OBJECTIVES: To investigate the distribution of myositis-specific antibodies (MSA) in juvenile dermatomyositis (JDM) and the relationship between MSA and clinical features of JDM. METHODS: Clinical data of 72 children with JDM hospitalized from January 2020 to April 2025 were reviewed retrospectively, all of whom had been tested for MSA. The relationship between common MSA subtypes and clinical features was analyzed. RESULTS: Among the 72 children, 45 (62%) were positive for MSA, including 27 anti-NXP2-positive cases (38%), 10 anti-MDA5-positive cases (14%), and 3 anti-cN1A-positive cases (4%). Compared with the MSA-negative group, the anti-MDA5-positive patients showed significantly higher incidence rates of fever, arthritis, and interstitial lung disease (P<0.05). The anti-NXP2-positive patients exhibited significantly higher incidence rates of calcinosis, fever, soft tissue edema, and interstitial lung disease than the MSA-negative patients (P<0.05). Compared with the anti-MDA5-positive group and MSA-negative group, the anti-NXP2-positive group had significantly higher levels of creatine kinase and creatine kinase isoenzyme (P<0.017) and a significantly lower score of the Childhood Myositis Assessment Scale (P<0.017). CONCLUSIONS The positive rate of MSA is high in children with JDM, with different subtypes correlating with specific clinical manifestations and organ involvement. Detection of MSA is crucial for diagnosis and clinical management of JDM.
Humans ; Dermatomyositis/immunology* ; Male ; Female ; Child ; Retrospective Studies ; Interferon-Induced Helicase, IFIH1/immunology* ; Child, Preschool ; Autoantibodies/blood* ; Adolescent