POS0593 THE REDUCTION OF RETINAL MICROVASCULAR ALTERATIONS AND THE DECREASE OF A POTENTIALLY RELATED T-CELL SUBSET IN PATIENTS WITH ACTIVE RHEUMATOID ARTHRITIS TREATED WITH ABATACEPT

Abstract

Background:T-cells play a pivotal role in the pathogenesis of rheumatoid arthritis (RA) and in its cardiovascular (CV) comorbidities, acting at microvascular level [1]. Since small artery remodeling is the earliest form of target organ damage in hypertension, the evaluation of microvascular alterations might provide clinically useful information. The evaluation of retinal arterioles is a non-invasive technique to identify a precocious microvascular damage, which is related to an increase of the wall-to-lumen ratio (WLR) [2]. CD3+CD31+CXCR4+ T-cells may be involved in damaged endothelium repair and are increased in patients with morphological microvascular alterations [3]. In addition to its effect on disease activity, abatacept (ABA), a co-stimulator blocker which is approved for the treatment of RA, may have specific CV protective action, modulating the numbers of certain subtypes of lymphocytes [4].Objectives:To non-invasively investigate morphological characteristics of retinal arterioles and to evaluate CD3+CD31+CXCR4+T-cells in a cohort of RA patients treated with ABA.Methods:Eleven RA patients [median (25th-75thpercentile) age=58 (50-65) years, baseline C-reactive protein (CRP)-DAS28=4.4 (3.8-4.6), body mass index (BMI)=23.4 (21.6-25.6) kg/m2, rheumatoid factor (RF) positive:45%, anti-citrullinated peptide autoantibodies (ACPA) positive:73%] without known CV risk factors (arterial hypertension, diabetes, hypercholesterolemia, previous CV events, smoking) were evaluated by adaptive optics, a validated technique quantifying microvascular damage [5], before and every 6 months of therapy with ABA (T0, T6 and T12). Phenotypic analysis of peripheral blood T lymphocytes was made by flow-cytometry in 5 patients of the cohort at T0 and T6.Results:A progressive significant reduction of the WLR of retinal arterioles was observed [T0=0.28 (0.25-0.30), T6=0.27 (0.24-0.31), T12=0.23 (0.23-0.26); p T0 vs T6=0.4; p T6 vs T12=0.01; p T0 vs T12=0.01] (Figure 1), without significant variations in the other parameters [internal diameter: T0=94.4 (84.1-104.0), T6=94.8 (84.6-107.7), T12=99.2 (89.1-109.1) µm; external diameter: T0=125.8 (111.1-131.0), T6=122.4 (109.1-134.5), T12=125.6 (113.9-134.4) µm; wall thickness: T0=13.2 (12.2-14.4), T6=13.4 (11.7-14.4), T12=12.5 (11.6-13.0) µm; wall cross-sectional area: T0=4581.0 (3788.7-5263.7), T6=4563.3 (3788.5-5295.2), T12=4099.7 (3899.0-5145.7) µm2)]. In 5 patients evaluated also for T-cell immunophenotyping a negative correlation was observed between CD3+CD31+CXCR4+ T-cell number and the retinal wall thickness at baseline (R=0.871;p=0.05). After ABA therapy a trend for reduction of CD3+CD31+CXCR4+T-cells [19.0 (13.8-38.3) vs 12.4 (5.2-18.0) % of CD3+], was observed as well as of significant reduction of retinal wall cross-sectional area [5123.3 (4385.0-5470.3) vs 4852.3 (4118.3-5228.0) µm2;p=0.04].Conclusion:In a cohort of RA patients without known CV risk factors, a reduction in retinal microvascular alterations arterioles was demonstrated after treatment for 12 months with ABA. CD3+CD31+CXCR4+T-cell number was inversely related to the possible presence of subclinical CV involvement. These results may suggest the possibility of microvascular abnormalities regression induced by the immune system modulation.