1 and IL-6 pathways. Beyond these, a range of novel agents are on the horizon, some of them already being used on a compassionate use basis, including JAK inhibitors and biologic agents that target IL-18, IFNγ, or IL-1β and IL-18 simultaneously. However, sJIA, sJIA-MAS and sJIA-LD still pose challenging conundrums to rheumatologists treating paediatric and adult patients worldwide. Although national and international consensus treatment plans exist for the treatment of 'classic' sJIA, the treatment approaches for early sJIA without arthritis, and for refractory or complicated sJIA, are not well defined. Therefore, in this Review we outline current approaches for the treatment of sJIA and provide an outlook on knowledge gaps.

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.

Diagnosis and Management of the Systemic Juvenile Idiopathic Arthritis Patient with Emerging Lung Disease

Chronic lung disease in children with systemic juvenile idiopathic arthritis (SJIA-LD) is an emerging and potentially life-threatening disease complication. Despite recent descriptions of its clinical spectrum, preliminary immunologic characterization, and proposed hypotheses regaarding etiology, optimal approaches to diagnosis and management remain unclear. Here, we review the current clinical understanding of SJIA-LD, including the potential role of biologic therapy in disease pathogenesis, as well as the possibility of drug reactions with eosinophilia and systemic symptoms (DRESS). We discuss approaches to evaluation of children with suspected SJIA-LD, including a proposed algorithm to risk-stratify all SJIA patients for screening to detect LD early. We review potential pharmacologic and non-pharmacologic treatment approaches that have been reported for SJIA-LD or utilized in interstitial lung diseases associated with other rheumatic diseases. This includes lymphocyte-targeting therapies, JAK inhibitors, and emerging therapies against IL-18 and IFNγ. Finally, we consider urgent unmet needs in this area including in basic discovery of disease mechanisms and clinical research to improve disease detection and patient outcomes.

Molecular Pathways in the Pathogenesis of Systemic Juvenile Idiopathic Arthritis

Systemic juvenile idiopathic arthritis (sJIA) is a rare childhood chronic inflammatory disorder with risk for life-threatening complications including macrophage activation syndrome and lung disease. At onset, sJIA pathogenesis resembles that of the autoinflammatory periodic fever syndromes with marked innate immune activation, expansion of neutrophils and monocytes, and high levels of interleukin-18. Here, we review the current conceptual understanding of sJIA pathogenesis with a focus on both innate and adaptive immune pathways. Finally, we consider how recent progress toward understanding the immunologic basis of sJIA may support new therapies for refractory disease courses.

Derivation and validation of four patient clusters in Still's disease, results from GIRRCS AOSD-study group and AIDA Network Still Disease Registry

BACKGROUND

Different patient clusters were preliminarily suggested to dissect the clinical heterogeneity in Still's disease. Thus, we aimed at deriving and validating disease clusters in a multicentre, observational, prospective study to stratify these patients.

METHODS

Patients included in GIRRCS AOSD-study group and AIDA Network Still Disease Registry were assessed if variables for cluster analysis were available (age, systemic score, erythrocyte sedimentation rate (ESR), C reactive protein (CRP) and ferritin). K-means algorithm with Euclidean metric and Elbow plot were used to derive an adequate number of clusters.

RESULTS

K-means clustering assessment provided four clusters based on means standardised according to z-scores on 349 patients. All clusters mainly presented fever, skin rash and joint involvement. Cluster 1 was composed by 115 patients distinguished by lower values of age and characterised by skin rash myalgia, sore throat and splenomegaly. Cluster 2 included 128 patients identified by lower levels of ESR, ferritin and systemic score; multiorgan manifestations were less frequently observed. Cluster 3 comprised 31 patients categorised by higher levels of CRP and ferritin, they were characterised by fever and joint involvement. Cluster 4 contained 75 patients derived by higher values of age and systemic score. Myalgia, sore throat, liver involvement and life-threatening complications, leading to a high mortality rate, were observed in these patients.

CONCLUSIONS

Four patient clusters in Still's disease may be recognised by a multidimensional characterisation ('Juvenile/Transitional', 'Uncomplicated', 'Hyperferritinemic' and 'Catastrophic'). Of interest, cluster 4 was burdened by an increased rate of life-threatening complications and mortality, suggesting a more severe patient group.

