Association with HLA-DRß1 position 37 distinguishes juvenile dermatomyositis from adult-onset myositis.

Juvenile dermatomyositis (JDM) is a rare, severe autoimmune disease and the most common idiopathic inflammatory myopathy of children. JDM and adult-onset dermatomyositis (DM) have similar clinical, biological and serological features, although these features differ in prevalence between childhood-onset and adult-onset disease, suggesting that age of disease onset may influence pathogenesis. Therefore, a JDM-focused genetic analysis was performed using the largest collection of JDM samples to date. Caucasian JDM samples (n = 952) obtained via international collaboration were genotyped using the Illumina HumanCoreExome chip. Additional non-assayed human leukocyte antigen (HLA) loci and genome-wide single-nucleotide polymorphisms (SNPs) were imputed. HLA-DRB1*03:01 was confirmed as the classical HLA allele most strongly associated with JDM [odds ratio (OR) 1.66; 95% confidence interval (CI) 1.46, 1.89; P = 1.4 × 10-14], with an independent association at HLA-C*02:02 (OR = 1.74; 95% CI 1.42, 2.13, P = 7.13 × 10-8). Analyses of amino acid positions within HLA-DRB1 indicated that the strongest association was at position 37 (omnibus P = 3.3 × 10-19), with suggestive evidence this association was independent of position 74 (omnibus P = 5.1 × 10-5), the position most strongly associated with adult-onset DM. Conditional analyses also suggested that the association at position 37 of HLA-DRB1 was independent of some alleles of the Caucasian HLA 8.1 ancestral haplotype (AH8.1) such as HLA-DQB1*02:01 (OR = 1.62; 95% CI 1.36, 1.93; P = 8.70 × 10-8), but not HLA-DRB1*03:01 (OR = 1.49; 95% CR 1.24, 1.80; P = 2.24 × 10-5). No associations outside the HLA region were identified. Our findings confirm previous associations with AH8.1 and HLA-DRB1*03:01, HLA-C*02:02 and identify a novel association with amino acid position 37 within HLA-DRB1, which may distinguish JDM from adult DM.

Clinical Characteristics of Adolescents With Juvenile Idiopathic Arthritis Transitioning to Adult Rheumatology Care in Canada: Results From the CAPRI Registry.

OBJECTIVE: Using Canadian Alliance of Pediatric Rheumatology Investigators (CAPRI) juvenile idiopathic arthritis (JIA) registry data, we describe (1) clinical characteristics of patients with JIA transitioning to adult care, (2) prevalence of disease-related damage and complications, and (3) changes in disease activity during the final year prior to transfer. METHODS: Registry participants who turned 17 years between February 2017 and November 2021 were included. Clinical characteristics and patient-reported outcomes (PROs) at the last recorded pediatric rheumatology visit, and changes observed in the year prior to that visit were analyzed. Physicians completed an additional questionnaire characterizing cumulative disease-related damage and adverse events by age 17 years. RESULTS: At their last visit, 88 of 131 participants (67%) had inactive and 42 (32%) had active disease. Overall, 96 (73%) were on medications and 41 (31%) were on biologic disease-modifying antirheumatic drugs. Among 80 participants for whom the additional questionnaire was completed, 26% had clinically detected joint damage, 31% had joint damage on imaging, 14% had uveitis, and 7.5% had experienced at least 1 serious adverse event. During the final year, 44.2% of patients were in remission, 28.4% attained inactive disease, and 27.4% became or remained active. Mean scores of PROs were stable overall during that last year, but a minority reported marked worsening. CONCLUSION: A substantial proportion of youth with JIA transitioning to adult care in Canada had a high disease burden, which was reflected by their degree of disease activity, joint damage, or ongoing medication use. These results will inform pediatric and adult providers of anticipated needs during transition of care.

Tofacitinib in juvenile idiopathic arthritis: a double-blind, placebo-controlled, withdrawal phase 3 randomised trial.

