AB0219 BIOMARKER EXPRESSION IN MONOCYTE SUBPOPULATIONS IN SSC PATIENTS
Authors: Laiana Schneider, Natalia Marcondes, Vanessa Hax, Isadora Moreira, Carolina Yuka, Rafaella Romeiro, Ricardo Xavier, Rafael Chakr
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by vasculopathy and fibrosis, which can be classified into diffuse cutaneous (dSSc) and limited cutaneous (lSSc) subtypes. Monocytes are key agents in the pathophysiology of systemic autoimmune diseases, including systemic sclerosis (SSc). M1 cells (CD14++CD16-) represent a predominantly pro-inflammatory phenotype and M2 cells (CD14-/+CD16+/++) are more associated to an regulatory/pro-fibrotic phenotype. <h3>Objectives</h3> Our aim was to evaluate circulating blood monocyte subpopulations [classical (M1), intermediate and non-classical (M2)] and analyze the expression of CD163, CD169, CD206 and HLA-DR (function and activation monocytes receptors). <h3>Methods</h3> Fifty consecutive patients fulfilling the 2013 ACR/EULAR classification criteria for SSc were included in a cross-sectional study. Monocyte subpopulations were identified and characterized according to the expression of CD64, CD16, CD14, CD163, CD169, CD206 and HLA-DR. Thirty-eight age- and sex-matched healthy individuals were recruited as a control group. <h3>Results</h3> SSc patients mean age was 57.2 ± 12.8 years (HC 55.2 ± 11.4) and 94% were female. Limited form of disease was present in 72% of SSc patients and. SSc patients had an increased number of circulating peripheral blood monocytes compared to healthy subjects (table 1). Absolute counts of CD16+ (intermediary and non-classical) monocyte subpopulations were higher in SSc patients compared to HC [79.9 (53.4-103.5)/mm<sup>3</sup> vs. 55.9 (26.8-85.8)/mm<sup>3</sup>, p=0.003]. HLA-DR intensity of expression was higher in all monocyte subsets from lSSc and dSSc patients when compared to control. There was a higher percentage of classical [1.56 (0.84-2.98) vs. 0.68 (0.37-1.88); p=0.003]and intermediate monocytes [15.9 (9.5-29.9) vs. 6.1 (3.7-11.5); p&lt;0.001] with CD206 expression in SSc patients compared to HC, and a higher percentage of CD169 expression in dSSc patients compared to control and lSSc groups (p&lt;0.01). <h3>Conclusion</h3> In our study, SSc patients show greater monocytes counts than HC with a predominantly regulatory/pro-fibrotic phenotype (M2). dSSc seems to be more associated to CD169 than lSSc. <h3>References</h3> [1] Trombetta AC, Soldano S, Contini P, Tomatis V, Ruaro B, Paolino S, et al. A circulating cell population showing both M1 and M2 monocyte/macrophage surface markers characterizes systemic sclerosis patients with lung involvement. Respir Res. 2018. [2] Lescoat A, Lecureur V, Roussel M, Sunnaram BL, Ballerie A, Coiffier G, et al. CD16-positive circulating monocytes and fibrotic manifestations of systemic sclerosis. Clin Rheumatol. 2017. <h3>Disclosure of Interests</h3> Laiana Schneider: None declared, Natalia Marcondes: None declared, Vanessa Hax: None declared, Isadora Moreira: None declared, carolina yuka: None declared, rafaella romeiro: None declared, Ricardo Xavier Consultant for: Abbvie, Pfizer, Novartis, Janssen, Lilly, Roche, Rafael Chakr: None declared