OP0052 Microparticles as potential biomarkers of disease activity in anti-neutrophil cytoplasmic antibody – associated vasculitis. (12th June 2018)

• Record Type: Journal Article
• Authors: Antovic, A.; Kostic, M.; Mobarrez, F.; Nordin, A.; Vojinovic, J.; Bruchfeld, A.; Gunnarsson, I.
• Is Part Of: Annals of the rheumatic diseases. Volume 77(2018)Supplement 2
• Page Start: 77
• Page End: 77
• Publication Date: 2018-06-12
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2018-eular.5465
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background: Microparticles (MPs) are submicron particles, which are released from plasma membrane upon cell activation and during the early phase of apoptosis. Increased levels of circulating MPs, mainly of endothelial cell origin, but also platelet derived, have been shown to correlate with autoinflammatory disease activity, such as anti-neutrophil cytoplasm antibody (ANCA) – associated vasculitis (AAV). Objectives: The aim was to evaluate levels of activity markers expressed on MPs from patients with AAV, during active disease and remission, compared to healthy control subjects. Methods: Our study included 46 AAV patients and 23 healthy age and gender matched control subjects. We analysed the concentration of MPs in plasma by flow cytometry. MPs were phenotyped by expression: CD142 (tissue factor-TF), anti-H3cit (citrulinated Histone 3 directed against neutrophil extracellular traps – NETs), anti-pentraxin3 (pentraxin3), HMGB1 (high mobility group box 1 protein-HMGB1), anti-TWEAK (tumour necrosis factor-like weak inducer of apoptosis-TWEAK), anti-plasminogen (plasminogen), anti-C3a (C3a) and anti-C5a (C5a). The assessment of vasculitis disease activity was performed using the Birmingham Vasculitis Activity Score (BVAS), where active disease was defined as BVAS ≥1 and inactive (remission) as BVAS=0. Results: Half of the patients group 23 had active vasculitis (13 male/10 female, mean age 61±14 years) and 23 had inactive disease (12 male/11 female, mean age 64±13 years). Concentration of MPs expressing TF, H3cit, pentraxin-3 and HMGB1 in active patients were significantly higher than in those in remission and healthy controls (p<0.01, p<0.0001, respectively). MPs expressing C5a and C3a were significantly higher in both active and inactive patients compared to controls (p<0.001). Additionally, levels of MPs expressing C5a and C3a strongly correlated with BVAS in patients with active disease (r=0.78, p<0.0001; r=0.5, p<0.01, respectively), while there was no significant correlation between other explored markers and BVAS. Conclusions: Our results support recently postulated role of the complement system in AAV pathogenesis and disease activity. Evaluated proteins expressed on MPs, especially C5a and C3a, could be used as potential biomarkers which might reflect inflammation and disease activity in AAV patients. Further investigations are necessary to confirm our preliminary results and to validate the most promising biomarker in AAV. Disclosure of Interest: None declared