Myositis is a rare autoimmune condition associated with muscle weakness, systemic involvement, and long-term disability. People living with rare conditions frequently use online platforms to share experiences and seek information beyond formal healthcare settings. This exploratory study applied automated natural language processing (NLP) methods to analyse public posts and comments from the myositis subreddit between 2020 and 2024. The dataset comprised 1223 unique posts and 18 453 unique comments contributed by 3987 users. Seven sentiment models and one ensemble were evaluated, with RoBERTa-based transformer models selected for contextual analysis. Topic modeling was conducted using Latent Dirichlet Allocation and BERTopic. While BERTopic initially generated highly granular clusters, hierarchical merging produced stable, clinically interpretable themes. Six dominant discussion themes were identified: (i) autoimmune diagnosis and systemic symptoms; (ii) organ-specific concerns; (iii) fatigue, mobility, and sleep; (iv) navigating care pathways; (v) life impact; and (vi) coping strategies, lifestyle changes, and anxiety. Topic-linked sentiment analysis showed predominantly neutral sentiment overall. More negative sentiment was associated with unresolved symptoms and diagnostic uncertainty, and sentiment became increasingly negative at deeper comment levels, suggesting escalation toward unmet needs. Highly active users mainly contributed neutral, informational content. Temporal analysis identified episodic increases in engagement, including a peak in mid-2024 linked to discussions involving dermatomyositis, COVID-19, and treatment decisions. These findings demonstrate the feasibility of scalable NLP analysis of rare-disease online discourse and highlight how topic-linked emotional signals may indicate periods of uncertainty or emerging concerns.

Lung transplantation is a definitive lifesaving option for end-stage lung disease; however, its role in rapidly progressive interstitial lung disease (RP-ILD) associated with anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibodies remains debated. We retrospectively analyzed two anti-MDA5-positive RP-ILD (MDA5[+] RP-ILD) patients who underwent bilateral lung transplantation and synthesized pertinent literature to evaluate clinical value and the impact of therapeutic interventions. Both patients recovered postoperatively and were discharged after symptomatic management and supportive care. One patient subsequently developed cerebral infarction and died approximately 8 months after transplantation, whereas the other remains clinically stable under regular follow-up. Given the limited efficacy of conventional therapies and the overall poor prognosis of anti-MDA5-positive dermatomyositis (MDA5[+] DM) with RP-ILD, our observations-together with prior reports-support lung transplantation, with extracorporeal membrane oxygenation (ECMO) as a bridge when necessary, as a promising and reliable therapeutic strategy. Lung transplantation may offer definitive treatment in carefully selected patients, underscoring its important clinical value.

Streptococcus dysgalactiae subspecies equisimilis (SDSE) is an emerging human pathogen closely related to group A streptococcus. However, its genetic requirements for survival and growth in different conditions and for causing invasive infections remain poorly understood. To address this gap, Transposon-Directed Insertion-site Sequencing (TraDIS) was used to identify genes contributing to fitness in experimental necrotizing myositis in non-human primates (NHPs). Using two SDSE stG62647 human clinical isolates, MGCS36044 and MGCS36089, highly saturated transposon mutant libraries were generated and analyzed following in vitro growth and in vivo infection in eight NHPs. A total of 398 essential genes were identified to be shared by both strains during growth in vitro and in vivo, and 17 and seven conditionally essential genes required only in vitro or only in vivo, respectively. Additionally, 117 and 110 genes in MGCS36044 and MGCS36089, respectively, were found to be associated with fitness during necrotizing myositis. Transposon insertions in 34 MGCS36044 genes conferred increased fitness, whereas mutation of 83 genes conferred decreased fitness. Similarly, in MGCS36089, mutations in 38 and 72 genes conferred increased or decreased fitness, respectively. Importantly, both strains shared 46 fitness-associated genes, including an enrichment of transporter genes, highlighting nutrient acquisition as a dominant requirement during infection. The results provide critical information for guiding future translational efforts to develop preventive and therapeutic strategies against human SDSE infections.

