Clinical features of anti-signal recognition particle antibody-positive patients with dermatomyositis or clinically amyopathic dermatomyositis / 中华皮肤科杂志

ABSTRACT

Objective@#To investigate the clinical features of anti-signal recognition particle (SRP) antibody-positive patients with dermatomyositis/clinically amyopathic dermatomyositis (DM/CADM) .@*Methods@#Clinical data were collected from 90 patients with DM/CADM, who were hospitalized at the Department of Dermatology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from June 2015 to July 2017. Immunoblotting assay was performed to determine the serum level of anti-SRP antibody in these patients. Statistical analysis was carried out using t test and Chi-square test.@*Results@#Of the 90 patients with DM/CADM, 11 (12.2%) were positive for serum anti-SRP antibody, including 6 with DM and 5 with CADM. Among 82 adult patients with DM/CADM, the prevalence of malignant tumors was significantly higher in the patients with anti-SRP antibody than in those without (7/9 vs. 31.5%[23/73], χ2 = 7.394, P = 0.006) . The 11 patients with anti-SRP antibody had typical DM skin lesions, and their cutaneous dermatomyositis disease area and severity index (CDASI) was 18.1 ± 2.9. The prevalence of "angel wings sign" (aliform erythema on the trunk) was significantly higher in the patients with anti-SRP antibody than in those without (7/11 vs. 29.9%[20/67], Fisher′s exact test, P = 0.028) . The positive rate of antinuclear antibody was significantly higher in the patients with anti-SRP antibody than in those without (4/8 vs. 16.7%[13/78], χ2 = 6.053, P = 0.014) . Magnetic resonance imaging of muscles of both thighs of the 10 patients with anti-SRP antibody (6 with DM and 4 with CADM) showed the presence of abnormal signals in the thigh muscle group in 8, swelling of the muscle group in 2, subcutaneous edema in 2, myofascial swelling in 1, and no abnormities in 2. No interstitial lung disease or myocardial involvement was observed in the patients with anti-SRP antibody.@*Conclusions@#The anti-SRP antibody-positive patients with DM/CADM showed a high prevalence of "angel wings sign" , and a high risk of malignant tumors. Early detection of the anti-SRP antibody in patients with DM/CADM is helpful to predict the occurrence of malignant tumors.