AB0283 Indices of antibodies to fibronectin associated with clinical manifestations of rheumatoid arthritis
Authors: O.A. Rusanova, I.P. Gontar, O.I. Emelyanova, N.I. Emelyanov, I.A. Zborovskaya
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> According to available data, fibronectin (FN) is implicated in progressing cartilage destruction in arthritis of varying etiology. It is established that it is not native FB that has the ability to enhance the expression of chondrocyte catabolism gene thus causing. Antibodies enhance both resorption and synthesis of osseocartilaginous tissue; they affect proteoglycan and glycosaminoglycan production in connective tissue, and also block active centres of FN molecule. <h3>Objectives</h3> Determining the level of FN antibodies using fibronectin-based magnetocontrollable immobilised adsorbents is an additional criterion of rheumatoid arthritis disease activity. Demonstrating the FN indices and its antibodies in blood serum of healthy individuals, and in that of RA patients depending on the disease activity. Demonstrating that the level of FN antibodies in the blood serum of RA patients reliably differs from that of healthy people. <h3>Methods</h3> 117 RA patients receiving hospital treatment at Municipal hospital 25 of Volgograd were examined. The patients' mean age was 49.9±13.9. The mean duration of disease was 9.1±1.57 years. Low (I) disease activity was noted in 14 patients (12%), moderate (II) – in 66 (56.4%), and high (III) – in 37 (31.6%) patients with RA. According to the degree of articular dysfunction the patients were classified in the following way: 11 patients (9.4%) showed articular insufficiency functional class II (intact occupational ability), 87 patients (74.41%) showed insufficiency functional class III (lost occupational ability), and 19 patients (16.2%) showed insufficiency functional class IV (lost autonomy). The articular syndrome underlies all clinical presentations of RA. In most patients (102 individuals, 87.2%) RA took the form of polyarthritis; in the remaining 15 people (12.8%) oligoarthritis was noted. 107 patients (91.5%) showed hand joint involvement, 99 (71.8%) – knee joints, 71 (60.7%) – talocrural joints, 61 (52.1%) – elbow joint, 49 (41.9%) – shoulder joints, and 37 patients (31.6%) showed foot joint involvement. Serum from 30 apparently healthy individuals, donors from the regional hemotransfusion centre in Volgograd, was used as control. The FN antibody titer was determined using an original technique: enzyme immunoassay with FN-based immobilised granulated antibodies with magnetic properties. <h3>Results</h3> The mean FN content in the plasma of healthy people was 351.0±65.1 mcg/ml. The mean concentration of specific antibodies in donor sera was 0.031±0.0029 optical density units. An elevated concentration of plasma FN was detected in 39 RA patients (33.3%). The mean concentration of serum antibodies to FN in RA patients was 0.095±0.014 optical density units, which exceeded the values in the control group (p&lt;0.05). An elevated content was noted in 49 patients (41.9%). <h3>Conclusions</h3> A correlation analysis revealed a positive association between FN antibody concentration, and parameters of ESR (r=0.27, p&lt;0.03), and circulating immune complex (r=0.43, p&lt;0.05), as well as indices indicating the degree of exudative-inflammatory process in the joints, and the extent of pain syndrome (DAS score of 28, articular index, pain score, swelling index) (p&lt;0.05). <h3>Disclosure of Interest</h3> None declared