Leukotriene C4 and histamine in early allergic reaction in the nose

We have examined the measurements of LTC4 and histamine in nasal lavage fluids and blown secretions as a possible model of the early mediator events during nasal allergy. A nasal challenge with grass pollen extract was undertaken on two separate occasions in 20 patients with a history of seasonal rhinitis and a positive immediate skin test to grass pollen. A 2 ml nasal lavage was performed before allergen challenge, and blown secretion collected separately 15 min after the provocation, followed by a final 2 ml nasal lavage. The dilution of nasal secretion by the lavage fluid was determined using 99mTc-labelled albumin as an exogenous marker added to the fluid. The amounts of admixture in the nasal lavages did not correlate to the concentrations of LTC4 and histamine, indicating that the variable amounts of nasal secretion in nasal lavage do not constitute a confounding variable for measurements of LTC4 and histamine. In the pre-challenge lavages, the median concentrations, of LTC4 and histamine were 1.7 and 52 nmol/l respectively. Following allergen challenge neither LTC4 nor histamine measured in nasal lavage showed any significant change from pre-challenge baseline values. However, measurements of both mediators in the blown secretion showed a significantly higher concentration than in the pre- or post-challenge lavage samples, compatible with transitory release during the acute allergic reaction. However, it seems doubtful whether measurements of LTC4 or histamine can be compared between blown secretion and nasal lavage fluid, even if the dilution factor is disregarded.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increase of albumin, eosinophil cationic protein, histamine, leukotrienes and mast cell tryptase in nasal lavage fluid after challenge with inhalant allergen extract

Allergic rhinitis patients underwent nasal challenge with allergen extract. Before and up to 10 h after nasal provocation, nasal lavage was performed every hour. In about one-third of the patients a biphasic influx of albumin was observed: an initial increase of albumin within 30 min after provocation and a 2nd peak 6–8 h after provocation. Allergen-induced changes in histamine levels were less pronounced than those of albumin, but with some patients biphasic responses were also seen. Increased leukotriene formation mainly occurred within one hour after allergen provocation.From nasal washings of some patients, mast cell tryptase and eosinophil cationic protein (ECP) were estimated. Whereas tryptase was released within one hour after nasal provocation, significant ECP release started 3 h later.     

Allergen-induced inflammation in the nose: a comparison of acute and repeated low-dose allergen exposure

To investigate allergic rhinitis induced by two experimental provocation models, we compared local inflammation with markers of eosinophil activity in peripheral blood. Patients with strictly seasonal allergic rhinitis were selected and investigated outside the pollen season. An acute challenge with increasing doses of allergen every 15 min until symptoms occurred was performed in nine patients. Nasal lavage and blood samples were taken before and 4 and 24 h after challenge. After a 6-week washout period, 10 patients were submitted to 7 days of repeated low allergen exposures. One small dose (∼ 1/100 of the acute dose) was given each day. Blood and lavage samples were taken prior to and after the period. As control four patients were challenged with diluent only. The acute challenge resulted in sneezing and nasal discharge and blockage and was accompanied by a rise in histamine and eosinophil cationic protein (ECP) in lavage fluid after 4 h and continuing after 24 h, when there also was a rise in the number of eosinophils and ECP in peripheral blood. The repeated low-dose exposures caused very few symptoms but produced increased ECP in the lavage fluid and a trend toward increased histamine concentration. There were no changes in ECP, intracellular EG2 binding, or number of eosinophils in the blood. No changes were seen in the control group. Our findings show that changes in eosinophil mediator release in nasal lavage can be seen after very low, but repeated, allergen exposures despite no, or minimal, clinical symptoms.     

