Nasal eosinophilia and IL-5 mRNA expression in seasonal allergic rhinitis induced by natural allergen exposure: Effect of topical corticosteroids

• Published in: Journal of allergy and clinical immunology 1998-10, Vol.102 (4), p.610-617
• Main Authors: Masuyama, Keisuke, Till, Stephen J., Jacobson, Mikila R., Kamil, Asma, Cameron, Lisa, Juliusson, Sigurdur, Lowhagen, Olle, Kay, A.Barry, Hamid, Qutayba A., Durham, Stephen R.
• Format: Article
• Language: English
• Subjects: Administration, Intranasal; allergy; Androstadienes - administration & dosage; Androstadienes - therapeutic use; Anti-Inflammatory Agents - administration & dosage; Anti-Inflammatory Agents - therapeutic use; Biological and medical sciences; Biopsy; CD3 Complex - analysis; Cells, Cultured; corticosteroids; cytokines; Eosinophilia - complications; Eosinophilia - metabolism; Eosinophilia - pathology; eosinophils; Fluticasone; Glucocorticoids; Granulocyte-Macrophage Colony-Stimulating Factor - biosynthesis; Granulocyte-Macrophage Colony-Stimulating Factor - genetics; Histamine and antagonists. Allergy; Humans; IL-5; In Situ Hybridization; Interleukin-5 - biosynthesis; Interleukin-5 - genetics; Medical sciences; Nasal Mucosa - drug effects; Nasal Mucosa - metabolism; Nasal Mucosa - pathology; Pharmacology. Drug treatments; Poaceae; Pollen; rhinitis; Rhinitis, Allergic, Seasonal - complications; Rhinitis, Allergic, Seasonal - metabolism; Rhinitis, Allergic, Seasonal - pathology; RNA, Messenger - metabolism; Skin Tests; T cells; T-Lymphocytes - chemistry; T-Lymphocytes - immunology
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/S0091-6749(98)70277-5

Background: Nasal allergen provocation in patients with allergic rhinitis leads to expression of the proeosinophilic cytokines IL-5 and GM-CSF and tissue eosinophilia. Objective: We sought to examine the effect of natural seasonal allergen exposure on IL-5 and GM-CSF mRNA expression and nasal eosinophilia and to evaluate the effects of topical corticosteroid therapy on these responses. Methods: Nasal biopsy specimens were collected from 46 grass pollen–sensitive patients with seasonal rhinitis before the grass pollen season. A second biopsy specimen was collected during the pollen season, by which time patients had received 6 weeks treatment with either fluticasone propionate (200 μg twice daily) or placebo nasal spray. Results: Fluticasone treatment was clinically effective ( P < .005). Patients receiving placebo, but not fluticasone, showed increased numbers of epithelial and submucosal EG2+ eosinophils ( P < .005) and IL-5 and GM-CSF mRNA–expressing cells ( P < .0001) during the pollen season. Colocalization experiments showed that greater than 80% of IL-5 mRNA–expressing cells were submucosal CD3+ T cells in both groups. The numbers of submucosal CD3+ T cells did not increase during the pollen season or decrease with fluticasone treatment. Fluticasone also inhibited IL-5 secretion by grass pollen–stimulated peripheral blood T cells from patients with seasonal rhinitis ( n = 5, inhibitory concentration of 50% = 10 –9 to 10 –10 mol/L). Conclusions: These results suggest that topical corticosteroids may reduce eosinophilia in seasonal rhinitis by inhibiting T cell IL-5 production. (J Allergy Clin Immunol 1998;102:610-7.)