Clinical and laboratory features associated with macrophage activation syndrome in Still's disease: data from the international AIDA Network Still's Disease Registry

To characterize clinical and laboratory signs of patients with Still's disease experiencing macrophage activation syndrome (MAS) and identify factors associated with MAS development. Patients with Still's disease classified according to internationally accepted criteria were enrolled in the AutoInflammatory Disease Alliance (AIDA) Still's Disease Registry. Clinical and laboratory features observed during the inflammatory attack complicated by MAS were included in univariate and multivariate logistic regression analysis to identify factors associated to MAS development. A total of 414 patients with Still's disease were included; 39 (9.4%) of them developed MAS during clinical history. At univariate analyses, the following variables were significantly associated with MAS: classification of arthritis based on the number of joints involved (p = 0.003), liver involvement (p = 0.04), hepatomegaly (p = 0.02), hepatic failure (p = 0.01), axillary lymphadenopathy (p = 0.04), pneumonia (p = 0.03), acute respiratory distress syndrome (p < 0.001), platelet abnormalities (p < 0.001), high serum ferritin levels (p = 0.009), abnormal liver function tests (p = 0.009), hypoalbuminemia (p = 0.002), increased LDH (p = 0.001), and LDH serum levels (p < 0.001). At multivariate analysis, hepatomegaly (OR 8.7, 95% CI 1.9-52.6, p = 0.007) and monoarthritis (OR 15.8, 95% CI 2.9-97.1, p = 0.001), were directly associated with MAS, while the decade of life at Still's disease onset (OR 0.6, 95% CI 0.4-0.9, p = 0.045), a normal platelet count (OR 0.1, 95% CI 0.01-0.8, p = 0.034) or thrombocytosis (OR 0.01, 95% CI 0.0-0.2, p = 0.008) resulted to be protective. Clinical and laboratory factors associated with MAS development have been identified in a large cohort of patients based on real-life data.

Incidence and Risk Factors for Eosinophilia and Lung Disease in Biologic-Exposed Children With Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

Although interleukin-1 (IL-1)/IL-6 inhibitors are effective therapies for systemic juvenile idiopathic arthritis (JIA), some patients develop eosinophilia and lung disease during treatment. This study was undertaken to retrospectively evaluate incidence and risk factors for eosinophilia and describe lung disease outcomes in IL-1/IL-6 inhibitor-exposed patients with systemic JIA.

METHODS

Among JIA patients at our institution exposed to interleukin-1 (IL-1)/IL-6 inhibitors (1995-2022), we compared incidence rate of eosinophilia in systemic JIA compared to other JIA, stratified by medication class (IL-1/IL-6 inhibitors, other cytokine inhibitors, methotrexate). We used Cox models to identify predictors of eosinophilia during IL-1/IL-6 inhibitor use and summarized treatment changes and outcomes after eosinophilia, including lung disease. HLA typing was performed on a clinical or research basis.

RESULTS

There were 264 new medication exposures in 75 patients with systemic JIA and 41 patients with other JIA. A total of 49% of patients with systemic JIA with HLA typing (n = 45) were positive for HLA-DRB1*15 alleles. Eosinophilia was common during IL-1/IL-6 inhibitor use and did not differ by systemic JIA compared to other JIA (0.08 and 0.07 per person-year, respectively; P = 0.30). Among systemic JIA patients, pretreatment macrophage activation syndrome (MAS) was associated with a higher rate of subsequent eosinophilia on biologic therapy (unadjusted hazard ratio 3.2 [95% confidence interval 1.2-8.3]). A total of 4 of 5 patients who switched therapy within 10 weeks of eosinophilia experienced disease flare compared to none of the patients who continued the original therapy. A total of 8 of 25 patients with pulmonary evaluations had lung disease, and all had severe manifestations of systemic JIA (MAS, intensive care unit stay). One death was attributed to systemic JIA-lung disease.

CONCLUSION

Eosinophilia is common in JIA patients using IL-1/IL-6 inhibitors. Severe disease may be associated with eosinophilia and lung disease in systemic JIA.

HLA-DRB1*15 and Eosinophilia Are Common Among Patients With Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

Concern exists that medications used to treat patients with systemic juvenile idiopathic arthritis (JIA), particularly interleukin (IL)-1 and IL-6 blocking agents, might be causing adverse drug reactions and lung disease (systemic JIA-LD). Carriage of HLA-DRB1*15 has been reported as a risk factor for adverse drug reactions among patients with systemic JIA. We performed a retrospective chart review to evaluate these factors at our center.

