Juvenile Dermatomyositis Patients Research Articles

Coordinated immune dysregulation in Juvenile Dermatomyositis revealed by single-cell genomics.

Juvenile Dermatomyositis (JDM) is one of several childhood-onset autoimmune disorders characterized by a type I interferon response and autoantibodies. Treatment options are limited due to incomplete understanding of how the disease emerges from dysregulated cell states across the immune system. We therefore investigated the blood of JDM patients at different stages of disease activity using single-cell transcriptomics paired with surface protein expression. By immunophenotyping peripheral blood mononuclear cells, we observed skewing of the B cell compartment towards an immature naive state as a hallmark of JDM at diagnosis. Furthermore, we find that these changes in B cells are paralleled by T cell signatures suggestive of Th2-mediated inflammation that persist despite disease quiescence. We applied network analysis to reveal that hyperactivation of the type I interferon response in all immune populations is coordinated with previously masked cell states including dysfunctional protein processing in CD4+ T cells and regulation of cell death programming in NK, CD8+ T cells and gdT cells. Together, these findings unveil the coordinated immune dysregulation underpinning JDM and provide insight into strategies for restoring balance in immune function.

Belimumab ameliorates symptoms and disease activity in dermatomyositis and juvenile dermatomyositis patients refractory to standard therapy: a retrospective observational study

Belimumab ameliorates symptoms and disease activity in dermatomyositis and juvenile dermatomyositis patients refractory to standard therapy: a retrospective observational study

Elevated type I IFN signalling directly affects CD8+ T-cell distribution and autoantigen recognition of the skeletal muscles in active JDM patients

The link between type I IFN and adaptive immunity, especially T-cell immunity, in JDM still remained largely unclear. This study aimed to understand the effect of elevated type I IFN signaling on CD8+ T cell-associated muscle damage in juvenile dermatomyositis (JDM). This study used flow cytometry (FC) and RT‒PCR were used to examine the circulating cell ratio and type I IFN response. And scRNA-seq was used to examine peripheral immunity in 6 active JDM patients, 3 stable JDM patients, 3 juvenile IMNM patients and 3 age-matched healthy children. In vivo validation experiments were conducted using a mouse model induced by STING agonists and an experimental autoimmune myositis model (EAM). In vitro experiments were conducted using isolated CD8+ T-cells from JDM patients and mice. We found that active JDM patients showed an extensive type I IFN response and a decreased CD8+ T-cell ratio in the periphery (P < 0.05), which was correlated with muscle involvement (P < 0.05). Both new active JDM patients and all active JDM patients showed decreased CD8+ TCM cell ratios compared with age and gender matched stable JDM patients (P < 0.05). Compared with new pediatirc systemic lupus erythematosus (SLE) patients, new active JDM patients displayed decreased CD8+ T-cell and CD8+ TCM cell ratios (P < 0.05). Active JDM patient skeletal muscle biopsies displayed an elevated type I IFN response, upregulated MHC-I expression and CD8+ T-cell infiltration, which was validated in EAM mice. sc-RNAseq demonstrated that type I IFN signalling is the kinetic factor of abnormal differentiation and enhances the cytotoxicity of peripheral CD8+ T cells in active JDM patients, which was confirmed by in vivo and in vitro validation experiments. In summary, the elevated type I IFN signalling affected the differentiation and function of CD8+ T cells in active JDM patients. Skeletal muscle-infiltrating CD8+ T cells might migrate from the periphery under the drive of type I IFN and increased MHC I signals. Therapies targeting autoantigen-specific CD8+ T cells may represent a potential new treatment direction.

Unveiling Cardiac Involvement in Juvenile Dermatomyositis Through Speckle-Tracking Echocardiography.

