Circulating microparticles and plasma levels of soluble E- and P-selectins in patients with systemic sclerosis.

Objectives: Microparticles (MPs) may be involved in the pathogenesis of systemic sclerosis (SSc), which includes vasculopathy, endothelial cell activation, and coagulation activation. Circulating MPs from SSc patients were characterized and their relationship with soluble markers of vascular activation investigated.Method: This study included 121 SSc patients [79 with limited (lcSSc) and 42 with diffuse cutaneous SSc (dcSSc)] and 49 sex- and age-matched healthy controls (HCs). The MPs were characterized by flow cytometry for annexin V (AnxV)-binding capacity and their expression of surface markers of platelets (PMPs), leucocytes (LMPs), or endothelial cells (EMPs). Plasma levels of soluble (s) E- and P-selectins were determined by enzyme-linked immunosorbent assay (ELISA).Results: The total concentrations of MPs and of PMPs, LMPs, and EMPs were 22−42% lower in SSc patients than in HCs (p < 0.001). However, within the cell-derived MP pool, a 47% higher fraction of AnxV non-binding MPs (F-AnxV− MPs) was fou...