Systemic and Tissue Inflammation in Juvenile Dermatomyositis: From Pathogenesis to the Quest for Monitoring Tools

Juvenile Dermatomyositis (JDM) is a systemic immune-mediated disease of childhood, characterized by muscle weakness, and a typical skin rash. Other organ systems and tissues such as the lungs, heart, and intestines can be involved, but may be under-evaluated. The inflammatory process in JDM is characterized by an interferon signature and infiltration of immune cells such as T cells and plasmacytoid dendritic cells into the affected tissues. Vasculopathy due to loss and dysfunction of endothelial cells as a result of the inflammation is thought to underlie the symptoms in most organs and tissues. JDM is a heterogeneous disease, and several disease phenotypes, each with a varying combination of affected tissues and organs, are linked to the presence of myositis autoantibodies. These autoantibodies have therefore been extensively studied as biomarkers for the disease phenotype and its associated prognosis. Next to identifying the JDM phenotype, monitoring of disease activity and disease-inflicted damage not only in muscle and skin, but also in other organs and tissues, is an important part of clinical follow-up, as these are key determinants for the long-term outcomes of patients. Various monitoring tools are currently available, among which clinical assessment, histopathological investigation of muscle and skin biopsies, and laboratory testing of blood for specific biomarkers. These investigations also give novel insights into the underlying immunological processes that drive inflammation in JDM and suggest a strong link between the interferon signature and vasculopathy. New tools are being developed in the quest for minimally invasive, but sensitive and specific diagnostic methods that correlate well with clinical symptoms or reflect local, low-grade inflammation. In this review we will discuss the types of (extra)muscular tissue inflammation in JDM and their relation to vasculopathic changes, critically assess the available diagnostic methods including myositis autoantibodies and newly identified biomarkers, and reflect on the immunopathogenic implications of identified markers

Juvenile dermatomyositis. Where are we now?

Juvenile onset idiopathic inflammatory myopathy (IIM) has many similarities and distinct differences from adult-onset disease. This review will focus on recent developments in understanding and treatment of juvenile dermatomyositis (JDM), the most common disease sub-type of IIM in childhood. JDM is a systemic immune mediated vasculopathy, increasingly recognised as a group of distinct phenotypes with variable presentation and outlook. This overview will describe long-term outlook and disease course including health-related quality of life and emerging treatments

The Effects of a Web-Based Tool for Parents of Children With Juvenile Idiopathic Arthritis: Randomized Controlled Trial

Background: Juvenile idiopathic arthritis (JIA) is a group of autoinflammatory diseases that cause pain and disability if not controlled by treatment. Parenting a child with JIA is stressful for parents, who express concerns about their child’s treatment and may experience anxiety and powerlessness concerning their child’s illness. Parenting stress is greater in parents of children with chronic illness than in those with healthy children and is related to poorer psychological adjustment in both parents and children. It is therefore important to develop interventions to support parents. This paper reports the evaluation of a web-based tool that provides information and practical skills to help increase parents’ confidence in managing their child’s illness and reduce parenting stress. Objective: The aim of this study is to evaluate the benefits of a web-based tool (WebParC) for parents of children with recently diagnosed JIA. Methods: A multicentered randomized controlled trial was conducted at pediatric rheumatology centers in England. We recruited parents of children aged ≤12 years who had been diagnosed with JIA within the previous 6 months. They were randomized to the intervention (WebParC access plus standard care) or the control (standard care alone) and followed up 4 months and 12 months after randomization. Where both parents participated, they were randomized by household to the same trial arm. The WebParC intervention consists of information about JIA and its treatment plus a toolkit, based on cognitive behavioral therapy, to help parents develop skills to manage JIA-related issues. The primary outcome was the self-report Pediatric Inventory for Parents measure of illness-related parenting stress. The secondary outcomes were parental mood, self-efficacy, coping, effectiveness of participation in their child’s health care, satisfaction with health care, and child’s health-related quality of life. Results: A total of 203 households comprising 220 parents were randomized to the intervention (100/203, 49.3%) or control (103/203, 50.7%) arm. Follow-up assessments were completed by 65.5% (133/203) of the households at 4 months (intervention 60/100, 60%, and control 73/103, 70.9%) and 61.1% (124/203) of the households at 12 months (intervention 58/100, 58%, and control 66/103, 64.1%). A main effect of the trial arm was found on the Pediatric Inventory for Parents: the intervention participants reported less frequency (subscales communication F1,120627=5.37; P=.02, and role function F1,27203=5.40; P=.02) and difficulty (subscales communication F1,2237=7.43; P=.006, medical care F1,2907=4.04; P=.04, and role function F1,821=4.37, P=.04) regarding illness-related stressful events than the control participants. Conclusions: The WebParC website for parents of children with JIA reduced illness-related parenting stress. This web-based intervention offers a feasible preventive approach for parents of children with JIA and potentially could be adapted and evaluated for parents of children with other chronic illnesses. Trial Registration: International Standard Randomized Controlled Trial Number (ISRCTN) 13159730; http://www.isrctn.com/ISRCTN1315973