BACKGROUND: Tofacitinib is an oral Janus kinase inhibitor. This trial assessed the efficacy and safety of tofacitinib versus placebo in patients with polyarticular course juvenile idiopathic arthritis (JIA). METHODS: This double-blind, withdrawal phase 3 trial enrolled patients with polyarticular course JIA (extended oligoarthritis, rheumatoid factor-positive or rheumatoid factor-negative polyarthritis, or systemic JIA without active systemic features) aged 2 years to younger than 18 years, and was done at 64 centres of the Paediatric Rheumatology International Trials Organisation and Pediatric Rheumatology Collaborative Study Group networks in 14 countries. Patients with psoriatic arthritis or enthesitis-related arthritis were enrolled for exploratory endpoints. During part 1 of the study, patients received oral open-label tofacitinib (weight-based doses; 5 mg twice daily or lower) for 18 weeks. Patients achieving at least JIA/American College of Rheumatology 30 response were randomly assigned (1:1) using an Interactive Response Technology system to continue tofacitinib or switch to placebo in part 2 of the study for 26 weeks. The primary endpoint was JIA flare rate by week 44 in part 2 in patients with polyarticular course JIA; the intention-to-treat principle was applied. Safety was evaluated throughout part 1 and part 2 of the study in all patients who received one dose or more of study medication. This trial is registered with ClinicalTrials.gov, NCT02592434. FINDINGS: Between June 10, 2016, and May 16, 2019, of 225 patients enrolled, 184 (82%) patients had polyarticular course JIA, 20 (9%) had psoriatic arthritis, and 21 (9%) had enthesitis-related arthritis. 147 (65%) of 225 patients received concomitant methotrexate. In part 2, 142 patients with polyarticular course JIA were assigned to tofacitinib (n=72) or placebo (n=70). Flare rate by week 44 was significantly lower with tofacitinib (21 [29%] of 72 patients) than with placebo (37 [53%] of 70 patients; hazard ratio 0·46, 95% CI 0·27-0·79; p=0·0031). In part 2 of the study, adverse events occurred in 68 (77%) of 88 patients receiving tofacitinib and 63 (74%) of 85 in the placebo group. Serious adverse events occurred in one (1%) and two (2%), respectively. In the entire tofacitinib exposure period, 107 (48%) of 225 patients had infections or infestations. There were no deaths during this study. INTERPRETATION: The results of this pivotal trial show that tofacitinib is an effective treatment in patients with polyarticular course JIA. New oral therapies are particularly relevant for children and adolescents, who might prefer to avoid injections. FUNDING: Pfizer.

Development and validation of the Kids Disability Screen for children with juvenile idiopathic arthritis: results from the CAPRI Registry.

OBJECTIVE: The aim of this study was to develop and validate a brief disability screen for children with JIA, the Kids Disability Screen (KDS). METHODS: A total of 216 children enrolled in the Canadian Alliance of Pediatric Rheumatology Investigators (CAPRI) Registry in 2017-2018 formed a development cohort, and 220 children enrolled in 2019-2020 formed a validation cohort. At every clinic visit, parents answered two questions derived from the Childhood Health Assessment Questionnaire (CHAQ): 'Is it hard for your child to run and play BECAUSE OF ARTHRITIS?' ('Hard' 0-10), and 'Does your child usually need help from you or another person BECAUSE OF ARTHRITIS?' ('Help', 0-10). We used 36-fold cross-validation and tested nine different mathematical methods to combine the answers and optimize psychometric properties. The results were confirmed in the validation cohort. RESULTS: Expressed as the mean of the two answers, KDS best balanced ease of use and psychometric properties, while a LASSO regression model combining the two answers with other patient characteristics [estimated CHAQ [eCHAQ]) had the highest responsiveness. In the validation cohort, 22.7%, 25.9% and 28.6% of patients had a score of 0 at enrolment for the KDS, eCHAQ and CHAQ, respectively. Responsiveness was 0.67, 0.74 and 0.62, respectively. Sensitivity to detect a CHAQ > 0 was 0.90 and specificity 0.56, KDS detecting some disability in 44% of children with a CHAQ = 0. CONCLUSION: This simple KDS has psychometric properties comparable with those of a full CHAQ and may be used at every clinic visit to identify those children who need a full disability assessment.

Impact of the COVID-19 pandemic on juvenile idiopathic arthritis presentation and research recruitment: results from the CAPRI registry.

