1. SYNOVIAL TISSUE TRANSCRIPTOME AND SYNOVIAL FLUID PROTEOME HAVE STRONGER DISCRIMINATORY POWER THAN SERUM IN DISSECTING INFLAMMATION IN RHEUMATOID ARTHRITIS Biljana Smiljanovic 1, Bruno Stuhlmüller 1, Silvial Pade 1, Marina Backhaus 1, Gerd R. Burmester 1, Andreas Radbruch 2, Andreas Grützkau 2, Thomas Häupl 1 1 Department of Rheumatology and Clinical Immunology, Charité University Hospital, Berlin, Germany 2 Deutsches Rheuma – Forschungszentrum, Berlin, Germany Rheumatoid arthritis (RA) is a chronic disease associated with polyarticular inflammation, cartilage and/or bone destruction. Current diagnosis of RA is based on clinical criteria and measurement of non-specific markers of inflammation in the blood. A main challenge in diagnosis of RA is to establish objective criteria able to provide a more detailed insight into joint pathobiology. In search for convenient biomarkers, gene-expression profiles from synovial tissues of RA and osteoarthritis (OA) patients were generated. These profiles were used for selection of candidate biomarkers that were measured at the protein level both in synovial fluid and matched serum samples from RA and OA patients. Conclusion: Materials and Methods : 2.2. 10 molecules as potential pattern that discriminated RA from OA were measured in synovial fluid and serum: CXCL13, CCL18, sCD14, sCD163, sCD44, uPAR, sICAM1, sVCAM1, sE-Sele, sP-Sele (A)The pattern of 10 potential markers measured in SF differentiated RA from OA, with few exceptions (B)The discriminatory power of the pattern of 10 potential markers was weaker in serum compared to SF (C)sE-Sele and sP-Sele measured in SF showed the best correlation with DAS28. However, this correlation was not evident in serum. In contrast, CXCL13 followed by sCD14 and CCL18 correlated with DAS28, both when measured in SF and serum (C) CORRELATION OF 10 MARKERS MEASURED IN SF AND SERUM WITH CLINICAL DATA 10 RA patients 11 OA patients (A) THE PATTERN OF 10 MARKERS IN SYNOVIAL FLUID (SF) Background: 10 RA patients10 OA patients Criteria for selection of top candidates: 1.high signal value (high mRNA level) 2. changes in >60% of pair-wise comparisons 3. high fold change CCL18 *p=0.0190 **p=0.0016 *p=0.0249 ***p<0.0001 CCL18 p=0.0806 ***p<0.0001 p=0.4928 ***p<0.0001 Results: 2.From synovial tissue transcriptome to validation at the protein level in synovial fluid and serum 1.Transcriptome generated form synovial tissues biopsies clearly discriminated RA from OA patients CXCL13 SYNOVIAL FLUID (SF)SERUM 2.1. CXCL13 and CCL18 as potential markers that discriminated RA from OA were measured in Synovial fluid and Serum Synovial tissue biopsies from 10 RA and 10 OA patients were used for transcriptome analyses. In total, 2019 Affymetrix IDs (~1500 genes) were differentially expressed including genes involved in: Chemotaxix, Cell adhesion, Extracellular matrix formation. Out of 2019 Affymetrix IDs, 20 top candidate genes were selected for validation at the protein level, including: (1) Cytokines: IL8, CCL2, CXCL9, CXCL10, CXCL13, CCL18 (2) Soluble surface molecules: CD14, CD163, CD44, ICAM1, VCAM1 (3) Proteolitical enzymes and their inhibitors: MMP1, MMP3, A1AT SYNOVIAL TISSUE TRANSCRIPTOME (2019 AFFYMETRIX IDS) 20 TOP CANDIDATE GENES SELECTED FROM TRANSCRIPTOME Disease-specific profiles were evident in the joint where both synovial tissue transcripts and related SF proteins revealed a clear differences between RA and OA. Despite blood is a favourable diagnostic material, the results from this study indicated that the capacity of blood to dilute and neutralise inflammation is robust enough to limit discrimination between RA and OA. Markers DAS_2 8ESRCRPRFANAACPA Synovial Fluid sCD140.56 0.18 0.67 0.370.18 0.57 sCD163 0.290.240.27 0.46 0.15 0.61 CXCL130.67 0.37 0.59 0.38-0.01 0.68 uPAR 0.330.310.380.08-0.10 0.58 CCL180.47 0.190.32-0.04-0.07 0.60 sCD440.44 0.090.180.17-0.040.37 sICAM10.41 0.230.380.310.14 0.53 sE-Sele0.73 0.39 0.150.250.37 sP-Sele0.75 0.19 0.47 -0.030.010.09 sVCAM10.57 0.200.360.11-0.440.31 Serum sCD140.42 0.180.300.250.300.16 sCD163 0.240.38-0.300.140.100.17 CXCL130.610.480.570.43 0.29 0.43 uPAR 0.390.35-0.070.23 0.49 -0.09 CCL180.40 0.37 0.48 0.230.35 0.72 sCD44 0.220.15-0.230.04 0.69 -0.15 sICAM1 0.140.340.360.27 0.640.51 sE-Sele 0.340.25-0.120.160.21-0.23 sP-Sele -0.05-0.18-0.03-0.200.24-0.72 sVCAM1 0.250.260.210.26 0.35 (B) THE PATTERN OF 10 MARKERS IN SERUM 10 RA patients 11 OA patients Healthy donors (ND) Gene-expression profiles from synovial tissues biopsis were generated by Affymetrix HG-U133A arrays. The BioRetis database was used for array analyses. ELISA and multiplex immunoassays were used for validation of the markers at the protein level. IL8 CCL18 CXCL13 MMP1 MMP3 CXCL10 ICAM1 Corr scale 1 0.5 0 -0.5 Biljana Smiljanovic Department of Rheumatology and Clinical Immunology, Charité University Hospital Charitéplatz 1 D-10117 Berlin Germany E-Mail: smiljanovic@drfz.de Funding:BTCure contract no 115142-2 ArthroMark grant no 01EC1009A