Early detection of cardiac involvement in Juvenile Dermatomyositis (JDM) is difficult due to the absence of clinical signs and symptoms, with systolic dysfunction often emerging in late stages and associated with a poor prognosis. This study aimed to employ two-dimensional speckle-tracking echocardiography (STE) for subclinical assessment of left ventricular (LV) systolic failure in JDM and explore potential associations between impaired LV systolic function (LV-GLS) and disease activity. A prospective study enrolled 20 healthy volunteers and 26 JDM patients (< 18years old) without cardiac symptoms. Clinical data were collected from medical records, and echocardiograms were conducted by a pediatric cardiologist. Our study cohort demonstrated similar age to controls (13.5 ± .6 vs. 13.8 ± 4.7; p = 0.465). Median illness duration at echocardiography was 5 (1.5-17.5) years, and conventional echocardiography indicated normal LV ejection fraction (> 55%) in all participants. However, STE revealed lowered LV GLS in JDM patients (-22.2 ± 4.1% vs. -26.5 ± 5.3% p = 0.022). Pulse steroid users displayed lower GLS average values compared to non-users (β = 4.99, 95% CI 1.34-8.64, p = 0.009). Negative correlations existed between LV-GLS and age at diagnosis (r = -0.499; p = 0.011), diastolic parameters (E/E' ratio) and age at diagnosis (r = -0.469; p = 0.018), as well as RV global strain and age at diagnosis (r = -0.443; p = 0.024). Employing STE in JDM patients facilitated the identification of preclinical cardiac dysfunction. Given JDM patients' younger age, early myocardial damage detection through STE may impact treatment decisions and long-term cardiovascular prognosis.

TIF1-gamma IgG2 isotype is not associated with malignancy in juvenile dermatomyositis patients.

TIF1-gamma IgG2 isotype is not associated with malignancy in juvenile dermatomyositis patients.

Increased percentage of HLA-DR T cells in untreated juvenile dermatomyositis

This study investigates HLA-DR expression on activated T cells and serum neopterin levels in Juvenile Dermatomyositis (JDM) children pre- and post-treatment. Sixty-nine JDM children (less than 18 years) were included. Elevated HLA-DR+ T cells (>7 %) were observed in 19 % of untreated cases. Post-treatment, mean HLA-DR+ T cells decreased from 5.1 to 2.9 (P < 0.001), and serum neopterin levels declined from 19.3 to 9.1 nmol/L (P < 0.0001). A positive correlation between serum neopterin and HLA-DR T cell percentage was observed (r = 0.39, P = 0.01). Intravenous steroid treatment exhibited a 47.4 % improvement in HLA-DR+ T cells and a 50.5 % reduction in serum neopterin levels, in contrast to 14.8 % and 34.1 % in the oral steroid group. In conclusion, treatment, particularly with IV steroids, significantly improved HLA-DR+ T cells percentage and neopterin levels. A correlation between HLA-DR+ T cells percentage and serum neopterin was noted in untreated JDM patients.

Interferon type I signature associated with skin disease in juvenile dermatomyositis.

Interferon type I (IFN-I) signaling system hyperactivation plays an important role in the pathogenesis of juvenile dermatomyositis (JDM). To analyze IFN-I score with disease activity in patients with JDM. Clinical manifestations laboratory data, and treatment options were analyzed in 15 children with JDM. Disease activity was assessed by CMAS (childhood myositis assessment tool) and CAT (cutaneous assessment tool) scores. IFN I-score was assessed by RT-PCR quantitation of 5 IFN I-regulated transcripts (IFI44L, IFI44, IFIT3, LY6E, MXA1). All patients had skin and muscle involvement, some had a fever (n = 8), swallowing disorders (n = 4), arthritis (n = 5), calcinosis (n = 3), lipodystrophy (n = 2), and interstitial lung disease (n = 5). Twelve patients had elevated IFN I-score and it was correlated with skin disease activity. Ten patients had clinically active disease and the level of IFN I-score and its components were higher than in patients with inactive disease (8.8 vs. 4.2, p = 0.011). IFN I-score was evaluated in nine patients during follow-up. The simultaneous reduction of IFN I-score and its components, CMAS and CAT scores was observed. Skin involvement in refractory JDM is a challenging problem requiring the use of additional medications. Serum IFN I-score might be suggested as the promising biomarker of skin disease activity in JDM patients. Further investigations on patients with JDM and recurrent disease activity are needed, especially concerning biomarkers that determine the response to JAK inhibitors and treatment options for patients who don't respond to them.

