BACKGROUND:Pollen grains with a diameter of more than 10 μm preferentially deposit in the upper airways. Their contribution to lower airway inflammation is unclear. One hypothesis is that lower airway inflammation is mainly caused by allergen containing pollen starch granules, which are released from the pollen grains and can easily enter the peripheral airways because of their smaller size.OBJECTIVE:To investigate the differential effect of pollen grains and pollen starch granules on nasal symptoms and lower airway inflammation.METHODS:In a 2-period crossover design, 30 patients with allergic rhinitis and mild intermittent asthma underwent 2 allergen challenges on consecutive days in an environmental challenge chamber with either a mixture of pollen grains plus starch granules or starch granules only. End points were the total nasal symptom score (TNSS), nasal secretion weight, nasal flow, spirometry, and exhaled nitric oxide (eNO).RESULTS:The presence of pollen grains had a significant and considerable effect on increase in TNSS and secretion weight and on decrease in nasal flow. Starch granules alone only had minimal effects on nasal symptoms. Challenges with starch granules significantly increased eNO. Pollen had no effect on eNO.CONCLUSION:Pollen grains cause nasal symptoms but do not augment lower airway inflammation, whereas starch granules trigger lower airway inflammation but hardly induce nasal symptoms.

Background: An environmental challenge chamber (ECC) is a useful tool to expose allergic patients to relevant allergens in a controlled indoor setting and to test anti-allergic treatment. Hitherto, ECC studies with grass pollen are conducted primarily outside of the pollen season to avoid the influence of natural pollen exposure.Objective: To investigate whether an established anti-allergic treatment, a combination of cetirizine (CET) and pseudoephedrine (PSE), shows an equivalent treatment effect within and outside of the grass pollen season when tested in an ECC.Methods: In a randomized, placebo-controlled, double-blind, four-way crossover study, the effect of a combination of 10 mg CET and 120 mg PSE compared with placebo on nasal symptoms, nasal flow, and nasal secretion was investigated in 70 patients with seasonal allergic rhinitis. Subjects underwent four 6-hour pollen challenges in an ECC with administration of the drugs after 2 hours. Two challenges were conducted within the grass pollen season and two out of the grass pollen season.Results: The active treatment significantly improved nasal symptoms and nasal flow and significantly reduced the amount of nasal secretion compared with placebo both within and outside of the pollen season (P < .0001 each). The treatment effect was not different between the seasons (P > .05).Conclusion: Controlled allergen provocation in an ECC can be used to test anti-allergic treatment both within and outside of the grass pollen season. Ann Allergy Asthma Immunol. 2011;106:336-341.

UNLABELLED:Antihistamines and nasal decongestants are well-established therapeutics in allergic rhinitis. However, no data are available which directly compare the effect size of the single substances with their combination in a single study including placebo (PLA) treatment.OBJECTIVE:The aim of this study was to evaluate the effect of a combination of cetirizine (CET) and pseudoephedrine (PSE) and to compare it to treatment with CET or PSE alone and to PLA during grass pollen allergen challenge in an environmental challenge chamber (ECC).MATERIAL AND METHODS:In a randomized, double-blind, placebo-controlled, four-way crossover study the effect of a combination of 10 mg CET with 120 mg PSE (CET + PSE) versus CET or PSE alone or PLA on symptoms, nasal flow, and nasal secretions was investigated in 49 patients with intermittent allergic rhinitis. Subjects underwent four 6-h pollen exposures in an ECC with administration of the drugs after 2 h.RESULTS:The induction of nasal symptoms, nasal secretion and nasal obstruction (measured as nasal flow) during the first 2 h of pollen exposure was highly reproducible at the 4 consecutive exposures. The symptom of nasal obstruction was significantly reduced after treatment with CET + PSE compared to the treatment with CET or PSE alone or PLA (p < 0.0001). Furthermore, the combination treatment significantly reduced the total nasal symptom score (TNSS) and visual analogue scale score (VAS) compared to the single treatments or PLA. Nasal flow was significantly increased after treatment with CET + PSE and PSE and nasal secretions were significantly reduced by CET + PSE and CET without significant additional improvement of the combination therapy.CONCLUSION:The combination treatment with CET and PSE is more effective than treatment with single substances in subjects with allergic rhinitis.