—筋炎関連自己抗体（3）—抗合成酵素症候群関連筋炎

Antisynthetase Syndrome-Associated Myositis

抗合成酵素症候群関連筋炎は自己免疫性筋炎の主要病型の1つで，抗アミノアシルtRNA合成酵素抗体の存在により定義される。骨格筋に加えて肺，関節，皮膚などが障害される。抗体のサブタイプにより症状の程度に違いがあり，抗OJ抗体では筋症状が重篤化しやすい。筋病理では筋束辺縁部壊死など筋束辺縁部から筋周鞘にかけての変化が目立つ。同部では形質細胞に有利な微小環境が生じており，病態理解のうえで注目される。

Abstract

Antisynthetase syndrome-associated myositis is a major form of autoimmune myositis defined by the presence of anti-aminoacyl tRNA synthetase autoantibodies. It involves the skeletal muscle as well as the lungs, joints, and skin. Severity of each symptom varies by autoantibody subtype; anti-OJ is associated with severe muscle involvement. Pathological changes from the perimysium to the adjacent perifascicular area, including perifascicular necrosis, is a distinctive feature. The skeletal muscle provides an immunological micro-milieu for specific plasma cells. Therapies against plasma cells or factors defining B cell/plasma cell niche may be a more effective mechanism-specific treatment.