METHODS

We reviewed the records of 86 subjects with systemic JIA followed for at least 6 months between 1996 and 2022. HLA typing was performed in 23 of the subjects. We compared characteristics of patients with or without eosinophilia. Among patients with HLA typing, we compared clinical characteristics of subjects with or without DRB1*15 and with or without systemic JIA-LD.

RESULTS

Among the 23 patients with HLA typing, 74% carried DRB1*15, and 63% of patients without systemic JIA-LD carried DRB1*15. Seven subjects had systemic JIA-LD, all of whom carried DRB1*15. Patients with systemic JIA-LD were younger at the time of diagnosis and more likely to have had macrophage activation syndrome. Exposure to IL-1 and IL-6 blockers was common, occurring in 95% of patients. Eosinophilia occurred in 39% of patients with systemic JIA, often before IL-1 or IL-6 blockade. Eosinophilia was associated with adverse drug reactions and macrophage activation syndrome. There was 1 death, unrelated to active systemic JIA disease.

CONCLUSION

Carriage of DRB1*15 was more common in this cohort of patients with systemic JIA than in the general population. Eosinophilia and systemic JIA-LD were more common among patients with severe systemic JIA complicated by macrophage activation syndrome.

Development of a Screening Algorithm for Lung Disease in Systemic Juvenile Idiopathic Arthritis

OBJECTIVE

Lung disease (LD) is an increasingly recognized complication of systemic juvenile idiopathic arthritis (sJIA). As there are no currently available guidelines for pulmonary screening in sJIA, we sought to develop such an algorithm at our institution.

METHODS

A multidisciplinary workgroup was convened, including members representing rheumatology, pulmonary, stem cell transplantation, and patient families. The workgroup leaders drafted an initial algorithm based on published literature and experience at our center. A modified Delphi approach was used to achieve agreement through three rounds of anonymous, asynchronous voting and a consensus meeting. Statements approved by the workgroup were rated as appropriate with moderate or high levels of consensus. These statements were organized into the final approved screening algorithm for LD in sJIA.

RESULTS

The workgroup ultimately rated 20 statements as appropriate with a moderate or high level of consensus. The approved algorithm recommends pulmonary screening for newly diagnosed patients with sJIA with clinical features that the workgroup agreed may confer increased risk for LD. These "red flag features" include baseline characteristics (young age of sJIA onset, human leukocyte antigen type, trisomy 21), high disease activity (macrophage activation syndrome [MAS], sJIA-related ICU admission, elevated MAS biomarkers), respiratory symptoms or abnormal pulmonary examination findings, and features of drug hypersensitivity-like reactions (eosinophilia, atypical rash, anaphylaxis). The workgroup achieved consensus on the recommended pulmonary work-up and monitoring guidelines.

CONCLUSION

We developed a pulmonary screening algorithm for sJIA-LD through a multidisciplinary consensus-building process, which will be revised as our understanding of sJIA-LD continues to evolve.

Systemic juvenile idiopathic arthritis: The Great Ormond Street Hospital experience (2005-2021)

Systemic juvenile idiopathic arthritis (sJIA) is a complex, systemic inflammatory disorder driven by both innate and adaptive immunity. Improved understanding of sJIA pathophysiology has led to recent therapeutic advances including a growing evidence base for the earlier use of IL-1 or IL-6 blockade as first-line treatment. We conducted a retrospective case notes review of patients diagnosed with sJIA over a 16-year period (October 2005-October 2021) at Great Ormond Street Hospital for Children. We describe the clinical presentation, therapeutic interventions, complications, and remission rates at different timepoints over the disease course. We examined our data, which spanned a period of changing therapeutic landscape, to try and identify potential therapeutic signals in patients who received biologic treatment early in the disease course compared to those who did not. A total of 76-children (female n = 40, 53%) were diagnosed with sJIA, median age 4.5 years (range 0.6-14.1); 36% (27/76) presented with suspected or confirmed macrophage activation syndrome. A biologic disease-modifying anti-rheumatic drug (bDMARD) alone was commenced as first-line treatment in 28% (n = 21/76) of the cohort; however, at last review, 84% (n = 64/76) had received treatment with a bDMARD. Clinically inactive disease (CID) was achieved by 88% (n = 67/76) of the cohort at last review; however, only 32% (24/76) achieved treatment-free CID. At 1-year follow-up, CID was achieved in a significantly greater proportion of children who received treatment with a bDMARD within 3 months of diagnosis compared to those who did not (90% vs. 53%, p = 0.002). Based on an ever-increasing evidence base for the earlier use of bDMARD in sJIA and our experience of the largest UK single-centre case series described to date, we now propose a new therapeutic pathway for children diagnosed with sJIA in the UK based on early use of bDMARDs. Reappraisal of the current National Health Service commissioning pathway for sJIA is now urgently required.

