第七届北京罕见病学术大会暨2019京津冀罕见病学术大会征文（131）

1Liu YL， 1Zheng YM， 2Jin YW， 2Xiong H， 3Zhang XH， 3Deng XR， 1Hao HJ， 1Gao F， 3Zhang ZL， 1Zhang W， 1Wang ZX， 1Yuan Y

Dermatomyositis is a common inflammatory diseases predominantly involving the skin and skeletal muscles. Anti-nuclear matrix protein-2 (NXP-2) antibodies were known to be specific for dermatomyositis (DM). We reported myopathological changes in patients with anti-NXP-2 antibodies. Methods: There were 13 patients with anti-NXP-2 antibodies， including 6 adult DM (ADM)， 7 juvenile DM (JDM). All patients presented with skin rashes. Except 2 patients with clinically amyopathic dermatomyositis， muscle weakness appeared in 11 patients. Myalgia， and weight loss appeared in some patients. Peripheral edema of limbs， dysphagia， hepatomegaly， hypoproteinemia and anemia appeared in 3 patients with severe general weakness. Creatine kinase had elevated. Electromyography showed myopathic pattern. Muscle magnetic resonance image (MRI) of thighs were performed in 6 patients with myopathy. Muscle biopsies were performed in all patients. Results: Muscle MRI showed severe edema in fascicule， subcutaneous tissue and muscles in patients with myopathy. In patients with with ADM or JDM， muscle biopsy showed thick of small vessel with loss of endothelial cells and thrombosis in perimysial arteries and endomysial capillaries in 10 patients. Additionally， there were regional muscle edema in all patients， scattered muscle fiber necrosis in 7 patients， perifascicular atrophy in 4 patients and micro-infarcts in 2 patients. Among 5 patients with 6 months follow-up period， 3 patients were refractory to steroid therapy combined with other immunosuppresants， IVIG or Rituximab. Conclusions: Our research suggested that microangiopathy with microinfarcts in the muscles was common in patients with anti-NXP-2 antibodies and some patients had poor treatment responses.