IDENTIFICATION OF IL-5 AND RANTES AS THE MAJOR EOSINOPHIL CHEMOATTRACTANTS IN THE ASTHMATIC LUNG

The study was carried out to identify those molecules that are importa nt in vivo in the attraction of eosinophil granulocytes to the lungs o f patients with asthma. Asthmatic patients with birch pollen allergy h ad lavages performed before and during the pollen season, and the chem otactic activity of the bronchoalveolar lavage fluid was tested agains t normal eosinophils. The activity was significantly increased during the pollen season as compared with the activity before the pollen seas on (p < 0.01). Neutralizing antibodies to IL-2, IL-5 and IL-8, leukemi a inhibitory factor, and to RANTES were added to the bronchoalveolar l avage fluid. Antibodies to IL-5 and RANTES, but not to IL-2 and IL-8 o r leukemia inhibitory factor, significantly inhibited the chemotactic activity for eosinophils (p < 0.001). It is concluded that IL-5 and RA NTES are important chemoattractants in the lungs of patients with alle rgic asthma. The effect of IL-5 may be that of a cofactor to the chemo tactic molecules, of which RANTES may be one of the most important in allergic asthma.