Updates on Juvenile Dermatomyositis from the Last Decade: Classification to Outcomes

Efficacy and safety of rhGH in juvenile dermatomyositis children with glucocorticoid-related growth failure

OBJECTIVE

To evaluate the efficacy and safety of recombinant human growth hormone (rhGH) in children with JDM experiencing glucocorticoid (GC)-induced growth failure.

METHODS

A retrospective cohort study included 16 refractory JDM patients treated with rhGH (0.10-0.15 IU/kg/day) for 6-24 months. Outcomes including height Z-score, growth velocity (GV), biochemical markers, disease activity and adverse events were recorded and analysed.

RESULTS

After 6 months of rhGH treatment, the height Z-score improved from -2.37 ± 1.15 at baseline to -1.73 ± 1.06 (P < 0.001), and GV increased from 2.74 ± 1.53 cm/year to 13.05 ± 3.64 cm/year (P < 0.001). Serum insulin-like growth factor 1 and alkaline phosphatase levels rose significantly (from 264.13 ± 81.24-351.59 ± 123.41 ng/ml and 242.40 ± 42.25-318.70 ± 86.12 U/l, respectively; P < 0.05). Creatine kinase levels increased but remained within the normal range (from 79.33 ± 27.56-111.60 ± 42.84 U/l; P < 0.01). Only one patient (1/16, 6.25%) experienced JDM relapse, a rate lower than the reported recurrence rate (31.6%) in JDM patients not receiving rhGH treatment‌. No adverse metabolic or endocrine effects were observed.

CONCLUSION

In JDM patients with growth failure, rhGH therapy may be considered as a potential treatment option, supported by preliminary evidence. Our study suggests an acceptable safety profile and potential efficacy in improving growth parameters, even in refractory cases. Further larger-scale multicentre studies will be necessary to confirm its application value in JDM.

Monoclonal antibody targeting IFNβ for the treatment of NXP2-positive ulcerative juvenile dermatomyositis

This report outlines the case of a 9-year-old girl with severe anti-nuclear matrix protein 2 antibody-positive juvenile dermatomyositis presenting with disease refractory to multiple traditional therapies. Treatment with an experimental monoclonal antibody inhibiting interferon beta (IFNβ) resulted in the rapid resolution of her muscle weakness and cutaneous and gastrointestinal ulcers. This case highlights the potential benefit of inhibiting IFNβ in the management of recalcitrant juvenile dermatomyositis.

Exploring the clinical profiles and management of juvenile dermatomyositis in Africa: a survey of African rheumatology care providers

BACKGROUND

There are limited studies of juvenile dermatomyositis (JDM) in low and middle-income countries (LMIC). Many demonstrate delays to care, high prevalence of severe manifestations, and high mortality. Given the disease-associated damage with JDM, understanding JDM in Africa further is critical. Our objectives are to understand the burden of JDM in Africa and provider access to diagnostic tools and therapy through survey methodology.

METHODS

A survey (available in English and French) was distributed via WhatsApp to 363 total members of the African League of Associations for Rheumatology (AFLAR; n = 233) and Paediatric Society of the African League Against Rheumatism (PAFLAR; n = 130) from November 2022-January 2023. Topics included respondent specialty, number of JDM patients followed, severe manifestations, and available diagnostic tools and medications (with and without considering cost).

RESULTS

Forty-three (12%) of the 363 providers who received the survey started it. Among the 43 who started the survey, 37 (86%) provided consent and manage JDM patients; of these 37 providers, 4 (11%) partially and 16 (43%) fully completed the survey. Most were adult and/or pediatric rheumatologists (n = 19; 95%). Respondents represented all 5 African regions and described 216 children with JDM within the last 10 years. There was high prevalence of calcinosis (as high as 100%) and interstitial lung disease (ILD) (as high as 32%); mortality rates in Kenya (6/42; 14%) and Zambia (2/7; 29%) exceeded the 1-3% mortality reported in studies of high-income countries. Thirteen of 27 diagnostic tools and medications were accessible to ≤ 50% of respondents after considering cost, mostly in Northern or Southern Africa (9/13; 69%). Despite being cost-free, disease assessment tools and physical exam to assess calcinosis were not reported as universally available or accessible.

