From the All-India Institute of Medical Sciences.
Department of Pediatrics.
J Clin Rheumatol. 2024 Oct 1;30(7):271-275. doi: 10.1097/RHU.0000000000002127. Epub 2024 Aug 22.
This study aimed to characterize the profile of myositis-specific and myositis-associated autoantibodies (MSAs/MAAs) in an Indian cohort of juvenile dermatomyositis (JDM) patients and correlate them with clinical features and outcomes.
Forty-three children diagnosed with JDM were enrolled for this observational study. Clinical details (presentation, course, and outcome) were noted in a predesigned proforma. Serum samples were tested for 16 MSAs/MAAs by line immunoassay. MSAs/MAAs were correlated with clinical features and outcome (defined as a complete clinical response [≥6 months' disease inactivity on medication] or complete remission [≥6 months' inactivity off all drugs]).
Thirty-five subjects (81.4%) had at least 1 MSA/MAA detected. The most common antibodies were anti-NXP2 (n = 13, 30.2%), anti-TIF1γ (n = 10, 23.2%), and anti-MDA-5 (n = 8, 18.6%). No patient had anti-Ku, anti-Pm Scl-100, anti-PL-12, anti-EJ, anti-OJ, or anti-Ro52. Thirty-two patients (74.4%) attained a complete clinical response over a median follow-up duration of 14 months, among which 6 (13.9%) achieved complete remission over a median follow-up duration of 30 months. Anti-TIF1γ was associated with younger age at onset (≤3 years) (odds ratio [OR], 6.25; 95% confidence interval [CI], 1.15-34.12; p = 0.034) and disease flares after attaining complete response (OR, 10.18; 95% CI, 1.64-70.93; p = 0.013). Patients with anti-NXP2 had higher odds of severe muscular weakness (OR, 3.73; 95% CI, 0.95-14.59; p = 0.058) and truncal weakness (OR, 3.89; 95% CI, 0.97-15.64; p = 0.056). One child with anti-MDA-5 positivity had interstitial lung disease. We found no association between the MSA/MAA profile and the achievement of complete clinical response or remission.
MSAs/MAAs were identified in 81% of children with JDM in our study, which is higher than most other studies. The most frequently observed antibodies displayed a pattern consistent with other studies. Anti-TIF1γ was associated with a younger age at onset and disease flares even after attaining a complete clinical response. Anti-NXP2 had higher odds of severe muscular weakness. These observations suggest consistency in certain phenotypic associations observed across geographic boundaries.
本研究旨在描述印度幼年特发性皮肌炎（JDM）患者肌炎特异性和肌炎相关自身抗体（MSAs/MAAs）的特征，并将其与临床特征和结局相关联。
本观察性研究纳入了 43 名确诊为 JDM 的儿童。临床详细信息（表现、病程和结局）记录在预先设计的表格中。通过线免疫分析法检测血清样本中的 16 种 MSAs/MAAs。MSAs/MAAs 与临床特征和结局（定义为完全临床缓解[药物治疗 6 个月以上无疾病活动]或完全缓解[所有药物停用 6 个月以上无疾病活动]）相关联。
35 名受试者（81.4%）至少检测到 1 种 MSA/MAA。最常见的抗体是抗 NXP2（n=13，30.2%）、抗 TIF1γ（n=10，23.2%）和抗 MDA-5（n=8，18.6%）。没有患者存在抗 Ku、抗 PM-Scl-100、抗 PL-12、抗 EJ、抗 OJ 或抗 Ro52。在中位随访 14 个月期间，32 名患者（74.4%）达到完全临床缓解，其中 6 名患者（13.9%）在中位随访 30 个月后达到完全缓解。抗 TIF1γ与发病年龄（≤3 岁）（比值比[OR]，6.25；95%置信区间[CI]，1.15-34.12；p=0.034）和达到完全缓解后的疾病复发（OR，10.18；95%CI，1.64-70.93；p=0.013）相关。抗 NXP2 阳性的患者发生严重肌肉无力（OR，3.73；95%CI，0.95-14.59；p=0.058）和躯干无力（OR，3.89；95%CI，0.97-15.64；p=0.056）的可能性更高。一名抗 MDA-5 阳性的患儿出现间质性肺病。我们未发现 MSA/MAA 特征与完全临床缓解或缓解的获得之间存在关联。
在本研究中，我们发现 81%的 JDM 患儿存在 MSAs/MAAs，高于大多数其他研究。最常观察到的抗体与其他研究一致。抗 TIF1γ与发病年龄较小和达到完全临床缓解后疾病复发相关。抗 NXP2 与严重肌肉无力的发生几率更高。这些观察结果表明，在跨越地理边界的情况下，某些表型关联存在一致性。
