Juvenile myositis is a rare and heterogeneous disease. Diagnosis is often difficult but early treatment is important in reducing the risk of associated morbidity and poor outcomes. Myositis specific ...autoantibodies have been described in both juvenile and adult patients with myositis and can be helpful in dividing patients into clinically homogenous groups. We aimed to explore the utility of myositis specific autoantibodies as diagnostic and prognostic biomarkers in patients with juvenile-onset disease.
Using radio-labelled immunoprecipitation and previously validated ELISAs we examined the presence of myositis specific autoantibodies in 380 patients with juvenile-onset myositis in addition to, 318 patients with juvenile idiopathic arthritis, 21 patients with juvenile-onset SLE, 27 patients with muscular dystrophies, and 48 healthy children.
An autoantibody was identified in 60% of juvenile-onset myositis patients. Myositis specific autoantibodies (49% patients) were exclusively found in patients with myositis and with the exception of one case were mutually exclusive and not found in conjunction with another autoantibody. Autoantibody subtypes were associated with age at disease onset, key clinical disease features and treatment received.
In juvenile patients the identification of a myositis specific autoantibody is highly suggestive of myositis. Autoantibodies can be identified in the majority of affected children and provide useful prognostic information. There is evidence of a differential treatment approach and patients with anti-TIF1γ autoantibodies are significantly more likely to receive aggressive treatment with IV cyclophosphamide and/or biologic drugs, clear trends are also visible in other autoantibody subgroups.
•Using immunoprecipitation, an autoantibody is identifiable in most children with juvenile-onset myositis.•Myositis specific autoantibodies are highly specific and were not identified in control groups.•Autoantibodies identify patient subgroups associated with clinically important disease features.•Evidence of an existing differential treatment approach between autoantibody subgroups is presented.
Musculoskeletal diseases affect up to 20% of adults worldwide. The gut microbiome has been implicated in inflammatory conditions, but large-scale metagenomic evaluations have not yet traced the ...routes by which immunity in the gut affects inflammatory arthritis. To characterize the community structure and associated functional processes driving gut microbial involvement in arthritis, the Inflammatory Arthritis Microbiome Consortium investigated 440 stool shotgun metagenomes comprising 221 adults diagnosed with rheumatoid arthritis, ankylosing spondylitis, or psoriatic arthritis and 219 healthy controls and individuals with joint pain without an underlying inflammatory cause. Diagnosis explained about 2% of gut taxonomic variability, which is comparable in magnitude to inflammatory bowel disease. We identified several candidate microbes with differential carriage patterns in patients with elevated blood markers for inflammation. Our results confirm and extend previous findings of increased carriage of typically oral and inflammatory taxa and decreased abundance and prevalence of typical gut clades, indicating that distal inflammatory conditions, as well as local conditions, correspond to alterations to the gut microbial composition. We identified several differentially encoded pathways in the gut microbiome of patients with inflammatory arthritis, including changes in vitamin B salvage and biosynthesis and enrichment of iron sequestration. Although several of these changes characteristic of inflammation could have causal roles, we hypothesize that they are mainly positive feedback responses to changes in host physiology and immune homeostasis. By connecting taxonomic alternations to functional alterations, this work expands our understanding of the shifts in the gut ecosystem that occur in response to systemic inflammation during arthritis.
Juvenile PsA (JPsA) has varied clinical features that are distinctive from other JIA categories. This study investigates whether such features impact patient-reported and clinical outcomes.
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 visual analogue scale), functional ability (Childhood Health Assessment Questionnaire (CHAQ)), pain (10 cm visual analogue scale), health-related quality of life (Child Health Questionnaire PF50 psychosocial score), mood/depressive symptoms (Moods and Feelings Questionnaire) and parent psychosocial health (General Health Questionnaire 30). Three-year outcome trajectories have previously been defined using active joint counts, physician and parent global assessments (PGA and PaGA, respectively). Patient-reported outcomes and outcome trajectories were compared in (i) CYP with JPsA vs other JIA categories and (ii) CYP within JPsA, with and without psoriasis via multivariable linear regression.
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).
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.
In JIA there is an unmet need for biomarkers with which to identify patients who will respond well to MTX. The aim of this study was to define the prognostic value of baseline serum proteins and ...clinical variables in response to MTX to help inform the clinician at time of diagnosis whether the patient is likely to respond well to MTX.
JIA patients were recruited into the Childhood Arthritis Response to Medication Study (CHARMS). Clinical data and venous blood were collected before administration of MTX and at follow-up. MRP8/14 and inflammatory cytokines were measured by ELISA and multiplex immunoassay, respectively. CRP and ESR were measured as part of routine clinical assessment. To explore which baseline factors might predict successful treatment, binary logistic regression models were fitted for outcome.
High disease activity (high serum MRP8/14, active joint count or physician's score) pre-MTX was observed in a subgroup of patients with a better response to therapy. In a multivariable analysis, after accounting for MRP8/14 at baseline, no other factors were independently significantly associated with outcome. Patients with baseline MRP8/14 >3000 ng/ml were more likely to respond to MTX at ACR50 or better: odds ratio 16.07 (95% CI 2.00, 129.3).
We have demonstrated that high levels of baseline serum MRP8/14 have prognostic value in predicting a subgroup of patients whose arthritis will improve on MTX. Routine collection of serum prior to the start of medication would be a valuable step in collaborative validation of such biomarkers.
Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory arthritis of childhood, characterized by various clinical phenotypes associated with variable prognosis. Significant ...progress has been achieved with the use of biologic treatments, which specifically block pro-inflammatory molecules involved in the disease pathogenesis. The most commonly used biologics in JIA are monoclonal antibodies and recombinant proteins targeting interleukins 1 (IL-1) and 6 (IL-6), and tumor necrosis factor α (TNF-α). Several biomarkers have been investigated in JIA.
To assess the level of evidence available regarding the role of biomarkers in JIA related to guiding clinical and therapeutic decisions, providing disease prognostic information, facilitating disease activity monitoring and assessing biologic treatment response in JIA, as well as propose new strategies for biologic therapy-related biomarker use in JIA.
We searched PubMed for relevant literature using predefined key words corresponding to several categories of biomarkers to assess their role in predicting and assessing biologic treatment response and clinical remission in JIA.
We reviewed serological, cellular, genetic, transcriptomic and imaging biomarkers, to identify candidates that are both well-established and widely used, as well as newly investigated in JIA on biologic therapy. We evaluated their role in management of JIA as well as identified the unmet needs for new biomarker discovery and better clinical applications.
Although there are no ideal biomarkers in JIA, we identified serological biomarkers with potential clinical utility. We propose strategies of combining biomarkers of response to biologics in JIA, as well as routine implementation of clinically acceptable imaging biomarkers for improved disease assessment performance.
To explore the different characteristics of the serological phenotypes identified in juvenile and adult myositis, consider how differences between the two groups might be explained and discuss how ...this enhances our understanding of disease pathogenesis.
Current research has focussed on two main areas: first, defining the autoantibody associated disease phenotype in greater detail, particularly with regard to cutaneous disease and within specified populations such as juvenile-onset disease and different ethnic groups, and second, we have gained new insights into disease pathogenesis through studies analysing genetic associations and autoantigen expression.
Although there are many clinically important differences between adult and juvenile-onset myositis, recent work has highlighted many of the similarities at least within autoantibody-defined subgroups. Viewing age at disease onset as a continuum with its own influence on disease phenotype strengthens the ability of autoantibodies to define homogenous disease groups, and may be important in understanding the relationship between autoantibodies and disease pathogenesis.
In childhood arthritis, collectively known as Juvenile idiopathic arthritis (JIA), the rapid rise of available licensed biological and targeted small molecule treatments in recent years has led to ...improved outcomes. However, real-world data from multiple countries and registries show that despite a large number of available drugs, many children and young people continue to suffer flares and experience significant periods of time with active disease for many years. More than 50% of young people with JIA require ongoing immune suppression well into adult life, and they may have to try multiple different treatments in that time. There are currently no validated tools with which to select specific treatments, nor biomarkers of response to assist in such choices, therefore, current management uses essentially a trial-and-error approach. A further consequence of recent progress is a reducing pool of available children or young people who are eligible for new trials. In this review we consider how progress towards a molecular based approach to defining treatment targets and informing trial design in JIA, combined with novel approaches to clinical trials, could provide strategies to maximise discovery and progress, in order to move towards precision medicine for children with arthritis.
Objective
The idiopathic inflammatory myopathies (IIMs) are heterogeneous diseases thought to be initiated by immune activation in genetically predisposed individuals. We imputed variants from the ...ImmunoChip array using a large reference panel to fine‐map associations and identify novel associations in IIM.
Methods
We analyzed 2,565 Caucasian IIM patient samples collected through the Myositis Genetics Consortium (MYOGEN) and 10,260 ethnically matched control samples. We imputed 1,648,116 variants from the ImmunoChip array using the Haplotype Reference Consortium panel and conducted association analysis on IIM and clinical and serologic subgroups.
Results
The HLA locus was consistently the most significantly associated region. Four non‐HLA regions reached genome‐wide significance, SDK2 and LINC00924 (both novel) and STAT4 in the whole IIM cohort, with evidence of independent variants in STAT4, and NAB1 in the polymyositis (PM) subgroup. We also found suggestive evidence of association with loci previously associated with other autoimmune rheumatic diseases (TEC and LTBR). We identified more significant associations than those previously reported in IIM for STAT4 and DGKQ in the total cohort, for NAB1 and FAM167A‐BLK loci in PM, and for CCR5 in inclusion body myositis. We found enrichment of variants among DNase I hypersensitivity sites and histone marks associated with active transcription within blood cells.
Conclusion
We found novel and strong associations in IIM and PM and localized signals to single genes and immune cell types.
Juvenile dermatomyositis (JDM) is a rare, potentially life-threatening systemic autoimmune disease primarily affecting muscle and skin. Recent advances in the recognition, standardised assessment and ...treatment of JDM have been greatly facilitated by large collaborative research networks. Through these networks, a number of immunogenetic risk factors have now been defined, as well as a number of potential pathways identified in the aetio-pathogenesis of JDM. Myositis-associated and myositis-specific autoantibodies are helping to sub-phenotype JDM, defined by clinical features, outcomes and immunogenetic risk factors. Partially validated tools to assess disease activity and damage have assisted in standardising outcomes. Aggressive treatment approaches, including multiple initial therapies, as well as new drugs and biological therapies for refractory disease, offer promise of improved outcomes and less corticosteroid-related toxicity.
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