Late phase response during nasal challenge: effect of astemizole on leukotriene B4 levels.

Nasal provocation (NP) in allergic rhinitis patients can elicit a late phase inflammatory response in which interleukins (IL), leukotrienes (LT), and neutrophils have been implicated. Certain antihistamines have been shown to have anti-inflammatory properties. The objective was to determine whether astemizole at 10 mgs/day has any anti-inflammatory characteristics. We clinically evaluated 20 patients with allergic rhinitis and measured nasal IL-8 and LTB4 during NP with increasing doses of grass and ragweed antigen in a double-blind placebo-controlled fashion after a 4-week course of treatment. Clinical symptom scores for sneezing, pruritus, and rhinorrhea were evaluated. Nasal fluid was examined by ELISA and RIA for IL-8 and LTB4 levels along with neutrophil assessment before NP and at 3, 6, and 8 hours. Symptom scores for nasal sneezing, pruritus, rhinorrhea, and nasal LTB4 levels at 6 and 8 hours and IL-8 at 3, 6, and 8 hours were generally lower in astemizole-treated patients compared to those on placebo. Nasal IL-8 levels corresponded to LTB4 levels at diluent and at 6 hours in the placebo group (P = 0.01). The percentage of neutrophils correlated with LTB4 levels at baseline, coefficient = 0.76, P = 0.02 and at 6 hours, coefficient = 0.62, P = 0.035 in the placebo group. This study is the first to demonstrate an effect of astemizole during NP on IL-8 and LTB4 levels with a significant correlation of neutrophil numbers in untreated patients during the nasal late phase response.