Role of interleukin-4 and vascular cell adhesion molecule-1 in selective eosinophil migration into the airways in allergic asthma.

Recent in vitro studies have suggested that interleukin-4 (IL-4) may be involved in the preferential migration of eosinophils into the airways in allergic asthma through its capacity to selectively increase vascular cell adhesion molecule-1 (VCAM-1) expression on vessels. To test this hypothesis, we studied the expression of VCAM-1, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) on vascular endothelium in bronchial mucosal biopsies from 20 allergic asthmatics using an immunohistochemistry technique and related the observations to IL-4 levels in bronchoalveolar lavage (BAL) fluid simultaneously obtained and to eosinophil infiltration in the bronchial mucosa. IL-4 was detectable in BAL fluid from nine subjects (range, 15.1 to 110 pg/ml in 20-fold concentrated BAL fluid) (IL-4-positive asthmatics) but unmeasurable in the remaining 11 subjects (IL-4-negative asthmatics). The IL-4-positive asthmatics showed a significantly increased expression of VCAM-1 but not E-selectin and ICAM-1 on vessels as c...