Anti-melanoma differentiation-associated gene 5–positive dermatomyositis (MDA5⁺ DM) is a rare autoimmune disease predominantly reported in East Asia. MDA5⁺ DM is an intractable disease with impressively high mortality due to rapid-progressive interstitial lung disease (RPILD). Other typical clinical manifestations comprise DM-specific rash (Gottron’s papules, heliotrope rash) and amyopathic/hypomyopathic muscle involvement. Multiple prognostic factors have been identified. Baseline forced vital capacity (FVC) %-based staging could serve as a simplified risk stratification system. Serum biomarkers including MDA5 Ab titers, ferritin, KL-6 levels, and CD4⁺CXCR4⁺ T cell percentage could provide additional surrogate value of ILD severity and treatment response, as well as potential predictive value for survival. Spontaneous pneumomediastinum (PNM), ground-glass opacity (GGO), and consolidation were demonstrated to be the most significant features in pulmonary high-resolution computed tomography (HRCT) findings of MDA5⁺ DM-ILD. The semi-quantitative assessment of lesions in HRCT has also been demonstrated relevant to the outcome. The current treatment of this disease is still largely empirical. Immunosuppressive treatments, i.e., “triple therapy” (combination of high-dose glucocorticoids, tacrolimus, and intravenous cyclophosphamide) and JAK inhibitor-based therapy, are the mainstream regimens for MDA5⁺ DM-ILD, supported by the recently published trials. However, more efficacious regimen with favorable safety profile and high-level evidence is still urgently demanded for patients with MDA5⁺ DM-ILD, especially those at advanced-stage. We will summarize the terminology, etiology and pathogenesis, clinical features and outcome, prognostic factors, and treatment of MDA5⁺ DM-ILD in this review.

抗黑色素瘤分化相关基因 5 阳性皮肌炎 (MDA5 ⁺ DM) 是一种罕见的自身免疫性疾病，主要在东亚报道。MDA5 ⁺ DM 是一种难治性疾病，由于快速进展性间质性肺病 (RPILD)，死亡率非常高。其他典型的临床表现包括 DM 特异性皮疹（Gottron 丘疹、天芥菜皮疹）和无肌病/肌病肌病。已经确定了多种预后因素。基于基线用力肺活量 (FVC) % 的分期可用作简化的风险分层系统。血清生物标志物，包括 MDA5 Ab 滴度、铁蛋白、KL-6 水平和 CD4 ⁺ CXCR4 ⁺T 细胞百分比可以提供 ILD 严重程度和治疗反应的额外替代值，以及生存的潜在预测值。自发性纵隔气肿 (PNM)、磨玻璃影 (GGO) 和实变被证明是 MDA5 ⁺ DM-ILD肺高分辨率计算机断层扫描 (HRCT) 发现的最重要特征。HRCT 中病灶的半定量评估也被证明与结果相关。目前对这种疾病的治疗仍然主要是经验性的。免疫抑制治疗，即“三联疗法”（联合大剂量糖皮质激素、他克莫司和静脉环磷酰胺）和以JAK抑制剂为基础的治疗是MDA5 ⁺的主流方案DM-ILD，得到最近发表的试验的支持。然而，对于MDA5 ⁺ DM-ILD患者，尤其是晚期患者，仍然迫切需要更有效、安全性良好、证据水平高的方案。我们将在这篇综述中总结MDA5 ⁺ DM-ILD的术语、病因和发病机制、临床特征和结果、预后因素和治疗。