OBJECTIVE: The COVID-19 pandemic has disrupted healthcare delivery and clinical research worldwide, with data from areas most affected demonstrating an impact on rheumatology care. This study aimed to characterize the impact of the pandemic on the initial presentation of JIA and JIA-related research in Canada. METHODS: Data collected from the Canadian Alliance of Pediatric Rheumatology Investigators JIA Registry from the year pre-pandemic (11 March 2019 to 10 March 2020) was compared with data collected during the first year of the pandemic (11 March 2020 to 10 March 2021). Outcomes included time from symptom onset to first assessment, disease severity at presentation and registry recruitment. Proportions and medians were used to describe categorical and continuous variables, respectively. RESULTS: The median time from symptom onset to first assessment was 138 (IQR 64-365) days pre-pandemic vs 146 (IQR 83-359) days during the pandemic. The JIA category frequencies remained overall stable (44% oligoarticular JIA pre-pandemic, 46.8% pandemic), except for systemic JIA (12 cases pre-pandemic, 1 pandemic). Clinical features, disease activity (cJADAS10), disability (CHAQ) and quality of life (JAQQ) scores were similar between the two cohorts. Pre-pandemic, 225 patients were enrolled, compared with 111 in the pandemic year, with the greatest decrease from March to June 2020. CONCLUSIONS: We did not observe the anticipated delay in time to presentation or increased severity at presentation, suggesting that, within Canada, care adapted well to provide support to new patient consults without negative impacts. The COVID-19 pandemic was associated with an initial 50% decrease in registry enrolment but has since improved.

The iCanCope pain self-management application for adolescents with juvenile idiopathic arthritis: a pilot randomized controlled trial.

OBJECTIVES: To evaluate the feasibility and preliminary effectiveness of iCanCope with Pain (iCanCope), a smartphone-based pain self-management program, in adolescents with JIA. iCanCope featured symptom tracking, goal-setting, pain coping skills and social support. METHODS: A two-arm pilot randomized controlled trial was used to evaluate the iCanCope app compared with a version with symptom tracking only. Primary (feasibility) outcomes were: participant accrual/attrition rates, success of app deployment, acceptability and adherence. Secondary (preliminary effectiveness) outcomes were: pain intensity, pain-related activity limitations and health-related quality of life. Outcomes were assessed at baseline and 8 weeks. Adherence was defined as the proportion of completed symptom reports: 'low' (≤24%); 'low-moderate' (25-49%); 'high-moderate' (50-75%); or 'high' (76-100%). Linear mixed models were applied for preliminary effectiveness analyses as per intention-to-treat. RESULTS: Adolescents (N = 60) were recruited from three paediatric rheumatology centres. Rates of accrual and attrition were 82 and 13%, respectively. Both apps were deployed with high success (over 85%) and were rated as highly acceptable. Adherence was similar for both groups, with most participants demonstrating moderate-to-high adherence. Both groups exhibited a clinically meaningful reduction in pain intensity (≥1 point) that did not statistically differ between groups. There were no significant changes in activity limitations or health-related quality of life. CONCLUSION: The iCanCope pilot randomized controlled trial was feasible to implement in a paediatric rheumatology setting. Both apps were deployed successfully, with high acceptability, and were associated with moderate-to-high adherence. Preliminary reductions in pain intensity warrant a future trial to evaluate effectiveness of iCanCope in improving health outcomes in adolescents with JIA. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02764346.

Risk factors associated with Pneumocystis jirovecii pneumonia in juvenile myositis in North America.

OBJECTIVES: Pneumocystis jirovecii pneumonia (PJP) is associated with significant morbidity and mortality in adult myositis patients; however, there are few studies examining PJP in juvenile myositis [juvenile idiopathic inflammatory myopathy (JIIM)]. The purpose of this study was to determine the risk factors and clinical phenotypes associated with PJP in JIIM. METHODS: An research electronic data capture (REDCap) questionnaire regarding myositis features, disease course, medications and PJP infection characteristics was completed by treating physicians for 13 JIIM patients who developed PJP (PJP+) from the USA and Canada. Myositis features and medications were compared with 147 JIIM patients without PJP (PJP-) from similar geographic regions who enrolled in National Institutes of Health natural history studies. RESULTS: PJP+ patients were more often of Asian ancestry than PJP- patients [odds ratio (OR) 8.7; 95% CI 1.3, 57.9]. Anti- melanoma differentiation associated protein 5 (MDA5) autoantibodies (OR 12.5; 95% CI 3.0, 52.4), digital infarcts (OR 43.8; 95% CI 4.2, 460.2), skin ulcerations (OR 12.0; 95% CI 3.5, 41.2) and interstitial lung disease (OR 10.6; 95% CI 2.1, 53.9) were more frequent in PJP+ patients. Before PJP diagnosis, patients more frequently received pulse steroids, rituximab and more immunosuppressive therapy compared with PJP- patients. Seven PJP+ patients were admitted to the intensive care unit and four patients died due to PJP or its complications. CONCLUSIONS: PJP is a severe infection in JIIM that can be associated with mortality. Having PJP was associated with more immunosuppressive therapy, anti-MDA5 autoantibodies, Asian race and certain clinical features, including digital infarcts, cutaneous ulcerations and interstitial lung disease. Prophylaxis for PJP should be considered in juvenile myositis patients with these features.

