Elevated serum L-selectin levels and decreased L-selectin expression on CD8(+) lymphocytes in systemic sclerosis

L-selectin is expressed on most circulating leucocytes and mediates leucocyte rolling on endothelium at sites of inflammation. Following rolling or activation of leucocytes, cell surface L-selectin is released as soluble L-selectin (sL-selectin). In the present study, we assessed serum levels of sL-selectin by ELISA and blood leucocyte L-selectin expression by flow cytometry in patients with systemic sclerosis (SSc). Serum levels of sL-selectin in patients with SSc (n = 51) were significantly higher than in normal controls (n = 30) while sL-selectin levels were similar for systemic lupus erythematosus patients (n = 20) and normal controls. Furthermore, SSc patients with elevated sL-selectin levels had inflammatory joint involvement, pitting scar/ulcers, and diffuse pigmentation more frequently than those with normal sL-selectin levels. The frequency of L-selectin(+) population among CD8(+) T cells was significantly decreased in SSc patients (n = 30) compared with normal controls (n = 20), while that among CD4(+) T cells, B cells, monocytes, and neutrophils was similar for SSc patients and normal controls. These suggest that elevated sL-selectin levels and decreased frequency of L-selectin+ CD8(+) T cells in SSc patients may be involved in inflammation associated with SSc.