Khan Nariman, Kazmi Zehra
UT Health San Antonio, Joe R. and Terry Lozano Long School of Medicine, Department of Internal Medicine, Texas, USA E-mail:
UT Health San Antonio, Joe R. and Terry Lozano Long School of Medicine, Department of Medicine, Division of Rheumatology, Texas, USA.
Qatar Med J. 2022 Feb 22;2022(1):6. doi: 10.5339/qmj.2022.6. eCollection 2022.
Immune-mediated necrotizing myopathy (IMNM) or necrotizing autoimmune myopathy includes a set of distinct disorders associated with marked myasthenia, myofiber necrosis, and high creatine kinase levels. Anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (anti-HMGCR) and anti-signal recognition particle (anti-SRP) are the two main autoantibodies associated with IMNM. Anti-HMGCR is usually associated with statin use. However, it may also be discovered in children without previous statin exposure, suggesting the existence of a complex genetic-environmental relationship in disease pathogenesis. Anti-SRP IMNM tends to present with more severe disease distinguished by pronounced myasthenia, worse neurologic outcomes, and treatment refractoriness. Its pathogenesis is also unknown; however, preliminary data suggest an antibody-complement-mediated mechanism of muscle cell lysis. Herein, we present the case of a 63-year-old man diagnosed with anti-HMGCR- and anti-SRP-positive IMNM that was treated with multiple immunosuppressants resulting in clinical improvement.
免疫介导的坏死性肌病（IMNM）或坏死性自身免疫性肌病包括一组与明显肌无力、肌纤维坏死和高肌酸激酶水平相关的不同疾病。抗3-羟基-3-甲基戊二酰辅酶A还原酶（抗HMGCR）和抗信号识别颗粒（抗SRP）是与IMNM相关的两种主要自身抗体。抗HMGCR通常与他汀类药物的使用有关。然而，它也可能在以前未接触过他汀类药物的儿童中发现，这表明在疾病发病机制中存在复杂的基因-环境关系。抗SRP IMNM往往表现为更严重的疾病，其特征为明显的肌无力、更差的神经学预后和治疗难治性。其发病机制也尚不清楚；然而，初步数据表明存在抗体-补体介导的肌肉细胞溶解机制。在此，我们报告一例63岁男性患者，诊断为抗HMGCR和抗SRP阳性的IMNM，经多种免疫抑制剂治疗后临床症状改善。