Nasal challenge studies with bradykinin: influence upon mediator generation

Previous studies have shown that nasal allergen provocation leads to dose-dependent increases of inflammatory mediators, e.g. histamine, kinins, LTC4 and PGD2 in nasal lavages. To investigate further the interaction of these mediators, a titration study with intranasal bradykinin (Bk) application (maximal dose 100 nmol/nostril) and consecutive lavage were performed in eight grass-pollen-allergic patients out of season, and five controls. The nasal lavages were analysed for albumin, N-alpha-tosyl-L-arginine methyl ester (TAME) esterase activity, histamine, 9 alpha,11 beta-PGF2, and LTC4. The clinical reactions were measured with a subjective symptom score. A dose-dependent elevation of albumin was found which was significantly higher in patients with allergic and non-allergic rhinitis compared with normal volunteers. TAME-esterase activity also increased in relation to the dosage of Bk given without significant difference between the various groups. No influence on histamine, LTC4 and 9 alpha,11 beta-PGF2, release (PGD2 metabolite) was seen. Short-lasting clinical symptoms like irritation, sneezing, and obstruction were noticed after the two highest Bk dosages (10 and 100 nmol). We conclude that intranasally applied Bk induces a dose-dependent plasma leakage into the nasal cavity, which is significantly higher in patients with seasonal allergic rhinitis out of season compared to normals. Bk does not seem to affect the mast cell since histamine, LTC4 and 9 alpha,11 beta-PGF2 levels do not alter. The ability to induce relevant symptoms of rhinitis provides strong support for the hypothesis that kinins may be important mediators of inflammatory disorders of the upper airways.     

Isolated early response after nasal allergen challenge is sufficient to induce nasal hyperreactivity.

Ten rhinitic patients allergic to grass pollen were challenged with histamine intranasally 24 hours before and 24 hours after nasal provocation with grass pollen. Up to ten hours after allergen provocation nasal lavage fluid was obtained to characterize early and late phase reactions by measuring the levels of histamine and leukotrienes as indicators of mediator release, and albumin as a marker of increased vasopermeability. Ten minutes after allergen challenge with 10,000 BU grass pollen extract LTC4,D4, and albumin significantly increased from 62 to 576 pg/mL (P = .008) and from 15 to 81 micrograms/mL (P = .008), respectively, without significant changes after placebo challenge a week earlier. Although the patients showed increased responsiveness to histamine after allergen challenge compared with a placebo-challenged control group (P = .02), one patient only demonstrated a late phase nasal allergic reaction characterized by recurrence of clinical symptoms eight to ten hours after allergen challenge and recurrence of mediators in lavage fluid. It is concluded that an isolated early response after allergen challenge is sufficient to induce nasal hyperreactivity. A biochemically or clinically defined late phase allergic reaction does not necessarily accompany allergen-induced hyperreactivity.     

Immunological and non-immunological release of leukotrienes and histamine from human nasal polyps

Nasal polyps were obtained from 22 patients undergoing polyp surgery. They were chopped into fragments of approximately 2 mm2, washed free of blood, and passively sensitized with serum from timothy allergen sensitive patients (RAST 30-40%), then, challenged with timothy allergen. Analysis of the incubation medium after a 30 min challenge as assessed by reversed phase high performance liquid chromatography and bioassay revealed the presence of leukotriene (LT) LTB4, LTC4, LTD4 and LTE4 (29 +/- 9, 6.6 +/- 3, 62 +/- 13 & 86 +/- 23 pmol/g tissue wet weight, respectively). The human nasal polyps also released histamine which reached a maximum after approximately 5 min (2.8 +/- 1.28 nmol/g tissue), as measured by radioenzymatic assay. A similar profile of leukotrienes and histamine release was observed when the nasal polyps were stimulated with ionophore A23187. However, the ionophore stimulated release was greater than that observed for the antigen challenge. When human polyps were stimulated with a mixture of the ionophore and arachidonic acid, all the above products as well as 5-hydroxy-eicosatetraenoic acid (5-HETE), 12-HETE, and 15-HETE were detected in the medium. These data, taken together, demonstrate that human nasal polyps are able to release significant amounts of leukotrienes and histamine upon both immunological and non-immunological stimulations and that these responses might significantly contribute to the symptoms of allergic rhinitis.     

