Abstract. Cysteinyl leukotrienes (LT) play a vital role in the pathogenesis of allergic rhinitis (AR), but few studies have investigated the nasal mucosal physiological response to LTs in AR patients. The aim of the present study was to establish the methodology and investigate the diagnostic value and safety of a leukotriene D4 (LTD4) nasal provocation test. LTD4 nasal provocation tests were performed in 26 AR patients and 16 normal control subjects. Nasal airway responsiveness was assessed by calculating the concentration of LTD4 required to cause a 60% increase in nasal airway resistance (PC 60 NAR-LTD4), which was measured using rhinomanometry and a composite symptom score. Receiver operating characteristic (ROC) curve was applied to evaluate the diagnostic value of LTD4 nasal provocation test, and adverse events were recorded. The study protocol was registered with the U.S. National Institutes of Health (https://clinicaltrials. gov/ct2/show/NCT01963741). PC 60 NAR-LTD4 in AR was significantly lower compared with that of normal controls . No serious adverse events were observed. Thus, the present results indicate that AR patients exhibited nasal hyperactivity to LTD4, and the established procedure of LTD4 nasal provocation testing is effective and safe for use in the diagnosis of AR.
IntroductionThe levels of cysteinyl leukotrienes(LTs) in nasal secretions are elevated following allergen challenge or during natural exposure to allergens in allergic rhinitis (AR) patients (1,2). LTs play a vital role in the pathogenesis of AR and asthma (3,4), and as asthma patients frequently exhibit AR, patients that suffered from asthma and AR were particular good candidates for anti-LT therapy (5).Anti-LT therapy has been indicated to be effective in relieving the symptoms of AR or asthma in large-scale randomized, double-blind, placebo-controlled clinical trials (6,7). Nasal congestion and rhinorrhea in AR were reduced via the administration of montelukast, a LT receptor antagonist (LTRA), to a degree similar to that of antihistamines (8,9); however, the results of other trials were inconsistent with this (6,7,10). It remains unclear which population group may benefit most since the efficacy of the LTRA varied among asthmatic patients. Since it is difficult to predict responsiveness to anti-LT therapy in an individual patient, it is critical to develop a simplified method to identify the treatment response.LTC and LTD can induce an increase in nasal mucosal blood flow and nasal airway resistance (NAR); however, inhalation of LTD4 is associated with higher potency (11) and slow deactivation in vivo (12) as compared with LTC4 and LTE4. It has been reported that LTC4 is ~10 times (13), while LTD4 was ~5,000 times, as potent as histamine in achieving a 150% increase in NAR (14), as measured by rhinomanometry. Furthermore, LTD4 has been suggested to be an effective bronchial provocation agent in our previous studies (15,16). Consequently, LTD4 is speculated to be a potentially useful provocation agent (15). To the best of our...