The Determination Of Anti-sRP Antibody And Its Clinical Significance In Patients With Dermatomyositis/Amyopathic Dermatomyositis

Objective: To detect anti-signal recognition particle(SRP)antibodies in patients with dermatomyositis/clinical myopathy dermatomyositis(DM/CADM)and to explore the relationship between anti-SRP antibodies and clinical features.Materials and Methods: The clinical data and serum of 90 patients with DM/CADM admitted to the dermatology ward of Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine from June 2015 to July 2017 were collected.Anti-SRP antibody in serum was detected by immunoblotting.The age,gender and other clinical symptoms were recorded.Relevant laboratory indicators were improved,including ESR,CK,LDH,ANA,etc.Tumor screening was performed,muscle magnetic resonance imaging,skin and muscle biopsy and other examinations were improved,and film reading,analysis and research were conducted.Statistical analysis was performed using methods such as t test and Chi-square test.Results: Of the 90 patients with dermatomyositis/clinical myositis dermatomyositis,11(12.2%)were positive for serum anti-SRP antibodies,including 6 with DM and 5 with CADM.(1)Among 82 adult DM/CADM patients,the incidence of malignant tumors in anti-SRP antibody-positive patients was significantly higher than that in antibody-negative patiests(77.8% vs 31.5%,P=0.0065).(2)11 cases of anti-SRP antibody-positive patients had typical dermatomyositis rash,and the dermatomyositis lesion area and severity index(CDASI)was 18.1±2.9.The incidence of pterygium in the lower back of the antibody was significantly higher in antibody-positive patients than in antibody-negative patients(63.6% vs 29.9%,P=0.0279).None of the anti-SRP antibody-positive patients had pulmonary interstitial lesions and myocardial involvement.(3)The positive rate of antinuclear antibodies was 16.7% in 90 patients,and the proportion of antinuclear antibody positive in anti-SRP antibody positive patients was significantly increased(50.0% vs 16.7%,P=0.014).(4)In the 11 anti-SRP antibody-positive patients,6 were DM,5 were in CADM,and 8 of the thigh muscles had abnormal magnetic resonance,including muscle and myofascial swelling and subcutaneous edema,which was different from immune-mediated necrotic myopathy.Conclusion: Patients with anti-SRP antibody-positive DM/CADM have a high incidence of erythema in the lower back of the trunk.The risk of merging tumors is significantly increased.Early detection of anti-SRP antibody levels in patients with DM/CADM helps predict malignancy.Muscle magnetic resonance helps to assess the condition,evaluate the treatment of the disease,and detect changes in the condition.