AB0056 Measurement of the pro-coagulant activity of microparticles in patients with inflammatory rheumatic diseases: prospective study

Abstract

BackgroundMicroparticles (MPs) are small membrane-bound vesicles that arise from activated and dying cells. Although the majority of MPs in the blood originate from platelets, all cells appear to be able to release MPs. Many studies have raised the implication of these MP in various processes: inflammation, thrombosis, angiogenesis. Previous studies reported inconsistent results in inflammatory rheumatic diseases. Studies have shown the correlation between the circulating MPs, platelet MPs and lymphocyte MPs in patients with spondyloarthritis (SpA) compared to control patients. For rheumatoid arthritis (RA), platelet MPs levels were correlated with DAS28.ObjectivesThe aim of this study was to search a possible correlation between the disease activity and the pro-coagulant property of microparticles, potential indirect marker of inflammation.MethodsThe test used (STA Procoag PPL) is a standardised automated test. Results are expressed as coagulation times (in seconds). It is a functional test that provides information on the procoagulant potential of microparticles. The microparticles supply the phospholipids expressed on their membrane surface and the test provides calcium and factor Xa necessary to initiate coagulation: the shorter the coagulation time the greater the procoagulant activity of the phospholipids being studied, suggesting a higher number of MP.This is a prospective, single-centre study, including 39 patients with spondyloarthritis (ASAS criteria), 37 with rheumatoid arthritis (ACR criteria) and 26 control patients (healthy subjects, osteoarthritis). All patients underwent STA Procoag PPL test, and we collected medical data: disease activity (BASDAI, BASFI, DAS28vs and DAS28crp and HAQ), biological inflammation (VS, CRP), duration of disease, and current treatment.ResultsThe in vitro clotting time of serum of patients with spondyloarthritis and rheumatoid arthritis compared with controls was not significantly different (p=0.23 and p=0.44, respectively). Regarding the activity scores of inflammatory rheumatic disease: BASDAI and BASFI, DAS28esr, DAS28crp and HAQ for patients with RA, no correlation between these data and coagulation time was found; the same goes for biological inflammation (ESR, CRP), duration and type of treatment (Nonsteroidal anti-inflammatory drugs, DMARDs, biologics).Abstract AB0056 – Table 1STA PPLControls (n=26)SpA (n=39)pRA (n=37)p Mean±SD62,70±11,5866,48±12,77p=0,2365,25±13,54p=0,44 BASDAIr=0,0602 p=0,72DAS28 esrr=0230 p=0,17BASFIr=-0,125 p=0,45DAS28 crpr=0151 p=0,37ConclusionsIn this study, there is neither difference in values of procoagulant activity of MPs between inflammatory rheumatic diseases and control subjects, nor correlation with their activity scores or biological inflammation.Disclosure of InterestNone declared