CONCLUSIONS

This is the first study to explore experiences of providers caring for children with JDM in Africa. Respondents identified 216 children with JDM seen within the last 10 years, exceeding the 196 children with JDM reported within the last 25 years but likely still underestimating prevalence. Our findings align with reports of severe manifestations and poor outcomes in African children with JDM. Access to many diagnostics and medications is limited, and differences in accessibility parallel regional healthcare disparities. The potential differences in JDM severity warrant systematic study and highlight the need to include patients and providers from LMIC in collaborative research efforts.

Juvenile Dermatomyositis: Updates in Pathogenesis and Biomarkers, Current Treatment, and Emerging Targeted Therapies

Juvenile dermatomyositis is a rare systemic inflammatory autoimmune disease involving muscle, skin, and vessels. Most patients do not fully respond to initial therapy, instead having a chronic refractory or polycyclic disease course. Pathogenesis is not completely understood, but immune cell dysregulation, particularly of B cells, mitochondrial dysfunction, changes in neutrophils and neutrophil extracellular traps (NETs), and increased type I and type II interferon (IFN) signaling have been described. There are limited randomized controlled trials of drugs in juvenile dermatomyositis (JDM), and treatment is largely based on lower-quality data such as case series, retrospective studies, and open-label prospective studies. These data have been compiled into expert recommendations or consensus treatment plans, which help guide therapy. While initial therapy is more standard with most including corticosteroids (high-dose oral and/or pulse intravenous methylprednisolone) and methotrexate, for refractory patients, guidelines are more varied with multiple options or combinations, including biologic therapies. There is a clear need for more efficacious and personalized therapy in JDM. Emerging treatment options worthy of further study in JDM include targeting IFN-signaling (JAK, IFNAR1, IFN beta), B-cells (CD20, CD19, BAFF, TACI, CD38, BCMA) including Chimeric Antigen Receptor (CAR)-T cell therapy, mitochondrial dysfunction, and NETs.

Achieving Medication-Free Remission in Patients With Juvenile Dermatomyositis

OBJECTIVE

Prognostic factors associated with medication discontinuation in children with juvenile dermatomyositis (JDM) remain largely elusive. We aim to identify the predictors of medication-free remission (MFR) in children with JDM.

METHODS

In this retrospective study, patients diagnosed with JDM according to Peter & Bohan criteria and followed for ≥18 months at a tertiary care center from 2006 through 2022 were included. Data extracted included demographics, physical examination, laboratory results, and medications. MFR was defined as inactive JDM after discontinuation of all systemic immunosuppressives for ≥6 months, in line with international consensus guidelines for trials of therapies in idiopathic inflammatory myopathies. A two-sided P < 0.05 was considered statistically significant.

RESULTS

Of 55 patients with JDM (63.6% female, age median [interquartile range (IQR)] 6 [3.5-12] years), 29 (52.7%) achieved MFR after a median (IQR) of 33 (22.5-55.2) months. MFR was more common in those who were younger at JDM diagnosis (median 5 vs 8 years, P = 0.008), had early resolution of disease activity (median 11 vs 18 months, P < 0.001), and presented with Gottron papules (χ2 = 5.25; P = 0.022) and elevated lactate dehydrogenase (χ2 = 4.82, P = 0.028). Diagnosis of JDM before 5 years old (odds ratio 4.5, 95% confidence interval [CI] 1.2-16.7) was the only predictor of MFR in our multivariate model (area under the curve 0.65, 95% CI 0.53-0.76).

CONCLUSION

Half of our patients with JDM achieved MFR. Age at JDM diagnosis may be an important predictor of achieving MFR.

Childhood Arthritis and Rheumatology Research Alliance Biologic Disease-Modifying Antirheumatic Drug Consensus Treatment Plans for Refractory Moderately Severe Juvenile Dermatomyositis

OBJECTIVE

The objective was to develop consensus treatment plans (CTPs) for patients with refractory moderately severe juvenile dermatomyositis (JDM) treated with biologic disease-modifying antirheumatic drugs (bDMARDs).

