MuSK抗体陽性重症筋無力症の病態

Pathogenesis of MuSK Antibody-positive Myasthenia Gravis

重症筋無力症（myasthenia gravis：MG）の長期的な寛解は稀で患者のhealthy-related QOLは健常者に比べて低い。MG患者の約5％は筋特異的チロシンキナーゼ（muscle-specific tyrosine kinase：MuSK）抗体が陽性のMGで，全般的に症状が重く難治例や筋萎縮が残存するなど予後不良例がある。最近，MuSK抗体陽性MGの発症メカニズムの研究から難治性の原因が明らかになりつつある。本論で最新の知見を概説する。

Abstract

Long-term remission is rare in patients with myasthenia gravis (MG), and health-related quality of life is lower in patients with MG than in healthy individuals. Approximately 5% of patients with MG show positive results on muscle-specific kinase (MuSK) antibody testing and usually have severe symptoms, refractory disease, residual muscle atrophy, and poor prognosis. Recent studies that have investigated the pathogenesis of MuSK antibody-positive MG have reported contributors to treatment refractoriness in cases of MG. In this article, we review the most recent findings.