Mediator release after endobronchial antigen challenge in patients with respiratory allergy.

The aim of the present study was to evaluate the release of some potential mediators of allergic reactions, such as histamine, peptide leukotrienes (LTs), LTB4 and prostaglandin D2 (PGD2), in bronchoalveolar lavage (BAL) fluids from 11 patients with respiratory allergy (eight with bronchial asthma and three with allergic rhinitis), who underwent specific endobronchial challenge. Histamine, peptide LT, and PGD2 levels in BAL fluids increased significantly after antigen stimulation both in patients with asthma and in patients with rhinitis. By contrast, LTB4 concentration was always below the limits of detection of the radioimmunoassay. In patients with asthma, histamine concentration increased from 5.3 +/- 0.6 ng/ml in lavages obtained before provocation to 20.2 +/- 5.8 ng/ml (mean +/- SEM; p less than 0.04) 5 minutes after bronchoprovocation. Peptide LTs increased from 0.32 +/- 0.08 to 0.82 +/- 0.21 ng/ml (p less than 0.02) and PGD2 from 0.06 +/- 0.01 ng/ml to 0.36 +/- 0.09 ng/ml (p less than 0.02). Elevated histamine, peptide LT, and PGD2 concentrations were also found in the 15-minute postchallenge BAL fluids. Similar results were obtained in patients with rhinitis. Histamine concentration was 3.4 +/- 0.6 ng/ml in prechallenge bronchial lavages and 11.3 +/- 1.7 ng/ml in postchallenge lavages; peptide LTs increased from 0.13 +/- 0.008 ng/ml to 0.73 +/- 0.21 ng/ml, and PGD2 from 0.05 +/- 0.01 ng/ml to 0.26 +/- 0.06 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of allergen-induced late inflammatory reactions in the nose and in the skin in house dust mite-allergic patients with or without asthma

BACKGROUND: It remains to be established which factors contribute to the occurrence of asthma in allergic individuals. We hypothesized that differences in the late allergic inflammatory reaction to allergen between asthmatic and non-asthmatic house dust mite-allergic individuals might contribute to the difference in the clinical presentation of allergy. AIM: To compare allergen-induced changes in parameters for cellular inflammation during the phase of the late allergic reaction in the skin and nose, in house dust mite-allergic individuals with or without asthma. MATERIAL AND METHODS: Nasal and dermal allergen challenges with house dust mite (Dermatophagoides pteronyssinus) extract were performed in 52 house dust mite-allergic individuals, of whom 26 had mild to moderate persistent asthma and 26 had perennial rhinitis without current or past asthmatic symptoms. Serial nasal lavage samples were analyzed for the presence of inflammatory cells (eosinophils and neutrophils) and soluble markers associated with cellular inflammation [interleukin-5 (IL-5), interleukin-8 (IL-8), eosinophil cationic protein (ECP) and myeloperoxidase (MPO)]. Macroscopic late phase skin reactions were studied after intracutaneous skin tests with house dust mite extract. RESULTS: Fixed dose nasal allergen provocation elicited a similar degree of immediate allergic reaction as judged by plasma protein exudation and histamine concentrations in asthma and non-asthmatic rhinitis. Subsequently, no differences between groups were found during the phase of the late allergic reaction (4-24 h) in inflammatory cell influx, plasma protein leakage, ECP or MPO. Likewise, there were no differences in levels of chemotactic cytokines IL-5 and IL-8. In agreement with the results of nasal challenge, the late skin reaction after dermal challenge with a fixed allergen dose and after an allergen dose 10,000 times above the skin threshold for an early skin reaction did not differ between the groups. CONCLUSION: House dust mite-allergic patients with or without asthma have very similar late allergic inflammatory reactions in the skin and in the nose after allergen challenge. Hence, it is unlikely that the occurrence of pulmonary symptoms in asthma is explained by a general tendency of asthmatics to have an enhanced late allergic cellular inflammatory response. Nasal and dermal allergen provocations are adequate models to study allergen-induced inflammation but probably lack the pivotal link which is essential for the development of asthma.     

