AB0637 THE CLINICAL CHARACTERISTICS OF KOREAN PRIMARY SJÖGREN’S SYNDROME (pSS) PATIENTS WITH POSITIVE ANTI-DOUBLE-STRANDED DNA (ANTI-dsDNA) ANTIBODY BY THE FARR METHOD

Background Anti-Ro/SSA antibody is considered to play a crucial role in distinguishing the clinical features of pSS. However, the association of anti-dsDNA antibody on the characteristics and prognosis of pSS is not well known. Objectives We aimed to clarify the clinical characteristics of pSS patients presenting with positive anti-dsDNA antibody. Methods This retrospective study assessed 1255 pSS patients, fulfilling the classification criteria proposed by the American–European Consensus Group in 2002 or American College of Rheumatology/European League Against Rheumatism (EULAR) in 2016, who regularly visited Seoul St. Mary’s Hospital between 2013 and 2021. Patients with other autoimmune diseases including SLE were excluded from this study. Of the total 1255 patients, 174 were in the anti-dsDNA antibody positive group (measured by using Farr assay, cut-off = 7 IU/ml) and 1081 were in the negative group. Data were compared between the two groups, including demographic features, extra-glandular manifestations (EGMs), clinical indices, and laboratory values at baseline. Results Patients in the anti-dsDNA (+) pSS group were younger ( p = 0.015), and had higher proportion of positive finding in ocular staining score (OSS) by Sjögren’s International Collaborative Clinical Alliance (SICCA) method (OSS ≥ 5) and minor salivary gland biopsy (Focus score ≥ 1) ( p = 0.021 and p = 0.040, respectively). Among the EGMs, more frequent lymphadenopathy, lymphoma, pulmonary, cutaneous, renal, and CNS involvement were observed at baseline in the anti-dsDNA (+) pSS group. Total EULAR Sjögren’s syndrome disease activity index (ESSDAI) scores were also higher in the anti-dsDNA (+) pSS group (median value [IQR]: 5.9 [5.1-6.7] vs 3.7 [3.4-3.9], p = 0.001). More frequency of leukopenia ( p = 0.001), anemia (p = 0.001), rheumatoid factor positivity (p < 0.001), anti-Ro/SSA antibody positivity ( p < 0.001), low C3 ( p =0.024), low C4 (p=0.003) and hypergammaglobulinemia ( p < 0.001) were found in the laboratory data in the anti-dsDNA (+) pSS group. Conclusion Korean pSS patients with positive anti-dsDNA antibody by Farr method showed distinct clinical characteristics at baseline including higher disease activity of SS, frequent several types of EGMs, and difference of laboratory data. Close monitoring for development of above clinical features in anti-dsDNA positive pSS patients is necessary. Reference [1]Goules AV, Tzioufas AG. Primary Sjögren’s syndrome: clinical phenotypes, outcome and the development of biomarkers. Immunol Res . 2017;65(1):331-344. Acknowledgements No acknowledgments to declare. Disclosure of Interests None Declared.