Variations in histamine concentration in nasal secretion in patients with allergic rhinitis

The histamine concentration and content in nasal secretion and the volume of nasal secretion in nasal washing samples were measured under different conditions in 28 patients with allergic rhinitis sensitive to birch pollen. The mean histamine concentration was significantly lower after intranasal birch pollen challenge (2.08 micrograms/ml) than in prechallenge samples (6.96 micrograms/ml), and was also significantly lower in untreated patients during the birch pollen season (2.30 micrograms/ml) than off-season (7.18 micrograms/ml). The same relationship was found between the histamine content of the secretion samples obtained on these occasions. The mean secretion volume was greater after than before challenge, but not significantly higher during the season than off-season. A partial reversion of the changes in histamine concentration and content that occurred during the season was observed during intranasal corticosteroid therapy. The concentration and content of histamine in nasal secretion from symptomatic patients after intranasal histamine challenge did not differ significantly from those in asymptomatic subjects before challenge. It was concluded that although the histamine level in nasal secretion can be used as a marker of changes in the severity of allergic rhinitis, it is not ideal for this purpose.     

Histamine concentrations in nasal secretion and secretory activity in allergic rhinitis

The prerequisites for using the assayed histamine concentration in nasal secretion as an objective measure of disease activity in allergic rhinitis were investigated. It was demonstrated that in histamine determination procedures the presence of quenching substances in the nasal secretion could lead to underestimation of the histamine concentration. This bias was eliminated in a modified spectrofluorometric assay. Only an insignificant fraction of the histamine in samples collected by nasal spray washing was bound to unfiltrable particles or cells. The mean histamine concentration in nasal secretions from 15 healthy subjects was 11.2 micrograms/ml and in a group of nine patients with allergic rhinitis out of season 3.36 micrograms/ml. The histamine concentration in the latter group decreased during the pollen season and after positive allergen challenge. It is suggested that this decrease is caused by the increase in volume of the secretion during the allergic response. The use of lithium as an exogenous marker permitted quantitation of the increase in the relative amount of nasal secretion recovered by washing in the symptomatic subjects.     

Changes in airway inflammation following nasal allergic challenge in patients with seasonal rhinitis

BACKGROUND: Seasonal allergic rhinitis could predispose to the development of chronic bronchial inflammation as observed in asthma. However, direct links between nasal inflammation, bronchial inflammation and airway responsiveness in patients with seasonal allergic rhinitis and without asthma are not fully understood. The aim of this study was to analyse the changes induced by allergic nasal challenge outside the pollen season in airway responsiveness and bronchial inflammation of patients with seasonal allergic rhinitis. METHODS: Nine patients were evaluated after either grass pollens or placebo nasal challenge in a randomized cross-over double-blinded trial. Nasal parameters were recorded hourly and airway responsiveness was assessed by methacholine challenge. Cytological examinations and cytokine measurements were performed in nasal lavage and induced sputum. Eosinophil activation was investigated by eosinophil-cationic protein expression and secretion. RESULTS: Airway responsiveness was increased after allergic nasal challenge. Total eosinophils and eosinophils expressing eosinophil-cationic protein were increased in induced sputum after allergic nasal challenge. Both eosinophil number and eosinophil-cationic protein concentration in induced sputum were correlated to methacholine responsiveness. CONCLUSIONS: These results suggest that eosinophils participate to the bronchial inflammation in patients with seasonal allergic rhinitis following allergic nasal challenge outside the pollen season and might explain changes in airway responsiveness.     

Desloratadine reduces systemic allergic inflammation following nasal provocation in allergic rhinitis and asthma patients

BACKGROUND: Preclinical studies have demonstrated that some second-generation antihistamines have anti-inflammatory effects. It is not known whether these effects are also demonstrable in vivo. In this study we investigated the effect of treatment with desloratadine (DL) on systemic inflammation and on nasal and bronchial mucosal inflammation after nasal allergen provocation (NP) in subjects with grass-pollen-allergic rhinitis and asthma. METHODS: Twenty-six subjects with grass-pollen-allergic rhinitis and asthma were randomly allocated to 8 days of treatment with DL (n = 13) or placebo (n = 13) outside the grass pollen season. On day 7 they underwent nasal provocation with grass pollen allergen. Nasal and bronchial biopsies were taken for immunohistochemical evaluation, and blood samples were analysed. Rhinitis and asthma symptoms, peak nasal inspiratory flow and peak expiratory flow, were also measured at specified times. RESULTS: The number of circulating eosinophils decreased during DL treatment, and there was a reduced increase in circulating eosinophils after NP in these subjects. There was also a significant reduction in early bronchial clinical response. There was no significant lessening in the severity of the nasal symptoms. Nasal and bronchial mucosal inflammation parameters did not alter under DL treatment. CONCLUSION: These data suggest that treatment with DL reduces systemic eosinophilia and prevents the increase in circulating eosinophils after NP. DL also significantly reduces the early bronchial clinical response to NP. However, airway mucosal inflammation is not altered by 1 week of treatment.     

