AB1113 DIAGNOSTIC VALUE OF ANTI-Sa AND ANTI-hn RNP K ANTIBODIES IN SERONEGATIVE RHEUMATOID ARTHRITIS. (2nd June 2020)

• Record Type: Journal Article
• Authors: Volkava, M.; Kundzer, A.
• Is Part Of: Annals of the rheumatic diseases. Volume 79(2020)Supplement 1
• Page Start: 1846
• Page End: 1846
• Publication Date: 2020-06-02
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2020-eular.5407
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background: The diagnostics of seronegative rheumatoid arthritis (RA) remains the important issue in modern rheumatology. Other biomarkers are studied to close the diagnostic gap. Objectives: The aim of work was to assess anti-Sa and anti-hnRNP K in patients with RA and to evaluate their diagnostic value in seronegative by anti-CCP and RF RA. Methods: In the study were included 270 patients, which fulfill EULAR/ACR 2010 criteria for RA and 50 healthy controls. The mean of patients age was 52.80 (95% CI:51.70-54.80 years). Levels of antibodies to anti-CCP and anti-Sa were evaluated by ELISA according to the instructions of the manufacturer (Euroimmune, Germany), anti-hnRNP K according to the instructions of the manufacturer ((Medipan, Germany). Levels of rheumatoid factor (RF) were assessed by kinetic nephelometry using an automatic analyzer Beckman Coulter (USA). Results: Anti-CCP in patients were found 209 (77.41%) patients, RF - in 192 (71.11%) patients, anti-Sa – in 163 (60.37%) patients, anti-hnRNP K – in 63 (23.33%) patients. The incidence of Anti-CCP, RF, anti-Sa, anti-hnRNP K in RA was significantly higher (p<0.05) than in healthy individuals (0 (0%), 0 (0%), 1 (2.00%), 0 (0%) respectively). The diagnostic sensitivity and specificity of anti-Sa to discriminate seronegative by anti-CCP and RF RA patients from healthy controls by ROC – analysis were determined and made up for anti-Sa - 50, 00% (95%CI: 26.1 – 73.9) and 96.77% (95%CI: 83.2 – 99.5) respectively (area under ROC-curve 0.734; 95%CI: 0.588-0.850, p=0.0026), for anti-hnRNP K - 55, 56% (95%CI:35, 3 - 74, 5), 100, 00% (95%CI: 95, 7 - 100, 0) respectively (area under ROC-curve 0.778; 95%CI: 0.689-0.851, p=0.0001). There were no significant differences in clinical (DAS 28, CDAI, SDAI, treatment options) and laboratory characteristics (ESR, CRP, anti-CCP, RF levels) between anti-Sa-positive and anti-Sa-negative patients (p>0.05) as well as between anti-hnRNP K-positive and anti-hnRNP K-negative patients (p>0.05). Conclusion: Anti-Sa and anti-hnRNP K may serve as potential additional laboratory biomarkers for seronegative RA to allow to close the seronegative RA gap and confirm the diagnosis of RA. Disclosure of Interests: None declared