Ab0165 biomarkers associated with giant cell arteritis in patients with polymyalgia rheumatica features

Background Polymyalgia Rheumatica (PMR) is a frequent inflammatory rheumatism associated with giant cell arteritis (GCA) in 16-21% of cases. GCA is characterised by large vessel vasculitis which is absent in isolated PMR [1]. The identification of serum biomarkers reflecting vascular involvement could allow the selection of PMR patients in whom further investigations are indicated to confirm or rule out GCA. Objectives This study aimed to identify serum biomarkers associated with GCA in a population of patients with PMR features. Methods Patients were prospectively enrolled in Dijon University Hospital, France. At inclusion, no patient had yet received glucocorticoids or immunosuppressive treatment. All PMR patients fulfilled 2012 ACR/EULAR classification criteria [2] and GCA was ruled out by at least an exam evaluating temporal arteries (biopsy and/or color doppler ultrasound) and another evaluating large vessels (angio-CT or FDG-PET/CT). All GCA patients fulfilled the 2022 ACR/EULAR classification criteria [3]. Usual clinical, biological, and therapeutic data were recorded at diagnosis. Several serum biomarkers were measured by Luminex assays: CD141, CD146, CD31, ICAM-1, VCAM-1, ANGPTL-4, ANGPTL-6, and C3L1. Student t test or Mann-Whitney test were performed to compare data, as appropriate. The significance threshold was set at P<0.05 (two-tailed). Analyses were performed with Graphpad PRISM software. Results Fifty patients with PMR without GCA (isolated PMR) and 33 patients with PMR and GCA overlap were included. In PMR/GCA overlap patients, 14 (42.4%) had aortitis. Serum level of CD141 was significantly higher in the PMR/GCA overlap group in comparison to isolated PMR group (mean = 6854 pg/mL vs. 5558 pg/mL, p = 0.003). The area under cover (AUC) was 0.68 (CI95%: 0.56; 0.80). No differences were found regarding serum levels of ANGPTL-4 (p = 0.39), ANGPTL-6 (p = 0.22), CD31 (p = 0.74), CD146 (p = 0.35), C3L1 (p = 0.75), ICAM-1 (p = 0.94) and VCAM-1 (p = 0.52) between PMR without GCA and PMR/GCA overlap. Likewise, no significant differences were found for the usual markers of inflammation between both groups: ESR (p = 0.22), CRP (p = 0.39) or fibrinogen (p = 0.92). Comparison between PMR without GCA and PMR/GCA overlap with aortitis found higher level of ANGPTL-4 and ANGPTL-6 in isolated PMR patients (median = 160.7 ng/mL vs. 128.9 ng/mL [p = 0.04] and 4.3 ng/mL vs. 3.1 ng/mL [p = 0.02], respectively). CD141 was positively correlated with CD146 (r =0.48; p < 0.001) and VCAM-1 (r = 0.34; p = 0.001). VCAM-1 was positively correlated with CD141 (r = 0.34; p = 0.001), C3L1 (r = 0.35; p = 0.001) and ANGPTL-4 (r = 0.47; p < 0.001) Conclusion This study found lower serum concentrations of CD141 in PMR patients without GCA versus those having PMR and GCA overlap. However, the diagnostic performance of CD141 does not appear to be sufficiently discriminative to rule out GCA in PMR patients. ANGPTL-4 and ANGPTL-6 could be interesting serum biomarkers to detect aortitis in patients with PMR features. The study of other biomarkers reflecting endothelial aggression during GCA is needed with larger patients’ cohorts. References [1]Buttgereit F, Dejaco C, Matteson EL, Dasgupta B. Polymyalgia Rheumatica and Giant Cell Arteritis: A Systematic Review. JAMA 2016;315:2442–58. [2]Dasgupta B, Cimmino MA, Maradit-Kremers H, Schmidt WA, Schirmer M, Salvarani C, et al. 2012 provisional classification criteria for polymyalgia rheumatica: a European League Against Rheumatism/American College of Rheumatology collaborative initiative. Ann. Rheum. Dis. 2012;71:484–92. [3]Ponte C, Grayson PC, Robson JC, Suppiah R, Gribbons KB, Judge A, et al. 2022 American College of Rheumatology/EULAR classification criteria for giant cell arteritis. Ann Rheum Dis 2022;81:1647–53. Acknowledgements: NIL. Disclosure of Interests None Declared.