Exploring cardiovascular implications of juvenile dermatomyositis: Insights from aortic stiffness analysis and 3D echocardiography.

Our goal was to use three dimensional (3D) strain analysis to evaluate myocardial function and ascending aorta elasticity changes in juvenile dermatomyositis (JDM). Between 2019 and 2021, 23 JDM patients and 20 healthy volunteers participated. Both groups underwent 2D and 3D strain analysis, assessing aortic stiffness using aortic distensibility, stiffness index, strain, and elastic modulus. JDM patients had a median age of 13.3±5.2 years, while controls had a median age of 13.8±4.76 years. 3D strain analysis revealed significantly lower global longitudinal (GLS) and circumferential strain (GCS) in JDM patients compared to controls. Specifically, 3D GLS was notably reduced in patients (-28.1% vs. -31%, p=.047) compared to controls, and 3D GCS was also lower in patients (-27.5% vs. -30.5%, p=.019) compared to controls. Aortic strain and elastic modulus were significantly lower in JDM patients, while aortic stiffness index and distensibility showed no significant differences. Correlation analyses within the JDM group revealed a negative correlation between 3D GLS and age at diagnosis (r=-.561, p=.04), as well as a positive correlation between 3D GLS and both aortic strain (r=.514, p=.0001) and elastic modulus (r=.320, p=.03) in JDM patients. Our study demonstrated a trend towards lower ejection fraction and strain in patients with JDM, along with increased aortic stiffness using 3D echocardiography. These findings suggest potential cardiovascular involvement in juvenile dermatomyositis, emphasizing the importance of comprehensive cardiac assessments in these patients.

Nailfold capillary dropout precedes the presentation of pneumatosis intestinalis and micro-perforation in juvenile dermatomyositis

Juvenile dermatomyositis (JDM) is a rare autoimmune disease characterized by chronic inflammation of the skin and muscle vasculature. Loss of nailfold capillary end row loops (ERL) is associated with disease activity. We now present the first report of serious gastrointestinal (GI) events in two JDM patients, both preceded by a precipitous drop in their ERL, which contributes to the consideration of JDM as a member of the vasculitis group of myopathies. These cases demonstrate that the sudden and significant loss of ERL density appears to be a novel and reliable indicator of severe systemic microangiopathy, including gastrointestinal vasculopathy, in selected children with JDM.

Could ultrasound and muscle elastography be associated with clinical assessment, laboratory and nailfold capillaroscopy in juvenile dermatomyositis patients?

BackgroundJuvenile Dermatomyositis (JDM) is the most common idiopathic inflammatory myopathy in children. Imaging exams are useful for muscle assessment, with ultrasonography (US) being a promising tool in detecting disease activity and tissue damage. There are few studies about muscle elastography.ObjectivesOur aim was to associate clinical, laboratory, and nailfold capillaroscopy (NC) assessments with US in JDM patients; and to compare the findings of US and Strain Elastography (SE) from patients and healthy controls.MethodsAn analytic cross-sectional study was performed with JDM patients and healthy controls. Patients underwent clinical exam to access muscle strength and completed questionnaires about global assessment of the disease and functional capacity. Patients were submitted to NC and measurement of muscle enzymes. All subjects underwent US assessment, using gray scale, Power Doppler (PD), and SE.ResultsTwenty-two JDM patients and fourteen controls, aged between 5 and 21 years, matched for age and sex were assessed. In qualitative and semi-quantitative gray scale, we observed a higher frequency of alterations in patients (p < 0.001), while in PD, there was a higher frequency of positivity in patients’ deltoids and anterior tibialis (p < 0.001). Active disease was associated with an important change in the semi-quantitative gray scale in deltoids (p = 0.007), biceps brachii (p = 0.001) and quadriceps femoris (p = 0.005). The SE demonstrated a high negative predictive value of 87.2.ConclusionUS was able, through gray scale, to differentiate JDM patients from controls, while PD achieved such differentiation only for deltoids and anterior tibialis. The semi-quantitative gray scale showed disease activity in proximal muscles. SE was not able to differentiate patients from controls.