Monitoring nasal allergic inflammation by measuring the concentration of eosinophil cationic protein and eosinophils in nasal secretions

Quantitative measurement of the eosinophil cationic protein (ECP) concentration and the percentage of eosinophils in nasal secretions has greatly improved our understanding of the inflammatory process after natural allergen exposure. ECP and eosinophils were measured in the nasal secretions of 40 symptomatic patients with seasonal allergic rhinitis during the pollen season. Results showed a significant relationship between a high concentration of ECP (median: 410 ng/g, range: 6–2380 ng/g) and a high percentage of eosinophils (median: 13.5%, range: 1–85%). This quantitative study again demonstrated that infiltration by eosinophils and release of ECP play a key role in allergic rhinitis. It also suggests that the combined measurement of the percentage of eosinophils together with the ECP concentration in nasal secretions seems to be a very useful model in monitoring and assessing the condition of chronic nasal inflammation in patients with allergic rhinitis.     

Eosinophil markers in seasonal allergic rhinitis

Background The purpose was to study activation markers of the eosinophil granulocytes in seasonal allergic rhinitis, and the impact of topical steroid therapy thereupon.
Methods Sixty-three rhinitis patients with monoallergy to grass were examined before and at peak pollen season. Blood eosinophil count, eosinophil cationic protein (ECP), and eosinophil peroxidase (EPO) in serum and nasal lavage fluid were measured. During the season, patients were randomized to treatment with intranasal fluticasone propionate 0.1 mg o.d. ( n =26), 0.2 mg o.d. ( n =25), or placebo (n = 12). Six healthy persons served as controls.
Results During the season, all parameters, except nasal lavage ECP, increased in the placebo group (P<0.001 – P<0.05). Significant differences were seen between the steroid grotips and the placebo group for all parameters (P<0.001–F<0.05). Higher eosinophil count (P<0.05), serum EPO (F<0.02), and nasal lavage EPO (P<0.05) were found in patients before season than in controls. The following winter, 44 patients returned for repeated measurement. Lower levels of nasal lavage EPO were observed for patients than levels at the beginning of the season (P<0.0001).
Conclusions Intranasal fluticasone propionate reduced inflammation of the nasal mucosa, demonstrated locally by nasal lavage ECP and EPO, and systemically by blood eosinophils, serum ECP, and serum EPO. EPO seemed more sensitive than ECP as indicator of allergic inflammation. EPO demonstrated some perennial eosinophil activity in hay fever patients, increasing locally during spring.     

Nasal conditioning in perennial allergic rhinitis after nasal allergen challenge

BACKGROUND: Antigen challenge in seasonal allergic rhinitis is considered to be associated with an increased ability of the nose to condition inspired air. In contrast, little is known about air conditioning after antigen challenge in perennial allergic rhinitis (PAR). OBJECTIVE: The aims of this study were to investigate whether antigen challenge in PAR changes nasal air conditioning and to assess the relationship between nasal conditioning and nasal patency and geometry. METHODS: Nineteen subjects with PAR were enrolled into this study. Measurement of nasal conditioning, active anterior rhinomanometry (AAR), acoustic rhinometry (AR), and clinical symptom evaluation were performed before and after nasal allergen challenge with allergen extracts from house dust mites. RESULTS: Ten and 20 min after nasal allergen challenge, the total water content of the air measured in the nasopharynx and the water gradient across the nose were significantly higher in the nasal cavity in which the allergen extract was sprayed. The temperature on both sides of the nose increased non-significantly after nasal allergen challenge. No correlation to data obtained by AAR, AR, and clinical symptom evaluation after nasal allergen challenge was found. CONCLUSION: We suggest that an increase in mucosal humidity due to the allergic provocation might be responsible for the increase in nasal conditioning capacity because no correlation to changes in nasal perimeter and patency was found.     

