ORIGINAL RESEARCH article

Front. Immunol.

Sec. Autoimmune and Autoinflammatory Disorders : Autoimmune Disorders

The clinical, serological and myopathological features of a cohort of Chinese patients with inclusion body myositis: A single center analysis

  • 1. Peking University First Hospital Department of Neurology, Beijing, China

  • 2. Peking University First Hospital Rare Diseases Medical Center, Beijing, China

  • 3. Peking University Shenzhen Hospital Department of Neurology, Shenzhen, China

  • 4. Beijing Jishuitan Hospital Affiliated to Capital Medical University Department of Neurology, Beijing, China

The final, formatted version of the article will be published soon.

Abstract

Background: This study aimed to investigate the clinical, serological and myopathological features of Chinese patients with inclusion body myositis (IBM). Methods: This study retrospectively recruited patients diagnosed with IBM according to the 2024 European Neuromuscular Center (ENMC) criteria at Peking University First Hospital between 2004 and 2024. Clinical features, pathological changes and laboratory data were collected. Subgroups were analyzed by sex, dysphagia, anti-cN1A antibody status, and complement deposition. Results: Forty-three IBM patients (25 males) were included in this cohort. The mean age at onset was 54.9±9.6 years old. All the patients developed weakness in hip flexion, and 81.4% of them with weakness in both knee extension and finger flexion. Dysphagia was reported in 17 patients (39.5%). Endomysial inflammation was observed in all the patients, and 79.1% with rimmed vacuoles, and 76.9% with mitochondrial abnormalities. Female patients more frequently developed dysphagia (P = 0.005) and neck flexion weakness (P < 0.001). Anti-cN1A antibody was positive in 20 patients (66.7%). Seropositive cases were associated with a later age of onset (P = 0.034). Complement deposition was observed in 77.4% of patients and was associated with more severe muscle weakness. Conclusion: This cohort of Chinese IBM patients suggested an earlier age at onset than previously reported. Hip flexors were most commonly affected. Female patients showed a higher frequency of dysphagia and neck flexor weakness. Our study reported a high frequency of complement deposition in muscle tissue. Complement deposition was associated with disease severity, suggesting a potential role of complement in the pathophysiology of IBM.

Summary

Keywords

anti-cN1A antibody, Complement deposition, dysphagia, IBM, inclusion body myositis

Received

06 January 2026

Accepted

18 February 2026

Copyright

© 2026 Qiu, Yang, Guo, Leng, Zhao, Yu, Zheng, Meng, Lv, Deng, Zhang, Wang, Yuan and Gang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Zhaoxia Wang; Yun Yuan; Qiang Gang

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