Autoantibodies associated with immune-mediated necrotizing myopathy: pathogenesis and clinical implication

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K09784
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Neurology
• Research Institution: Keio University
• Principal Investigator: Suzuki Shigeaki 慶應義塾大学, 医学部(信濃町), 准教授 (50276242)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 自己抗体 / 炎症性筋疾患 / 免疫介在性壊死性ミオパチー / 抗SRP抗体 / 抗HMGCR抗体 / 抗合成酵素症候群 / 抗ARS抗体

Outline of Final Research Achievements

Inflammatory myopathies are a heterogeneous group of immune-mediated diseases that involve skeletal muscle as well as many other organs. In addition to a histological diagnosis at muscle biopsy, the clinical phenotypes of inflammatory myopathies can be defined by various autoantibodies that are originally detected by RNA or protein immunoprecipitation.Immune-mediated necrotizing myopathy (IMNM), characterized by significant necrotic and regeneration muscle fibers with minimal or no inflammatory cell infiltration, is associated with the presence of autoantibodies. IMNM is now classified as a distinct category of inflammatory myopathies. We divided autoantibodies into three groups: those associated with IMNM, those against aminoacyl transfer RNA synthetase, and those associated with dermatomyositis. The screening of autoantibodies has clinical relevance for managing patients with inflammatory myopathies.

Free Research Field

神経内科

Academic Significance and Societal Importance of the Research Achievements

近年，新たな病型や自己抗体の登場があり，筋炎の疾患概念には大きな変遷があった．我々の研究グループの一連の成果により，自己抗体の重要性が証明され，実地の臨床現場でも必須の検査となった．IMNMの患者血清中に特異的な自己抗体である抗SRP抗体と抗HMGCR抗体が検出される．「筋炎の統合的診断研究」では最も頻度の高い病型であるIMNMにおいて40%で抗SRP抗体，25%で抗HMGCR抗体が検出された．両者が同一の患者血清中に存在することはなく，互いに独立した血清マーカーである．我々はこれらの自己抗体の測定系を樹立し，実臨床で使用されている．今後，筋炎における自己抗体の病態機序の解明が望まれる．