Characteristics and Outcomes of Juvenile Dermatomyositis (JDM) in Thai Children: Experience from a Tertiary Referral Center

Background: Juvenile dermatomyositis (JDM) is the most common autoimmune myositis in children. However, there is a paucity of data on the clinical characteristics of JDM patients in Thailand. Objective: To describe the clinical manifestations, investigations, treatments, complications, and outcomes of JDM in Thailand. Materials and Methods: A bidirectional descriptive study based on past medical records review. All children younger than15 years diagnosed with JDM by Bohan and Peter criteria at King Chulalongkorn Memorial Hospital between January 2010 and December 2022 were enrolled. Results: Thirteen cases were identified with 69% female. The median age at diagnosis and median time to diagnosis were 3.4 (IQR 2 to 6.5) years and 3.5 (IQR 1.2 to 8) months, respectively. The common clinical presentations at disease onset were weakness at 100%, Gottron papules at 69%, and heliotrope rash at 46%. Lactate dehydrogenase was elevated in all cases at diagnosis. Evidence of muscle inflammation was found in 78% of biopsies, 80% of EMGs, and 100% of MRIs. The most common myositis specific Ab was anti-NXP2 at 64%. Most patients had polyphasic disease courses. More than half of the patients, or 62%, developed calcinosis. Six of thirteen cases received recommended treatment with prednisolone and methotrexate at diagnosis. One patient with calcinosis had a good response with infliximab. Conclusion: The present review underscores that JDM patients with younger age at diagnosis will need to be monitored closely and need aggressive long-term treatment. Prompt treatment should be managed according to the severity of symptoms to improve clinical outcomes and prevent serious complications. Keywords: JDM; Calcinosis cutis; Myositis autoantibody; Children; Developing countries

Biologic drugs in the treatment of juvenile dermatomyositis: a literature review.

There is no clear consensus in the literature regarding the choice of biologic therapies and efficacy in juvenile dermatomyositis (JDM). In this review, we aimed to examine previous studies regarding biologic drug use in JDM patients. We screened MEDLINE and Scopus for articles involving JDM patients treated with biologic drugs. We identified 74 articles describing 495 JDM patients treated with biologic drugs (538 biologic treatments) during our literature search. The median (min-max) age of these patients was 9.8 (1-17) years (F/M:1.8). The most frequently used biologic drugs were rituximab (RTX, 50%) and tumor necrosis factor (TNF) inhibitors (34.8%). In a few cases, abatacept (4.3%), anti-interleukin-1 agents (0.9%), tocilizumab (0.9%), bortezomib (0.4%), ustekinumab (0.2%), eculizumab (0.2%), and golimumab (0.2%) were used. RTX was most frequently preferred in patients with severe skin involvement (46.3%). Improvement with RTX was obtained in 60.1% of RTX treatments. Infliximab was most frequently preferred in calcinosis (43.3%), while adalimumab in skin involvement (50%) and etanercept in resistant/recurrent diseases (80%). Improvement was achieved in 44.4% of anti-TNF treatments. Adverse events were observed in 46.8% (58/124) of all treatments. Our results suggest that biologic agents may be a promising alternative for the treatment of particularly resistant JDM cases. Controlled studies are required to provide higher level of evidence for the timing of biologic use in JDM treatment. Key Points • There is no consensus on the choice and efficacy of biologic therapies in JDM. • RTX and TNF inhibitors are the most commonly used biologic drugs. • Biologics were especially preferred in severe skin involvement, calcinosis, and resistant diseases.

