Expression of adhesion molecules on mononuclear cells from individuals with stable atopic asthma

Activated mononuclear cells (lymphocytes and monocytes) (MNCs) circulate in peripheral blood and accumulate in the airways of individuals with steady-state asthma. The expression of adhesion molecules on MNCs of 10 patients with steady-state atopic asthma and 10 non-atopic control subjects was measured by flow cytometry. The mean fluorescence intensity of CD23 (P = 0.0003), CD11a (P = 0.034), and very late antigen-4 (VLA-4) (P = 0.016) was increased on lymphocytes of asthmatic patients relative to those of controls. Although the expression of CD16 (P = 0.002) and CD23 (P = 0.002), which are associated with differentiation into macrophages, was increased on monocytes of patients relative to those of controls, monocyte expression of VLA-4 (P = 0.006) and sialyl Lewis x (P = 0.005) was reduced. The concentration of interleukin-4 (IL-4) in serum was significantly higher in asthmatic patients than in normal subjects (P = 0.023), and a significant correlation was apparent between the serum concentration of IL-4 and the expression of VLA-4 on lymphocytes (p = 0.71, P = 0.03) or on monocytes (p = -0.72, P = 0.03) in asthmatic patients. Results suggest that IL-4 may contribute to the priming of adhesion molecule expression on lymphocytes even in steady-state conditions in individuals with chronic allergic inflammation.