Background The assessment of biological drug levels and immunogenicity might be essential in terms of a more effective and rational use of biological therapies and it is dependent upon the establishment of efficient standardized assays or a consensus that could allow a direct comparison of drug levels and anti-drug antibodies (ADA) data with clinical outcome. Objectives To determine whether an enzyme-linked immunosorbent assay (ELISA) performed with two versions of a commercial kit to assess IFX and ADL levels and ADA yield similar results. Methods The diagnostic capability of two ELISA versions [Promonitor® IFX R1 and R2 (V.1), Promonitor® IFX and Anti-IFX (V.2); Promonitor® ADL R1 and R2 (V.1), Promonitor® ADL and Anti-ADL (V.2) kits (Progenika Biopharma, Spain)] was evaluated in patients with RA treated either with infliximab (IFX; n=24) or adalimumab (ADL; n=24) by three different laboratories. The reliability was determined using the Cohen's Kappa coefficient (K), the Pearson's r, the intraclass correlation coefficient (ICC) and the Lin's concordance correlation coefficient (CCC). The Bland-Altman plots of differences between V.1 and V.2 were drawn to compare values of each assay. Results The qualitative discordant results for IFX levels V.1 were 9/24 samples (K= good) and 2/23 V.2 (K= very good), for ADL levels V.1 were 7/24 (K= moderate) and for V.2 were 0/24 (K= very good). For IFX-ADA were 0/24 in V.1 and V.2 (K= excellent), while for ADL-ADA were 1/24 in V.1 and 4/24 in V.2 (K= from very good to good). The quantitative agreement is shown in table 1, we found a good linear association using the Pearson's r, the ICC was questionable to excellent for both versions in IFX and ADL levels. The CCC results were poor in all determinations. Bland-Altman plots for both, IFX and ADL levels demonstrate the differences between both versions (Fig. 1 and 2, respectively). Conclusions We observed a better agreement in the qualitative than in the quantitative results in both, for IFX and ADL levels and for IFX-ADA and ADL-ADA. We have found a good linear association (Pearson's r) but a low agreement (K, ICC and CCC) comparing results for V.1 and V.2. Further interlaboratory investigations are necessary to improve results and determine their possible clinical application. Disclosure of Interest L. Valor: None declared, D. Hernández Flόrez: None declared, I. de la Torre: None declared, F. Llinares: None declared, J. Rosas: None declared, J. Yaque: None declared, E. Naredo Grant/research support: UCB and MSD, Consultant for: Abbvie, Roche Farma, Bristol-Myers Squibb, Pfizer, UCB, General Electric Healthcare, and Esaote, C. Gonzalez: None declared, J. Lόpez-Longo: None declared, I. Monteagudo Consultant for: Abbvie, Roche Farma, Bristol-Myers Squibb, Pfizer, UCB, General Electric Healthcare, MSD and Esaote, M. Montoro: None declared, L. Carreño Perez: None declared DOI 10.1136/annrheumdis-2014-eular.3290

BackgroundInflammatory myopathies (IIM) are a heterogeneous group of autoimmune rheumatic diseases characterized by muscle inflammation and progressive weakness. They include any kind of primary inflammatory muscle disease that is not otherwise better explained by metabolic, toxic, infectious, neurologic or inherited causes. The presence of autoantibodies (AA) in IIM is variable and they can recognize nuclear and cytoplasmic cellular components.ObjectivesTo evaluate the AA profile in patients diagnosed with IIM.MethodsWe evaluated 479 patients that included 12 hospitals belonging to the IIM registry of the Rheumatology Society in Madrid (SORCOM-REMICAM) with diagnosis from January 1980 to December 2014. All patients were diagnosed of IIM according to Bohan and Peter criteria. The AAs evaluated were ANA (n=476), anti-Jo1 (n=457), anti-RNP (n=427), anti-MI2 (n=159) and ACA (n=293), according to the standard techniques in the respective laboratories. The presence of ANA was considered valid with at least two positive determinations. The AAs were compared according to the classification I) as dermatomyositis (primary and secondary dermatomiositis) (DM) and polymyositis (PM) including the rest of the patients. Also, IIM were classified (II) as primary polimiositis (PPM), primary dermatomyositis (PDM), overlap syndrome (OSd), juvenile myopathies (JM), cancer-associated myopathies (CAM), autoimmune necrotizing myopathy and inclusion body myositis (these were grouped as other myositis; OM).ResultsIn the PM and DM groups 250 and 229 (52.2% and 47.8%) patients were included respectively. Positive ANA, anti-Jo1 and anti-RNP were higher in the PM than in the DM group (67, 22 and 19% vs. 56, 11 and 6%) (p=0.21, p=0.002, p=0.0001, respectively). The presence of anti-MI2 was higher in the DM group (p=0.024), according to the classification II, we found statistically