Subcutaneous dosing regimens of tocilizumab in children with systemic or polyarticular juvenile idiopathic arthritis.

OBJECTIVES: To determine s.c. tocilizumab (s.c.-TCZ) dosing regimens for systemic JIA (sJIA) and polyarticular JIA (pJIA). METHODS: In two 52-week phase 1 b trials, s.c.-TCZ (162 mg/dose) was administered to sJIA patients every week or every 2 weeks (every 10 days before interim analysis) and to pJIA patients every 2 weeks or every 3 weeks with body weight ≥30 kg or <30 kg, respectively. Primary end points were pharmacokinetics, pharmacodynamics and safety; efficacy was exploratory. Comparisons were made to data from phase 3 trials with i.v. tocilizumab (i.v.-TCZ) in sJIA and pJIA. RESULTS: Study participants were 51 sJIA patients and 52 pJIA patients aged 1-17 years who received s.c.-TCZ. Steady-state minimum TCZ concentration (Ctrough) >5th percentile of that achieved with i.v.-TCZ was achieved by 49 (96%) sJIA and 52 (100%) pJIA patients. In both populations, pharmacodynamic markers of disease were similar between body weight groups. Improvements in Juvenile Arthritis DAS-71 were comparable between s.c.-TCZ and i.v.-TCZ. By week 52, 53% of sJIA patients and 31% of pJIA patients achieved clinical remission on treatment. Safety was consistent with that of i.v.-TCZ except for injection site reactions, reported by 41.2% and 28.8% of sJIA and pJIA patients, respectively. Infections were reported in 78.4% and 69.2% of patients, respectively. Two sJIA patients died; both deaths were considered to be related to TCZ. CONCLUSION: s.c.-TCZ provides exposure and risk/benefit profiles similar to those of i.v.-TCZ. S.c. administration provides an alternative administration route that is more convenient for patients and caregivers and that has potential for in-home use. TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, NCT01904292 and NCT01904279.

Open-label phase 3 study of intravenous golimumab in patients with polyarticular juvenile idiopathic arthritis.

OBJECTIVES: To assess efficacy, pharmacokinetics (PK) and safety of intravenous (i.v.) golimumab in patients with polyarticular-course JIA (pc-JIA). METHODS: Children aged 2 to <18 years with active pc-JIA despite MTX therapy for ≥2 months received 80 mg/m2 golimumab at weeks 0, 4, then every 8 weeks through week 52 plus MTX weekly through week 28. The primary and major secondary endpoints were PK exposure and model-predicted steady-state area under the curve (AUCss) over an 8-week dosing interval at weeks 28 and 52, respectively. JIA ACR response and safety were also assessed. RESULTS: In total, 127 children were treated with i.v. golimumab. JIA ACR 30, 50, 70, and 90 response rates were 84%, 80%, 70% and 47%, respectively, at week 28 and were maintained through week 52. Golimumab serum concentrations and AUCss were 0.40 µg/ml and 399 µg ⋅ day/ml at week 28. PK exposure was maintained at week 52. Steady-state trough golimumab concentrations and AUCss were consistent across age categories and comparable to i.v. golimumab dosed 2 mg/kg in adults with rheumatoid arthritis. Golimumab antibodies and neutralizing antibodies were detected via a highly sensitive drug-tolerant assay in 31% (39/125) and 19% (24/125) of patients, respectively. Median trough golimumab concentration was lower in antibody-positive vs antibody-negative patients. Serious infections were reported in 6% of patients, including one death due to septic shock. CONCLUSION: Body surface area-based dosing of i.v. golimumab was well tolerated and provided adequate PK exposure for clinical efficacy in paediatric patients with active pc-JIA.ClinicalTrials.gov number NCT02277444.

A new Canadian inception cohort for juvenile idiopathic arthritis: The Canadian Alliance of Pediatric Rheumatology Investigators Registry.

