Juvenile dermatomyositis (JDM) is the most common and severe form of juvenile idiopathic inflammatory myopathy. We conducted a global mapping of the JDM scientific literature to assess publication trends, collaboration patterns, intellectual structure, and emerging priorities. We identified English-language original articles on JDM published between 1976 and 2024 in the Web of Science Core Collection (Science Citation Index Expanded), limited to clinically relevant categories. Bibliometrix and VOSviewer were used to generate key bibliometric indicators. Disruption Index was applied to distinguish disruptive from consolidating work. A total of 1113 articles were published in 201 journals by 5626 researchers. Publication output peaked in 2024, with an annual growth rate of 7.8%. The United States produced the largest number of publications, whereas the United Kingdom achieved the highest time-normalized citation rate. Recent research has increasingly focused on immunological endotyping, myositis-specific antibodies (MSAs), disease activity indices, and registry-based studies. Disruption Index analysis showed that disruptive contributions clustered around epidemiologic baselines, core outcome sets, treatment strategies, and clinical definitions. JDM research has evolved into a measurement-driven, collaborative field focused on immunological profiling and standardized assessment. Strengthening international networks and registry-based designs may further accelerate progress in this rare disease domain. This study presents a comprehensive bibliometric analysis of juvenile dermatomyositis research spanning nearly five decades. The study identifies key publication trends, intellectual structures, and disruptive contributions shaping the field. The findings demonstrate that international collaboration and standardization efforts significantly enhance citation impact and field-wide influence. The study provides a strategic roadmap for future research, emphasizing endotype-based classification, registry integration, and cross-specialty dissemination to accelerate progress in this rare disease.

Juvenile dermatomyositis (JDM) is a heterogeneous autoimmune inflammatory myopathy characterized by muscle and skin involvement. Myositis-specific autoantibodies (MSAs) define distinct clinical subgroups, yet the underlying inflammatory mechanisms remain unclear. This study aimed to investigate serum cytokine profiles in patients with JDM and their associations with MSA subgroups, clinical features, and laboratory findings. Serum levels of interferon (IFN)-α, interleukin (IL)-18, C-X-C motif chemokine ligand 9 (CXCL9), soluble tumor necrosis factor receptor type II (sTNF-RII), and IL-6 were measured in patients with JDM using enzyme-linked immunosorbent assays. Results were compared with clinical symptoms and laboratory parameters in each MSA subgroup. To explore cytokine-based disease classification, principal component analysis (PCA) and hierarchical clustering were performed. Serum cytokine profiles differed across MSA subgroups. Patients with anti-melanoma differentiation-associated protein 5 (MDA5) antibodies exhibited significantly elevated IFN-α, IL-18, and CXCL9 levels, correlating with lung involvement. Patients with anti-nuclear matrix protein 2 (NXP2) antibodies demonstrated increased sTNF-RII and IL-6 levels, which were strongly associated with muscle injury markers. Patients with anti-transcriptional intermediary factor 1 gamma (TIF1γ) antibodies exhibited slight increase in cytokine levels, suggesting a different inflammatory pathway. PCA and clustering analysis further supported the cytokine-based classification of JDM. Distinct cytokine signatures in the JDM subgroups underscore their role in disease heterogeneity and clinical presentation. These findings support cytokine profiling as a potential tool for patient classification and personalized treatment.

Interstitial lung disease (ILD) has a significant impact on morbidity and mortality in juvenile idiopathic inflammatory myopathies (JIIM). Early and noninvasive detection methods are crucial to improve outcomes through timely diagnosis and intervention. Fractional exhaled nitric oxide (FeNO) is commonly used to assess airway inflammation; however, its utility for the diagnosis of ILD in JIIM remains uncertain. This study investigates the role of FeNO as a potential noninvasive biomarker for ILD in pediatric JIIM patients. We enrolled 34 pediatric JIIM patients and classified them into ILD (n = 13) and non-ILD (n = 21) groups based on clinical and high-resolution computed tomography (HRCT) findings. Pulmonary function tests (PFTs), diffusing capacity for carbon monoxide (DLCO) and FeNO measurements were analyzed. Statistical analyses included correlations and receiver operating characteristic (ROC) analyses. The prevalence of ILD in our cohort was 38.2%. ILD patients had significantly reduced lung function parameters including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), total lung capacity (TLC), and diffusing capacity for carbon monoxide corrected for alveolar volume (DLCOcSB/VA) compared to the non-ILD group (p < 0.05). FeNO levels were significantly higher in patients with ILD (median 17 ppb vs. 10 ppb; p = 0.011). Furthermore, FeNO was negatively correlated with TLC, and ROC analysis showed discriminatory power in identifying ILD (AUC = 0.797; p = 0.011). Therefore, FeNO could be considered a valuable marker for detecting ILD. FeNO correlates with impaired lung function in JIIM-associated ILD and thus shows considerable potential as a noninvasive biomarker to differentiate ILD in pediatric JIIM patients. Our results suggest that integrating FeNO measurements into clinical practice could improve early detection, facilitate timely intervention, and enhance clinical management. Importantly, this study is the first to specifically investigate the clinical utility of FeNO in JIIM patients with ILD. Further large-scale, prospective studies are warranted to validate the role of FeNO in predicting disease progression and therapeutic decisions.

