AB0640 Implausible anti-smith antibody is not implausible to autoimmune disease in chinese population using the euroimmun line immunoassays. (12th June 2018)

• Record Type: Journal Article
• Authors: Wu, Y.; Meng, Y.
• Is Part Of: Annals of the rheumatic diseases. Volume 77(2018)Supplement 2
• Page Start: 1466
• Page End: 1467
• Publication Date: 2018-06-12
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2018-eular.2368
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background: Anti-Sm antibody is important test for lupus. In China, many labs detected anti-Sm using Euroimmun line immunoassays (LIA) kit, which mixture with purified Sm and RNP antigens as target antigens in Sm/RNP band and purified Sm antigens in Sm band. On the instruction, anti-Sm results should be determined according to the 2 bands. That is divided as true anti-Sm positive cases (having positive Sm and Sm/RNP bands) and implausible cases (having Sm band without Sm/RNP band), the value of implausible anti-Sm is not very clear now. Objectives: We aimed at investigating the clinical value of the implausible anti-Sm in Chinese population. Methods: Total of 39 766 patients were analysed for anti-Sm antibody using the EURO lineimmuno assay skit, of which 1208 cases are positive for anti-Sm. All cases with positive anti-Sm were divided into true anti-Sm group and implausible group according to the result of Sm/RNP band. The proportion of clinical diagnosis including autoimmune diseases (AIDs) and non-immune diseases (NAIDs) and the level of some clinical serum indexeswere retrospectively analysed for the implausible anti-Sm cases. Results: Implausible anti-Sm were evidenced in 271/1208 (22.42) of all positive anti-Sm cases. Among patients with positive anti-Sm, 177 cases have definitive diagnoses (65.31%, 177/271), with autoimmune diseases accounting for 68.36% (121/177), of whom 96 had systemic lupus erythematosus (SLE) (79.34%). In addition, there are 5 implausible cases with rheumatoid arthritis (RA), 3 with Sjogren syndrome (SS) and 10 with mixed connective tissue diseases (MCTDs). The titer of antinuclear antibodies (ANA) in patients with implausible anti-Sm is lower than ones with true anti-Sm. Impausible group have the same gender ratio, mean onset age and frequency of autoantibodies with true group. The prevalence of one of NAIDs, kidney disease, was significantly lower in implausible group than in true group (X2=3.841, p=0.05). Conclusions: Implausible anti-Sm have great diagnostic value in AIDs just as true anti-Sm. Patients with implausible anti-Sm have less incidence of evolving to autoimmune injury and kidney injury. Patients with implausible anti-Sm but without autoimmune diseases may be potential autoimmune disease victims. Acknowledgements: This work was supported by fund of Department of Science and Technology of Sichuan Province, Grant No. 2016 JY0035 and the fund of Health and Family Planning Commission of Sichuan Province, Great. No.16pg326. Disclosure of Interest: None declared