ObjectiveTo evaluate the effectiveness of a lower initial glucocorticoid (GC) dose (0.4-0.6 mg/kg/day) compared to the conventional dose (0.8-1.2 mg/kg/day) in achieving complete renal response (CRR) at 12 months in Japanese patients with proliferative lupus nephritis (LN).MethodsThis multicentre, retrospective observational study analyzed data from 344 Japanese patients diagnosed with LN (class III or IV ± V) via renal biopsy. Patients were divided into two groups based on their initial dose of GC. 1:1 propensity score matching (PSM) based on key baseline variables, 23 patients were included in each group. The primary endpoint was CRR at 12 months, defined according to the BLISS-LN trial criteria. A non-inferiority margin of -10% was prespecified.ResultsAfter PSM, the CRR rate at 12 months was 87.0% in the low-dose group and 73.9% in the conventional-dose group (risk difference: 13.1%; 95% confidence interval [CI]: -9.4% to 35.6%), confirming statistical non-inferiority. While GC doses differed significantly during the initial 3 months, they became comparable between the groups after 6 months.ConclusionA reduced initial GC dose of 0.4-0.6 mg/kg/day achieved renal outcomes comparable to conventional dosing in Japanese patients with LN. Given the risks of GC toxicity, these findings may support the potential for lower-dose GC strategies in LN treatment.

Immune checkpoint inhibitors (ICI) used for the treatment of cancer can cause immune related adverse events (irAEs) when immune activation affects non-tumor tissues. Rheumatologists care for patients with a variety of rheumatic irAEs; these included inflammatory arthritis (ICI-IA), polymyalgia rheumatica (ICI-PMR), and myositis (ICI-myositis) among others. Rheumatic irAEs are commonly impactful on patients' quality of life and function and sometimes can cause significant morbidity and mortality. This review will highlight the diagnosis and assessment of rheumatic irAEs. Then treatment for individual irAEs will be discussed in depth with considerations to supportive care, corticosteroid dosing and tapering, steroid sparing immunosuppression and monitoring. Finally, the safety of immunosuppression as it relates to tumor outcomes and considerations by oncologists when selecting ICI therapy will be reviewed.

This is the official English summary of the Japanese 2025 guide. The first edition of the guide for the diagnosis and management of connective tissue disease (CTD) associated with interstitial lung disease (ILD) was published in 2020 as a joint initiative by the Japanese Respiratory Society and the Japanese College of Rheumatology. This updated edition reflects major advances over the past five years, incorporating the latest international guidelines, consensus statements, and considerations unique to the Japanese healthcare reimbursement system. The guide is structured to facilitate timely clinical decision-making by highlighting key diagnostic and therapeutic milestones. The newly added content includes a conceptual framework for understanding ILD in CTD, practical clinical flowcharts, screening strategies, and risk factors, an overview of acute exacerbations, and a comprehensive approach to rehabilitation. Notably, treatment algorithms for ILD associated with polymyositis/dermatomyositis and systemic sclerosis have been revised to align with the most recent evidence and disease-specific recommendations, thereby enhancing their relevance to real-world practice. In addition, a provisional algorithm was proposed for the management of rheumatoid arthritis-associated ILD. The updated guide aims to standardize the multidisciplinary management of CTD-associated ILD and offers future perspectives to guide research and improve patient outcomes.

In March 2024, a severe mass mortality event occurred at a grass carp (Ctenopharyngodon idella) farm in Zhejiang, China, resulting in a cumulative mortality rate of 70%. To identify the causative agent, 12 bacterial isolates that exhibited the same phenotypic characteristics were isolated from diseased fish. A further phylogenetic (16S rDNA) characterization identified the bacterium as Flavobacterium psychrophilum. Genetic characterization revealed that all 12 bacterial isolates belonged to serotype Type-1 and sequence type ST418, a newly documented ST closely associated with cyprinid fish hosts. In infection trials, the bacterium exhibited clear virulence in grass carp, producing clinical signs consistent with those observed during the outbreak. Furthermore, histopathology of diseased fish with F. psychrophilum revealed ulcerative dermatitis with associated myositis, proliferative branchitis, vascular congestion and focal necrosis in the liver, multifocal necrosis in the spleen, and tubular dilation with renal corpuscle necrosis in the kidney. Given the potential risk of cross-species transmission among cyprinid fish, we also evaluated the pathogenicity of this bacterium in Prussian carp (Carassius gibelio), a widely cultured species in China. To our knowledge, this study represents the first report of F. psychrophilum causing mass mortality in farmed grass carp in China and provides essential information to support improved prevention and risk mitigation strategies for this emerging disease.

