The effect of nasal corticosteroid therapy on allergic rhinitis is uncertain. In a double-blind, placebo-controlled study over 3 months, we investigated the influence of a new corticosteroid spray, fluticasone propionate aqueous nasal spray (FPANS), on Langerhans cells (CD1a+ cells), HLA-DR+ cells, and T cells in nasal mucosa. Efficacy was evaluated by nasal symptom score. This treatment significantly decreased the number of CDla+ cells and HLA-DR+ cells in the nasal mucosa. Furthermore, a clear trend of decreasing numbers of T cells in nasal epithelium was found. No change in nasal symptom score was found after the treatment period. These findings suggest that fluticasone propionate aqueous nasal spray decreases the antigen presentation in nasal allergy.