Soluble L-selectin in the connective tissue diseases.

Plasma levels of the leucocyte adhesion molecule L-selectin were measured by ELISA in 41 patients with rheumatoid arthritis, 18 with ankylosing spondylitis, 18 with systemic sclerosis and 27 with vasculitis together with 42 age- and sex-matched controls. Low levels of soluble L-selectin were found in systemic sclerosis (797 +/- 302 ng/ml, P < 0.05) and vasculitis (941 +/- 329 ng/ml, P < 0.05) relative to controls (1244 +/- 269 ng/ml). The exact reasons for low levels of soluble L-selectin are unclear, but may reflect reduced shedding from leucocytes and/or strong binding to its cell membrane ligand(s). An approximate inverse relationship between soluble L-selectin and disease severity may have clinical relevance.