Shared and Distinctive Transcriptomic and Proteomic Pathways in Adult and Juvenile Dermatomyositis.

Transcript and protein expression were interrogated to examine gene locus and pathway regulation in the peripheral blood of active adult dermatomyositis (DM) and juvenile DM (JDM) patients receiving immunosuppressive therapies. Expression data from 14 DM and 12 JDM patients were compared to matched healthy controls. Regulatory effects at the transcript and protein level were analyzed by multi-enrichment analysis for assessment of affected pathways within DM and JDM. Expression of 1,124 gene loci were significantly altered at the transcript or protein levels across DM or JDM, with 70 genes shared. A subset of interferon-stimulated genes was elevated, including CXCL10, ISG15, OAS1, CLEC4A, and STAT1. Innate immune markers specific to neutrophil granules and neutrophil extracellular traps were up-regulated in both DM and JDM, including BPI, CTSG, ELANE, LTF, MPO, and MMP8. Pathway analysis revealed up-regulation of PI3K/AKT, ERK, and p38 MAPK signaling, whose central components were broadly up-regulated in DM, while peripheral upstream and downstream components were differentially regulated in both DM and JDM. Up-regulated components shared by DM and JDM included cytokine:receptor pairs LGALS9:HAVCR2, LTF/NAMPT/S100A8/HSPA1A:TLR4, CSF2:CSF2RA, EPO:EPOR, FGF2/FGF8:FGFR, several Bcl-2 components, and numerous glycolytic enzymes. Pathways unique to DM included sirtuin signaling, aryl hydrocarbon receptor signaling, protein ubiquitination, and granzyme B signaling. The combination of proteomics and transcript expression by multi-enrichment analysis broadened the identification of up- and down-regulated pathways among active DM and JDM patients. These pathways, particularly those which feed into PI3K/AKT and MAPK signaling and neutrophil degranulation, may be potential therapeutic targets.

E33 Identifying and understanding JDM in Africa: a survey of rheumatology care providers from Africa

Abstract Background It is estimated that millions of children in Africa suffer from pediatric rheumatic diseases (PRD). Despite this, as of 2021, there were just 28 pediatric rheumatologists in only 10 of the 54 African countries. With ∼700 million children living in Africa, this number falls far short of the recommended minimum 1750 pediatric rheumatologists needed for ideal care. Rheumatic and musculoskeletal diseases are the second leading cause of disability globally. However, there is a paucity of data on PRD in low and middle-income countries (LMIC) due to limited diagnostic capacities, scarcity of pediatric rheumatologists, and limited awareness of PRD. We have much to learn about the prevalence of PRD as well as clinical manifestations, optimal treatments, and outcomes in African children with PRD. Juvenile dermatomyositis (JDM) can cause significant morbidity and irreversible damage when inadequately treated, resulting in medical, social, and economic burden on patients, families, and healthcare systems, particularly in LMIC. The few studies of JDM in Africa suggest high rates of severe manifestations, including calcinosis, vasculitis, and pulmonary involvement. The objective of this survey is to better understand the scope of JDM burden in Africa by obtaining an overview of JDM and comparing this to data in previously published work. Methods A survey was distributed to members of the African League of Associations for Rheumatology (AFLAR; n = 233) and Paediatric Society of the African League Against Rheumatism (PAFLAR; n = 130) via WhatsApp groups. Respondents were queried about the total number of JDM patients seen currently or within the last 10 years; morbidities and clinical outcomes, including calcinosis, interstitial lung disease (ILD), clinically inactive disease, remission, and death; and availability and accessibility of diagnostic tools and medications. Results A total of 43 (12%) individuals started the survey, with 4 (9%) partially and 16 (37%) fully completing it, describing 216 JDM patients. One general pediatrician participated; the remainder were adult (n = 10; 50%), pediatric (n = 7; 35%), or adult/pediatric (n = 2; 10%) rheumatologists. Respondents represented the 5 regions of Africa, primarily Northern Africa (n = 12; 60%). Mortality was reported at 14% and 29% in Kenya and Zambia, respectively (Table 1). Many respondents identified limited availability of medications (56%), unfamiliarity with JDM by caregivers (69%) and other medical providers (44%), and delayed presentation to care (75%). Access and/or cost limited use of diagnostic tools and medications. Of the 27 queried diagnostic tools and medications, 13 were reported to be accessible to only 50% or fewer of respondents, the majority (69%) of whom were from Northern or Southern African countries. Despite the lack of cost or other apparent access barriers, disease assessment tools are used by only 53% of respondents. Conclusion This is the first study to explore JDM on a broad scale across the African continent. We identified 216 African children with JDM within the past 10 years, exceeding the previously published reports of 196 JDM patients seen in the last 25 years and likely still underestimating prevalence. Our results suggest substantially higher rates of severe disease, with mortality rates in some countries vastly different from the 1–3% reported in high-income countries. Many respondents were limited in their capacity to diagnose and treat JDM, but there was a wide range across African regions that seemed to parallel known disparities in healthcare resource availability in Africa. This survey highlighted important possible differences in disease manifestations and outcomes that warrant further study. Future collaboration with our African colleagues is critical to raise awareness of JDM to ultimately improve disease severity and outcomes. Ethics Institutional review board approval was obtained with waiver of informed consent.