OBJECTIVES: The aim was to describe the design, methods and initial findings of a new Canadian inception cohort of children with JIA, The Canadian Alliance of Pediatric Rheumatology Investigators (CAPRI) JIA Registry. METHODS: The CAPRI JIA Registry was started in 2017 to collect information prospectively on children enrolled within 3 months of JIA diagnosis across Canada. The registry has a non-traditional modular design, with no artificially set times for registry visits to occur, streamlined multi-method data collection that requires 2-4 min per visit, and reports cumulative incidence of treatments, outcomes and adverse events calculated by Kaplan-Meier survival methods. RESULTS: A total of 166 patients, enrolled a median of 6 weeks after JIA diagnosis at 10 centres, were included. The median age at diagnosis was 9 years [interquartile range (IQR) 3, 13], 61% were female and 51% had oligoarticular JIA. The median three-variable clinical Juvenile Arthritis Disease Activity Score was 6.5 (IQR 4, 10) at enrolment, and the median time to first attainment of clinically inactive disease (CID) was 24 weeks (by 1 year, 81%). Within 1 year of diagnosis, 70% of patients had started a DMARD and 35% a biologic agent. The rates of adverse events and serious adverse events were 60 and 5.8 per 100 patient-years, respectively. CONCLUSION: This streamlined and flexible registry minimizes the burden of data collection and interference with clinic operations. Initial findings suggest that treatments for newly diagnosed patients with JIA in Canada have intensified, and now 81% of patients attain CID within 1 year of diagnosis.

Testing population-based performance measures identifies gaps in juvenile idiopathic arthritis (JIA) care.

BACKGROUND: The study evaluates Performance Measures (PMs) for Juvenile Idiopathic Arthritis (JIA): The percentage of patients with new onset JIA with at least one visit to a pediatric rheumatologist in the first year of diagnosis (PM1); and the percentage of patients with JIA under rheumatology care seen in follow-up at least once per year (PM2). METHODS: Validated JIA case ascertainment algorithms were used to identify cases from provincial health administrative databases in Manitoba, Canada in patients < 16 years between 01/04/2005 and 31/03/2015. PM1: Using a 3-year washout period, the percentage of incident JIA patients with ≥1 visit to a pediatric rheumatologist in the first year was calculated. For each fiscal year, the proportion of patients expected to be seen in follow-up who had a visit were calculated (PM2). The proportion of patients with gaps in care of > 12 and > 14 months between consecutive visits were also calculated. RESULTS: One hundred ninety-four incident JIA cases were diagnosed between 01/04/2008 and 03/31/2015. The median age at diagnosis was 9.1 years and 71% were female. PM1: Across the years, 51-81% of JIA cases saw a pediatric rheumatologist within 1 year. PM2: Between 58 and 78% of patients were seen in yearly follow-up. Gaps > 12, and > 14, months were observed once during follow-up in 52, and 34%, of cases, and ≥ twice in 11, and 5%, respectively. CONCLUSIONS: Suboptimal access to pediatric rheumatologist care was observed which could lead to diagnostic and treatment delays and lack of consistent follow-up, potentially negatively impacting patient outcomes.

The risk and nature of flares in juvenile idiopathic arthritis: results from the ReACCh-Out cohort.

OBJECTIVE: To describe probabilities and characteristics of disease flares in children with juvenile idiopathic arthritis (JIA) and to identify clinical features associated with an increased risk of flare. METHODS: We studied children in the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh-Out) prospective inception cohort. A flare was defined as a recurrence of disease manifestations after attaining inactive disease and was called significant if it required intensification of treatment. Probability of first flare was calculated with Kaplan-Meier methods, and associated features were identified using Cox regression. RESULTS: 1146 children were followed up a median of 24 months after attaining inactive disease. We observed 627 first flares (54.7% of patients) with median active joint count of 1, physician global assessment (PGA) of 12 mm and duration of 27 weeks. Within a year after attaining inactive disease, the probability of flare was 42.5% (95% CI 39% to 46%) for any flare and 26.6% (24% to 30%) for a significant flare. Within a year after stopping treatment, it was 31.7% (28% to 36%) and 25.0% (21% to 29%), respectively. A maximum PGA >30 mm, maximum active joint count >4, rheumatoid factor (RF)-positive polyarthritis, antinuclear antibodies (ANA) and receiving disease-modifying antirheumatic drugs (DMARDs) or biological agents before attaining inactive disease were associated with increased risk of flare. Systemic JIA was associated with the lowest risk of flare. CONCLUSIONS: In this real-practice JIA cohort, flares were frequent, usually involved a few swollen joints for an average of 6 months and 60% led to treatment intensification. Children with a severe disease course had an increased risk of flare.

The outcomes of juvenile idiopathic arthritis in children managed with contemporary treatments: results from the ReACCh-Out cohort.