Lipid profiles in patients with juvenile idiopathic arthritis: a systematic literature review and meta-analysis

OBJECTIVE

The purpose of this study was to comprehensively evaluate the lipid profiles in patients with juvenile idiopathic arthritis (JIA).

METHODS

The literature and relevant reviews were searched for published clinical studies on the relationship between JIA and blood lipid levels. The Newcastle-Ottawa scale (NOS) was applied to evaluate the risk and methodological value of the included case‒control and cohort studies. Standardized mean differences (SMDs) and 95% confidence intervals were derived for all variables with adequate unprocessed data. This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines.

RESULTS

In total, 16 studies were incorporated through screening. The analysis findings revealed that the levels of very low-density lipoprotein cholesterol [SMD=-0.411, 95% CI (-0.774~-0.048), P = 0.026], high-density lipoprotein cholesterol [SMD=-0.528, 95% CI (-0.976~-0.079), P = 0.021], and apolipoprotein A1 [SMD=-1.050, 95% CI (-1.452~-0.647), P = 0.000] in JIA patients were statistically lower than those observed in healthy controls. The level of low-density lipoprotein cholesterol [SMD = 0.202, 95% CI (0.003 ~ 0.400), P = 0.046] was significantly higher in JIA patients than in healthy controls. In JIA patients, body mass index [SMD=-0.189, 95% CI (-0.690 ~ 0.311), P = 0.459], high-density lipoprotein [SMD =-1.235, 95% CI (-2.845 ~ 0.374), P = 0.133), low-density lipoprotein [SMD = 0.616, 95% CI (-0.813 ~ 2.046), P = 0.398), triglycerides (SMD = 0.278, 95% CI (-0.182 ~ 0.738), P = 0.236], total cholesterol [SMD=-0.073, 95% CI (-0.438 ~ 0.293), P = 0.696] and apolipoprotein B levels [SMD = 0.226, 95% CI (-0.133 ~ 0.585), P = 0.217] were not significantly different from those in healthy controls.

CONCLUSIONS

The outcomes of this meta-analysis suggest that dyslipidemia is common in JIA patients compared to healthy controls. Patients with JIA have a significantly increased risk of atherosclerosis and cardiovascular disease later in life.

New developments related to lung complications in pediatric rheumatic disease

PURPOSE OF REVIEW

While substantial progress has been made understanding lung disease in adult patients with rheumatic disease, pediatric lung disease has not been well addressed. Several recent studies provide new insights into diagnosis, management and treatment of lung disease in children with rheumatic disease.

RECENT FINDINGS

Building on previous research, newly diagnosed patients may have abnormalities in pulmonary function tests and chest computed tomography imaging even when asymptomatic. New guidelines for screening for rheumatic-associated lung disease provide important recommendations for clinicians. New theories have been proposed about immunologic shifts leading to the development of lung disease in children with systemic juvenile idiopathic arthritis. Additionally, there are new antifibrotic agents that are being explored as treatments in pediatric patients with fibrotic lung diseases.

SUMMARY

Patients appear to have frequent lung function abnormalities while being clinically asymptomatic, emphasizing importance for rheumatologists to refer for pulmonary function tests and imaging at diagnosis. New advances are helping define optimal approaches to treatment of lung disease, including use of biologic agents and antifibrotic medicines for pediatric patients with rheumatologic diseases.

Lung Ultrasound in Children With Systemic Juvenile Idiopathic Arthritis-Associated Interstitial Lung Disease

OBJECTIVE

Systemic juvenile idiopathic arthritis (JIA) associated with lung disease (JIA-LD) is a potentially life threating complication in children with systemic JIA. Although high-resolution computed tomography (HRCT) is considered the gold standard imaging modality for evaluating interstitial lung disease (ILD), lung ultrasound (US) has shown utility for ILD screening in adults with connective tissue diseases at lower cost and without using ionizing radiation. The goals of this pilot study were to describe lung US features in children with known systemic JIA-LD and to assess the feasibility of lung US in this population.

