AB0172 ANTI-MITOFUSIN-1 AND THROMBOSPONDIN-1 AS POTENTIAL MARKERS FOR POLYMYALGIA RHEUMATICA

Background Polymyalgia rheumatica (PMR) is a chronic, inflammatory disorder characterized by aching and stiffness in the proximal regions of extremities elevated markers inflammation. PMR giant cell arteritis (GCA) are two conditions frequently coexisting [1,2], with increased incidence large vessel vasculitis aneurysm development found at long term follow-up. Furthermore, can be one manifestations GCA 20-40% cases [3]. The etiology diseases still largely unknown, specific serological markers, including to monitor arterial disease, lacking. Recent studies have shown that mitochondrial dysfunction may play central role immune activation could act as potential source antigens, mitofusin-1 (MFN1), autoimmune [4,5,6]. Objectives To determine whether patients PMR, or without overlapping GCA, levels platelet (e.g. thrombospondin-1; TSP-1), autoantibodies anti-MFN1). Methods Plasma anti-MFN-1 IgG TSP-1 were measured healthy controls (HC) (n=30) (n=60), before after treatment glucocorticoids using in-house commercial ELISAs, respectively. Results compared HC, both corticosteroids (p<0.001). highest Co-existence did not affect either anti-MFN1 TSP-1, nor response corticosteroids. Elevated significantly symptoms from hips/glutes (n=39) these (n=13), median (P25-P75) 27.11 ug/mL (22.5-35.0) vs 19.6 (14.1-27.9), p=0.046. Lower concentration was spine (n=31) comparison those (n=21), 0.37 U/mL (0.27-0.57) 0.54 (0.47-0.96), p=0.043. Conclusion Increased decreased corticosteroids, although higher than HC. individuals hips/glutes. concentrations suggested novel biomarkers for further, serve response. References [1]Michet CJ, Matteson EL. rheumatica. BMJ. 2008 Apr 5;336(7647):765-9. [2]Brooks RC, McGee SR. Diagnostic dilemmas polymyalgia Arch Intern Med. 1997 Jan 27;157(2):162-8. [3]Dejaco C et al. spectrum rheumatica: revisiting concept disease. Rheumatology (Oxford). 2017 1;56(4):506-515. [4]Clayton SA Mitochondria Key Players Pathogenesis Treatment Rheumatoid Arthritis. Front Immunol. 2021 29;12:673916. [5]Barrera MJ Dysfunctional mitochondria critical players inflammation diseases: Potential Sjögren’s syndrome. Autoimmun Rev. Aug;20(8):102867. [6]Becker YLC Identification Mitofusin 1 Complement Component 1q Subcomponent Binding Protein Mitochondrial Targets Systemic Lupus Erythematosus. Arthritis Rheumatol. 2022 Jul;74(7):1193-1203. Acknowledgements: NIL. Disclosure Interests Linda Johansson: None declared, Despina Michailidou Consultant of: Advisory Board fees ChemoCentryx., Grant/research support from: NIH grant award #5T32HL007028-44., Solbritt Rantapää Dahlqvist: Christian Lood board Redd Pharma., Receives research funding Eli Lilly, Gilead Sciences, Boehringer Ingelheim, Pharma, Amytryx, Horizon Pfizer, Bristol Meyers Squibb.