Enhanced Production and Gene Expression of lnterleukin-5 in Patients with Bronchial Asthma: Possible Management of Atopic Diseases by Down-Regulation of lnterleukin-5 Gene Transcription

Interleukin (IL)-5 was produced in vitro by peripheral blood mononuclear cells (PBMCs) of mite-sensitive atopic patients upon challenge with specific allergen, while PBMCs of healthy controls produced essentially no IL-5. Stimuli delivered by the combination of phorbol ester (PMA) and CA2+ ionophore (ionomycin) induced marked IL-5 production by PBMCs obtained from atopic as well as nonatopic asthmatics. CD2- or CD4-bearing-cell depletion almost completely removed IL-5 production and gene transcription while CD8 depletion did not. These findings indicated that CD4+ T cells are the principal source of IL-5 in asthmatic PBMCs. The capacity of PBMCs of atopic asthmatics, nonatopic asthmatics and healthy controls to produce IL-2, IL-3, IL-4, interferon-gamma and granulocyte/macrophage-colony-stimulating factor was comparable among the three groups. FK506 suppressed IL-5 production and gene expression in vitro in a dose-dependent manner.