Release of prostaglandin D2 and leukotriene C4 in response to hyperosmolar stimulation of mast cells

BACKGROUND: Mannitol-induced bronchoconstriction in subjects with exercise-induced asthma is associated with increased urinary excretion of 9alpha, 11beta-PGF(2), a metabolite of prostaglandin D(2) (PGD(2)) serving as a mast cell marker. It has however been questioned whether or not human mast cells release PGD(2) and leukotriene C(4) (LTC(4)) after osmotic challenge with mannitol in vitro. METHODS: Cord blood-derived human mast cells were stimulated osmotically, immunologically or with a combination of both. Supernatants were analysed for PGD(2), LTC(4) and histamine contents with enzyme immunoassays. RESULTS: Significant release of de novo synthesized eicosanoids, predominantly PGD(2) [12 (8.8, 14) pmol/10(6)cells; median (25th, 75th percentile) but also LTC(4) (0.1 (0.08, 0.15) pmol/10(6) cells] were found in mast cells in vitro in response to 0.7 M mannitol stimulation. A massive release of histamine [70 (5.3)% of total; mean (SEM)] was also found. There were no correlations between the levels of released mediators after mannitol stimulation. In contrast, there was a correlation between release of PGD(2) and LTC(4), following immunological stimulation. CONCLUSION: The findings support that hyperosmolar challenge activates mast cells, but different than antigen stimulation.     

Mucosal output of eotaxin in allergic rhinitis and its attenuation by topical glucocorticosteroid treatment

BACKGROUND: Eotaxin is a chemokine that attracts and activates eosinophils. The present study examines the occurrence of eotaxin in nasal mucosal surface liquids in patients with seasonal allergic rhinitis without allergen exposure and during repeat allergen challenge with and without topical glucocorticosteroid treatment. The number of subepithelial eosinophils and mucosal outputs of bulk plasma (alpha2-macroglobulin) and eosinophil cationic protein (ECP) are also examined. METHODS: Twelve patients underwent daily allergen challenges for 6 days. Separately, 14 patients, who were receiving budesonide and placebo in a parallel group design, also underwent allergen challenge for 6 days. Nasal biopsies were obtained before and 24 h after the allergen challenge series, and lavages were carried out before and 15 min after selected allergen challenges. RESULTS: At baseline nasal lavage fluid levels of eotaxin correlated to levels of alpha2-macroglobulin and ECP. After the first allergen challenge there was a correlation between nasal lavage fluid levels of eotaxin and ECP. Repeat allergen exposure increased the mucosal output of eotaxin (P <0.05) and ECP (P <0.01) as well as eosinophil numbers (P <0.01), but no correlation was found between increased eosinophil numbers and eotaxin. Budesonide reduced eotaxin levels during repeat allergen challenge (P <0.05). CONCLUSIONS: Repeat allergen exposure in allergic rhinitis is associated with increased mucosal output of eotaxin. Topical budesonide attenuates this effect, suggesting the possibility that inhibitory effects on mucosal eotaxin may contribute to anti-eosinophilic actions of topical glucocorticosteroids.     

Optimisation of grass pollen nasal allergen challenge for assessment of clinical and immunological outcomes