METHODS

Children age <18 years with systemic JIA-LD and healthy controls were enrolled. Lung US acquisition was performed at 14 lung positions. Demographic, clinical, and HRCT data were collected and reviewed. Feasibility was assessed through patient surveys. Lung US findings were qualitatively and semiquantitatively assessed and compared to HRCT findings.

RESULTS

Lung US was performed in 9 children with systemic JIA-LD and 6 healthy controls and took 12 minutes on average to perform. Lung US findings in systemic JIA-LD included focal to diffuse pleural irregularity, granularity, and thickening, with associated scattered or coalesced B-lines, and subpleural consolidations. Lung US findings appeared to correspond to HRCT findings.

CONCLUSION

Lung US in systemic JIA-LD reveals highly conspicuous abnormalities in the pleura and subpleura that appear to correlate with peripheral lung findings on HRCT. Lung US is a feasible imaging tool in children even from an early age. This study suggests a potential role of lung US in systemic JIA-LD screening, diagnosis, and/or prognostication.

Rescue of Pap-Mas in Systemic JIA Using Janus Kinase Inhibitors, Case Report and Systematic Review

INTRODUCTION

Biological disease-modifying anti-rheumatic drugs (bDMARDs) targeting interleukin (IL)-6 and IL-1β represent a steroid-sparing first-line therapy used in systemic-onset juvenile idiopathic arthritis (sJIA). Recently, the occurrence of pulmonary alveolar proteinosis (PAP) in sJIA patients was reported with early-onset and exposure to bDMARDs as potential risk factors. We report on a new case with longitudinal immunomonitoring successfully treated by Janus Kinase inhibitors (JAKi) and review past clinical descriptions of this new entity.

METHODS

We report one case of pulmonary alveolar proteinosis and macrophage activation syndrome (PAP-MAS) with longitudinal immunomonitoring. We then conducted a review of the literature of seven publications reporting 107 cases of PAP-MAS sJIA, and included the main characteristics and evolution under treatment.

RESULTS

Of the seven articles analyzed, the incidence of PAP-MAS among sJIA patients varied from 1.28% to 12.9%. We report here a single case among a cohort of 537 sJIA patients followed in the pediatric department of the Hospices Civils de Lyon over the last 15 years. This child presented with all clinical and immunological characteristics of PAP-MAS. After several lines of treatment, he benefited from JAKi and improved with respect to both systemic symptoms and lung disease. In the literature, strategies with monoclonal antibodies targeting either INF-γ or IL-1β/IL-18 have been tested with variable results. Orally taken JAKi presents the advantage of targeting multiple cytokines and avoiding parenteral injections of monoclonal antibodies that may contribute to the pathogenesis.

CONCLUSIONS

JAKi represent a promising option in the treatment of lung disease associated with sJIA.

Mouse models of systemic juvenile idiopathic arthritis and macrophage activation syndrome

Macrophage activation syndrome (MAS) is a life-threatening complication of pediatric rheumatic diseases, occurring most commonly in children with systemic juvenile idiopathic arthritis (SJIA). Despite several classes of currently available treatment options for SJIA, including biologic agents targeting IL-1 or IL-6, there remain severe cases suffering from refractory disease and recurrent MAS. The phenotype of MAS is similar to hemophagocytic lymphohistiocytosis (HLH), but the underlying pathophysiology of MAS complicating SJIA or other disorders has not been fully clarified. These facts make it challenging to develop and utilize animal models to study MAS. To date, there is no "perfect" model replicating MAS, but several models do demonstrate aspects of SJIA and/or MAS. In this review, we examine the proposed animal models of SJIA and MAS, focusing on how they reflect these disorders, what we have learned from the models, and potential future research questions. As we better understand the key features of each, animal models can be powerful tools to further define the pathophysiology of SJIA and MAS, and develop new treatment targets and strategies.

Clinical Presentation and Treatment of Juvenile Idiopathic Arthritis Combined with Lung Disease: A Narrative Review

Juvenile idiopathic Arthritis (JIA) is a common rheumatic disorder in children that can cause multiple systems to be affected simultaneously, leading to severe clinical symptoms and a high mortality rate in those with pulmonary involvement. Pleurisy is the most common manifestation of pulmonary involvement. At the same time, other conditions, such as pneumonia, interstitial lung disease, occlusive bronchiectasis, and alveolar protein deposition, have been increasingly reported in recent years. This review aims to provide an overview of the clinical manifestations of JIA lung damage and the current treatment options to assist in identifying and treating JIA lung involvement.

