Elevated serum levels of soluble CD146 in patients with systemic sclerosis.

CD146, a transmembrane glycoprotein member of the immunoglobulin superfamily, acts as an adhesion molecule that helps maintain the cell monolayer. Human endothelial cells expressing CD146 are involved in angiogenesis and inflammation. Recently, we developed a sandwich ELISA for detecting soluble CD146 (sCD146) in human serum specimens. The aim of this study is to determine serum levels of sCD146 in patients with systemic sclerosis (SSc) and to examine the relationship between sCD146 levels and clinical manifestations. We quantified serum sCD146 levels in 47 serum samples from patients fulfilling criteria for SSc, 23 serum samples from patients fulfilling criteria for rheumatoid arthritis (RA), and 25 healthy controls. We also investigated the relationship between sCD146 levels and various clinical characteristics with SSc patients. Levels of sCD146 were significantly higher in the 47 patients with SSc than in the 25 healthy controls and 23 patients with RA (12.50 vs. 6.91 vs. 9.95 ng/ml; p < 0.001). Serum sCD146 levels in SSc patients with pulmonary arterial hypertension (PAH) were lower than in SSc patients without PAH (10.12 vs.13.17 ng/ml; p < 0.01). The serum levels of sCD146 were elevated in patients with SSc. However, decreased sCD146 levels were observed in SSc patients with PAH. Further studies are necessary to elucidate the sources and the mechanisms.