Objective To analyze the influence of age of the onset on myositis organ damage and to identify the factors influencing myositis organ damage, as clinical manifestations of myopathies differ by the age of onset and the background of patients. Methods Factors influencing organ damage [the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index (SDI)] were identified using the Japanese multicenter myositis registry (MYKO, n=220). Factors influencing organ damage were identified using a multivariate analysis. SDI was compared among juvenile-onset (<20 years old), adolescent-onset (20-64 years), and elderly-onset (>64 years) groups. Results There was a correlation between the age at onset and the SDI score (Spearman's rank correlation coefficient ρ=0.28). Elderly patients exhibited more widespread organ damage, including neuropsychiatric, renal, pulmonary, cardiovascular, peripheral vascular, gastrointestinal, skin, and diabetes, whereas juvenile-onset patients exhibited musculoskeletal damage. Adolescent-onset patients had the lowest incidence of ocular and malignant damage. A regression analysis revealed that an older onset age (coefficient, β=0.03), longer disease duration (β=0.05), and total dose of glucocorticoid (β=3.35×10-5) influenced SDI. After adjusting for disease duration, the influences of anti-melanoma differentiation-associated gene 5 (MDA5) [hazard ratio (95% confidence interval), 4.47 (2.17-9.21)] on pulmonary fibrosis and a history of steroid pulse [2.16 (1.16-4.05)] on muscle atrophy or weakness were shown. Conclusion There were associations between the age of onset and autoantibodies with myositis organ damage. Musculoskeletal damage was greater in patients with a juvenile onset. An older age of onset is associated with severe organ damage. These findings highlight the importance of considering the age of onset and autoantibodies for assessing the prognosis and developing treatment plans for myopathies.

To determine the incidence and health outcomes for juvenile idiopathic inflammatory myopathy (JIIM) in a long-term whole-population study. We included patients under 18 years hospitalized in Western Australia (WA) from 1985 and 2015 with incident JIIM as defined by pertinent diagnostic codes for dermatomyositis (JDM) polymyositis (JPM), other JIIM and overlap myositis (JOM). We compared clinical outcomes and modified Charlson comorbidity scores with age and gender matched (2:1 ratio) patients with new onset juvenile idiopathic arthritis (JIA). Trends over time for annual incidence rate per million child-population (AIR) were analyzed by least square regression and survival by Kaplan-Meier curves. We included 40 patients with JIIM (63% female, median age 8.5 years) for an average AIR of 2.52 per million (CI 1.09-5.57). AIR was stable over time leading to a point prevalence of 52.61 (CI 40.57-67.06) in 2015. Most patients (80%) were classified as JDM with an AIR for JDM of 2.02 (CI 1.09-5.58) and AIR for the combined other JIIM at 0.51 (CI 0.24-1.15). There was female preponderance (62.5%) in both JIIM groups, but no evidence of seasonality. Over a median follow-up of 13 years, one- and ten-year survival was 94.1%. Compared to JIA patients, readmission (80.4 vs. 63.7, p = .02) and infection rates (15.2 vs. 9.6, p < .01) per 100 person-years were higher for JIIM, with similar frequency of interstitial lung disease, fractures, and thrombotic events. At last observation, nearly all patients in both JIIM cohorts (97.5 vs. 92.5%) had accrued some form of comorbidity. The overall incidence of JIIM leading to hospitalization in WA was stable over 30 years. JIIM prognosis remains suboptimal due to early mortality and accrual of long-term comorbidity.