中文摘要：

目的：通过检测多发性肌炎/皮肌炎患者血清中的抗Mi-2抗体,分析该抗体阳性患者的临床特征和肌肉病理学特点.方法：用免疫印迹法检测125例多发性肌炎/皮肌炎患者（其中皮肌炎89例,多发性肌炎36例）血清中抗Mi-2抗体的阳性率,并通过系统的文献回顾,分析此抗体阳性患者的临床特征.结果：125例患者中抗Mi-2抗体阳性5例,均为皮肌炎患者,多发性肌炎患者中未检出;在皮肌炎患者中占5.6％.该抗体阳性的患者与阴性的患者相比,Gottron皮疹、Heliotrope疹、面部红斑、四肢肌肉受累的发生率较高,但无统计学差异.该抗体阳性者的肺间质病变、吞咽困难也较为常见,但合并心脏受累较少见,与伴发肿瘤无明显关联,免疫治疗应答率高.肌组织病理主要表现为血管周围炎症细胞浸润,肌细胞组织相容复合物-1表达上调,T淋巴细胞浸润为主.结论：抗Mi-2抗体对皮肌炎诊断较为特异,阳性率低,与皮疹和肌肉受累关系密切,治疗反应良好,预后个体差异较大.

英文摘要：

Objective：To analyze the prevalence of anti-Mi-2 antibodies and their association with clinical and muscle pathologic characteristics in a large Chinese dermatomyositis （DM）and polymyositis（PM）cohort. Methods：Serum from 89 patients with DM and 36 patients with PM were detected for anti-Mi-2 antibodies by imnmnoblotting tests.Clinical and muscle pathologic characteristics were collected by review of medical records.Statistical analyses were done with Mann-Wittney U test and Fisher exact test.Then through systemic literature review,we analyzed the characteristics of this autoantibody.Results： Serum of 5 DM patients （5.6%）in 89 were positive for anti-Mi-2 antibodies,while none of PM patients was positive.The rates of Gottron＇s papules/sign,heliotrope rash,facial erythema,limbs muscle involvement were higher in anti-Mi-2 positive group than in negative group,but without statistical significance.Interstitial lung diseases dysphagia were also common findings in this group,but cardiac involvement and cancers were rare.Anti-Mi-2 antibodies positive patients showed a good response to immunosuppressive treatment.Muscle pathology findings were mainly peri-vascular inflammatory ceils infiltration with T lymphocytes as the principal infiltrating cells,and up-regulated expression of major histocompatibility complex-I in the surface of muscle fibers.Conclusion：The anti-Mi-2 antibodies are relatively specific for the diagnosis of DM ,though their low positive rate.They have a strong associtation with skin rash and muscle lesions,and good response to immunosuppressive treatment.The prognoses are rather dif- ferent among individuals.