Inhibition of GM-CSF secretion by topical corticosteroids and nedocromil sodium. A comparison study using nasal polyp epithelial cells.

Nasal epithelial cells maintain eosinophil survival by secreting granulocyte/macrophage colony-stimulating factor (GM-CSF). Corticosteroids antagonize eosinophil viability induced by GM-CSF. We investigated the effect of topical corticosteroids and nedocromil sodium on the release of GM-CSF from nasal polyp epithelial cells. Epithelial cells were obtained from 19 patients undergoing nasal polypectomy and cultured. After reaching confluence, cultured cells were stimulated with 10% foetal calf serum in the absence and presence of four topical corticosteroids and nedocromil sodium for 48 h. GM-CSF was measured by enzyme linked immunosorbent assay (ELISA). Fluticasone propionate was the most potent inhibitor of GM-CSF release (IC25 = 46 pM) closely followed by budesonide (IC25 = 4 nM), beclomethasone dipropionate (IC25 = 40 nM) and triamcinolone acetonide (IC25 = 75 nM). Nedocromil sodium had no effect on GM-CSF release. We conclude that the effect of topical steroids on reducing eosinophil infiltration in nasal polyps may be due in part to downregulation, among other cytokines, of epithelial GM-CSF production which prolongs eosinophil viability. Quantitatively, fluticasone propionate inhibited GM-CSF production more potently than budesonide, beclomethasone dipropionate and triamcinolone acetonide.