Imaging findings of COPA Syndrome

BACKGROUND

Autosomal dominant mutations in the coatomer-associated protein alpha (COPA) gene cause an immune dysregulation disorder associated with pulmonary hemorrhage, lymphoid hyperplasia, arthritis, and glomerulonephritis.

OBJECTIVE

To describe the thoracic, musculoskeletal, and renal imaging findings of COPA syndrome with a focus on the evolution of the pulmonary findings.

MATERIALS AND METHODS

With approval of the Institutional Review Board, consensus retrospective review of findings on chest radiography and computed tomography (CT), musculoskeletal radiography and magnetic resonance imaging (MRI), and renal ultrasound (US) was performed for pediatric COPA syndrome patients. COPA syndrome patients < 18 years of age presenting between 1992 and 2019 were identified from an institutional rheumatology registry.

RESULTS

Twelve pediatric COPA syndrome patients (mean age of 6.5 years at first imaging exam; 6 females) were identified. Imaging exams available for review included 45 chest CT exams on 12 patients, 37 musculoskeletal exams on 4 patients, and 10 renal US exams on 5 patients. All 12 had abnormal chest CT exams, with findings including ground-glass opacities (12/12), cysts (8/12), septal thickening (9/12), nodules (8/12), fibrosis (7/12), crazy-paving (2/12), consolidation (1/12), hilar/mediastinal lymphadenopathy (11/12), and chest wall deformity (5/12). Nine had at least one follow-up chest CT, which showed improvement in nodules (7/9), ground-glass opacities (4/9), and lymphadenopathy (9/9), but worsening of septal thickening (3/9), cyst formation (3/9), and fibrosis (3/9). Four had musculoskeletal imaging revealing synovitis (2/4), bone erosions (1/4), tenosynovitis (1/4), enthesitis (1/4), and subcutaneous nodules (1/4). Five had at least one renal US, revealing renal size abnormalities (4/5) and cortical hyperechogenicity (3/5).

CONCLUSION

The most prevalent imaging finding of COPA syndrome is diffuse lung disease related to early childhood-onset recurrent pulmonary hemorrhage and lymphoid hyperplasia that may progress to pulmonary fibrosis. Other imaging findings manifesting later in childhood or adolescence relate to arthritis and glomerulonephritis.

Fibrosing Interstitial Lung Disease in Children: An HRCT-Based Analysis

OBJECTIVE

To determine high resolution CT (HRCT) patterns of pulmonary fibrosis (PF) in children; and their etiological correlates.

METHODS

This was a retrospective study involving 149 children with diffuse lung disease (DLD). Patterns of involvement were classified based on dominant lung finding as ground glass opacity (GGO) dominant, nodule dominant, cystic lung disease, or PF. Patterns of PF were classified based on distribution and morphology into airway centric fibrosis (ACF), subpleural fibrosis (SPF), progressive massive fibrosis (PMF) and fibrocavitary. A comparison was made between the two dominant groups for apicobasal distribution, associated findings (GGO, nodules, cysts), and pulmonary artery hypertension (PAH).

RESULTS

Nineteen patients showed PF on HRCT. ACF was commonest (52.6%), followed by SPF (42.1%). The common etiology was sarcoidosis (30%) in ACF, and connective tissue disorders (CTD) (50%) in SPF. Significant difference was found between ACF and SPF in apicobasal distribution (p = 0.04), presence of nodules (p = 0.03), and cysts (p = 0.02).

CONCLUSION

PF may present as an end stage of several childhood lung diseases. PF on imaging has discernible morphological patterns that correlate with underlying etiology.

Improvement of Refractory Systemic Juvenile Idiopathic Arthritis-Associated Lung Disease with Single-Agent Blockade of IL-1β and IL-18

Systemic juvenile idiopathic arthritis associated with interstitial lung disease (SJIA-LD) represents a highly morbid subset of SJIA for which effective therapies are lacking. We report the case of a patient with refractory SJIA-LD who underwent treatment with MAS-825, an investigational bispecific monoclonal antibody targeting IL-1β and IL-18. MAS-825 treatment was associated with a marked reduction in total IL-18 and free IL-18 in both serum and bronchoalveolar lavage fluid (BAL). Baseline oxygen saturation, exercise tolerance, and quality of life metrics improved after treatment with MAS-825, while pulmonary function testing remained stable. Following treatment, the BAL showed no evidence of pulmonary alveolar proteinosis and inflammatory infiltrates were markedly reduced, reflected by decreased numbers of CD4 T-cells, CD8 T-cells, and macrophages. The patient was able to wean entirely off systemic corticosteroids and other biologics after 10 months of treatment with MAS-825 and experienced no side effects of the drug. This case demonstrates improvement in pulmonary symptoms, lung inflammation, and burden of immunomodulatory therapy after treatment with MAS-825 and suggests that simultaneous targeting of both IL-1β and IL-18 may be a safe and effective treatment strategy in SJIA-LD.