Risk factors for developing calcinosis in juvenile dermatomyositis: subcutaneous and myofascial edema in initial magnetic resonance imaging.

Calcinosis is a sequela of Juvenile Dermatomyositis (JDM) with significant morbidity. A retrospective study observing risk factors for JDM calcinosis, including a possible association between higher intensity of subcutaneous and myofascial edema in initial magnetic resonance imaging (MRI) and development of calcinosis was performed at a tertiary pediatric medical center. Data from the past 20years on JDM patients with MRIs at the time of JDM diagnosis were obtained. MRIs were individually evaluated by two pediatric musculoskeletal radiologists who blindly graded the intensity of edema on a 0-4 Likert scale. Clinical data and edema scores were compared between patients who developed calcinosis and who did not. Forty-three patients (14 with calcinosis and 29 without calcinosis) were identified. The calcinosis group contained more racial and ethnic minorities, younger ages of JDM onset and longer time to reach JDM diagnosis. Muscle enzyme levels at JDM diagnosis were lower in the calcinosis group, especially Creatinine Kinase (CK) (p = 0.047) and Alanine Aminotransferase (ALT) (p = 0.015). The median score for edema in both groups was 3 (p = 0.39) with an inter-rater reliability of 95%. There was no association between increased subcutaneous and myofascial edema in MRIs at the time of JDM diagnosis and development of calcinosis. Earlier age of JDM onset, racial and ethnic minority, and delay in JDM diagnosis could be risks for developing calcinosis. The calcinosis group presented with lower muscle enzyme levels at the time of JDM diagnosis, especially CK and ALT with statistical significance. This could reflect delay in diagnosis and treatment.

Body Composition and Phase Angle: How to Improve Nutritional Evaluation in Juvenile Dermatomyositis Patients.

(1) Background: This study aimed to assess body composition (BC) using bioelectrical impedance and food intake in juvenile dermatomyositis (JDM) patients. Associations between BC and physical activity, disease activity/cumulative damage and health-related quality of life parameters were also evaluated; (2) Methods: This was a cross-sectional study with 30 consecutive JDM patients (18 female and 12 male) and 24 healthy volunteers (14 female and 10 male) of both sexes followed at our pediatric rheumatology unit. The gathering of anthropometric and dietary data, and the performance of physical activity and bioelectrical impedance were undertaken in face-to-face meetings and through questionnaires. Clinical and therapeutic data were collected from medical records according to information from routine medical appointments; (3) Results: The frequency of high/very high body fat was significantly higher in controls compared with JDM patients (66.7% vs. 91.7%; p = 0.046). The median phase angle was significantly lower in patients compared with controls (5.2 ± 1.3 vs. 6.1 ± 1.0; p = 0.016). Body fat and lean mass were positively correlated with disease duration (rs = +0.629, p < 0.001 and rs = +0.716, p < 0.001, respectively) and phase angle (PhA) (rs = +0.400, p = 0.029 and rs = +0.619, p < 0.001, respectively). JDM patients with PhA ≥ 5.5 presented higher lean mass when compared with patients with PhA < 5.5 (p = 0.001); (4) Conclusions: Bioelectrical impedance can be a useful auxiliary exam in the medical and nutritional follow-up of JDM patients, because it seems to impact functional ability. These findings may assist professionals when advising JDM patients about the importance of physical activity and healthy eating in the preservation of lean mass.

