Objective This study aimed to investigate the relationship between serum superoxide dismutase (SOD) and interstitial lung disease (ILD) among patients with anti-melanoma differentiation–associated gene 5 antibody–positive dermatomyositis (anti-MDA5-positive DM). Method In this retrospective study, serum SOD of 90 health checkups were tested in our hospital. 94 hospitalised patients with anti-MDA5-positive DM having ILD. Their serum SOD, serum ferritin, and autoantibody levels were determined, and lung high-resolution computed tomography was performed. Results The serum SOD level was significantly lower in the anti-MDA5-positive DM group compared with the control group. The SOD level was significantly lower in patients positive for both anti-MDA5 antibodies and anti-Ro-52 antibodies than in those positive for only anti-MDA5 antibodies before treatment. The SOD level was significantly lower in the higher serum ferritin group compared with the lower serum ferritin group before treatment. After treatment, the serum SOD level decreased in patients with exacerbation of ILD, while it increased in those with alleviated ILD. The SOD level was significantly lower in the death group than in the survival group before treatment. Conclusions In patients with anti-MDA5-positive DM, (1) the low SOD level before treatment indicated the presence of oxidative stress in the disease; (2) the serum SOD level was affected by anti-Ro-52 antibodies and ferritin; (3) there is a close relationship between serum SOD level and ILD among patients with anti-MDA5-positive DM, suggesting that SOD might serve as an effective indicator to evaluate the changes in ILD in these patients; and (4) the low SOD level is an important indicator of poor prognosis in these patients, which deserves attention from rheumatologists.

中文翻译：

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评估超氧化物歧化酶在间质性肺病相关抗 MDA5 阳性皮肌炎中的价值

目的 本研究旨在探讨抗黑色素瘤分化相关基因5抗体阳性皮肌炎（抗MDA5阳性DM）患者血清超氧化物歧化酶（SOD）与间质性肺病（ILD）的关系。方法本次回顾性研究对我院90例体检者的血清SOD进行了检测。94 例患有 ILD 的抗 MDA5 阳性 DM 住院患者。测定了他们的血清 SOD、血清铁蛋白和自身抗体水平，并进行了肺部高分辨率计算机断层扫描。结果抗MDA5阳性DM组血清SOD水平明显低于对照组。抗 MDA5 抗体和抗 Ro-52 抗体均呈阳性的患者的 SOD 水平显着低于治疗前仅抗 MDA5 抗体呈阳性的患者。与治疗前较低血清铁蛋白组相比，较高血清铁蛋白组的SOD水平显着降低。治疗后，ILD加重患者血清SOD水平降低，而ILD缓解患者血清SOD水平升高。治疗前死亡组SOD水平明显低于存活组。结论 抗MDA5阳性DM患者：（1）治疗前SOD水平低提示疾病存在氧化应激；(2)血清SOD水平受抗Ro-52抗体和铁蛋白的影响；(3)抗MDA5阳性DM患者血清SOD水平与ILD密切相关，提示SOD可作为评价此类患者ILD变化的有效指标；(4)低SOD水平是此类患者预后不良的重要指标，值得风湿病专家重视。