SAT0660 Clinical significance of anti-ra33 autoantybodies in rheumatoid arthritis
Authors: M. Volkava, A. Kundzer
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 pathogenetic 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/.<sup>EULAR 2010</sup> Autoantibodies to RNP B1 IgG was assessed in samples of blood serum by enzyme immunoassay (ELISA; Medipan AG, Germany). 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> In our cohort of patients with RA, the incidence rate of RF IgM was 96.02%, anti-CCP – 81.75%, anti-Sa – 69.88%, anti-RA33%–35.97% of patients. For further analysis of the clinical significance of anti-RA33 patients were divided into 2 groups: anti-RA33 positive and anti-RA33negative. Positive and negative for anti-RA33 patients did not differ (p&gt;0.05) by key characteristics, such as age, gender, duration of disease, and indicators of disease activity (CRP levels, DAS28, SDAI, CDAI). In contrast to the data obtained Maslyansky A. L. and co-authors the correlation relationship between the levels of anti-RA33 and indicators of disease activity as well as duration of disease has not been established. At the same time seronegative for anti-RA33 patients demonstrated a higher frequency of exrtaarticular manifestations (p&lt;0,05). When analysing the frequency of occurrence of anti-CCP, RF IgM, anti-Sa and anti-RA33 autoantibodies, there were no differences between the groups of seropositive and seronegative for anti-RA33. Correlation relationship between the levels of the investigated autoantibodies is not established. <h3>Conclusions</h3> Thus anti-RA33 is a perspective independent biomarker of RA, which has its own potential. The possible pathogenic significance of anti-RA33 as a biomarker of a more favourable course of the RA should be considered. 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