POS0007 LOSS OF BALANCE BETWEEN PROTECTIVE AND PRO-INFLAMMATORY SYNOVIAL TISSUE T CELL POLYFUNCTIONALITY PREDATES CLINICAL ONSET OF RHEUMATOID ARTHRITIS

Background: Effective treatment of Rheumatoid arthritis (RA) patients is achievable within a short window opportunity following diagnosis. T-cells are early drivers synovial inflammation RA, therefore, identification pathogenic T-cell subsets at the tissue pre-RA, arthralgia subjects, would greatly improve our understanding disease pathogenesis. Comparative analysis healthy control, subject and RA-patient derived responses will lead to as well protective cytokine milieu, thus enabling therapeutic targets help steer immune response towards resolution. Objectives: Characterization polyfunctionality in periphery ’at-risk; subjects (Arthralgia) RA-patients controls (HC). Identification specific, pathogenic, subsets. Methods: Synovial biopsies from AR HC were obtained by arthroscopic surgery followed RNAseq (Guo et al., PLoS One, 2018). Single cell suspensions paired PBMC stimulated vitro polyfunctional examined flow cytometric analysis, SPICE visualization FlowSom clustering. Flow-Imaging, was utilised confirm specific cluster identification. Fluorescent Lifetime Imaging Microscopy (FLIM) used visualise metabolic status populations. Results: associated pro-inflammatory gene pathways increased compared biopsies. Flow (TNF-α, IFN-γ, IL-2, GM-CSF, IL-17A, IL-22) production ex vivo revealed marked T-cells, providing evidence for dysregulated that pre-dates clinical onset disease. Importantly, harbours small, albeit surprisingly polyfunctional, CD4 population characterised significantly IL-4 GM-CSF (P<0.001 P=0.01) P=0.004) tissue. However, not all equal their potential. Therefore, order identify highly data using unsupervised algorithm performed led clusters with unique characteristics. Specifically + CD8 double positive (DP) high scores identified. Hybrid cytometry imaging technique confirmed co-expression population. DP enriched fluid tissue, but absent accumulation strongly (P=0.002) correlates DAS28(CRP) RA-patients. Initial studies utilising novel, non-invasive FLIM visualisation cellular NAD, have profile indicative activated memory T-cells. Conclusion: These highlight key loss balance between emergence RA. Figure 1. . A. Cluster (asterisks indicate clusters). B. , C. D. Correlation frequency severity. Disclosure Interests: Achilleas Floudas: None declared, Nuno Neto: Mary Canavan: Trudy McGarry Employee of: Novartis, Vinod Krishna Janssen, Sunil Nagpal GSK, Michael Monaghan: Douglas Veale Speakers bureau: Abbvie, MSD, Pfizer, UCB, Consultant Grant/research support from: Ursula Fearon UCB.