Detection of novel autoantibodies in idiopathic inflammatory myopathies and their clinical application

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K17454
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 54020:Connective tissue disease and allergy-related
• Research Institution: Iwate Medical University (2023); Tokai University (2020-2022)
• Principal Investigator: Hosono Yuji 岩手医科大学, 医学部, 特任准教授 (60868090)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 自己抗体 / 炎症性筋疾患 / 悪性腫瘍

Outline of Final Research Achievements

In this study, we investigated the novel autoantibodies in Japanese inflammatory muscle disease patient and the clinical significance of anti-SP4 antibodies, a novel autoantibody discovered by the applicant(Ann Rheum Dis.2023;82:246-252.). Among DM patients, 55% of anti-Sp4 autoantibodies were detected in patients with anti- anti-TIF1γ, 36% were in anti-MDA5 and 18% were in anti-Mi-2 autoantibodies. None of anti-SP4 autoantibody-positive DM patients had cancer. Among anti-TIF1γ-positive DM patients, none of patients with coexisting anti-Sp4 had cancer, while 60% of those without anti-SP4 had (0% vs. 60%; p< 0.05, Chi-squared test). In this study, anti-SP4 autoantibodies were frequency detected in PM/DM patients, and none of anti-SP4 autoantibody-positive DM patients had cancer. Coexisting of anti-SP4 autoantibodies may reduce the risk of malignancy in IIM patients, and screening for anti-SP4 autoantibodies is recommended at the diagnosis of IIM.

Free Research Field

リウマチ膠原病

Academic Significance and Societal Importance of the Research Achievements

炎症性筋疾患(IIM)は筋組織のみならず皮膚、肺、関節など全身に炎症がおよぶ自己免疫疾患で、初発症状、臨床経過、病態など様々な形式をとるが、診断・治療開始にあたっては併存疾患のスクリーニングが重要である。中でも悪性腫瘍は治療方針の決定や患者予後に大きく関わることから、IIM診断時には特に入念な精査が求められる。患者血清中に高頻度で検出される自己抗体は早期段階での診断・病型分類、さらには治療反応・予後予測に基づく治療方針の早期決定が可能となるが、筆者らが発見した抗Sp4抗体の検出は悪性腫瘍のリスクを大きく下げることが示され、IIMにおける悪性腫瘍との病態及び臨床的意義の更なる探究が期待される。