AB0368 The occurrence of antibodies depending on the duration of rheumatoid arthritis
Authors: M. Volkava
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Recently heterogeneous nuclear ribonucleoproteins (hnRNPs) were identified as antigenic targets for autoantibodies in RA. Autoantibodies to RNP B1, B2 and heterogeneous complex A2/b are the most studied and are referred to as "antigen RA33". Clinical value of anti-RA33 in RA continues to be studied, so the question is about the diagnostic and pathogenic significance of these autoantibodies in patients with RA remains open. <h3>Objectives</h3> The aim of this study was to investigate the frequency of occurrence of anti – RA33y patients with RA and compare them with clinical manifestations and immunological parameters of disease. <h3>Methods</h3> The study included 139 patients with RA. The diagnosis was verified according to the classification criteria of ACR/EULAR 2010 Autoantibodies to RNP B1 IgG was assessed in samples of blood serum by enzyme immunoassay (ELISA; Medipan AG, Germany). A recombinant human RNP antigen B1 was used as the antigen, which was synthesised in the E. coli. system of the protein production. Anti-CCP, RF and antibodies to Sa-antigen (anti-Sa) was evaluated by ELISA according to the manufacturer's instructions (Euroimmun AG company, Germany). The results were expressed in relative units (U/ml). Statistical data processing was carried out using the software Statistica 7.0 (StatSoft, USA) and Medcalc 12.5.0.0 (USA), including standard methods of parametric and nonparametric analysis. Differences were considered significant at p&lt;0.05. <h3>Results</h3> Levels and frequency of occurrence of anti-RA33, anti-CCP, RF IgM and anti-Sa were analysed for the examined patients depending on disease duration. Patients were divided into two groups: patients with early RA (disease duration less than 12 months) and patients with established RA (disease duration over 12 months). In the analysis it was found that the incidence of anti-Sa in established RA are much higher in comparison with the early RA (77.98% vs. 52.00% respectively, p&lt;0.05). The levels of anti-Sa autoantibodies were lower in early RA than in established RA 21,57 U/L; 95% CI 12,10–27,42 vs. 33,10 U/L; 95% CI27,58–37,71 respectively, p&lt;0.05). Frequency of occurrence of anti-CCP and RF IgM is no different in the early and developed stage of RA. The frequency of occurrence of anti-RA33 in early RA was higher than in established RA (52.00% vs. 32.45% respectively, p&lt;0.05. <h3>Conclusions</h3> Thus, anti-RA33 is a perspective independent biomarker of RA, which has its own potential. Further study of the anti-RA33 as a diagnostic biomarker of early stage RA is promising. Based on preliminary studies the anti-RA33 could have diagnostic and prognostic value in diagnosis and evaluation of patients with early RA, and its differentiation from other small joint disorders, particularly when the other serologic tests are negative. To clarify the diagnostic and pathogenic value of anti-RA33 further research with a large sample size, comparison of immunological data with genetic factors, the results of other laboratory and instrumental studies, clinical manifestations of the disease are required. The obtained data will allow us to more thoroughly study the pathogenesis of RA and contribute to the search for new therapeutic options. <h3>Disclosure of Interest</h3> None declared