Nasal allergen challenge can be used to assess the clinical and immunological aspects of rhinitis due to inhalant allergens. We aimed to develop a reproducible technique for grass pollen nasal allergen challenge and to study biomarkers within nasal secretions. 20 Grass pollen allergic individuals underwent nasal challenges with purified Timothy grass allergen. An initial dose-titration challenge was used to determine dose-response characteristics. Subsequently, volunteers underwent 3 further challenges using individualised threshold doses. Symptom scores, visual analogue scores, and peak nasal inspiratory flow (PNIF) were recorded at baseline and up to 6h after challenge. Nasal secretions were collected at each time point using synthetic filter papers or absorptive polyurethane sponges and analysed for IL-4, -5, -10, -13, IFN-γ, Tryptase and Eosinophil Cationic Protein (ECP). Challenges gave reproducible symptom scores and decreased PNIF. Tryptase levels in nasal fluid peaked at 5min after challenge and returned to baseline levels at 1h. ECP, IL-5, IL-13 and IL-4 levels were increased from 2-3h and showed progressive increases to 5-6h. Sponges proved the superior nasal fluid sampling technique. We have developed a reproducible nasal allergen challenge technique. This may be used as a surrogate clinical endpoint in trials assessing the efficacy of treatments for allergic rhinitis. Tryptase in local nasal secretions is a potential biomarker of the early phase response; ECP and the Th2 cytokines IL-5, -13 and -4 markers of late phase allergic responses. Our model allows correlation between clinical responses and local biomarkers following nasal allergen challenge.     

In vivo and ex vivo inhibitory effects of loratadine on histamine release in patients with allergic rhinitis

Background The aim of this study was to evaluate the in vivo and ex vivo effects of the H.-antagonist loratadine on histamine release.
Methods The study was designed as a double-blind, crossover trial. Ten patients with allergic rhinitis due to Dermatophagoides pteronyssinus were treated with loratadine (10 mg daily p.o.) and with placebo for 1 week, with a 2-week interval between the two treatments. Nasal lavages with saline solution were done before and after challenge with the relevant allergen at the end of treatments with loratadine and placebo. Venous blood was taken after treatments, and basophil histamine release induced by anti-IgE (10 μg/ml), N-formyl-methionyl-leucyl-phenylalanine (fMLP, 1 μM). and Ca²⁺ ionophore A23187 (1 μM) was evaluated by ati automated fluorometric method.
Results Treatment with loratadine attenuated early antigen-tnduced nasal obstruction, rhinorrhea. and itching. Nasal symptoms were accompanied by a significant histamine release in the nasal lavages collected 5 min after stimulation when the patients received placebo (median 4 ng/ml, range 1-28; P<0.05). After treatment with loratadine, histamine release in the 5-min postchallenge lavages was almost abrogated (median 0.5 ng/ml, range 0-3; P<0.01 vs placebo). Median anti-IgE-induced histamine release from basophils was 41.9% (range 27.8-79.2) after placebo and 30.0% (range 1.7-73.3, P < 0.05) after loratadine. Active treatment exerted an inhibitory effect also on basophil histamine release induced by fMLP and Ca²⁺ ionophore A23187.
Conclusions Treatment for 1 week with loratadine reduces allergen-mduced nasal symptoms and inhibits in vivo and ex vivo histamine release in patients with allergic rhinitis.     

Effects of bβ‐endorphin on nasal allergic inflammation

Background πβ‐endorphin is a derivative of pro‐opiomelanocortin. Cells of the immune system can also synthesize and secrete β‐endorphin. Its concentration is increased during the allergic reaction and during stress. Increased reactivity during psychological stress of allergic subjects is also well known. Objective Is β‐endorphin one physiological link between stress and an exacerbation of the allergic reaction? Methods First, intranasal β‐endorphin challenges with subsequent lavages to determine histamine and albumin levels and measurements of nasal flow and resistance in dose‐response and time course experiments were performed. Secondly, we examined whether β‐endorphin pre‐treatment increased the antigen‐induced release of histamine and albumin in nasal lavages and the clinical symptoms. Results Exogenous β‐endorphin (100 pM?10 µM/mL) induced a dose‐dependent increase in nasal symptoms in asymptomatic allergic subjects with rhinitis (n = 14) as well as in non‐allergic controls (n = 10), but did not release any mediators into nasal secretion. However, comparing the antigen‐evoked release of mediators into nasal secretions with that of a β‐endorphin pre‐treated antigen challenge we could note a significant enhancement of human serum albumin influx (P < 0.05) and histamine liberation (P < 0.05) 10 min after antigen challenge compared with the allergen challenge alone, with also a correlation with the more pronounced decrease in nasal flow (P < 0.05). Conclusion These results suggest that β‐endorphin‐induced increase in nasal congestion is mediated through direct neuroendocrine receptor activation independent of mast cell activation and that during the allergic reaction there is a β‐endorphin/mast cell interaction that enhances the mediator response to nasal allergen challenge.     

