BackgroundSpondyloarthritis (SpA) is a major form of chronic inflammatory arthritis characterized by inflammation of axial and peripheral joints and by pathologic new bone formation leading to ankylosis. Consistent genetic, experimental, and clinical evidence indicates that IL-23/IL-17 immune axis plays a pivotal role in the pathophysiology SpA. It remains, however, unknown which IL-23 responsive cells are the major cellular source of IL-17 in SpA. Innate lymphoid cells (ILCs) are an emerging family of innate immune cells that produce various cytokines, including IL-17 and IL-22, and play critical roles in regulation of inflammation and tissue remodeling.ObjectivesIn this study we investigated the presence and phenotype of ILCs in the peripheral blood and inflamed peripheral joints of patients with SpA.MethodsPaired peripheral blood (PB), synovial fluid (SF) and synovial tissue (ST) were obtained from SpA patients with actively inflamed knee joints. ILCs (lineage negative, CD45+CD127+ CD161+) were analysed by flow cytometry.ResultsILCs were present in all three compartments of patients with SpA. Analysis of ST revealed a significantly increased frequency of total ILCs in the joint compared with PB ((median (IQR) 0.37 (0.12-1.12)% of the lymphocyte population in ST versus 0.06 (0.04-0.09) % in PB, p=0.016). Immunophenotyping of ILC subsets showed a statistically significant increase in the frequency of ILC1 (CRTH2-NKp44-ckit-) in ST (37.8%; 74.43-20.47%) versus SF (7.27%; 0.6-25.1%, p=0.008) and PB (3.45%; 1.45-9.25%, p=0.004). The second most prominent ILCs in the joint were NCR-negative ILC3 (CRTH2-NKp44-ckit+), composing 33.45% (9.54-50.64%) of the total ILCs. NCR-positive ILC3 (CRTH2-NKp44+ckit+) and ILC2 (CRTH2+) populations were present in synovium at lower frequencies.ConclusionsWe observed an absolute and relative enrichment of both ILC1 and NCR-negative ILC3 in the inflamed ST of patient with spondyloarthritis as compared to PB and SF. As studies in other tissues such as gut and tonsil revealed that these IL-23 responsive ILC subsets can be an important source of IL-17 and /or IL-22 (1, 2), we will further investigate the cytokine production by these synovial ILCs.ReferencesGeremia et al. J Exp Med. 2011 208(6):1127-1133Bernink et al. Nature Immunology 14(3):221-229Disclosure of InterestNone declared

BackgroundAlthough the diagnostic delay in spondyloarthritis (SpA) has been significantly reduced over the last decade, studying the earliest disease phases remains challenging. Systematic screening of individuals at high risk, including first degree relatives (FDRs) of patients, might help to address this challenge.ObjectivesTo assess clinical, laboratory, and imaging features of SpA in seemingly healthy FDRs of ankylosing spondylitis (AS) patients.MethodsFDRs of HLA-B27 positive AS patients between an age of 18-40 years were included in Pre-SpA, a prospective inception cohort study. Clinical (including medical history, disease activity, and clinical examination), biological (HLA-B27, CRP, ESR, and calprotectin) and imaging (X-rays and MRI of the spine and sacroiliac joints (SIJ)) data were obtained. FDRs were classified according to the Assessment of Spondyloarthritis international Society for axial SpA (ASAS axSpA), ASAS peripheral SpA, the modified New York (mNY), the European Spondyloarthropathy Study Group (ESSG) and the ClASsification for Psoriatic ARthritis (CASPAR) criteria.ResultsWe report the baseline features of the first 51 FDRs included in this ongoing prospective study. Thirty (59%) FDRs had back pain, of whom 9 (18%)had inflammatory back pain. None of the FDRs had peripheral arthritis/enthesitis or extra-articular manifestations although 39% reported a history of arthralgia and 16% had a tender joint count of 1 or more. Three (6%) FDRs had low grade sacroiliitis on X-ray, 1 (2%) FDR had cervical syndesmophytes on X-ray, and 11 (22%) FDRs showed bone marrow oedema of the SIJ on MRI and none of the FDRs had abnormalities of the spine on MRI. Thirteen out of 51 (25%) FDRs fulfilled any of the classification criteria: 9 (18%) fulfilled the ASAS axSpA criteria, 10 (20%) fulfilled the ESSG criteria, and 6 (12%) fulfilled both the ESSG and the ASAS axSpA criteria. None of the FDRs fulfilled any of the other classification criteria. FDRs fulfilling SpA criteria had more frequently back pain and inflammatory back pain, had a higher disease activity (including BASDAI), and worse function (BASFI), but there was no difference in inflammatory parameters, peripheral and extra-articular disease, and HLA-B27 status. In addition to the 13 (25%) FDRs fulfilling SpA criteria, 6 of the 38 (16%) FDRs not fulfilling any criteria had imaging abnormalities suggestive of SpA (5 on MRI and 1 on X-ray).ConclusionsA substantial proportion of seemingly healthy FDRs of HLA-B27 positive AS patients had clinical and/or imaging abnormalities suggestive of SpA. Twenty-five percent of the FDRs were classified as having SpA. Further follow-up of this cohort will show which FDRs will develop clinically overt SpA over time, which initial features can predict this development, and which sequence of events is followed during disease development.Disclosure of InterestNone declared