Case report: Emapalumab for active disease control prior to hematopoietic stem cell transplantation in refractory systemic juvenile idiopathic arthritis complicated by macrophage activation syndrome

Introduction

Macrophage activation syndrome (MAS), a secondary form of hemophagocytic lymphohistiocytosis, is a serious life-threatening complication associated with systemic juvenile idiopathic arthritis (sJIA). MAS is characterized by fever, hepatosplenomegaly, liver dysfunction, cytopenias, coagulation abnormalities, and hyperferritinemia and may progress to multiple organ failure and death. Overproduction of interferon-gamma is a major driver of hyperinflammation in murine models of MAS and primary hemophagocytic lymphohistiocytosis. A subset of patients with sJIA may develop progressive interstitial lung disease, which is often difficult to manage. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can potentially be a curative immunomodulatory strategy for patients with sJIA refractory to conventional therapy and/or complicated by MAS. The use of emapalumab (anti-interferon gamma antibody) for the active control of MAS in refractory cases of sJIA and associated lung disease has not been reported. Herein we report a patient with refractory sJIA complicated by recurrent MAS and lung disease that was managed with emapalumab and ultimately followed by an allo-HSCT, which resulted in permanent correction of the underlying immune dysregulation and improvement of lung disease.

Case Report

We present a 4-year-old girl with sJIA complicated by recurrent MAS and progressive interstitial lung disease. She developed a progressively worsening disease that was refractory to glucocorticoids, anakinra, methotrexate, tocilizumab, and canakinumab. She had a chronic elevation of serum inflammatory markers, notably soluble interleukin-18, and CXC chemokine ligand 9 (CXCL9). Emapalumab, initiated at 6 mg/kg (1 dose) and continued at 3 mg/kg twice weekly for a total of 4 weeks, resulted in MAS remission along with normalization of inflammatory markers. The patient received a matched sibling donor allo-HSCT after a reduced-intensity conditioning regimen with fludarabine/melphalan/thiotepa and alemtuzumab, along with tacrolimus and mycophenolate mofetil for graft-vs.-host disease prophylaxis. At 20 months following her transplant, she has maintained a full donor engraftment with complete donor-derived immune reconstitution. She had complete resolution of sJIA symptoms including marked improvement in her lung disease along with normalization of serum interleukin-18 and CXCL9 levels.

Conclusion

The use of emapalumab followed by allo-HSCT could help achieve a complete response in refractory cases of sJIA complicated by MAS who have failed standard treatment.

Immune dysregulation

The understanding of immune dysregulation in many different diseases continues to grow. There is increasing evidence that altered microbiome and gut barrier dysfunction contribute to systemic inflammation in patients with primary immunodeficiency and in patients with rheumatic disease. Recent research provides insight into the process of induction and maturation of pathogenic age-associated B cells and highlights the role of age-associated B cells in creating tissue inflammation. T follicular regulatory cells are shown to help maintain B-cell tolerance, and therapeutic approaches to increase or promote T follicular regulatory cells may help prevent or decrease immune dysregulation. Meanwhile, novel studies of systemic-onset juvenile idiopathic arthritis reveal a strong HLA association with interstitial lung disease and identify key aspects of the pathogenesis of macrophage activation syndrome. Studies of hyperinflammatory syndromes, including the recently described multisystem inflammatory syndrome of children, characterize similarities and differences in cytokine profiles and T-cell activation. This review focuses on recent advances in the understanding of immune dysregulation and describes potential key factors that may function as biomarkers for disease or targets for therapeutic interventions. Future trials are necessary to address the many remaining questions with regards to pathogenesis, diagnosis, and treatment of autoimmune, inflammatory, and immunodeficiency syndromes.