significant differences in ANA, anti-Jo1, anti-RNP and anti-ACA. The OSd group had the highest proportion of ANA, anti-RNP and ACA positive AA and the JM group had the lowest frequency of Anti-Jo1 (see Table 1).ConclusionsThe AA associated with the IIM subtypes is consistent with published scientific evidence on other cohorts for ANA, anti-Jo1, anti-RNP and anti-MI2, in spite of the small sample size. The OSd group showed higher ANA and anti-RNP frequencies which might be explained by the coexistence of SLE and MCTD patients. It could be interesting to follow up those PPM patients with positive AA because they could be in the future diagnosed with a connective tissue disease. Carrying out longitudinal studies that include a greater proportion of patients may help to evaluate and predict the clinical course of IIM.References Bohan A, Peter JB. N Engl J Med 1975 Feb 13;292(7):344–7. Acknowledgements.Disclosure of InterestNone declared

BackgroundIdiopathic inflammatory myopathies (IIM) comprise a heterogeneous group of autoimmune conditions. Joint involvement can be considered to be part of the IIM systemic manifestations, together with a possible gastrointestinal, cardiovascular and/ or pulmonary involvement. Although articular involvement in the IIM has been described as variable and non-specific with a chronic course it might be an early symptom of dermatomiositis in up to 30% of cases and in those patients with overlap syndromes.ObjectivesTo evaluate and to identify joint manifestations in IIM patients.MethodsWe evaluated a cohort of 479 patients that included 12 hospitals in the Community of Madrid belonging to the IIM registry of the Society of Rheumatology of Madrid (SORCOM-REMICAM) with diagnosis from January 1980 to December 2014. All patients were diagnosed of IIM according to Bohan and Peter criteria (1). The presence of arthralgia and arthritis was considered. IIM were classified as dermatomyositis (primary and secondary dermatomiositis) (DM) and polymyositis (PM) including the rest of the patients (classification I). Also, IIM were classified (II) as primary polimiositis (PPM), primary dermatomyositis (PDM), overlap syndrome (OSd), juvenile myopathies (JM), cancer-associated myopathies (CAM), autoimmune necrotizing myopathy and inclusion body myositis (these were grouped as other myositis; OM).ResultsWe found 70 (18%) patients with acute arthritis (<6 weeks), 74 (19%) patients with chronic arthritis (>6 weeks) and 245 (65%) patients without any joint manifestations. Using the Tanimoto et al. criteria (1), the presence of erosive arthritis was observed in 149/479 (38.3%) of the patients. When comparing the joint manifestations in the PM and DM groups (n=250, 52.2% vs. n=229, 47.8%) no statistically significant differences were observed. However, assessing joint manifestations according to classification II, we observed that the highest prevalence was found in the OSd group, followed by the PDM group (p=0.0001). The group with less joint manifestations was JM compared to OSd and PDM (Table 1.ConclusionsThe presence of joint manifestations associated with IIM in our cohort is higher compared to other studies described in the literature so far and emphasize the importance of an accurate joint examination in these patients. The OSd group showed more joint manifestations which might be explained by the coexistence of SLE and MCTD patients in this group. Currently, no association between the clinical subtypes of IIM, overall, these results are encouraging and suggest that joint assessment in follow up may be helpful in differentiating subtypes of IIM.References Bohan A, Peter JB. N Engl J Med 1975 Feb 13;292(7):344–7. Disclosure of InterestNone declared

Background Ankylosing spondylitis (AS) is a chronic inflammatory disease which can result in invalidating deformities of the joints and spine at an early age. The introduction of tumor necrosis factor (TNF) blocking agents has changed the treatment options in AS. Nevertheless, the reasons for lack or loss of response to infliximab (IFX) are unclear. So far determinations of both, IFX serum levels and the presence of anti-drug antibodies (ADA) anti-IFX have not been standardized for clinical use. Objectives To assess the correlation between two available versions (V.1 and V.2) of a commercial enzyme-linked immunosorbent assay (ELISA) for serum levels of IFX and IFX-ADA in patients with AS. Methods In this cross sectional study we assessed 40 serum samples taken prior to infusion from patients diagnosed with AS treated with IFX for more than 12 months (1st line of biological treatment). IFX levels and IFX-ADA were measured using two different ELISA assays [Promonitor® IFX R1 and R2 (V.1), Promonitor® IFX and Anti-IFX (V.2) (Progenika Biopharma, Spain)] according to manufacturer's specifications. The