Abstract: Objective　To study the efficacy and adverse reactions of tocilizumab（TCZ）in the treatment of antinuclear matrix protein 2（NXP2）antibody-positive juvenile dermatomyositis（JDM）and the prognosis，and compare its therapeutic efficacy with that of cyclophosphamide（CTX）. Methods　Five children with anti-NXP2 antibody-positive JDM treated with TCZ were retrospectively enrolled，who were admitted to and followed up at the Department of Rheumatology and Immunology，Capital Center for Children’s Health，Capital Medical University，from November 2021 to September 2025. The following items were analyzed and compared at different time points before and after treatment：skin rash，muscle strength，muscle enzymes，amount of glucocorticoid（GC）use and adverse reactions. Results　This study enrolled five anti-NXP2 antibody-positive JDM patients（3 male and 2 female）treated with TCZ，with onset age ranging from 1 to 12  years old（median 5 years old）.All patients received treatment combining TCZ，GC and immunosuppressants. From baseline to the end of follow-up，all patients showed significant improvement in skin rash，muscle strength，muscle enzymes， and MRI findings of muscles.The GC was rapidly reduced until discontinued，two patients achieved complete drug-free remission，and no serious adverse reactions affecting medication efficacy were reported.Compared with patients treated with CTX，those treated with TCZ demonstrated comparable efficacy in terms of rash，muscle strength，and muscle enzyme levels，exhibited faster tapering of GC，and had fewer cases of infection.Two cases of recurrence in the CTX group responded effectively to TCZ. Conclusion　In patients with anti-NXP2 antibody-positive JDM，TCZ has demonstrated efficacy in improving rash and muscle strength while reducing muscle enzyme levels，with therapeutic effects comparable to those of CTX.TCZ enables rapid tapering of GC until withdrawal， and no adverse reactions that influence medication have been found.Recurrent cases in the CTX group respond well to TCZ，which suggests that TCZ may serve as a potential effective drug for JDM cases.

Key words:  , juvenile dermatomyositis, anti-NXP2 antibody, tocilizumab, cyclophosphamide

摘要： 目的　研究托珠单抗（TCZ）治疗抗核基质蛋白2（NXP2）抗体阳性幼年皮肌炎（JDM）的疗效、不良反应及预后，并与环磷酰胺（CTX）进行疗效对比。方法　回顾性纳入2021 年11 月至2025 年9 月在首都医科大学附属首都儿童医学中心就诊并随访的5 例应用TCZ 治疗的抗NXP2-JDM 患者，随访时间24~39 个月，分析并比较治疗前后不同时间患儿皮疹、肌力、肌酶、糖皮质激素（GC）用量情况及不良反应等。结果　5 例应用TCZ治疗的抗NXP2-JDM 患者，男女比例3  ︰2，发病年龄1~12 岁（中位数5 岁），均应用TCZ+GC+ 免疫抑制剂治疗。从基线到随访终点，所有患者皮疹、肌力、肌酶、肌肉磁共振成像结果明显改善，GC 快速减量到停用，2 例无药完全缓解，未发生影响用药的严重不良反应。与应用CTX 患者相比，应用TCZ 患者在皮疹、肌力、肌酶缓解方面疗效相当，GC 减量速度更快，感染发生例次更少。CTX 组有2 例复发给予TCZ 有效。结论　TCZ 在改善抗NXP2 -JDM 患者的皮疹和肌力、降低肌酶方面有效，疗效与CTX 相当，且GC 可以快速减量到停用，未发现影响用药的不良反应，CTX 组复发病例换用TCZ 有效，提示TCZ 可能是JDM 患者潜在的有效药物。

关键词: 幼年皮肌炎, 抗核基质蛋白2 抗体, 托珠单抗, 环磷酰胺