EXPRESSION OF CD44 AND INTEGRINS IN BRONCHIAL-MUCOSA OF NORMAL AND MILDLY ASTHMATIC SUBJECTS

We have investigated the expression of cell surface markers and leucoc yte cell adhesion molecules by immunohistochemistry in bronchial biops ies from 10 mild atopic asthmatics and 8 normal, nonatopic subjects. S ignificantly increased numbers of eosinophils (p<0.01) were evident in the bronchial submucosa of asthmatic subjects, In epithelium there we re more CD44+ (p<0.02) and lymphocyte function-associated antigen-1 (L FA-1)+ (p<0.06) leucocytes in asthmatics than in normal subjects, Bron chial epithelial cells stained positively with anti-CD44 monoclonal an tibodies (moAb) in both groups; however, when the staining was express ed as percentage of the total basement membrane, a considerable and hi ghly significant increase was observed in the asthmatics (median an 80 vs 22%, p=0.003). Few leucocytes were positive for very late activati on antigen (VLA)-1, VLA-2 and VLA-4, The moAb for VLA-6 stained the ba sement membrane of the bronchial epithelium; while intracellular adhes ion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were constitutively expressed in endothelium. A positive correlation was found between LFA-1+ cells and activated eosinophils (EG2+) in the submucosa (p<0.005; r(s)=0.80). We conclude that even in mild asthma there is evidence of increased expression of cell surface ligands, and suggest that adhesive mechanisms play a role both in cell recruitment and disease activity.