IFIH1 and DDX58 gene variants in pediatric rheumatic diseases.

The IFIH1 gene codes the MDA5 protein and the DDX58 gene codes the RIG-I receptor. Both proteins are parts of the interferon (IFN) I signaling pathway and are responsible for antiviral defense and innate immune response. IFIH1 and DDX58 polymorphisms are associated with a spectrum of autoimmune diseases. Rare gain-of-function IFIH1 mutations have been found in Singleton-Merten and Aicardi-Goutières syndrome, while DDX58 mutation can cause atypical Singleton-Merten syndrome. To characterize children with pediatric rheumatic diseases (PRD) carrying DDX58 or IFIH1 variants. Clinical exome sequencing was performed on 92 children with different PRD. IFIH1 and DDX58 variants have been detected in 14 children. IFN-I score has been analyzed and the clinical characteristics of patients have been studied. A total of seven patients with systemic lupus erythematosus (SLE) (n = 2), myelodysplastic syndrome with SLE features at the onset of the disease (n = 1), mixed connective tissue disease (MCTD) (n = 1), undifferentiated systemic autoinflammatory disease (uSAID) (n = 3) have 5 different variants of the DDX58 gene. A common non-pathogenic variant p.D580E has been found in five children. A rare variant of uncertain significance (VUS) p.N354S was found in one patient with uSAID, a rare likely non-pathogenic variant p.E37K in one patient with uSAID, and a rare likely pathogenic variant p.Cys864fs in a patient with SLE. Elevated IFN-I score was detected in 6 of 7 patients with DDX58 variants. Seven patients had six different IFIH1 variants. They were presented with uSAID (n = 2), juvenile dermatomyositis (JDM) (n = 1), SLE-like disease (n = 1), Periodic fever with aphthous stomatitis, pharyngitis, and adenitis syndrome (n = 1), and systemic onset juvenile idiopathic arthritis (n = 1). Three patients have VUS p.E627X, one patient has benign variant p.I923V. Rare VUS p.R595H was detected in the JDM patient. Another rare VUS p.L679Ifs*2 and previously not reported variant p.V599Ffs*5 were detected in the patient with uSAID. One patient with uSAID has rare VUS p.T520A. All patients had elevated IFN-I scores. Rare compound-heterozygous IFIH1 variant (p.L679Ifs*2 and p.V599Ffs*5), heterozygous IFIH1 variant (p.T520A) and heterozygous DDX58 variant (p.Cys864fs) are probably disease causative for uSAID and SLE. The majority of patients with different DDX58 and IFI1 variants had hyperactivation of the IFN I signaling pathway.

Analysis of the clinical characteristics and therapeutic effect of refractory juvenile dermatomyositis to tofacitinib