relation comparing V.1 and V.2 for IFX levels and IFX-ADA concentrations was performed using the coefficient of variation (CV), the Cohen's Kappa coefficient, the Pearson's r, the intraclass correlation coefficient (ICC) and the Lin's concordance correlation coefficient (CCC). Bland-Altman plots were drawn to compare both versions of the assays. Results As shown in the table below, we found a greater CV for IFX levels than for IFX-ADA. Regarding the qualitative results the Cohen's Kappa was from moderate to fair and considering the quantitative results the Pearson's r was low for IFX levels and high for IFX-ADA, the ICC was questionable for both versions and both determinations. We also determined the CCC and the results showed a poor agreement. Bland-Altman plots showed the difference between both versions for IFX levels (Fig. 1). Conclusions A low reliability for IFX levels and IFX-ADA was obtained for both versions. There is a need to standardize laboratory techniques (variability inter/intra-assay and inter/intra-laboratory) in order to validate this information and its possible clinical application. Disclosure of Interest D. Hernández Flόrez: None declared, L. Valor: None declared, J. C. Nieto: None declared, L. Martinez: None declared, I. de la Torre: None declared, T. del Río: None declared, C. Gonzalez: None declared, J. Lopez-Longo: None declared, I. Monteagudo Consultant for: Abbvie, Roche Farma, Bristol-Myers Squibb, Pfizer, UCB, General Electric Healthcare, and Esaote, E. Naredo Grant/research support: UCB and MSD, Consultant for: Abbvie, Roche Farma, Bristol-Myers Squibb, Pfizer, UCB, General Electric Healthcare, and Esaote, M. Montoro: None declared, L. Carreño Perez: None declared DOI 10.1136/annrheumdis-2014-eular.3274

Background The treatment of rheumatoid arthritis (RA) has improved in the last years because of both: an increased understanding of its pathogenesis and the use of biological therapies. It is well known that B cells play a pivotal role in the development of autoimmune processes mainly as a precursor of antibody-secreting cells and also as antigen-presenting cells (APC). The development, survival and maturation of B-cells depend among others factors on specific membrane receptors. In this longitudinal study we have evaluated BAFF-Binding Receptors [BBR: BAFF-R (B-cell activating factor), TACI (transmembrane activator and calcium-modulating and cyclophilin ligand interactor), BCMA (B-cell maturation antigen)] and the activation marker CD86 expression on B-cells in response to three different therapeutic targets, anti-TNF (tumor necrosis factor): [infliximab (IFX), adalimumab (ADA), etanercept (ETA)]; anti-IL6R (Interleukin-6 receptor): tocilizumab (TCZ) and the anti-CTLA4 (Cytotoxic T-Lymphocyte Antigen 4): abatacept (ABC). Objectives To investigate the possible role of biological therapies in B-cells phenotype changes and therefore in their survival/maturation process in patients with RA. Methods 39 patients diagnosed with RA and naive to biological therapies, started treatment with ADA (n=7), ETN (n=9) IFX (n=3), TCZ (n=15) and ABC (n=5). They were assesed at baseline and every 4 month for one year. Peripheral whole blood was stained with conjugated monoclonal antibodies directed to CD19, CD27, IgD, CD38, BAFF-R, BCMA, TACI and CD86 and then evaluated by multiparametric flow cytometry. The patients were classified according to the therapeutic target: ADA+ETN+IFX (anti-TNF), TCZ (anti-IL6R) and ABC (anti-CTL4). Results We found decreased percentages (%) of memory B-cells (CD19+/CD27+) and an inversely proportional increase of naïve B-cells (CD19+/CD27−) in the groups ABC vs. anti-TNF and TCZ. Regarding the B-cell subsets, % of memory resting B-cells (CD19+/IgD+/CD38−) were lower in all three groups being more marked in the ABC group, whereas % of post-germinal center B-cells (CD19+/IgD−/CD38+) were lower in anti-TNF and ABC vs. TCZ. Regarding the BBR expression on memory B-cells, we found a decreased TACI expression in TCZ vs. anti-TNF and ABC, and also a decreased CD86+ expression in ABC vs. anti-TNF and TCZ. Conclusions In this exploratory study, the regulatory effect (TACI) on the B-cell phenotype and CD86 expression was more evident in the TCZ and ABC groups. These changes might be explained by two different key pathways for immune-regulation, the effect of cytokines and the cell-cell interaction process. Our data suggested that the monitoring of B-cells may be useful to further understand the role of specific B-cell receptors in the pathogenesis of RA and its association with clinical response to biological therapies. Disclosure of Interest D. Hernández Flόrez: None declared, L. Valor: None declared, I. de la Torre: None declared, A. Gallego: None declared, E. Chamizo: None declared, T. del Río: No...