Effect of continuous allergen challenge on clinical symptoms and mediator release in dust-mite-allergic patients

This study investigated the early, prolonged immediate, and late-phase reactions of dust-mite-sensitive subjects undergoing long-term challenge in the Vienna challenge chamber (VCC) in terms of clinical symptoms and inflammatory mediator level patterns in nasal lavage fluids. A concentration of 70 ng Der p 1/m³ of air (feces of Dermatopliagoides) was maintained over 8 h in the VCC. To show the clinical impact of this challenge model, the effect of a histamine H₁-receptor antagonist that also has some antiallergic properties (loratadine) was also investigated. The study followed a doubleblind, placebo-controlled, crossover design. Medication was given orally over 7 days before the provocation at a dose of 10 mg once daily. All 12 patients, whose dust-mite sensitivity was confirmed by disease history, skin prick test, and RAST, completed the challenge session. The documentation of the chosen parameters was performed every 30 min. Subjective nasal and ocular symptoms were assessed via a visual analog scale of 100 mm. nasal flow was recorded by active anterior rhinomanometry, and mediator release was evaluated with nasal lavages. Clinical aspect: the whole sample population showed a rise of nasal and ocular symptom severity and a nasal flow reduction, which were perceptibly, but not significantly attenuated by active drug treatment. Mediator pattern: in each patient, prostaglandin (PG)D₂ and leukotriene (LT)C₄ levels peaked within the first 2 h of provocation, PGD₂ then moving toward baseline levels, and LTC₄ then again rising continuously. Eosinophil cationic protein (ECP) exhibited a constant level increase over the whole provocation period, and tryptase levels did not change significantly. Whereas the area under the curve values of tryptase and ECP were higher in drug-treated patients than the placebo group, the early PGD, peak occurring during the first two challenge hours seemed to be mitigated by loratadine. These results reveal that there is no link between the clinical symptoms, the drug efficacy, and the released mediators (LTC₄, PGD₂, ECP and tryptase).     

Effect of intranasal fluticasone proprionate on the immediate and late allergic reaction and nasal hyperreactivity in patients with a house dust mite allergy

Background Patients with perennial allergic rhinitis develop nasal symptoms not only after allergen exposure, but generally also after non-specific stimuli. Objective To evaluate the effect of 2 week's treatment with fluticasone propionate aqueous nasal spray (FPANS) on the nasal clinical response, inflammatory mediators and nasal hyperreactivity. Methods Twenty-four rhinitis patients allergic to house dust mite (HDM). participated in a douhle-blind. placebo-controlled crossover study. After 2 week's treatment with placebo or 200 μg FPANS twice daily, patients were challenged with HDM extract. Symptoms were recorded and nasal lavages were collected for up to 9.5 h after challenge. Nasal hyperreaclivity was determined by histamine challenge 24 h later. Results Because of a carry-over effect for the immediate symptom score, for this variable only the data from the first treatment period were used. FPANS treatment resulted in a significant decrease of nasal symptoms with 70%. 69% and 63% after 100. 1000 and 10000 Biological Units (BU)/mL of HDM extract respectively. Active treatment resulted in a 76% decrease of the late-phase symptoms. FPANS treatment significantly reduced albumin influx after HDM 1000 BU/mL with 62% and tended to reduce tryptase release after HDM 1000 BU ml. (P 0.0629). During the late phase FPANS treatment reduced albumin influx with 67% and eosinophil cationic protein (ECP) release with 83%. No effect of FPANS was seen on histamine levels. FPANS significantly decreased histamine-induced symptom score with 34%, secretion with 32%, and sneezes with 41%. Conclusion FPANS significantly inhibits the immediate and late allergic response, and nasal hyperreactivity, probably by suppressing mast cells and eosinophils in the nasal mucosa.     

