The von Willebrand Factor Antigen Reflects the Juvenile Dermatomyositis Disease Activity Score

Expert Perspective: Diagnostic Approach to Differentiating Juvenile Dermatomyositis From Muscular Dystrophy

Clinical tools that can aid in the diagnostic differentiation of juvenile dermatomyositis from muscular dystrophy.

Monozygotic twins discordant for juvenile dermatomyositis: clinical, serological and gene expression studies

BACKGROUND

Juvenile Dermatomyositis (JDM) is a rare pediatric autoimmune disease involving a combination of environmental and genetic susceptibility factors. Monozygotic twins provide a unique opportunity to examine disease-specific gene expression as they share the same DNA. The goal of this study is to characterize gene expression differences between monozygotic twins discordant for JDM.

METHODS

Five pairs of monozygotic twins were included. Each twin set was discordant for JDM. Detailed clinical and laboratory assessments were performed at enrollment. Nailfold capillary end row loops (ERL) count was obtained for all study subjects. Serum levels of cytokines and chemokines were measured using the Meso Scale Discovery® technique. Three pairs of twins had their peripheral blood mononuclear cells (PBMCs) tested by RNASeq.

RESULTS

The JDM twin had significantly lower nailfold capillary ERL than the healthy control, and two non-JDM twins also had decreased ERL In addition, serum endoglin was significantly lower in both JDM and non-JDM twins than in the healthy control. RNASeq identified four genes differentially expressed between the JDM and non-JDM twins: DCD, KRT14, COL1A1, and COL3A1.

CONCLUSIONS

JDM twins (and two of the non-JDM twins) had significantly lower nailfold capillary ERL and decreased serum endoglin levels compared to healthy controls. Further studies are needed to explore the role of the differentially expressed genes (DCD, KRT14, COL1A1, and COL3A1) in the pathophysiology of JDM.

Neutrophil and mononuclear leukocyte pathways and upstream regulators revealed by serum proteomics of adult and juvenile dermatomyositis

OBJECTIVES

Serum protein abundance was assessed in adult and juvenile dermatomyositis (DM and JDM) patients to determine differentially regulated proteins, altered pathways, and candidate disease activity biomarkers.

METHODS

Serum protein expression from 17 active adult DM and JDM patients each was compared to matched, healthy control subjects by a multiplex immunoassay. Pathway analysis and protein clustering of the differentially regulated proteins were examined to assess underlying mechanisms. Candidate disease activity biomarkers were identified by correlating protein expression with disease activity measures.

RESULTS

Seventy-eight of 172 proteins were differentially expressed in the sera of DM and JDM patients compared to healthy controls. Forty-eight proteins were differentially expressed in DM, 32 proteins in JDM, and 14 proteins in both DM and JDM. Twelve additional differentially expressed proteins were identified after combining the DM and JDM cohorts. C-X-C motif chemokine ligand 10 (CXCL10) was the most strongly upregulated protein in both DM and JDM sera. Other highly upregulated proteins in DM included S100 calcium binding protein A12 (S100A12), CXCL9, and nicotinamide phosphoribosyltransferase (NAMPT), while highly upregulated proteins in JDM included matrix metallopeptidase 3 (MMP3), growth differentiation factor 15 (GDF15), and von Willebrand factor (vWF). Pathway analysis indicated that phosphoinositide 3-kinase (PI3K), p38 mitogen-activated protein kinase (MAPK), and toll-like receptor 7 (TLR7) signaling were activated in DM and JDM. Additional pathways specific to DM or JDM were identified. A protein cluster associated with neutrophils and mononuclear leukocytes and a cluster of interferon-associated proteins were observed in both DM and JDM. Twenty-two proteins in DM and 24 proteins in JDM sera correlated with global, muscle, and/or skin disease activity. Seven proteins correlated with disease activity measures in both DM and JDM sera. IL-1 receptor like 1 (IL1RL1) emerged as a candidate global disease activity biomarker in DM and JDM.

CONCLUSION

Coordinate analysis of protein expression in DM and JDM patient sera by a multiplex immunoassay validated previous gene expression studies and identified novel dysregulated proteins, altered signaling pathways, and candidate disease activity biomarkers. These findings may further inform the assessment of DM and JDM patients and aid in the identification of potential therapeutic targets.

Dyslipidemia in Juvenile Dermatomyositis

This study investigates the prevalence of dyslipidemia and its association with disease activity in children with Juvenile Dermatomyositis (JDM). A retrospective chart review of 142 JDM patients who had fasting lipid profiles was conducted. Clinical, and laboratory indicators of disease activity at the time of lipid assessment were obtained. JDM patients displayed a high prevalence (72%) of abnormal or borderline fasting lipid profiles, particularly involving HDL and triglycerides. Treatment-naïve patients exhibited the most significant dyslipidemia, with significantly lower median HDL levels compared to those on medication (30 vs. 49 mg/dL, p < 0.0001). HDL levels inversely correlated with various disease activity measures, including disease activity score (DAS) total (r= -0.38, p < 0.001), DAS muscle weakness (r= -0.5, p < 0.001), DAS skin (r= -0.25, p = 0.003), neopterin (r= -0.41, p < 0.001), ESR (r= -0.25, p = 0.006), and vWF Ag (r= -0.21, p = 0.02). In conclusion, JDM patients have a high prevalence of dyslipidemia, especially low HDL and elevated triglycerides. The severity of dyslipidemia (low HDL) correlates with disease activity, with treatment-naïve patients demonstrating the lowest HDL levels. These findings suggest the importance of annual lipid profile monitoring in JDM patients, potentially followed by early interventions such as dietary adjustments and exercise programs.