Background Biomarkers complementing clinical evaluations may help to reduce the length and size of proof-of-concept (PoC) trials aimed to obtain quick “go/no go” decisions in the clinical development of new treatments. Objectives We aimed to identify and validate serum biomarkers to predict clinical response in spondyloarthritis (SpA) PoC trials. Methods The candidate biomarkers high sensitive-C-reactive protein (hs-CRP), interleukin-6 (IL-6), pentraxin-3 (PTX-3), alpha-2-macroglobulin (alpha-2-MG), matrix metalloproteinase-3 (MMP-3), calprotectin, and Vascular Endothelial Growth Factor (VEGF) were determined by ELISA in healthy controls (n=20) and SpA patients before and after 2 weeks of infliximab (n=18) or placebo (n=19) treatment. Clinical outcome was evaluated at week 12. Results were validated in ankylosing spondylitis (AS) with infliximab and peripheral SpA with etanercept. Results Serum levels of calprotectin, hs-CRP, PTX-3, VEGF (all P<0.001) and MMP-3 (P=0.062), but not IL-6 and alpha-2-MG, were increased in SpA versus healthy controls. Treatment with infliximab, but not placebo, significantly decreased calprotectin (P<0.001) and hs-CRP (P<0.001) levels, with a similar trend for MMP-3 (P=0.063). The Standardized Response Mean (SRM), which reflects the ability to detect changes over time, was high for calprotectin (1.26), good for hs-CRP (0.96) and moderate for MMP-3 (0.52). Calprotectin and hs-CRP, but not MMP-3, were good biomarkers of treatment response in axial SpA as evaluated in 2 separate cohorts. All 3 markers reflected response to etanercept treatment in peripheral SpA with SRMs above 0.5. Conclusions Calprotectin and hs-CRP are good serum biomarkers to predict clinical response at the group level in small-scale, short term PoC trials in SpA. Disclosure of Interest M. Turina: None declared, N. Yeremenko: None declared, J. Paramarta: None declared, L. De Rycke: None declared, D. Baeten Grant/research support: AbbVie, Centocor, Janssen-Cilag, MSD, Novartis, and Pfizer, Consultant for: AbbVie, BMS, Boehringer Ingelheim, Centocor, Janssen, MSD, Novartis, Pfizer, and UCB DOI 10.1136/annrheumdis-2014-eular.2837

Background Inflammation in Rheumatoid Arthritis leads to impaired bone formation. The activity of the Wnt pathway influences osteoblast differentiation. Dickkopf-1 (Dkk1) and Sclerostin (Sost) are important negative regulators of bone formation, they bind and inactivate signaling of the LRP-5 receptor. This inhibition is amplified in case Dkk-1 also binds to the transmembrane receptor Kremen-1. Data are emerging that Wnt signaling is important to maintain the integrity of joints and that TNF-α induced changes in Dkk-1 affect the balance between bone formation and resorption. Objectives Since the severity of joint destruction in Rheumatoid Arthritis is in part influenced by genetic factors, we aimed to study the influence of genetic variants in Dkk-1, Sost, LRP-5 and Kremen-1 on the radiographic progression rate. Methods 1,418 RA-patients with 4,885 X-ray sets of both hands and feet of four independent cohorts were studied. First, explorative analyses were performed on 600 RA-patients enrolled in the Leiden-Early-Arthritis-Clinic on the SNPs tagging Dkk-1 (8), Sost (9), Kremen-1 (16) and LRP5 (44). Significantly associating SNPs were genotyped in cohorts from Groningen (NL), Sheffield (UK) and Lund (Sweden). In each dataset the relative increase of the progression rate per year in the presence of a genotype was assessed. Subsequently, data were summarized in a meta-analysis. In groups of 80, on their genotype selected, RA-patients from Leiden, serum levels of functional Dkk-1 and Sclerostin (Biomedica, Austria) were measured with ELISA and studied in relation to genotypes. Results In the first cohort, 7 SNPs on Dkk-1, 3 SNPs on Sost, 1 SNP on Kremen-1 and 10 LRP-5 SNPs were significant. The SNPs on Kremen-1 and LRP-5 were not replicated in the second phase. 3 Dkk-1 SNPs associated significantly with progression of joint damage in the meta-analysis, also after FDR-correction for multiple testing (rs1896368, rs1896367 and rs1528873). Additionally, 2 Sost SNPs tended to significance (rs4792909 and rs6503475, p=0.01 and 0.03 in the meta-analysis and p=0.07 after FDR-correction). Epistasis between SNPs on Dkk-1 and Sost was observed. Sclerostin levels were not correlated to the SNPs in Sost. However, serum levels of Dkk-1 were significantly correlated with the genotypes in rs1896368 and rs1896367 (p=0.002). Patients carrying risk alleles (associated with more radiographic progression) had higher levels of Dkk-1. Conclusions The present data of four cohort studies show that RA-patients carrying the risk alleles of several genetic variants in Dkk-1 have higher serum levels of functional Dkk-1 and more progressive joint destruction over time. These data illustrate the relevance of Dkk-1 to progression of joint destruction in RA. Disclosure of Interest None Declared