From the Muscle Disease Unit, Laboratory of Muscle Stem Cells and Gene Regulation (I.P.-F., M.C.-D., K.P., Y.H., W.H., A.L.M.), National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda; Departments of Neurology (I.P.-F., M.C.-D., A.M.C., L.C.-S., A.L.M.) and Medicine (C.A.M., J.A., E.T., J.J.P., S.K.D., L.C.-S., A.L.M.), Johns Hopkins University School of Medicine, Baltimore, MD; Faculty of Health Sciences (I.P.-F.), Universitat Oberta de Catalunya, Barcelona, Spain; Department of Medicine (J.H.), Medstar Georgetown University Hospital, Washington, DC; and Department of Medicine (C.J.), Hospital of the University of Pennsylvania, Philadelphia.
Neurology. 2019 Nov 5;93(19):e1768-e1777. doi: 10.1212/WNL.0000000000008443. Epub 2019 Oct 8.
To define the clinical phenotype of dermatomyositis (DM) with anti-Mi2 autoantibodies.
In this longitudinal cohort study, the prevalence and severity of clinical features at disease onset and during follow-up in patients with anti-Mi2-positive DM were compared to patients with anti-Mi2-negative DM, antisynthetase syndrome (AS), and immune-mediated necrotizing myopathy (IMNM). Longitudinal anti-Mi2 autoantibody titers were assessed.
A total of 58 patients with anti-Mi2-positive DM, 143 patients with anti-Mi2-negative DM, 162 patients with AS, and 170 patients with IMNM were included. Among patients with anti-Mi2-positive DM, muscle weakness was present in 60% at disease onset and occurred in 98% during longitudinal follow-up; fewer patients with anti-Mi2-negative DM developed weakness (85%; = 0.008). Patients with anti-Mi2-positive DM were weaker and had higher creatine kinase (CK) levels than patients with anti-Mi2-negative DM or patients with AS. Muscle biopsies from patients with anti-Mi2-positive DM had prominent necrosis. Anti-Mi2 autoantibody levels correlated with CK levels and strength ( < 0.001). With treatment, most patients with anti-Mi2-positive DM had improved strength and CK levels; among 10 with multiple serum samples collected over 4 or more years, anti-Mi2 autoantibody titers declined in all and normalized in 3, 2 of whom stopped immunosuppressant treatment and never relapsed. Patients with anti-Mi2-positive DM had less calcinosis (9% vs 28%; = 0.003), interstitial lung disease (5% vs 16%; = 0.04), and fever (7% vs 21%; = 0.02) than did patients with anti-Mi2-negative DM.
Patients with anti-Mi2-positive DM have more severe muscle disease than patients with anti-Mi2-negative DM or patients with AS. Anti-Mi2 autoantibody levels correlate with disease severity and may normalize in patients who enter remission.
定义抗 Mi2 自身抗体阳性的皮肌炎（DM）的临床表型。
在这项纵向队列研究中，比较了抗 Mi2 阳性 DM 患者在疾病发作时和随访期间的临床特征的患病率和严重程度，以及抗 Mi2 阴性 DM、抗合成酶综合征（AS）和免疫介导的坏死性肌病（IMNM）患者。评估了纵向抗 Mi2 自身抗体滴度。
共纳入 58 例抗 Mi2 阳性 DM 患者、143 例抗 Mi2 阴性 DM 患者、162 例 AS 患者和 170 例 IMNM 患者。在抗 Mi2 阳性 DM 患者中，疾病发作时存在肌肉无力的患者占 60%，在纵向随访期间发生肌肉无力的患者占 98%；抗 Mi2 阴性 DM 患者中出现无力的患者较少（85%；=0.008）。与抗 Mi2 阴性 DM 或 AS 患者相比，抗 Mi2 阳性 DM 患者更虚弱，肌酸激酶（CK）水平更高。抗 Mi2 阳性 DM 患者的肌肉活检存在明显坏死。抗 Mi2 自身抗体水平与 CK 水平和肌力呈正相关（<0.001）。经治疗，大多数抗 Mi2 阳性 DM 患者的肌力和 CK 水平均有所改善；在 10 例连续 4 年以上采集了多次血清样本的患者中，所有患者的抗 Mi2 自身抗体滴度均下降，其中 3 例正常化，这 2 例停止免疫抑制治疗且从未复发。抗 Mi2 阳性 DM 患者的钙沉着症（9%比 28%；=0.003）、间质性肺病（5%比 16%；=0.04）和发热（7%比 21%；=0.02）较少。
与抗 Mi2 阴性 DM 或 AS 患者相比，抗 Mi2 阳性 DM 患者的肌肉疾病更严重。抗 Mi2 自身抗体水平与疾病严重程度相关，在进入缓解期的患者中可能恢复正常。