OBJECTIVE: To describe clinical outcomes of juvenile idiopathic arthritis (JIA) in a prospective inception cohort of children managed with contemporary treatments. METHODS: Children newly diagnosed with JIA at 16 Canadian paediatric rheumatology centres from 2005 to 2010 were included. Kaplan-Meier survival curves for each JIA category were used to estimate probability of ever attaining an active joint count of 0, inactive disease (no active joints, no extraarticular manifestations and a physician global assessment of disease activity <10 mm), disease remission (inactive disease >12 months after discontinuing treatment) and of receiving specific treatments. RESULTS: In a cohort of 1104 children, the probabilities of attaining an active joint count of 0 exceeded 78% within 2 years in all JIA categories. The probability of attaining inactive disease exceeded 70% within 2 years in all categories, except for RF-positive polyarthritis (48%). The probability of discontinuing treatment at least once was 67% within 5 years. The probability of attaining remission within 5 years was 46-57% across JIA categories except for polyarthritis (0% RF-positive, 14% RF-negative). Initial treatment included joint injections and non-steroidal anti-inflammatory drugs for oligoarthritis, disease-modifying antirheumatic drugs (DMARDs) for polyarthritis and systemic corticosteroids for systemic JIA. CONCLUSIONS: Most children with JIA managed with contemporary treatments attain inactive disease within 2 years of diagnosis and many are able to discontinue treatment. The probability of attaining remission within 5 years of diagnosis is about 50%, except for children with polyarthritis.

Purpura, petechiae, and bullae as first signs of juvenile granulomatosis with polyangiitis.

UNLABELLED: We present a case of a 14-year-old girl who had a severe form of granulomatosis with polyangiitis (GPA) with extensive dermatological involvement, whose initial presentation was nonspecific leading to diagnostic confusion and initial consideration of infectious and other vasculitis causes. The patient presented with fever, congestion, malaise, and sinus pain. She was diagnosed with bacterial sinusitis and treated with antibiotics. Within weeks, she developed abdominal pain, hematuria, migratory arthritis, and palpable purpura and was diagnosed with Henoch-Schonlein purpura. She went on to develop hemoptysis and progression of the rash into erosive bullae. Investigations revealed that she was ANCA positive and had pauci-immune glomerulonephritis. Given her upper airway, pulmonary and renal involvement, and antineutrophil cytoplasmic antibodies positivity, a definitive diagnosis of a severe form of GPA was made. GPA is a chronic relapsing, life threatening vasculitis that predominantly affects small vessels. CONCLUSION: Our case demonstrates that GPA can present initially with nonspecific symptoms, including extensive dermatological involvement, leading to diagnostic confusion, and delays in treatment. In the case of a severe peripheral rash in the juvenile population and/or resistant upper airway symptoms, it is vital to consider a diagnosis of GPA to avoid serious organ or life threatening consequences.

Relationship of Fatigue, Pain Interference, and Physical Disability in Children Newly Diagnosed With Juvenile Idiopathic Arthritis.

OBJECTIVE: Our objectives were to quantify the relationships among fatigue, pain interference, and physical disability in children with juvenile idiopathic arthritis (JIA) and to test whether fatigue mediates the relationship between pain interference and physical disability in JIA. METHODS: Patients enrolled within three months of JIA diagnosis in the Canadian Alliance of Pediatric Rheumatology Investigators (CAPRI) Registry between February 2017 and May 2023 were included. Their parents completed the Patient-Reported Outcomes Measurement Information System fatigue and pain interference short proxy questionnaires and the Childhood Health Assessment Questionnaire disability index at registry enrollment. Associations were assessed using Pearson correlations and multiple linear regression. Structural equation modeling (SEM) was used to test if fatigue mediates the relationship between pain interference and physical disability. RESULTS: Among 855 patients (61.4% female, 44.1% with oligoarthritis), most reported fatigue and pain interference scores similar to those in the reference population, but 15.6% reported severe fatigue and 7.3% reported severe pain interference, with wide variation across JIA categories. Fatigue was strongly correlated with pain interference (r = 0.72, P < 0.001) and with physical disability (r = 0.60, P < 0.001). Pain interference (ß = 0.027, P < 0.001) and fatigue (ß = 0.013, P < 0.001) were both associated with physical disability after controlling for each other and potential confounders. SEM supported our hypothesis that fatigue partially mediates the relationship between pain interference and physical disability. CONCLUSION: Our findings suggest both fatigue and pain interference are independently associated with physical disability in children newly diagnosed with JIA, and the effect of pain interference may be partly mediated by fatigue.

Biomarker Changes in Response to Tofacitinib Treatment in Patients with Polyarticular Course Juvenile Idiopathic Arthritis.

