THU0005 PTX3 AS A UNIVERSAL MARKER OF VASCULAR INFLAMMATION IN MULTIPLE IMMUNE-MEDIATED DISEASES
Authors: Giuseppe Alvise Ramirez, Enrico Tombetti, Patrizia Rovere-Querini, Miriam Blasi, Mattia Baldini, Rebecca De Lorenzo, Enrica Bozzolo, Roberto Leone, Alessandro Ambrosi, Alberto Mantovani, Angelo Manfredi
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Pentraxin-3 (PTX3) is a prototypic innate humoral pattern recognition receptor with a multi-functional role in tissue homeostasis from host defence to fertility, cancer biology, autoimmunity, regulation of angiogenesis and tissue repair. PTX3 is selectively expressed at sites of inflammation and rises in the circulating blood during disease activity in many (but not all) immune-mediated inflammatory conditions. Research on PTX3 as a biomarker has so far focused on single diseases. <h3>Objectives</h3> To identify correlations among PTX3 elevation in plasma and clinical and pathophysiological phenotypes in multiple immune-mediated diseases. <h3>Methods</h3> Three-hundred-sixty-six subjects encompassing 79 healthy controls and 287 patients with autoimmune diseases were enrolled. Autoimmune diseases included systemic lupus erythematosus (SLE, n=55), rheumatoid arthritis (RA, n=21), polymyalgia rheumatica (PMR, n=10), ANCA-associated vasculitides (AAV, n=63), giant cell arteritis (GCA, n=96) and Takayasu's arteritis (TA, n=42). Plasma PTX3 concentrations were measured by ELISA. Basic demographics (including gender, age at sampling and disease duration), disease activity and accrued irreversible damage, dose of prednisone or equivalents, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values at time of sampling were recorded. Disease activity and damage scores were made homogeneous by calculating Z-scores (i.e. (x-mean)/(standard deviation): Z-activity and Z-damage). <h3>Results</h3> Patients with SLE, AAV, TA and GCA, but not patients with RA and PMR, had higher PTX3 levels than HC (2.33 ng/ml, IQR: 1.26-4.89 vs 1.22 ng/ml, IQR: 0.80-1.98; p&lt;0.001). PTX3 concentration correlated with Z-activity (p=0.016), ESR and CRP (p&lt;0.001 and p=0.035 respectively) and prednisone dose (p=0.001). It was higher in females (p=0.018), in patients with disease onset within 6 months from sampling (p=0.041) and in those with previous or current active vasculitis (both p&lt;0.001) at univariate analysis. Active small-(B=6.706, Std.Err=1.473, p&lt;0.001), or large- vessel vasculitis (B=4.269, Std.Err=0.844, p=0.008) were the main independent variables influencing PTX3 levels at multivariate analysis. <h3>Conclusion</h3> High levels of PTX3 in the blood can contribute to identify an increased risk of vascular involvement in patients with systemic immune-mediated diseases. <h3>References</h3> [1] Erreni M, et al. Immunological reviews. 2017 [2] Ramirez GA, et al. Arthritis research &amp; therapy. 2015 [3] Rovere P, et al. Blood. 2000 <h3>Disclosure of Interests</h3> Giuseppe Alvise Ramirez: None declared, Enrico Tombetti: None declared, Patrizia Rovere-Querini Grant/research support from: Adienne Pharma &amp; Biotech, Miriam Blasi: None declared, Mattia Baldini: None declared, Rebecca De Lorenzo Grant/research support from: Adienne Pharma &amp; Biotech, Enrica Bozzolo: None declared, Roberto Leone: None declared, Alessandro Ambrosi: None declared, Alberto Mantovani: None declared, Angelo Manfredi: None declared