Relationships between allergic inflammation and nasal airflow in children with persistent allergic rhinitis due to mite sensitization

BACKGROUND: Allergic rhinitis is associated with Th2-dependent inflammation. Nasal obstruction is the most typical symptom in children with mite allergy. OBJECTIVES: The aim of this study was to evaluate the possible relationships among nasal symptoms, allergic inflammation, including inflammatory cells and cytokine pattern, and nasal airflow in children with persistent allergic rhinitis because of mite sensitization. METHODS: Twenty children (13 males and seven females, mean age 13.4 +/- 1.6 years) with persistent rhinitis because of mite allergy were evaluated. All of them had moderate-severe grade of nasal obstruction. Total symptom score (TSS), rhinomanometry, nasal lavage, and nasal scraping were obtained in all subjects. Inflammatory cells were counted by conventional staining; interleukin (IL)-5, and IL-8 were measured by immunoassay on fluids recovered from nasal lavage. RESULTS: Eosinophils were significantly associated with TSS (R = 74.4%, P = 0.0002), with IL-5 (R = 90.6%, P < 0.0001) and with nasal flow (R = -69%, P = 0.0007), but not with IL-8 (R = 0.1%, P = 0.995). Eosinophil levels were shown to independently predict nasal flow (P < 0.001), with flow decreasing linearly for increasing eosinophils, together with a significant effect of neutrophils (P = 0.016, linear increase in flow) and a borderline effect of IL-8 (P = 0.063, linear increase in flow). CONCLUSIONS: This study demonstrates the close association between IL-5 concentration and eosinophil infiltration. In addition, there is clear evidence concerning the relationship between eosinophil infiltration and nasal airflow. Thus, nasal eosinophils can be regarded as the most important predictor of upper airway function. These findings constitute first evidence of the relationship between nasal airflow impairment and Th2-related eosinophilic inflammation in children with persistent allergic rhinitis because of mite sensitization.     

Airway function and nasal inflammation in seasonal allergic rhinitis and asthma

BACKGROUND: Allergic rhinitis (AR) and asthma are frequently associated and characterized by a Th2-dependent inflammation. Nasal and bronchial obstruction may be objectively measured. OBJECTIVE: The aim of this study was to evaluate the relationships among upper and lower airway function and nasal inflammation in subjects with seasonal allergic rhinitis (SAR) and asthma. METHODS: Twenty out-patients (12 males and eight females, mean age: 23.4+3.6 years) with SAR and asthma were evaluated during the pollen season. All of them showed a moderate-severe grade of nasal obstruction. Total symptom score, rhinomanometry, spirometry, nasal lavage, and nasal scraping were obtained in all subjects. Eosinophils were counted by conventional staining; IL-4 and IFN-gamma were measured by immunoassay on fluids recovered from nasal lavage. RESULTS: Functional parameters, i.e. nasal airflow and forced expiratory volume in 1 s (FEV(1)), were correlated with nasal eosinophils (R(2)>0.83, P<0.001). Inflammatory parameters, i.e. eosinophils were correlated with immunological parameters, i.e. IL-4 and IFN-gamma levels (R(2)=0.93, P<0.001). Nasal symptoms were correlated with nasal airflow (rho=-0.71, P< or =0.01) and eosinophils (rho=0.72, P<0.01). Nasal airflow was correlated with FEV(1) (r=0.89, P<0.0001). CONCLUSIONS: This study demonstrates the close connection between Th2 cytokines and eosinophil infiltration in the nose. There is also clear evidence concerning the relationships between eosinophils infiltration and cytokines levels. Nasal eosinophils can be regarded as the most important predictors of upper and lower airway functions. These findings constitute first evidence of a relationship among nasal Th2-related inflammation and nasal and bronchial airflow in patients with SAR and asthma.     

