Clinical Correlation Of Myositis-specific Autoantibodies In Idiopathic Inflammatory Myopathy

Objective To collect clinical data from patients with idiopathic inflammatory myopathy(IIM)and detect types of myositis-specific autoantibodies(MSAs)in their serum,describe the clinical data of IIM,the distribution characteristics of each type of MSAs,and the correlation between MSAs and specific clinical phenotype,so as to contribute to the diagnosis,differential diagnosis,complication prediction,and prognosis of the IIM,and guide the clinician to select a more individualized treatment plan.Methods A total of 153 patients with IIM admitted to the Affiliated Hospital of Qingdao University from November 2017 to October 2018 were selected,including 122 patients with dermatomyositis(DM)and 31 patients with polymyositis(PM),all of whom met the1975 Bohan/Peter recommended PM/DM diagnostic criteria.Record the patients’basic information,symptoms,signs and auxiliary examination results in detail,collect the patients’blood sample,and detect 12 subtypes of MSAs by immunospot.Statistical analysis and correlation analysis were performed on the obtained data.All data were statistically analyzed using SPSS 17.0 statistical software,and the difference was statistically significant at P<0.05.Results 1.Of the 153 patients with IIM,15 patients have malignant tumors,accounting for9.80%.50.98%(78/153)of patients have ILD,and 11.11%(17/153)have a history of statin use.75.16%(115/153)of patients have characteristic rashes,heliotrope rashes were the most common,and the positive rate was about 59.48%(91/153).Patients with muscle weakness accounted for 79.74%(122/153).42.48%(65/153)of patients had elevated transaminases,30.72%(47/153)of patients showed dysphagia,and only 3 patients developed dyspnea.The main cardiac manifestations of patients were arrhythmia,pericardial effusion and myocarditis,with the incidence rates 20.26%(31/153),16.99%(26/153),and 2.61%(4/153),respectively.The positive rate of MSAs was 57.52%(88/153).The most common types of MSAs were anti-Jo-1 antibody,anti-MDA5antibody and anti-Mi-2 antibody,and the positive rates were 16.99%,15.03%,and11.11%,respectively.No anti-PL-12 antibody positive was found.2.According to whether the MSAs can be detected in the patient’s serum,the samples were divided into MSAs-positive group and MSAs-negative group,and the clinical data of the two groups were compared.The MSAs-positive group was more prone to V-type sign(45.45%,27.69%,χ~2=5.01,P=0.03),arthritis(50.00%,32.31%,χ~2=4.79,P=0.03),ILD(61.36%,36.92%,χ~2=8.94,P<0.01)and elevated transaminase(52.27%,29.23%,χ~2=8.12,P<0.01)than the negative group,the difference between the two groups was statistically significant.3.Patients were divided into DM group and PM group according to the type of disease,and the distribution characteristics of MSAs types were compared between the two groups.Anti-SRP antibody positive was more specific for the diagnosis of PM(χ2=7.54,P<0.01),while anti-MDA-5 antibody positive was more specific for the diagnosis of DM(χ2=5.48,P=0.02).4.Logistic regression analysis showed that anti-MDA5 antibody positive was an independent risk factor for arthritis[OR=5.96,95%CI(1.97,18.04),P<0.01].Anti-Jo-1antibody[OR=4.45,95%CI(1.66,11.93),P<0.01]and anti-MDA-5 antibody[OR=4.38,95%CI(1.53,12.56),P<0.01]positive were Independent risk factors for ILD.Anti-Jo-1antibody[OR=4.15,95%CI(1.62,10.65),P<0.01]and anti-NXP2 antibody[OR=13.89,95%CI(1.57,122.56),P=0.02]positive were Independent risk factors for elevated transaminase.Patients with positive anti-Jo-1 antibodies were less likely to develop heliotrope rash[OR=0.32,95%CI(0.12,0.83),P=0.02],anti-Mi-2 antibody[OR=6.83,95%CI(1.45,32.15),P=0.02]and anti-MDA5 antibodies[OR=4.69,95%CI(1.42,15.50),P=0.01]positive were independent risk factors for heliotrope rash.Anti-MDA5antibody positive was an independent risk factor for the Gottron papules[OR=8.30,95%CI(2.53,27.27),P<0.01].Anti-Mi-2 antibody positive was an independent risk factor for the“V”sign[OR=44.03,95%CI(5.47,354.36),P<0.01].Anti-TIF1-γantibody positive was an independent risk factor for the“shawl”sign[OR=8.44,95%CI(1.33,53.72),P=0.02].Anti-Mi-2 antibody[OR=4.06,95%CI(1.35,12.24),P=0.01]and anti-NXP2 antibody[OR=7.42,95%CI(1.32,41.81),P=0.02]were independent risk factors for dysphagia,anti-MDA5 antibody-positive patients with less dysphagia,but no statistically significant[OR=0.29,95%CI(0.06,1.34),P=0.11].Anti-Jo-1 antibody[OR=4.93,95%CI(1.32,18.39),P=0.02]and anti-SRP antibody[OR=33.43,95%CI(2.69,414.93),P<0.01]were independent risk factors for malignant tumors.Conclusion 1.MSAs have obvious correlation with different clinical phenotypes,and can be used as predictive indicators to guide clinical work.2.Anti-Jo-1 antibody-positive patients need to be monitored for ILD,and anti-MDA5antibodies and anti-PL-7 antibody-positive patients are prone to rapid progression of ILD.3.Patients with positive anti-Jo-1 antibodies,anti-SRP antibodies,and anti-TIF1-γantibodies should be tested for tumors and followed up. 4.Patients with positive anti-SRP antibodies,anti-HMGCR antibodies,anti-SAE antibodies,and anti-NXP2 antibodies are prone to severe muscle symptoms and should be treated aggressively as soon as possible.