IL-5 SECRETION BY ALLERGEN-STIMULATED CD4-CELLS IN PRIMARY CULTURE - RELATIONSHIP TO EXPRESSION OF ALLERGIC DISEASE( T)

Background: IL-5-producing allergen-specific T cells are thought to pl ay a prominent role in the pathogenesis of allergic inflammation, We h ypothesized that T cell allergen-driven IL-5 synthesis is elevated in patients with atopic disease as compared with that in atopic patients free of disease and nonatopic control subjects. Objectives: The purpos e of this study was to compare IL-5 and interferon-gamma (IFN-gamma) s ecretion and proliferation by peripheral blood T cells from sensitized atopic patients with asthma, rhinitis, and no symptoms and from nonat opic control subjects in response to the allergen Dermatophagoides pte ronyssinus (Der p) and the control recall antigen Mycobacterium tuberc ulosis purified protein derivative (PPD). Methods: To measure allergen -induced IL-5 production and proliferation, me developed a short-term culture technique that required a single antigenic stimulation of fres hly isolated peripheral blood mononuclear cells (PBMC), With this tech nique, we measured Der p- and PPD-induced IL-S production and prolifer ation in PBMC from atopic patients with asthma who were allergic to De r p, atopic patients with rhinitis, atopic patients with no symptoms, and a group of nonatopic normal control subjects. In four experiments, CD4(+) or CD8(+) T cells were depleted from PBMC to confirm that IL-5 synthesis was T cell dependent, Results: T cell IL-5 production, but not IFN-gamma production, in response to Der p was elevated in atopic patients with asthma and atopic patients with rhinitis compared with f indings in atopic patients with no symptoms or nonatopic control subje cts. IL-5 production was abrogated by depletion of CD4(+), but not CD8 (+), T cells, In subjects with asthma, allergen-driven IL-5 production correlated with bronchial hyperreactivity. Allergen-induced prolifera tion was also higher in patients with asthma than in atopic subjects w ith no symptoms or nonatopic controls. T cell IL-5 and IFN-gamma produ ction and proliferation in response to PPD were similar regardless of atopic status or disease. Conclusions: Elevated IL-5 production is a c haracteristic of allergen-specific peripheral blood CD4(+) T cells fro m sensitized patients with atopic disease but not atopy per se.