Study design.

Patients administered nasal spray containing either nasal fluticasone propionate or placebo (black arrows) for 2 weeks before and after nasal allergen provocation (NP) performed on two consecutive days. Blood samples for measurement of allergen-specific antibodies (white arrows) were obtained at the time of the first nasal provocation (day 1 = t1) and on days 8 (t2), 15 (t3), 29 (t4), 43 (t5) and 57 (t6).