OBJECTIVE: Examine levels of candidate blood-based biomarkers (CBB) in juvenile idiopathic arthritis (JIA) treated with tofacitinib. METHODS: JIA patients who participated in clinical trial NCT02592434 received tofacitinib from baseline to week 18. Serial serum samples were assayed for CBB (S100A8/9, S100A12, IL-18, SAA, resistin, VEGF, Angiopoietin-1, Angiopoietin-2, MMP8, MMP2, TIMP1, Leptin, CXCL9, sIL2R, ICAM-1, sTNFr, IL-6, IL-23, MCP1, CCL18, and CCL20). Association of CBB with JIA response to treatment from baseline to week 18 were assessed. RESULTS: This study included 166 patients with polyarticular-course JIA. Paired serum samples from 143 patients were available at both baseline and week 18. There were 35% (50/143) of patients with a JIA-American College of Rheumatology 90 (JIA-ACR90) level improvement while 90/121/137 (63%/85%/96%) achieved JIA-ACR70/50/30 improvement at wk18. Despite small numerical differences by JIA category, there were no baseline CBB values that independently predicted a decrease in JADAS-27 or JIA-ACR90 response by week 18. Decrease in resistin level (baseline to week 18) was significantly associated with wk18 improvement in JADAS-27 and JIA-ACR90 response, after adjusting for age, sex, JIA disease duration and baseline resistin [(r2 0.79, SE, 0.070, p<0.01 and OR(95%CI) = 1.134(1.018, 1.264)]. HLA-B27 positivity was significantly associated with not achieving a JIA-ACR90 response at week 18 (p=0.0097). CONCLUSION: Among the CBB included, only resistin was significantly associated with treatment response, and no CBB was identified that forecasts JIA improvement after initiation of tofacitinib. The association of HLA-B27 positivity with lower response to tofacitinib in JIA is intriguing and merits further study.

Anti-Valosin-Containing Protein (VCP/p97) Autoantibodies in Inclusion Body Myositis and Other Inflammatory Myopathies.

OBJECTIVE: The rationale for this study was based on reports that valosin-containing protein (VCP) mutations are found in hereditary inclusion body myositis (IBM) and VCP was detected in rimmed vacuoles of sporadic IBM (sIBM) muscle biopsies. Autoantibodies to VCP have not been reported in sIBM or other inflammatory myopathies (IIMs). The aim of this study was to determine the frequency and clinical significance of anti-VCP antibodies in sIBM and other IIMs. METHODS: Sera were collected from 73 patients with sIBM and 383 comparators or controls, including patients with IIM (n = 69), those with juvenile dermatomyositis (JDM) (n = 67), those with juvenile idiopathic arthritis (JIA) (n = 47), those with primary biliary cholangitis (PBC) (n = 105), controls that were age matched to patients with sIBM (similarly aged controls [SACs]) (n = 63), and healthy controls (HCs) (n = 32). Immunoglobulin G antibodies to VCP were detected by addressable laser bead immunoassay using a full-length recombinant human protein. RESULTS: Among patients with sIBM, 26.0% (19/73) were positive for anti-VCP. The frequency in disease controls was 15.0% (48/320). Among SACs, the frequency was 1.6% (1/63), and in HCs 0% (0/32). Frequencies were 17.5% (11/63) for IIM, 25.7% (27/105) for PBC, 3.0% (2/67) for JDM, and 17.0% (8/47) for JIA. The sensitivity, specificity, positive predictive value, and negative predictive value of anti-VCP for sIBM were 26.0%, 87.2%, 28.4%, and 85.9%, respectively. Of patients with sIBM, 15.1% (11/73) were positive for both anti-VCP and anti-cytosolic 5'-nucleotidase 1A (NT5c1A). Eleven percent of patients (8/73) were positive for anti-VCP, but negative for anti-NT5c1A. CONCLUSION: Anti-VCP has low sensitivity and moderate specificity for sIBM but may help fill the seronegative gap in sIBM. Further studies are needed to determine whether anti-VCP is a biomarker for a clinical phenotype that may have clinical value.