Low-dose local nasal immunotherapy in children with perennial allergic rhinitis due to Dermatophagoides

BACKGROUND: Allergen specific immunotherapy was known to be useful in the treatment of respiratory allergic disease. Local nasal immunotherapy (LNIT) offers advantages such as a good efficacy/safety ratio and a more convenient allergen delivery. The aim of this study was to assess the safety and clinical efficacy of a modified scheduling of LNIT in 32 children with allergic rhinitis due to Dermatophagoides. METHODS: A multicentre, randomized, double-blind placebo controlled study carried out for two years, with a modified schedule of LNIT treatment: a build-up phase at increasing dosages from 2.5 AU to 80 AU and a maintenance period at low dosage (80 AU) once a week. Symptom and medication scores. threshold dose with specific nasal provocation test (NPT) and immunological parameters (IgE and IgG4) were evaluated. RESULTS: No important local or systemic side-effects were observed in children who completed the study. Compared to placebo, the active treatment group showed significant improvement in rhinitis symptoms and a reduction of drug consumption after 18 months of LNIT. These results were confirmed by a significant reduction of allergen specific nasal reactivity. Serum and nasal specific IgE and IgG4 did not show any difference in the two groups. CONCLUSIONS: The safety and clinical efficacy of low-dose LNIT suggests that this therapy may be useful in the treatment of allergic rhinitis disease in children.     

Immediate and dual response to nasal challenge with Dermatophagoides pteronyssinus in local allergic rhinitis

Background Local allergic rhinitis (LAR) is characterized by in situ production of specific IgE (sIgE) antibodies and a positive response to a nasal allergen provocation test (NAPT) in the absence of atopy. Objective The aim of this study was to investigate the immunological mechanisms involved in the immediate and late responses after nasal exposure to Dermatophagoides pteronyssinus (DP) in patients with LAR. Methods A total of 40 subjects with LAR to DP were studied and compared with 50 healthy controls. Immediate and late responses to NAPT‐DP were assessed using a visual analogue scale of nasal symptoms and acoustic rhinometry. Tryptase, ECP, total and sIgE‐DP were measured in the nasal lavage by immunoassay at baseline, 15 min, 1, 6 and 24 h after nasal challenge. Results NAPT‐DP was positive in all patients, with significant increases in tryptase (45%), ECP (65%) and sIgE‐DP (25%) (P<0.05). Sixty percent of the LAR patients presented an immediate response to NAPT‐DP and 40% a dual response. Immediate responders showed a fast release of tryptase with a peak at 15 min after NAPT‐DP, and a progressive increase in nasal ECP and sIgE‐DP from 1 to 24 h after challenge, with a peak at 24 h. Dual responders presented persistently higher levels of tryptase from 15 min to 6 h after challenge, and a similar pattern of nasal release of ECP and sIgE‐DP to immediate responders. There were no isolated late responders. NAPT‐DP was negative in all healthy controls, with no increases in tryptase, ECP, or total and sIgE‐DP in nasal secretions. Conclusions The results demonstrated the existence of immediate and dual responses to a NAPT with DP in LAR patients, with the local presence of sIgE and mast cell/eosinophil activation. Cite this as: S. López, C. Rondón, M. J. Torres, P. Campo, G. Canto, R. Fernandez, R. Garcia, A. Martínez‐Cañavate and M. Blanca, Clinical & Experimental Allergy, 2010 (40) 1007–1014.     

Eosinophil cationic protein and specific IgE in serum and nasal mucosa of patients with grass-pollen-allergic rhinitis and asthma

BACKGROUND: After allergen exposure, IgE-bearing mast cells surface in respiratory mucosa. Eosinophils are also recruited locally by chemotactic mediators; they are the main cell directly involved in the late phase of allergic inflammation. IgE antibody and eosinophil cationic protein (ECP) are routinely determined mainly in serum although they exert their pathogenetic role more directly on mucosal surfaces. METHODS: We performed a comparative study of IgE antibody to grass and ECP on nasal mucosa and blood samples in order to evaluate the relevance of monitoring allergic inflammation in the target organ. Thirty-one patients and 10 nonatopic controls were enrolled in the protocol. Twenty-six subjects allergic to grass, 11 with rhinitis (group 1) and 15 with asthma and rhinitis (group 2), completed the study. Five patients dropped out. Specific IgE to grass and ECP was determined in nasal mucosa by our method based on in situ incubation. RESULTS: Serum IgE to grass did not increase during the pollen peak, as did nasal IgE, in group 1 from before the pollen peak, from 2.3 to 3.2 kU/l (P=0.02), and in group 2 at the pollen peak, from 4.8 to 12.2 kU/l (P=0.01). Serum ECP did not show any significant variation in group 1, but it increased at pollen peak from 6 to 11.2 microg/l (P=0.01) in group 2. Nasal ECP increased significantly in both groups even before the pollen peak. In group 1, ECP values rose from 15 to 39.9 microg/l (P=0.01). In group 2, ECP increase was much higher than in group 1, from 9 to 213 microg/l (P=0.001). Serum eosinophils, like nasal ECP, showed a significant increase of values from before the pollen peak in both groups, without correlation with serum ECP in rhinitic patients. CONCLUSIONS: Both specific IgE and ECP in the nasal mucosa showed a better correlation with allergen exposure than serum evaluations. With an appropriate method, allergic inflammation may be best monitored in the nasal mucosa.     

