Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy.
Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Humanitas Research Hospital, Rozzano, Italy.
Front Immunol. 2022 Jun 27;13:937667. doi: 10.3389/fimmu.2022.937667. eCollection 2022.
The SARS-CoV-2 infection has been advocated as an environmental trigger for autoimmune diseases, and a paradigmatic example comes from similarities between COVID-19 and the myositis-spectrum disease associated with antibodies against the melanoma differentiation antigen 5 (MDA5) in terms of clinical features, lung involvement, and immune mechanisms, particularly type I interferons (IFN).
We report a case of anti-MDA5 syndrome with skin manifestations, constitutional symptoms, and cardiomyopathy following a proven SARS-CoV-2 infection.
We systematically searched for publications on inflammatory myositis associated with COVID-19. We describe the main clinical, immunological, and demographic features, focusing our attention on the anti-MDA5 syndrome.
MDA5 is a pattern recognition receptor essential in the immune response against viruses and this may contribute to explain the production of anti-MDA5 antibodies in some SARS-CoV-2 infected patients. The activation of MDA5 induces the synthesis of type I IFN with an antiviral role, inversely correlated with COVID-19 severity. Conversely, elevated type I IFN levels correlate with disease activity in anti-MDA5 syndrome. While recognizing this ia broad area of uncertainty, we speculate that the strong type I IFN response observed in patients with anti-MDA5 syndrome, might harbor protective effects against viral infections, including COVID-19.
SARS-CoV-2 感染被认为是自身免疫性疾病的环境触发因素，一个典范的例子来自于 COVID-19 与与黑色素瘤分化抗原 5（MDA5）抗体相关的肌炎谱疾病之间的相似性，表现在临床特征、肺部受累和免疫机制方面，特别是 I 型干扰素（IFN）。
我们报告了一例抗 MDA5 综合征，在 SARS-CoV-2 感染后出现皮肤表现、全身症状和心肌病。
我们系统地搜索了与 COVID-19 相关的炎症性肌炎的出版物。我们描述了主要的临床、免疫学和人口统计学特征，特别关注抗 MDA5 综合征。
MDA5 是一种对病毒免疫反应至关重要的模式识别受体，这可能有助于解释一些 SARS-CoV-2 感染患者产生抗 MDA5 抗体。MDA5 的激活诱导具有抗病毒作用的 I 型 IFN 的合成，与 COVID-19 的严重程度呈负相关。相反，抗 MDA5 综合征中升高的 I 型 IFN 水平与疾病活动度相关。在认识到这是一个广泛存在不确定性的领域的同时，我们推测在抗 MDA5 综合征患者中观察到的强烈的 I 型 IFN 反应可能对包括 COVID-19 在内的病毒感染具有保护作用。