METHODS

The Biologics Workgroup of the Childhood Arthritis and Rheumatology Research Alliance JDM Research Committee used case-based surveys, consensus framework, and nominal group technique to produce bDMARD CTPs for patients with refractory moderately severe JDM.

RESULTS

Four bDMARD CTPs were proposed: tumor necrosis factor α (TNFα) inhibitor (adalimumab or infliximab), abatacept, rituximab, and tocilizumab. Each CTP has different options for dosing and/or route. Among 76 respondents, consensus was achieved for the proposed CTPs (93% [67 of 72]) as well as for patient characteristics, assessments, outcome measures, and follow-up. By weighted average, respondents indicated that they would most likely administer rituximab, followed by abatacept, TNFα inhibitor, and tocilizumab.

CONCLUSION

CTPs for the administration of bDMARDs in refractory moderately severe JDM were developed using consensus methodology. The implementation of the bDMARD CTPs will lay the groundwork for registry-based prospective comparative effectiveness studies.

Autologous CD19-Targeting CAR T Cells in a Patient With Refractory Juvenile Dermatomyositis

OBJECTIVE

The aim of this study is to report the safety and efficacy of CD19-targeting chimeric antigen receptor (CAR) T cells in a child with refractory juvenile dermatomyositis (JDM).

METHODS

We describe a 12-year-old White male with severe, chronically active JDM refractory to multiple immunosuppressive treatment lines, including B cell depletion with rituximab. The patient received a single infusion of fresh, autologous, second-generation anti-CD19 CAR T cell product (lentiviral vector) manufactured on the Prodigy device (1 × 106 CAR T cells/kg), after lymphodepletion with cyclophosphamide (1,000 mg/m2 over two days) and fludarabine (90 mg/m2 over three days). Immunosuppressive and glucocorticoid treatment were withdrawn before leukapheresis and CAR T cell infusion.

RESULTS

Before anti-CD19 CAR T cell therapy, the patient had persistent severe skin and muscular disease activity. CAR T cells expanded significantly (peak at day 7, 32.69 cells/μL). Complete B cell depletion was documented on day 5 in the blood and at week 2 in the bone marrow. The patient presented with fever as part of mild cytokine release syndrome (grade 1), transient anemia (grade 2), and neutropenia (grade 4). Neither infection nor neurotoxicity were observed. Laboratory tests, magnetic resonance imaging, Physician Global Assessment of disease activity, Childhood Myositis Assessment Scale, and Cutaneous Assessment Tool for myositis were performed at baseline and follow-up to assess treatment response, showing remarkable progressive improvement that persists over time, even after B cell recovery.

CONCLUSION

This patient with JDM with severe chronic disease, refractory to multiple treatments, achieved sustained B cell depletion and ongoing immunosuppressive drug-free clinical and radiologic improvement eight months after a single infusion of anti-CD19 CAR T cells.

Personalised medicine in juvenile dermatomyositis: From novel insights in disease mechanisms to changes in clinical practice

Juvenile dermatomyositis is characterized by childhood-onset chronic inflammation of the muscles and skin, with potential involvement of other organs. Patients are at risk for long-term morbidity due to insufficient disease control and steroid-related toxicity. Personalised treatment is challenged by a lack of validated tools that can reliably predict treatment response and monitor ongoing (subclinical) inflammation, and by a lack of evidence regarding the best choice of medication for individual patients. A better understanding of the involved disease mechanisms could reveal potential biomarkers and novel therapeutic targets. In this review, we highlight the most relevant immune and non-immune mechanisms, elucidating the effects of interferon overexpression on tissue alongside the interplay between the interferon signature, mitochondrial function, and immune cells. We review mechanism-based biomarkers that are promising for clinical implementation, and the latest advances in targeted therapy development. Finally, we discuss key steps needed for translating these discoveries into clinical practice.