Distinct phenotypes of multisystem inflammatory syndrome in children: a cohort study.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a severe disease with an unpredictable course and a substantial risk of cardiogenic shock. Our objectives were to (a) compare MIS-C phenotypes across the COVID-19 pandemic, (b) identify features associated with intensive care need and treatment with biologic agents. METHODS: Youth aged 0-18 years, fulfilling the World Health Organization case definition of MIS-C, and admitted to the Alberta Children's Hospital during the first four waves of the COVID-19 pandemic (May 2020-December 2021) were included in this cohort study. Demographic, clinical, biochemical, imaging, and treatment data were captured. RESULTS: Fifty-seven MIS-C patients (median age 6 years, range 0-17) were included. Thirty patients (53%) required intensive care. Patients in the third or fourth wave (indicated as phase 2 of the pandemic) presented with higher peak ferritin (µg/l, median (IQR) = 1134 (409-1806) vs. 370 (249-629), P = 0.001), NT-proBNP (ng/l, median (IQR) = 12,217 (3013-27,161) vs. 3213 (1216-8483), P = 0.02) and D-dimer (mg/l, median (IQR) = 4.81 (2.24-5.37) vs. 2.01 (1.27-3.34), P = 0.004) levels, and higher prevalence of liver enzyme abnormalities (n(%) = 17 (68) vs. 11 (34), P = 0.02), hypoalbuminemia (n(%) = 24 (100) vs. 25 (81), P = 0.03) and thrombocytopenia (n(%) 18 (72) vs. 11 (34), P = 0.007) compared to patients in the first two waves (phase 1). These patients had a higher need of non-invasive/mechanical ventilation (n(%) 4 (16) vs. 0 (0), P = 0.03). Unsupervised clustering analyses classified 47% of the patients in the correct wave and 74% in the correct phase of the pandemic. NT-proBNP was the only significant contributor to the need for intensive care in all applied multivariate regression models. Treatment with biologic agents was significantly associated with peak CRP (mg/l (median, IQR = 240.9 (132.9-319.4) vs. 155.8 (101.0-200.7), P = 0.02) and ferritin levels (µg/l, median (IQR) = 1380 (509-1753) vs. 473 (280-296)). CONCLUSIONS: MIS-C patients in a later stage of the pandemic displayed a more severe phenotype, reflecting the impact of distinct SARS-CoV-2 variants. NT-proBNP emerged as the most crucial feature associated with intensive care need, underscoring the importance of monitoring.

Synovial fluid mesenchymal progenitor cells from patients with juvenile idiopathic arthritis demonstrate limited self-renewal and chondrogenesis.

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of inflammatory diseases affecting joints with a prevalence of one in a thousand children. There is a growing body of literature examining the use of mesenchymal stem/progenitor cells (MPCs) for the treatment of adult and childhood arthritis, however, we still lack a clear understanding of how these MPC populations are impacted by arthritic disease states and how this could influence treatment efficacy. In the current study we examined the immunophenotyping, self-renewal ability and chondrogenic capacity (in vitro and in vivo) of synovial derived MPCs from normal, JIA and RA joints. Synovial MPCs from JIA patients demonstrated reduced self-renewal ability and chondrogenic differentiation capacity. Furthermore, they did not induce cartilage regeneration when xenotransplanted in a mouse cartilage injury model. Synovial MPCs from JIA patients are functionally compromised compared to MPCs from normal and/or RA joints. The molecular mechanisms behind this loss of function remain elusive. Further study is required to see if these cells can be re-functionalized and used in cell therapy strategies for these JIA patients, or if allogenic approaches should be considered.

Acceptability of an Adolescent Self-Management Program for Juvenile Idiopathic Arthritis.

OBJECTIVE: The study objective was to test the acceptability of a self-management program (SMP) for adolescents with juvenile idiopathic arthritis (JIA) focused on disease information, self-management, and social support needs. METHODS: This study was conducted using inductive qualitative methods to explore the acceptability of an in-person/videoconference SMP. Two groups of four adolescents with JIA (mean age = 13.5, SD = 0.8) and two groups of pediatric rheumatology health care professionals (n = 4, n = 5) participated in four feedback sessions each. The SMP was presented to study participants, and feedback was provided on the content, format, and structure of the program. Thematic analysis was used to analyze the data. RESULTS: Adolescents felt that the content was appropriate and would be effective in supporting self-management of their arthritis. Participants advised that the trustworthiness of the information would be increased if a rheumatology health care provider facilitated the session. Potential barriers to participation included distance and availability (weekdays and times), but the option for videoconference-based participation was an appropriate solution to both of these issues. Minor changes were made to content and format, and required changes were made to address participant recommendations for improvement. CONCLUSION: This study confirmed the acceptability of an in-person/videoconference SMP for patients with JIA. Modifications were made to the SMP based on the focus group feedback, and future directions include a pilot randomized controlled trial to assess feasibility and preliminary effectiveness of the program.