Eosinophil inflammation of the nasal mucosa in allergic and non-allergic rhinitis measured by eosinophil cationic protein levels in native nasal fluid and serum

Eosinophil inflammation is essential in many cases of allergic and non-allergic rhinitis. Activated eosinophils release toxic granule proteins. In this study, we compared the degree of local nasal and systemic eosinophil activation by the determination of eosinophil cationic protein (ECP) in serum and native nasal fluid from 119 patients. We found no significant differences in serum ECP levels of the various patient groups. In all patient groups, except in the vasomotor rhinitis group, nasal fluid ECP levels differed significantly from normal controls. We found a nasal fluid ECP (mean ± SEM) of 32·6 ± 81 ng/ml for normals, 106 ± 39·7 for non-rhinitic atopics, 87·6 ± 20·8 ng/ml for patients with chronic non-allergic sinusitis, 101·3 ± 40·4 ng/ml for patients with a history of pollinosis, 150·5 ± 35·1 ng/ml for patients with acute pollinosis, 84·7 ± 24·7 ng/ml for individuals with perennial allergic rhinitis and 112·9 ± 25·6 ng/ml for patients with both perennial and seasonal allergy. Patients with nasal polyps had mean nasal ECP levels of 146·9 ± 57·7 ng/ml in absence of allergy and 147·9 ± 54·9 ng/ ml in the presence of allergy. Nasal ECP was 67·0 ± 22·4 for patients with hyperreactive rhinitis. We found a significant correlation of 0·95 between nasal eosinophils and nasal ECP. Nasal ECP and a subjective symptom score only correlate significantly for chronic sinusitis. We conclude that monitoring native nasal fluid ECP levels may be useful in the diagnosis and mangement of nasal inflammation. Elevated ECP in nasal secretion may originate from upregulated eosinophil degranulation and thus is a marker for local inflammation although not specific for any particular nasal disease.     

Mometasone furoate monohydrate nasal spray for the treatment of nasal congestion in allergic rhinitis

Allergic rhinitis (AR) affects an estimated 20–40 million Americans annually. It is a multifaceted condition comprising a range of symptoms, including nasal congestion, arguably the most bothersome symptom. Of the various types of medications available for the treatment of AR, intranasal corticosteroids are considered the most effective. Mometasone furoate nasal spray is an intranasal corticosteroid with anti-inflammatory properties. It is indicated for the treatment of the nasal symptoms of seasonal AR and perennial AR in adults and children, for the prophylaxis of nasal symptoms of seasonal AR and for the treatment of nasal polyps. Numerous clinical trials have demonstrated that mometasone furoate nasal spray effectively relieves nasal congestion in adults and children with AR, while providing excellent safety and tolerability.     

Effect of topical corticosteroids on seasonal increases in epithelial eosinophils and mast cells in allergic rhinitis: a comparison of nasal brush and biopsy methods

