Elevated serum L-selectin levels and abnormal regulation of L-selectin expression on leukocytes in atopic dermatitis: Soluble L-selectin levels indicate disease severity

Abstract

Background: L-selectin mediates leukocyte rolling on endothelium at sites of inflammation, suggesting that L-selectin may be involved in the development of cutaneous lesions of atopic dermatitis (AD). After leukocyte activation, L-selectin is rapidly shed from the cell surface. Objective: The purpose of this study was to assess leukocyte L-selectin expression and quantitate levels of serum soluble L-selectin (sL-selectin) in patients with AD. Methods: Serum sL-selectin levels in patients with AD (n = 70), contact dermatitis (n = 18), and psoriasis (n = 23), as well as normal control subjects (n = 30), were examined by using an ELISA. The L-selectin expression on leukocytes in heparinized blood samples from patients with AD (n = 18) and normal control subjects (n = 10) was also examined by flow cytometry. Results: Serum levels of sL-selectin in patients with AD were significantly higher than those found in normal control subjects. Furthermore, sL-selectin levels correlated positively with disease severity and total serum IgE levels in AD. The expression of L-selectin on B cells, monocytes, and neutrophils was significantly decreased in patients with AD compared with normal control subjects, although those on CD4 + or CD8 + T cells from patients with AD were similar to those from normal control subjects. Conclusion: Elevated sL-selectin levels and the abnormal expression of L-selectin on some leukocyte subsets in patients with AD may correlate with inflammation associated with AD. Furthermore, the level of sL-selectin may be a useful immunologic indicator for disease activity in AD. (J Allergy Clin Immunol 1999;104:163-8.)