Personalised medicine in juvenile dermatomyositis: From novel insights in disease mechanisms to changes in clinical practice

Juvenile dermatomyositis is characterized by childhood-onset chronic inflammation of the muscles and skin, with potential involvement of other organs. Patients are at risk for long-term morbidity due to insufficient disease control and steroid-related toxicity. Personalised treatment is challenged by a lack of validated tools that can reliably predict treatment response and monitor ongoing (subclinical) inflammation, and by a lack of evidence regarding the best choice of medication for individual patients. A better understanding of the involved disease mechanisms could reveal potential biomarkers and novel therapeutic targets. In this review, we highlight the most relevant immune and non-immune mechanisms, elucidating the effects of interferon overexpression on tissue alongside the interplay between the interferon signature, mitochondrial function, and immune cells. We review mechanism-based biomarkers that are promising for clinical implementation, and the latest advances in targeted therapy development. Finally, we discuss key steps needed for translating these discoveries into clinical practice.

Decreased Peripheral Blood Natural Killer Cell Count in Untreated Juvenile Dermatomyositis Is Associated with Muscle Weakness

Juvenile Dermatomyositis (JDM) is the most common inflammatory myopathy in pediatrics. This study evaluates the role of Natural Killer (NK) cells in Juvenile Dermatomyositis (JDM) pathophysiology. The study included 133 untreated JDM children with an NK cell count evaluation before treatment. NK cell subsets (CD56low/dim vs. CD 56bright) were examined in 9 untreated children. CD56 and perforin were evaluated in situ in six untreated JDM and three orthopedic, pediatric controls. 56% of treatment-naive JDM had reduced circulating NK cell counts, designated "low NK cell". This low NK group had more active muscle disease compared to the normal NK cell group. The percentage of circulating CD56low/dim NK cells was significantly lower in the NK low group than in controls (0.55% vs. 4.6% p < 0.001). Examination of the untreated JDM diagnostic muscle biopsy documented an increased infiltration of CD56 and perforin-positive cells (p = 0.023, p = 0.038, respectively). Treatment-naive JDM with reduced circulating NK cell counts exhibited more muscle weakness and higher levels of serum muscle enzymes. Muscle biopsies from treatment-naive JDM displayed increased NK cell infiltration, with increased CD56 and perforin-positive cells.

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.

[Advances in the diagnostics and treatment of juvenile dermatomyositis]

Juvenile dermatomyositis (JDM) is by far the most frequent inflammatory myopathy in childhood and adolescence. It is clinically characterized by inflammatory changes of the skin and muscles but as a multisystemic disease can also affect the skeletal system, the gastrointestinal tract, lungs and heart. Intrinsic (multigenetic risk) and extrinsic factors (triggers) are involved in the pathogenesis resulting in endothelial damage, involvement of fascies, activation of the interferon system and autoimmune reactions including formation of myositis-specific autoantibodies (MSA). In contrast to dermatomyositis in adults, in children and adolescents there are no associations with malignant diseases. The variable expression, the rarity of the disease and the risk of long-term damage and complications necessitate pediatric rheumatological experience in the diagnostics and treatment. Recently, new approaches in drug treatment have substantially improved the outcome and prognosis but a multidisciplinary treatment (including physicians, physiotherapists, psychologists, social workers) is mandatory, especially in the first phases of the disease. Particularly important is a professionally correct treatment of the functional sequelae, which are a particular focus of this article.

Juvenile dermatomyositis: association between nail fold capillary end row loop- area under the curve- and disease damage indicators

BACKGROUND

Juvenile Dermatomyositis (JDM) is a rare autoimmune disease characterized by skin and muscle inflammation. The loss of nail fold capillary end row loops (ERL) is evidence of small vessel involvement in JDM. This study aimed to examine the specific association of ERL over the disease course with evidence of JDM disease damage.

METHODS

We analyzed data from 68 initially treatment-naïve JDM children who had been observed for at least five years with multiple ERL density assessments. The JDM disease course were categorized into monocyclic short, monocyclic long, polycyclic, and chronic. The ERL capillary count was cumulatively evaluated using the area under the curve (AUC) method.