ObjectiveTo investigate the clinical characteristics of pediatric systemic lupus erythematosus complicated by myositis.MethodsA retrospective analysis was conducted on the clinical data of six patients with SLE-associated myositis, examining manifestations of multisystem involvement, muscle injury markers, and autoantibody profiles.ResultsAmong the six patients, five were female and one male, with a median age of 12 years. All patients presented with myalgia and/or muscle weakness. Physical examination revealed muscle weakness (grade 2-4) in all six children, with bilateral lower limb myalgia in 4. Laboratory findings showed elevated creatine phosphokinase levels ranging from 217 to 3317 U·L[-1] in four patients. All patients also exhibited elevated lactate dehydrogenase levels, ranging from 293 to 949 U/L. After treatment, clinical symptoms resolved in all patients, with the majority achieving stable conditions. Only one case experienced recurrence due to inappropriate drug tapering, which resolved following readmission and intensive treatment.ConclusionMyositis is not a common feature of SLE. Patients with SLE complicated by myositis should complete relevant investigations at the earliest opportunity. Early diagnosis and stratified individualized treatment can effectively control the disease.

Amyopathic dermatomyositis (ADM) is a rare variant of dermatomyositis characterised by the pathognomonic cutaneous features of the disease in the absence of clinically significant muscle weakness for at least 6 months. Peripheral eosinophilia is an uncommon laboratory finding associated with ADM and is more commonly linked to allergic, parasitic or haematological disorders.We present the case of a woman in her 70s with classic cutaneous signs of dermatomyositis associated with pruritus for 3 years, preserved muscle strength and persistent peripheral eosinophilia. Secondary causes of eosinophilia were excluded, and a diagnosis of ADM was made based on clinical features and antibody positivity. The patient showed an adequate response to systemic corticosteroids, with resolution of skin lesions and normalisation of eosinophil counts.This case highlights the importance of considering ADM in patients presenting with unexplained eosinophilia and characteristic cutaneous manifestations and adds to the limited literature describing eosinophilic manifestations in inflammatory myopathies.

Eosinophilic Granulomatosis with Polyangiitis (EGPA) is a rare Anti-neutrophil cytoplasm antibodies (ANCA)-associated vasculitis with multi-organ involvement and eosinophilia. We present a 61-year-old male with a history of eosinophilic asthma who developed progressive weakness and muscle aches six weeks after his second COVID-19 booster. Four to six weeks post vaccination, he developed myal gias and weakness, especially in proximal muscles, leading to a severe decline in function. Lab results showed leukocytosis (29.54 cells/mm[3]); 54% eosinophils; and elevated erythrocyte sedimentation rate (ESR), C-reactive protein, and creatine kinase levels at 13 736 u/L. Anti-myeloperoxidase antibodies were positive, while PR-3, C-ANCA, and P-ANCA were negative. Magnetic resonance imaging of the lower extremities showed intramuscular edema. Muscle biopsies confirmed EGPA. Diagnosed per American College of Rheumatology (ACR)/ European Alliance of Associations for Rheumatology (EULAR) criteria, he received pulse dose IV methylprednisolone with significant improvement. He was discharged on 60 mg prednisone and started on mepolizumab (300 mg subcutaneous once every 4 weeks). Eosinophilic granulomatosis with polyangiitis progresses through stages: asthma, eosinophilia with organ involvement, and vasculitis. This case highlights a unique presentation of rapid myositis without significant involvement of any other organs and vasculitis post-mRNA vaccination. While environmental factors may trigger EGPA, the role of COVID-19 vaccines remains hypothesis-generating. This case underscores the importance of post-market surveillance for rare events, contributing to the understanding of vaccine-related rheumatic disease triggers Cite this article as: Memdani A, Busa V, Avula S, Ford A, Nesheiwat J. Unmasking Eosinophilic granulomatosis with polyangiitis: a case of rapid-onset myositis following COVID-19 booster in an eosinophilic asthma patient. Eur J Rheumatol. 2025, 13(1), 0016, doi:10.5152/eurjrheum.2026.25016.