BACKGROUND: Nasal brushing and nasal biopsy are well-tolerated sampling techniques. Seasonal grass pollen-induced rhinitis is characterized by epithelial mast cell infiltration and seasonal increases in both epithelial and sub-mucosal eosinophils. OBJECTIVE: To compare the ability of the nasal brush and nasal biopsy techniques to detect natural seasonal increases in eosinophils and mast cells, and to assess the influence of topical corticosteroid. METHODS: Nasal brush samples and nasal biopsies were collected from 46 grass pollen-sensitive seasonal rhinitis patients before the grass pollen season and at the peak of the pollen season following 6 weeks' treatment with either fluticasone propionate aqueous nasal spray (200 microg, twice daily) or placebo nasal spray. RESULTS: Placebo patients showed seasonal increases in epithelial eosinophils both with nasal brushing (P < 0.0001) and biopsy (P < 0.001). Epithelial mast cell numbers also increased during the pollen season as detectable by brushing (P < 0.0001) and biopsy (P < 0.03). Changes in cell numbers measured by nasal brushing correlated with those observed with nasal biopsy, both for eosinophils and mast cells (P < 0.05). Sub-mucosal eosinophils but not mast cells also increased during the pollen season (P < 0.002). Nasal brushing and biopsy revealed that fluticasone treatment inhibited seasonal increases in epithelial eosinophils (P < 0.00001) and epithelial infiltration by mast cells (nasal brushing P < 0.00001 and nasal biopsy P < 0.01). Fluticasone also inhibited seasonal increases in sub-mucosal eosinophils (P < 0.001) and significantly reduced nasal symptoms (P < 0.001). CONCLUSION: Nasal brushing harvests sufficient inflammatory cells from the surface of the nasal mucosa to be used in lieu of nasal biopsies in observation of the effect of drugs on the nasal epithelium.     

Comparison of five new antihistamines (H1-receptor antagonists) in patients with allergic rhinitis using nasal provocation studies and skin tests

BACKGROUND: It was the aim of the authors to compare all of the latest second-generation antihistamines and to see if there were significant differences in their efficacy. It is important for ENT specialists to know if these differences exist, as it is for general practitioners trying to choose between these drugs. METHODS: In 12 confirmed grass pollen allergic patients the authors performed nasal smears to asses eosinophilia, histamine/grass pollen skin tests, and grass pollen nasal provocation tests. All tests were performed before and after administration of one of five different antihistamines (cetirizine, loratadine, ebastine, fexofenadine, mizolastine) or placebo. The order of administration of antihistamines and placebo was randomised, and patients were not aware of which drug they were given. A decrease in nasal eosinophilia (nasal smear), or nasal or skin reactivity (provocation tests) was looked for. RESULTS: A significant decrease in nasal eosinophilia was observed for all antihistamines but not for placebo. For the grass pollen nasal provocation tests, the decrease was significant for nasal blockage and sneezing; for rhinorrhea there was an insignificant decrease that was true for all antihistamines. A significant reduction in histamine/grass pollen skin test reactivity was also observed for all antihistamines, during an 8 h observation period. A significant difference in efficacy between the different antihistamines could not be found with any of the tests performed. CONCLUSIONS: For the newer nonsedating H1-antagonists there appears to be no clinically relevant differences in activities--at least not in our study. Preference of the patient may be the most important factor in making a choice between these drugs.     

Modulation of neurotrophin and neurotrophin receptor expression in nasal mucosa after nasal allergen provocation in allergic rhinitis

Background: Patients with allergic rhinitis (AR) feature both allergic airway inflammation and a hyperresponsiveness to nonspecific stimuli which is partly neuronally controlled. Still, it is unclear whether or not neurotrophins are involved in airway pathophysiology of AR and in nasobronchial interaction. Methods: Nine AR patients with mono‐allergy to grass pollen and nine healthy controls underwent nasal allergen provocation (NP). Serum samples, nasal and bronchial biopsies were taken before (T₀) and 24 h after (T₂₄) NP. Pan‐neurotrophin receptor p75^NTR, tyrosine kinase A (trkA), trkB, nerve growth factor (NGF), and brain‐derived neurotrophic factor (BDNF) were assessed with immunohistochemistry, and NGF and BDNF levels with ELISA. Results: At T₂₄, BDNF and NGF were upregulated in nasal mucosa (P < 0.05) and increased in the peripheral blood of AR compared with T₀. The increase in nasal BDNF expression correlated positively with the maximum increase in total nasal symptom score in AR (P = 0.02). p75^NTR was expressed on peripheral nerves and epithelial layer, trkA on endothelial cells, and trkB on mast cells. trkB + mast cells significantly decreased after NP in AR (P < 0.01). NP did not modulate p75^NTR and trkA expression in nasal mucosa and had no effect on the expression of neurotrophins and receptors in bronchial mucosa. Conclusion: This study shows that neurotrophins and their receptors are expressed in human airways. Allergic rhinitis was characterized by a modulation of BDNF, NGF, and trkB in nasal mucosa after NP and a correlation of nasal BDNF with the maximal increase of total nasal symptom score. Therefore, our data suggest that neurotrophins participate in upper‐airway pathophysiology in AR, whereas their role in nasobronchial interaction remains unclear.