Update in juvenile myositis.

This update on childhood idiopathic inflammatory myopathies (IIMs) reviews recent progress in the field of translational science and clinical research over the past 12-18 months

Advances in the treatment of polyarticular juvenile idiopathic arthritis

Purpose of review: To review recent advances in the management strategies of polyarticular course juvenile idiopathic arthritis (JIA) and identify unanswered questions and avenues for further research. Recent findings: There is evidence for an early, aggressive, treat-to-target approach for polyarticular JIA. Clinical disease activity criteria have been recently defined and validated, including criteria for inactive disease and the juvenile arthritis disease activity score (JADAS). There is a need for evidence-based, defined disease targets and biomarkers for prediction of response, including targets for remission induction, and guidelines on drug withdrawal. Recent treatment consensus plans and guidelines are discussed and compared, including the 2015 NHS England clinical policy statement, the 2014 Childhood Arthritis and Rheumatology Research Alliance (CARRA) treatment plans and the 2011 American College of Rheumatology (ACR) guidelines. Evidence for new agents such as tocilizumab, rituximab, golimumab, ustekinumab, certolizumab and tofacitinib is promising: the recent clinical trials are summarized here. Stratification of individual patient treatment remains a goal, and predictive biomarkers have been shown to predict success in the withdrawal of methotrexate therapy. Summary: There are promising advances in the treatment approaches, disease activity criteria, clinical guidelines, pharmaceutical choices and individually stratified therapy choices for polyarticular JIA

The lived experience of juvenile idiopathic arthritis in young people receiving etanercept

BACKGROUND: This study explores young people's daily experiences of living with Juvenile Idiopathic Arthritis (JIA) and their thoughts, beliefs and feelings related to the biological drug Etanercept, prescribed as part of their treatment. METHODS: An Interpretive Phenomenological approach was used to allow in-depth examinations of the young people's personal accounts of their lived experiences. Data were obtained from 6 young people between the ages of 10-13 years, from one tertiary institution's Paediatric Rheumatology department using audio-taped open-ended interviews. RESULTS: The transcripts yielded seven thousand words of data and two hundred significant statements, which were reduced to five themes; 1) Who understands me, 2) Medicines and injections, 3) Challenges of schooling and friendships, 4) Being different, and 5) Exclusion from sports. There were marked similarities between the young people's statements; however, there were also some striking differences. The theme 'Who understands me' yielded the biggest section of data, but also produced the biggest disparity between the young people. Two patients were very clear that they thought everyone 'understands', whilst two other patients held the belief that 'no one understood'. This paper explores these statements in further detail. CONCLUSIONS: The findings from this study can give healthcare professionals novel insight into the likely reactions to treatment for JIA and, through this, enable them to offer improved support, education and early intervention before these issues become a concern. This study also provides insight into the emotional resilience of young people with JIA

Synovial Regulatory T Cells Occupy a Discrete TCR Niche in Human Arthritis and Require Local Signals To Stabilize FOXP3 Protein Expression

Although there is great interest in harnessing the immunosuppressive potential of FOXP3+ regulatory T cells (Tregs) for treating autoimmunity, a sizeable knowledge gap exists regarding Treg fate in human disease. In juvenile idiopathic arthritis (JIA) patients, we have previously reported that atypical CD25+FOXP32 Treg-like cells uniquely populate the inflamed site. Intrigu-ingly, their proportions relative to CD25+FOXP3+ Tregs associate with arthritis course, suggesting a role in disease. The ontogeny of these FOXP32 Treg-like cells is, however, unknown. In this study, we interrogated clonal relationships between CD4+ T cell subsets in JIA, using high-throughput TCR repertoire analysis. We reveal that FOXP3+ Tregs possess highly exclusive TCRb usage from conventional T cells, in blood, and also at the inflamed site, where they are clonally expanded. Intriguingly, the repertoires of FOXP3+ Tregs in synovial fluid are highly overlapping with CD25+FOXP32 Treg-like cells, indicating fluctuations in FOXP3 expression in the inflamed joint. Furthermore, cultured synovial Tregs rapidly downregulated FOXP3 protein (but not mRNA), and this process was prevented by addition of synovial fluid from JIA patients, through an IL-6–independent mechanism. Our findings suggest that most Tregs arise from a separate lineage from conventional T cells, and that this repertoire divergence is largely maintained under chronic inflammatory conditions. We propose that subsequent Treg expansions at the inflamed site creates an environment that leads to competition for limited resources within the synovium, resulting in the destabilization of FOXP3 expression in some Tregs. The Journal of Immunology, 2015, 195: 5616–5624.