Current evidence for janus kinase inhibitors in adult and juvenile dermatomyositis and key comparisons

INTRODUCTION

Adult dermatomyositis (DM) and juvenile dermatomyositis (JDM) are rare autoimmune diseases with characteristic skin rashes, weakness, and other systemic features. Upregulated interferon signaling has been consistently described in both adult and juvenile DM which makes janus kinase inhibitors (jakinibs) an attractive therapeutic agent that has a targeted mechanism of action.

AREAS COVERED

Herein is a review of the growing literature of jakinib use in adult and juvenile DM, including reports on specific disease features and safety of jakinibs in this population and a comparison between adult and juvenile DM. We performed a literature review using PubMed including all English-language publications before 1 February 2024 and abstracts from key recent rheumatology conferences.

EXPERT OPINION

Jakinibs are an exciting and promising treatment in both adult and juvenile DM. Current Phase 2 and 3 randomized placebo-controlled trials of jakinibs in both adult and JDM will provide significant insights into the efficacy of this class of medication as a potentially more mechanistically targeted treatment of both skin and muscle disease. In fact, these results will likely inform the treatment paradigm of dermatomyositis in that it may even be considered as first or second line. The next five years in the therapeutic landscape of both juvenile and adult DM is an exciting time for both patients and medical providers.

Updates on efficacy and safety janus kinase inhibitors in juvenile dermatomyositis

INTRODUCTION

Juvenile dermatomyositis (JDM) is a rare autoimmune disease most commonly with proximal weakness due to inflammation and characteristic skin rashes. Most patients have a chronic or polycyclic disease course on standard therapy so better treatments are needed. An interferon signature is well-established in key tissues of JDM. Janus kinase inhibitors (jakinibs), which can decrease IFN signaling, are therefore appealing as a targeted therapy.

AREAS COVERED

Herein is a review of the growing literature on JDM patients in jakinibs, including specifics of their jakinib exposure, summary of efficacy, disease features, and characteristics of patients treated, and safety parameters.

EXPERT OPINION

The vast majority of refractory JDM patients respond to jakinib therapy, though they have varied features, doses, and previous/concurrent medications, and data is largely retrospective. Jakinibs are an exciting and promising treatment in JDM. Evaluation with larger prospective controlled studies is needed to answer remaining questions about jakinibs in JDM regarding dosing, which JDM patients to treat with jakinibs, potential biomarkers to use, and how best to monitor safety risks in JDM.

Autoimmune inflammatory myopathy biomarkers

The autoimmune inflammatory myopathy disease spectrum, commonly known as myositis, is a group of systemic diseases that mainly affect the muscles, skin and lungs. Biomarker assessment helps in understanding disease mechanisms, allowing for the implementation of precise strategies in the classification, diagnosis, and management of these diseases. This review examines the pathogenic mechanisms and highlights current data on blood and tissue biomarkers of autoimmune inflammatory myopathies.

Performance of the 2016 ACR-EULAR myositis response criteria in juvenile dermatomyositis therapeutic trials and consensus profiles

OBJECTIVES

The 2016 ACR-EULAR Response Criteria for JDM was developed as a composite measure with differential weights of six core set measures (CSMs) to calculate a Total Improvement Score (TIS). We assessed the contribution of each CSM, representation of muscle-related and patient-reported CSMs towards improvement, and frequency of CSM worsening across myositis response criteria (MRC) categories in validation of MRC.

METHODS

Data from JDM patients in the Rituximab in Myositis trial (n = 48), PRINTO JDM trial (n = 139), and consensus patient profiles (n = 273) were included. Observed vs expected CSM contributions were compared using Sign test. Characteristics of MRC categories were compared by Wilcoxon tests with Bonferroni adjustment. Spearman correlation of changes in TIS and individual CSMs were examined. Agreement between physician-assessed change and MRC categories was evaluated by weighted Cohen's kappa.

RESULTS

Of 457 JDM patients with IMACS CSMs and 380 with PRINTO CSMs, 9-13% had minimal, 19-23% had moderate and 41-50% had major improvement. The number of improved and absolute percentage change of CSMs increased by MRC improvement level. Patients with minimal improvement by MRC had a median of 0-1 CSM worsened, and those with moderate/major improvement had a median of zero worsening CSMs. Of patients improved by MRC, 94-95% had improvement in muscle strength and 93-95% had improvement in ≥1 patient-reported CSM. IMACS and PRINTO CSMs performed similarly. Physician-rated change and MRC improvement categories had moderate-to-substantial agreement (Kappa 0.5-0.7).