Objective: To elucidate the clinical features of patients with refractory juvenile dermatomyositis (JDM), and to explore the efficacy and safety of tofacitinib in the treatment of refractory JDM. Methods: A total of 75 JDM patients admitted to the Department of Rheumatology and Immunology in Shenzhen Children's Hospital from January 2012 to January 2021 were retrospectively analyzed, and to analyze the clinical manifestations, efficacy and safety of tofacitinib in the treatment of refractory JDM. Patients were divided into refractory group with using of glucocorticoids in combination with two or more anti-rheumatic drugs for treatment, and the presence of disease activity or steroid dependence after a one-year follow-up. The non-refractory group is defined as clinical symptoms disappeared, laboratory indicators were normal, and clinical remission was achieved after initial treatment, and the clinical manifestations and laboratory indexes of the two groups were compared. The Mann-Whitney U test, Fisher's precision probability test was used for intergroup comparison. Binary Logistic multivariate regression analysis was used to identify risk factors for refractory JDM. Results: Among the 75 children with JDM, 41 were males and 34 were females with a age of onset of 5.3 (2.3, 7.8) years. The refractory group consisted of 27 cases with a age of onset of 4.4 (1.5, 6.8) years, while the non-refractory group consisted of 48 cases with a age of onset of 5.9 (2.5, 8.0) years. Compared with 48 cases in the non-refractory group, the proportion of interstitial lesions and calcinosis in the refractory group was higher than that in the non-refractory group (6 cases (22%) vs. 2 cases (4%), 8 cases (30%) vs. 4 cases (8%), both P<0.05). Binary Logistic regression analysis showed that observation group were more likely to be associated with to interstitial lung disease (OR=6.57, 95%CI 1.22-35.31, P=0.028) and calcinosis (OR=4.63, 95%CI 1.24-17.25, P=0.022). Among the 27 patients in the refractory group, 22 cases were treated with tofacitinib, after treatment with tofacitinib, 15 of 19 cases (86%) children with rashes showed improvement, and 6 cases (27%) with myositis evaluation table score less than 48 score both were improved, 3 of 6 cases (27%) had calcinosis were relieved, and 2 cases (9%) had glucocorticoid-dependence children were successfully weaned off. During the tofacitinib treatment, there was no increase in recurrent infection, blood lipids, liver enzymes, and creatinine were all normal in the 22 cases. Conclusions: Children with JDM with calcinosis and interstitial lung disease are more likely to develop refractory JDM. Tofacitinib is safe and effective for refractory JDM.

Association of Juvenile Dermatomyositis Disease Activity With the Expansion of Blood Memory B and T Cell Subsets Lacking Follicular Markers.

This study was undertaken to identify blood markers of juvenile dermatomyositis (DM) disease activity (DA), which are needed to improve disease management. The study comprised a total of 123 juvenile DM patients and 53 healthy controls. Results of laboratory tests (aldolase, creatinine kinase, lactate dehydrogenase [LDH], aspartate aminotransferase) and clinical measures of DA in patients with juvenile DM, including the Manual Muscle Testing in 8 muscles (MMT-8), Childhood Myositis Assessment Scale (CMAS), and disease activity scores (DAS) (total DAS for juvenile DM, the muscle DAS, and the skin DAS), were recorded when available. Surface phenotype of peripheral blood mononuclear cells was assessed using flow cytometry. Whole blood transcriptional profiles were studied using either RNA-sequencing or microarrays. Differential gene expression was determined using DESeq and compared by pathway and gene ontology analyses. Conventional memory (CD27+IgD-) B cells expressing low CXCR5 levels (CXCR5low/- CM B cells) were significantly increased in frequency and absolute numbers in 2 independent cohorts of juvenile DM patients compared with healthy controls. The frequency of CD4+ Th2 memory cells (CD45RA-CXCR5-CCR6-CXCR3-) was also increased in juvenile DM, especially in patients who were within <1 year from diagnosis. The frequency of CXCR5low/- CM B cells correlated with serum aldolase levels and with a blood interferon-stimulated gene transcriptional signature. Furthermore, both the frequency and absolute numbers of CXCR5low/- CM B cells correlated with clinical and laboratory measures of muscle DA (MMT-8, CMAS, aldolase, and LDH). These findings suggest that both CM B cells lacking the CXCR5 follicular marker and CXCR5- Th2 cells represent potential biomarkers of DA in juvenile DM and may contribute to its pathogenesis.

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

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. 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. 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). 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.