CD161(+) Tconv and CD161(+) Treg Share a Transcriptional and Functional Phenotype despite Limited Overlap in TCR beta Repertoire

Human regulatory T cells (Treg) are important in immune regulation, but can also show plasticity in specific settings. CD161 is a lectin-like receptor and its expression identifies an effector-like Treg population. Here, we determined how CD161+ Treg relate to CD161+ conventional T cells (Tconv). Transcriptional profiling identified a shared transcriptional signature between CD161+ Tconv and CD161+ Treg, which is associated with T helper (Th)1 and Th17 cells, and tissue homing, including high expression of gut-homing receptors. Upon retinoic acid (RA) exposure, CD161+ T cells were more enriched for CCR9+ and integrin α4+β7+ cells than CD161− T cells. In addition, CD161+ Tconv and CD161+ Treg were enriched at the inflamed site in autoimmune arthritis, and both CD161+ and CD161− Treg from the inflamed site were suppressive in vitro. CD161+ T cells from the site of autoimmune arthritis showed a diminished gut-homing phenotype and blunted response to RA suggesting prior imprinting by RA in the gut or at peripheral sites rather than during synovial inflammation. TCRβ repertoires of CD161+ and CD161− Tconv and Treg from blood showed limited overlap whereas there was clear overlap between CD161+ and CD161− Tconv, and CD161+ and CD161− Treg from the inflamed site suggesting that the inflamed environment may alter CD161 levels, potentially contributing to disease pathogenesis

T regulatory cells in childhood arthritis - novel insights.

In recent years, there have been many new developments in the field of regulatory T cells (Treg), challenging the consensus on their behaviour, classification and role(s) in disease. The role Treg might play in autoimmune disease appears to be more complex than previously thought. Here, we discuss the current knowledge of regulatory T cells through animal and human research and illustrate the recent developments in childhood autoimmune arthritis (juvenile idiopathic arthritis (JIA)). Furthermore, this review summarises our understanding of the fields and assesses current and future implications for Treg in the treatment of JIA

Current developments in the use of biomarkers for juvenile idiopathic arthritis

Use of biomarkers in clinical practice has proved extremely valuable and is a rapidly expanding field. However, despite the huge potential of biomarkers, for juvenile idiopathic arthritis (JIA) there are currently no validated paediatric biomarkers available to help with setting up a more tailored approach on which drug choice could be based, to achieve remission early in the course of disease. Early remission reduces burden of disease, limits side effects from toxic and unnecessary medication, and, most importantly, enhances quality of life. Several studies have suggested promising biomarkers: these may be a protein, cellular component, mRNA, or genetic component, for example a single nucleotide polymorphism (SNP). Here we describe recent developments in the use of biomarkers for JIA and their potential to assist in management of disease by predicting disease phenotype, severity, progression, and response to treatment, and determining when patients have reached stable remission and can safely discontinue treatment

Treatment of Juvenile Dermatomyositis: An Update

The idiopathic inflammatory myopathies of childhood consist of a heterogeneous group of autoimmune diseases characterised by proximal muscle weakness and pathognomonic skin rashes. The overall prognosis of juvenile myositis has improved significantly over recent years, but the long-term outcome differs substantially from patient to patient, suggestive of distinct clinical phenotypes with variable responses to treatment. High doses of corticosteroids remain the cornerstone of therapy along with other immunosuppressant therapies depending on disease severity and response. The advent of biological drugs has revolutionised the management of various paediatric rheumatologic diseases, including inflammatory myopathies. There are few data from randomised controlled trials to guide management decisions; thus, several algorithms for the treatment of juvenile myositis have been developed using international expert opinion. The general treatment goals now include elimination of active disease and normalisation of physical function, so as to preserve normal growth and development, and to prevent long-term damage and deformities. This review summarises the newer and possible future therapies of juvenile inflammatory myopathies, including evidence supporting their efficacy and safety

Modelling disease activity in juvenile dermatomyositis: A Bayesian approach

Juvenile dermatomyositis is the most common form of the juvenile idiopathic inflammatory myopathies characterised by muscle and skin inflammation, leading to symmetric proximal muscle weakness and cutaneous symptoms. It has a fluctuating course and varying prognosis. In a Bayesian framework, we develop a joint model for four longitudinal outcomes, which accounts for within individual variability as well as inter-individual variability. Correlations among the outcome variables are introduced through a subject-specific random effect. Moreover, we exploit an approach similar to a hurdle model to account for excess of a specific outcome in the response. Clinical markers and symptoms are used as covariates in a regression set-up. Data from an ongoing observational cohort study are available, providing information on 340 subjects, who contributed 2725 clinical visits. The model shows good performance and yields efficient estimations of model parameters, as well as accurate predictions of the disease activity parameters, corresponding well to observed clinical patterns over time. The posterior distribution of the by-subject random intercepts shows a substantial correlation between two of the outcome variables. A subset of clinical markers and symptoms are identified as associated with disease activity. These findings have the potential to influence clinical practice as they can be used to stratify patients according to their prognosis and guide treatment decisions, as well as contribute to on-going research about the most relevant outcome markers for patients affected by juvenile dermatomyositis