CONCLUSION

The ACR-EULAR MRC perform consistently across multiple studies, supporting its further use as an efficacy end point in JDM trials.

Association of anti-TPM4 autoantibodies with vasculopathic cutaneous manifestations in juvenile dermatomyositis

OBJECTIVES

AECAs are detected in multiple forms of vasculitis or vasculopathy, including JDM. High levels of tropomyosin alpha-4 chain (TPM4) gene expression in cutaneous lesions and TPM4 protein expression in some endothelial cells (ECs) have been proven. Furthermore, the presence of autoantibodies to tropomyosin proteins have been discovered in DM. We therefore investigated whether anti-TPM4 autoantibodies are an AECA in JDM and are correlated with clinical features of JDM.

METHODS

The expression of TPM4 protein in cultured normal human dermal microvascular ECs was investigated by Western blotting. Plasma samples from 63 children with JDM, 50 children with polyarticular JIA (pJIA) and 40 healthy children (HC) were tested for the presence of anti-TPM4 autoantibodies using an ELISA. Clinical features were compared between JDM patients with and without anti-TPM4 autoantibodies.

RESULTS

Autoantibodies to TPM4 were detected in the plasma of 30% of JDM, 2% of pJIA (P < 0.0001) and 0% of HC (P < 0.0001). In JDM, anti-TPM4 autoantibodies were associated with the presence of cutaneous ulcers (53%; P = 0.02), shawl sign rash (47%; P = 0.03), mucous membrane lesions (84%; P = 0.04) and subcutaneous edema (42%; P < 0.05). Anti-TPM4 autoantibodies significantly correlated with the use of intravenous steroids and IVIG therapy in JDM (both P = 0.01). The total number of medications received was higher in patients with anti-TPM4 autoantibodies (P = 0.02).

CONCLUSION

Anti-TPM4 autoantibodies are detected frequently in children with JDM and are novel myositis-associated autoantibodies. Their presence correlates with vasculopathic and other cutaneous manifestations of JDM that may be indicative of more refractory disease.

Imbalance of peripheral blood Th17/Treg increases neutrophil-to-lymphocyte ratio in patients with dermatomyositis

OBJECTIVE

To explore and analyze the association between peripheral blood Th17/Treg balance and neutrophil-to-lymphocyte ratio (NLR) in patients with dermatomyositis (DM).

METHODS

Data of 83 DM patients hospitalized between January 2020 to April 2022 were collected, including 43 patients in the active phase (DM active-phase group) and 40 in the remission phase (DM remission-phase group). Additionally, data of 50 healthy subjects who underwent physical examinations and immunologic function testing in the same period were taken as a control group. We detected the percentage of Th17 and Treg cells by flow cytometry, calculated patient's NLR and laboratory test indicators, and analyzed the correlation of Th17/Treg balance with NLR and laboratory indicators.

RESULTS

Th17 percentage and Th7/Treg ratio in the DM active-phase group were higher than those in the DM remission-phase group (P<0.05), while Treg percentage was lower in the active-phase group than in the remission-phase group (P<0.05). The creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), erythrocyte deposition rate (ESR), and NLR in DM patients were significantly higher than those of the control group (P<0.05), and were associated with the disease activity of DM. The ratio of Th17/Treg was positively correlated with CK, LDH, AST, ALT, ESR, and NLR (P<0.05). NLR was positively correlated with CK, LDH, AST, ALT, and ESR (P<0.05).

CONCLUSION

DM patients exhibit changes in immune balance of Th17/Treg and an increase in the NLR. The Th17/Treg ratio in the patients is closely associated with the NLR, which suggests that the immune balance mechanism may interact with the inflammatory response of the body, collectively contributing to the progression of DM.

