NASAL RESPONSE TO CAPSAICIN IN PATIENTS WITH ALLERGIC RHINITIS AND INHEALTHY-VOLUNTEERS - EFFECT OF COLCHICINE

We studied the effect of nasal administration of capsaicin in eight pa tients with allergic rhinitis and eight healthy subjects. We also stud ied the effect of colchicine, a drug known to inhibit microtubular axo nal transport of peptides, on nasal response to capsaicin in these sub jects. Colchicine or placebo was administered orally in a double-blind , randomized, crossover manner with a 35 day wash-out interval. Nasal challenge was performed on the last day of each period of treatment, u sing increasing doses of capsaicin (10(-9) to 3 x 10(-5) mmol). Capsai cin induced a dose-dependent decrease in nasal airflow conductance (ac tive posterior rhinomanometry) (p < 0.002) that was greater in patient s with allergic rhinitis (0.40 +/- 0.02 to 0.20 +/- 0.03) than in heal thy subjects(0.44 +/- 0.01 to 0.35 +/- 0.02) (p = 0.0001). Capsaicin p rovoked a greater number of sneezes in patients with allergic rhinitis than in healthy subjects (p < 0.001), but the amount of nasal secreti ons was similar in these two groups of subjects. In nasal lavage fluid , capsaicin induced an increase in total, epithelial, and neutrophil c ell counts in patients with allergic rhinitis (each comparison, p < 0. 05), but not in healthy subjects. Capsaicin induced a slight, although not significant, increase in the concentration of elastase in nasal l avage fluid in patients with allergic rhinitis (p = 0.07), but not in healthy subjects. Albumin concentration decreased in nasal lavage flui d in both groups of subjects (p < 0.05). The tendency of capsaicin to increase neutrophil elastase in nasal lavage fluid of patients with al lergic rhinitis was not observed after treatment with colchicine. No o ther action of colchicine was observed on capsaicin-induced effects. W e conclude that in patients with allergic rhinitis as compared with no rmal subjects, capsaicin induces a greater response on nasal obstructi on, sneezes, epithelial cell desquamation, and neutrophil cell count i n nasal ravage fluid. Colchicine had no significant effect on nasal re sponse to capsaicin in both groups of subjects, but seemed to prevent the tendency of capsaicin to induce neutrophil activation in patients with allergic rhinitis. Our study suggests that neurogenic inflammatio n may play a role in allergic rhinitis.