RESULTS

The mean ERL density for the treatment-naive JDM was significantly lower than that of their healthy age-matched controls (4.8 ± 1.6 /mm vs. 7.9 ± 0.9 /mm; p < 0.0001). The ERL AUC was significantly lower in children with a chronic disease course compared to those with a monocyclic short (p = 0.001) or monocyclic long disease course (p = 0.013). JDM patients with lipodystrophy had lower ERL AUC than those without lipodystrophy (p = 0.04). There was no association between ERL AUC and calcifications or fractures.

CONCLUSION

Persistently decreased ERL capillary density, reflected by low ERL AUC, is associated with a chronic disease course and lipodystrophy in JDM. Despite medical therapy, the mean ERL count remained below normal even after five years, particularly in polycyclic and chronic cases. It is not clear that restoring normal capillary density is currently feasible in children with JDM.

Juvenile Dermatomyositis: Association between Nail Fold Capillary End Row Loops Area Under the Curve and Disease Damage Indicators

Background

Juvenile Dermatomyositis (JDM) is a rare autoimmune disease characterized by skin and muscle inflammation. The loss of nail fold capillary end row loops (ERL) is evidence of small vessel involvement in JDM. This study aimed to examine the association of ERL over the disease course and evidence of disease damage.

Methods

We analyzed data from 68 initially treatment-naïve JDM children who had been observed for at least five years with multiple ERL density assessments. The JDM disease courses were categorized into monocyclic short, monocyclic long, polycyclic, and chronic. The ERL capillary count was cumulatively evaluated using the area under the curve (AUC) method.

Results

The mean ERL density for the treatment-naive JDM was significantly lower than that of their healthy controls (4.8±1.6 /mm vs. 7.9±0.9 /mm; p <0.0001). The ERL AUC was significantly lower in children with chronic disease course compared to those with monocyclic short (p =0.001) or monocyclic long disease course (p =0.013). JDM patients with lipodystrophy had lower ERL AUC than those without lipodystrophy (p =0.04). There was no association between ERL AUC and calcifications or fractures.

Conclusion

Persistently decreased ERL capillary density, evident by low ERL AUC, is associated with chronic disease course and lipodystrophy in JDM. Despite medical therapy, the mean ERL count remained below normal even after five years, particularly in polycyclic and chronic cases. Therefore, the goal of restoring normal capillary density in children with JDM might be challenging and require novel therapeutic strategies targeting their underlying endothelial dysfunction.

B Cell Lymphocytosis in Juvenile Dermatomyositis

In this study, we determined if B lymphocytosis may serve as a JDM biomarker for disease activity. Children with untreated JDM were divided into two groups based on age-adjusted B cell percentage (determined through flow cytometry): 90 JDM in the normal B cell group and 45 in the high B cell group. We compared through T-testing the age, sex, ethnicity, duration of untreated disease (DUD), disease activity scores for skin (sDAS), muscle (mDAS), total (tDAS), CMAS, and neopterin between these two groups. The patients in the high B cell group had a higher tDAS (p = 0.009), mDAS (p = 0.021), and neopterin (p = 0.0365). Secondary analyses included B cell values over time and BAFF levels in matched patients with JM (juvenile myositis) and concurrent interstitial lung disease (ILD); JM alone and healthy controls Patient B cell percentage and number was significantly higher after 3-6 months of therapy and then significantly lower on completion of therapy (p =< 0.0001). The JM groups had higher BAFF levels than controls 1304 vs. 692 ng/mL (p = 0.0124). This study supports B cell lymphocytosis as a JDM disease-activity biomarker and bolsters the basis for B cell-directed therapies in JDM.

Increased Otoferlin Expression in B Cells Is Associated with Muscle Weakness in Untreated Juvenile Dermatomyositis: A Pilot Study

Otoferlin mRNA expression is increased in JDM patients' PBMCs and muscle compared to healthy controls. This study aims to evaluate the role of otoferlin in JDM disease pathophysiology and its association with disease activity in untreated children with JDM. A total of 26 untreated JDM (88.5% female, 92.3% white, non-Hispanic) and 15 healthy controls were included in this study. Otoferlin mRNA expression was determined by qRT-PCR before and a few months after therapy. Detailed flow cytometry of various cell surface markers and cytoplasmic otoferlin was performed to identify cells expressing otoferlin. In addition, muscle otoferlin expression was evaluated in situ in six untreated JDM patients and three healthy controls. There was a significant increase in otoferlin expression in JDM children compared to controls (Median 67.5 vs. 2.1; p = 0.001). There was a positive correlation between mRNA otoferlin expression and the following disease activity markers: disease activity scores (DAS)-total (rs = 0.62, p < 0.001); childhood myositis assessment scale (CMAS) (rs = -0.61, p = 0.002); neopterin (rs = 0.57, p = 0.004) and von Willebrand factor antigen (vWF: Ag) (rs = 0.60, p = 0.004). Most of the otoferlin-positive cells were unswitched B cells (63-99.4%), with 65-75% of them expressing plasmablast markers (CD19+, IgM+, CD38hi, CD24-). The findings of this pilot study suggest that otoferlin expression is associated with muscle weakness, making it a possible biomarker of disease activity. Additionally, B cells and plasmablasts were the primary cells expressing otoferlin.