Juvenile idiopathic inflammatory myositis: an update on pathophysiology and clinical care

The childhood-onset or juvenile idiopathic inflammatory myopathies (JIIMs) are a heterogenous group of rare and serious autoimmune diseases of children and young people that predominantly affect the muscles and skin but can also involve other organs, including the lungs, gut, joints, heart and central nervous system. Different myositis-specific autoantibodies have been identified that are associated with different muscle biopsy features, as well as with different clinical characteristics, prognoses and treatment responses. Thus, myositis-specific autoantibodies can be used to subset JIIMs into sub-phenotypes; some of these sub-phenotypes parallel disease seen in adults, whereas others are distinct from adult-onset idiopathic inflammatory myopathies. Although treatments and management have much improved over the past decade, evidence is still lacking for many of the current treatments and few validated prognostic biomarkers are available with which to predict response to treatment, comorbidities (such as calcinosis) or outcome. Emerging data on the pathogenesis of the JIIMs are leading to proposals for new trials and tools for monitoring disease.

Treatment escalation patterns to start biologics in refractory moderate juvenile dermatomyositis among members of the Childhood Arthritis and Rheumatology Research Alliance

BACKGROUND

Despite new and better treatments for juvenile dermatomyositis (JDM), not all patients with moderate severity disease respond adequately to first-line therapy. Those with refractory disease remain at higher risk for disease and glucocorticoid-related complications. Biologic disease-modifying antirheumatic drugs (DMARDs) have become part of the arsenal of treatments for JDM. However, prospective comparative studies of commonly used biologics are lacking.

METHODS

The Childhood Arthritis and Rheumatology Research Alliance (CARRA) JDM biologics workgroup met in 2019 and produced a survey assessing current treatment escalation practices for JDM, including preferences regarding use of biologic treatments. The cases and questions were developed using a consensus framework, requiring 80% agreement for consensus. The survey was completed online in 2020 by CARRA members interested in JDM. Survey results were analyzed among all respondents and according to years of experience. Chi-square or Fisher's exact test was used to compare the distribution of responses to each survey question.

RESULTS

One hundred twenty-one CARRA members responded to the survey (denominators vary for each question). Of the respondents, 88% were pediatric rheumatologists, 85% practiced in the United States, and 43% had over 10 years of experience. For a patient with moderately severe JDM refractory to methotrexate, glucocorticoids, and IVIG, approximately 80% of respondents indicated that they would initiate a biologic after failing 1-2 non-biologic DMARDs. Trials of methotrexate and mycophenolate were considered necessary by 96% and 60% of respondents, respectively, before initiating a biologic. By weighed average, rituximab was the preferred biologic over abatacept, tocilizumab, and infliximab. Over 50% of respondents would start a biologic by 4 months from diagnosis for patients with refractory moderately severe JDM. There were no notable differences in treatment practices between respondents by years of experience.

CONCLUSION

Most respondents favored starting a biologic earlier in disease course after trialing up to two conventional DMARDs, specifically including methotrexate. There was a clear preference for rituximab. However, there remains a dearth of prospective data comparing biologics in refractory JDM. These findings underscore the need for biologic consensus treatment plans (CTPs) for refractory JDM, which will ultimately facilitate comparative effectiveness studies and inform treatment practices.

Anti-nuclear matrix protein 2+ juvenile dermatomyositis with severe skin ulcer and infection: A case report and literature review

BACKGROUND

Juvenile dermatomyositis (JDM) is an idiopathic inflammatory myopathy that occurs in childhood. It is characterized by muscle weakness and a characteristic rash. Previous literature reports have rarely described JDM with severe skin ulcers and infections.

CASE SUMMARY

Herein, we describe a case of a 2-year-old female patient who suffered from JDM, whose myositis-specific autoantibodies were positive for anti-nuclear matrix protein 2 antibody, with progressively worsening skin ulcers and severe infections. The patient was treated with glucocorticoids and various immunosuppressants. Nevertheless, further progression of the disease and the combination of primary disease and severe infection in the later period were fatal.

CONCLUSION

In children, anti-nuclear matrix protein 2+ JDM combined with skin ulcers often indicates severe disease. In such cases, personalized treatment for the primary disease and infection prevention and control are essential.