A national registry for juvenile dermatomyositis and other paediatric idiopathic inflammatory myopathies: 10 years' experience; the Juvenile Dermatomyositis National (UK and Ireland) Cohort Biomarker Study and Repository for Idiopathic Inflammatory Myopathies

Objectives: The paediatric idiopathic inflammatory myopathies (IIMs) are a group of rare chronic inflammatory disorders of childhood, affecting muscle, skin and other organs. There is a severe lack of evidence base for current treatment protocols in juvenile myositis. The rarity of these conditions means that multicentre collaboration is vital to facilitate studies of pathogenesis, treatment and disease outcomes. We have established a national registry and repository for childhood IIM, which aims to improve knowledge, facilitate research and clinical trials, and ultimately to improve outcomes for these patients. Methods: A UK-wide network of centres and research group was established to contribute to the study. Standardized patient assessment, data collection forms and sample protocols were agreed. The Biobank includes collection of peripheral blood mononuclear cells, serum, genomic DNA and biopsy material. An independent steering committee was established to oversee the use of data/samples. Centre training was provided for patient assessment, data collection and entry. Results: Ten years after inception, the study has recruited 285 children, of which 258 have JDM or juvenile PM; 86% of the cases have contributed the biological samples. Serial sampling linked directly to the clinical database makes this a highly valuable resource. The study has been a platform for 20 sub-studies and attracted considerable funding support. Assessment of children with myositis in contributing centres has changed through participation in this study. Conclusions: This establishment of a multicentre registry and Biobank has facilitated research and contributed to progress in the management of a complex group of rare muscloskeletal conditions

Maternal microchimerism in muscle biopsies from children with juvenile dermatomyositis

Objective. Recent advances in molecular techniques have revealed that there is bi-directional transfer of cells between mother and child during pregnancy, and the presence of a mother's cells in her child has been termed maternal microchimerism (MMc). There is the potential for maternal cells to provoke inappropriate immune responses in the child, which could be a factor in autoimmunity including JDM. The aim of this study was to determine whether maternal (female) cells could be detected in frozen muscle sections from seven males (age range 3–13 years) with JDM participating in the Juvenile Dermatomyositis National (UK and Ireland) Cohort Biomarker Study and Repository for Idiopathic Inflammatory Myopathies and sections of muscle controls (age range 2–12 years)

The impact of psoriasis on wellbeing and clinical outcomes in juvenile psoriatic arthritis

Objectives: Juvenile psoriatic arthritis (JPsA) has varied clinical features that are distinctive to other juvenile idiopathic arthritis (JIA) categories. This study investigates whether such features impact patient-reported and clinical outcomes. // Methods: Children and young people (CYP) were selected if recruited to the Childhood Arthritis Prospective Study, a UK multicentre JIA inception cohort, between January 2001 and March 2018. At diagnosis, patient/parent-reported outcomes (as age-appropriate) included the parental global assessment (10 cm VAS), functional ability (CHAQ), pain (10 cm VAS), health-related quality of life (CHQ psychosocial score), mood/depressive symptoms (MFQ) and parent psychosocial health (GHQ). Three-year outcome trajectories have previously been defined using active joint counts, physician and parent global assessments (PGA, PaGA respectively). Patient-reported outcomes and outcome trajectories were compared in i) CYP with JPsA versus other JIA categories, ii) CYP within JPsA, with and without psoriasis via multivariable linear regression. // Results: There were no significant differences in patient-reported outcomes at diagnosis between CYP with JPsA and non-JPsA. Within JPsA, those with psoriasis had more depressive symptoms (coefficient = 9.8, 95% CI = 0.5–19.0) than those without psoriasis at diagnosis. CYP with JPsA had 2.3 times the odds of persistent high PaGA than other ILAR categories, despite improving joint counts and PGA (95% CI 1.2, 4.6). // Conclusion: CYP with psoriasis at JPsA diagnosis report worse mood, supporting a greater disease impact in those with both skin and joint involvement. Multidisciplinary care with added focus to support wellbeing in children with JPsA plus psoriasis may help improve these outcomes