BACKGROUND:Nasal allergen challenge (NAC) leads to a nasal ocular reflex, which is augmented by allergic inflammation. This study was designed to confirm our previous observation that an intranasal steroid inhibits the nasal ocular reflex and to show that histamine does not play an important role in the genesis of this reflex. METHODS: We performed a randomized, double-blind, double-dummy, placebo (PL)-controlled, four-way crossover trial in subjects with seasonal allergic rhinitis out of season. Subjects were randomized to receive 1 week pretreatment with intranasal PL and intraocular (PL/PL), intranasal PL and intraocular olopatadine (PL/OLO), intranasal fluticasone furoate (FF) and intraocular PL (FF/PL), and the combination (FF/OLO). Subjects then underwent NAC on 2 consecutive days. The number of sneezes and nasal and ocular symptoms were recorded, and levels of tryptase and histamine were measured in nasal lavages. RESULTS: NAC after PL/PL resulted in increase in symptoms, histamine, and tryptase after the challenge on the 2nd day. There was a reduction in eye symptoms on the 2nd day of challenge from 6.0 after PL/PL to 0 after FF/PL (p = 0.001), 2.5 after PL/OLO (p = 0.3), and 1.5 after FF/OLO (p = 0.003). Furthermore, there was no significant difference between the response after FF/PL versus FF/OLO and a significant difference between FF/PL and PL/OLO (p = 0.02). Levels of tryptase followed a similar trend. The number of eosinophils in nasal lavages on the 2nd day of challenge were also reduced by the treatment arms containing FF compared with PL. CONCLUSION: Our data confirm the existence of a nasal ocular reflex after NAC. OLO alone or the addition of OLO to FF does not impact ocular symptoms caused by the naso-ocular reflex, suggesting that mast cells are not activated to release histamine in the conjunctiva during this process.
RCT Entities:
BACKGROUND: Nasal allergen challenge (NAC) leads to a nasal ocular reflex, which is augmented by allergic inflammation. This study was designed to confirm our previous observation that an intranasal steroid inhibits the nasal ocular reflex and to show that histamine does not play an important role in the genesis of this reflex. METHODS: We performed a randomized, double-blind, double-dummy, placebo (PL)-controlled, four-way crossover trial in subjects with seasonal allergic rhinitis out of season. Subjects were randomized to receive 1 week pretreatment with intranasal PL and intraocular (PL/PL), intranasal PL and intraocular olopatadine (PL/OLO), intranasal fluticasone furoate (FF) and intraocular PL (FF/PL), and the combination (FF/OLO). Subjects then underwent NAC on 2 consecutive days. The number of sneezes and nasal and ocular symptoms were recorded, and levels of tryptase and histamine were measured in nasal lavages. RESULTS:NAC after PL/PL resulted in increase in symptoms, histamine, and tryptase after the challenge on the 2nd day. There was a reduction in eye symptoms on the 2nd day of challenge from 6.0 after PL/PL to 0 after FF/PL (p = 0.001), 2.5 after PL/OLO (p = 0.3), and 1.5 after FF/OLO (p = 0.003). Furthermore, there was no significant difference between the response after FF/PL versus FF/OLO and a significant difference between FF/PL and PL/OLO (p = 0.02). Levels of tryptase followed a similar trend. The number of eosinophils in nasal lavages on the 2nd day of challenge were also reduced by the treatment arms containing FF compared with PL. CONCLUSION: Our data confirm the existence of a nasal ocular reflex after NAC. OLO alone or the addition of OLO to FF does not impact ocular symptoms caused by the naso-ocular reflex, suggesting that mast cells are not activated to release histamine in the conjunctiva during this process.
Authors: Anne K Ellis; Mena Soliman; Lisa Steacy; Marie-Ève Boulay; Louis-Philippe Boulet; Paul K Keith; Harissios Vliagoftis; Susan Waserman; Helen Neighbour Journal: Allergy Asthma Clin Immunol Date: 2015-04-24 Impact factor: 3.406