Serum-soluble selectin levels in patients with rheumatoid arthritis and systemic sclerosis

Soluble forms of selectins may play a regulatory role in inflammatory responses that are key to the pathophysiology of rheumatic diseases such as rheumatoid arthritis (RA) and systemic sclerosis (SSc). The aim of this study was to examine whether the elevated serum-soluble (s) selectin levels are associated with RA or SSc. Serum sE-, sL- and sP-selectin levels were measured by sandwich enzyme-linked immunosorbent assay in 34 RA patients, 30 SSc patients and 16 healthy subjects. The levels of sE-selectin were significantly higher in RA and SSc patients than those in healthy subjects. The sL-selectin level was significantly lower in RA patients compared to healthy subjects. Serum sP-selectin levels were not significantly different among the study groups. The active RA patients had significantly higher serum sE- and sL-selectin levels compared to inactive RA patients. Also, some correlations were observed between the serum selectin levels and measures of disease activity such as erythrocyte sedimentation rate and C-reactive protein in RA patients. The higher levels of sE-selectin were found in SSc patients with pulmonary fibrosis, and there was also a negative correlation between diffusion capacity for carbon monoxide and serum sE-selectin. Serum levels of selectins may provide a useful additional marker for disease activity in RA patients and for disease severity in SSc patients.