First-line options for systemic juvenile idiopathic arthritis treatment: an observational study of Childhood Arthritis and Rheumatology Research Alliance Consensus Treatment Plans

BACKGROUND

The Childhood Arthritis and Rheumatology Research Alliance (CARRA) developed consensus treatment plans (CTPs) to compare treatment initiation strategies for systemic juvenile idiopathic arthritis (sJIA). First-line options for sJIA treatment (FROST) was a prospective observational study to assess CTP outcomes using the CARRA Registry.

METHODS

Patients with new-onset sJIA were enrolled if they received initial treatment according to the biologic CTPs (IL-1 or IL-6 inhibitor) or non-biologic CTPs (glucocorticoid (GC) monotherapy or methotrexate). CTPs could be used with or without systemic GC. Primary outcome was achievement of clinical inactive disease (CID) at 9 months without current use of GC. Due to the small numbers of patients in the non-biologic CTPs, no statistical comparisons were made between the CTPs.

RESULTS

Seventy-three patients were enrolled: 63 (86%) in the biologic CTPs and 10 (14%) in the non-biologic CTPs. CTP choice appeared to be strongly influenced by physician preference. During the first month of follow-up, oral GC use was observed in 54% of biologic CTP patients and 90% of non-biologic CTPs patients. Five (50%) non-biologic CTP patients subsequently received biologics within 4 months of follow-up. Overall, 30/53 (57%) of patients achieved CID at 9 months without current GC use.

CONCLUSION

Nearly all patients received treatment with biologics during the study period, and 46% of biologic CTP patients did not receive oral GC within the first month of treatment. The majority of patients had favorable short-term clinical outcomes. Increased use of biologics and decreased use of GC may lead to improved outcomes in sJIA.

Lung Involvement in Systemic Juvenile Idiopathic Arthritis: A Narrative Review

Systemic juvenile idiopathic arthritis associated with lung disorders (sJIA-LD) is a subtype of sJIA characterized by the presence of chronic life-threatening pulmonary disorders, such as pulmonary hypertension, interstitial lung disease, pulmonary alveolar proteinosis and/or endogenous lipoid pneumonia, which were exceptionally rare before 2013. Clinically, these children show a striking dissociation between the relatively mild clinical manifestations (tachypnoea, clubbing and chronic cough) and the severity of the pulmonary inflammatory process. Our review describes sJIA-LD as having a reported prevalence of approximately 6.8%, with a mortality rate of between 37% and 68%. It is often associated with an early onset (<2 years of age), macrophage activation syndrome and high interleukin (IL)-18 circulating levels. Other risk factors may be trisomy 21 and a predisposition to adverse reactions to biological drugs. The most popular hypothesis is that the increase in the number of sJIA-LD cases can be attributed to the increased use of IL-1 and IL-6 blockers. Two possible explanations have been proposed, named the “DRESS hypothesis” and the “cytokine plasticity hypothesis”. Lung ultrasounds and the intercellular-adhesion-molecule-5 assay seem to be promising tools for the early diagnosis of sJIA-LD, although high resolution computed tomography remains the gold standard. In this review, we also summarize the treatment options for sJIA-LD, focusing on JAK inhibitors.

Refractory systemic onset juvenile idiopathic arthritis: current challenges and future perspectives

Systemic juvenile idiopathic arthritis (SJIA) is a rare disease with distinct features not seen in other categories of juvenile idiopathic arthritis. In recent years, advances in the understanding of disease immunopathogenesis have led to improved targeted therapies with significant improvement in patient outcomes. Despite these advances, there remain subsets of SJIA with refractory disease and severe disease-associated complications. This review highlights existing options for treatment of refractory SJIA and explores potential future therapeutics for refractory disease.Key Points:Despite targeted Interleukin IL-1 and IL-6 inhibitors a subset of SJIA remains refractory to therapy. About 1 in 7 SJIA patients will be refractory to targeted IL-1 or IL-6 therapy.There is no current agreed upon definition for refractory SJIA and we propose in this review that refractory SJIA is presence of active systemic or arthritic features despite treatment with anti-IL-1 or anti-IL-6 therapy or disease requiring glucocorticoids for control beyond 6 months.SJIA disease associated complications include presence of associated macrophage activation syndrome (MAS), interstitial lung disease (ILD) or amyloidosis and management of each differs.Refractory SJIA treatment options currently include additional conventional synthetic disease modifying anti-rheumatic drugs (csDMARDS), biologic (bDMARDS), combination biologic therapy, targeted synthetic (tsDMARDS) or other immunomodulatory therapies.