Mediator release is altered in immunotherapy-treated patients: a 4-ear study

In recent years, it has been possible to demonstrate mediator release into the nasal secretion after nasal allergen challenge in patients with allergic rhinitis. Using the nasal provocation model, we determined whether the mediator release was altered in immunotherapy-treated patients. Seventeen grass-pollen-allergic patients were examined under controlled, reproducible conditions. Serial challenges with increasing doses of grass pollen produced increasing numbers of clinical symptoms and release of mediators such as kinins, TAME-esterase activity, and histamine. Ten patients received a semidepot perennial grass-pollen extract for 4 years. Seven patients served as controls and did not receive immunotherapy during the observation period. Data from the group of patients receiving immunotherapy over the first year already showed a partially significant decline in the maximal mediator release after nasal allergen challenges compared to the results of pretreated challenges, whereas controls did not show any significant changes. Nasal allergen challenges after termination of 4 years' immunotherapy significantly modified the mediator release compared to pretreatment values (TAME-esterase activity P<0.05, kinins P<0.01, and histamine P<0.01). Decrease of mediator release paralleled the symptom-medication scores and quantitative skin prick test. Finally, we could demonstrate a significant correlation between specific IgG increase and mediator decrease in the treated group.     

Inhibition of mediator and cytokine release from dispersed nasal polyp cells by mizolastine

BACKGROUND: Mizolastine is a potent and selective H1-receptor antagonist with antiallergic properties; in in-vitro animal models, mizolastine was shown to inhibit 5-lipoxygenase activity and to decrease the release of leukotrienes (LT) and tumor necrosis factor-alpha (TNF-alpha). This study investigated the effects of three concentrations of mizolastine (0.1, 1.0, 10 microM) on the release of LT (LTB4 and LTC4/D4) and prostaglandin D2 (PGD2) after stimulation by anti-IgE, and on the spontaneous release of cytokines (TNF-alpha and granulocyte/macrophage-colony-stimulating factor [GM-CSF]), from dispersed cells obtained from surgically resected nasal polyps of patients with nasal polyposis. METHODS: Cells from nasal polyps were obtained using enzymatic dispersion. For experiments involving the measurement of LT and PGD2, the cells were preincubated with mizolastine or its dissolution vehicle for 20 min prior to challenge with 10 microg/ml epsilon-chain specific anti-IgE for 45 min at 37 degrees C; for the cytokine release, cells were incubated with mizolastine or its dissolution vehicle for 24 h. LT and PGD2 were measured by enzyme immunoassay (EIA) and cytokines by enzyme-linked immunosorbent assay (ELISA) using commercially available kits. RESULTS: Mizolastine inhibited significantly and in a dose-dependent manner the release of LTB4 and TNF-alpha at all concentrations, LTC4/D4 at 10 microM, and GM-CSF from 1 microM; no effect was observed on the release of PGD2. CONCLUSION: Mizolastine inhibits the release of LT, TNF-alpha and GM-CSF in this in vitro model, which mimics closely the inflammatory cells of allergic rhinitis.     

Eustachian tube function associated with histamine-induced and ragweed-induced rhinitis

Nasal allergies may contribute to Eustachian tube dysfunction and chronic middle ear problems. In exploring this association further, Eustachian tube function was measured in ten ragweed-allergic and eight non-allergic patients undergoing repetitive nasal provocation. Anterior nasal provocation was done using paper disks impregnated with either histamine or aqueous ragweed allergen. Increasing concentrations of the provocative agent were placed on both inferior nasal turbinates until moderate symptoms of rhinitis developed. Eustachian tube function was evaluated using the 9-step inflation-deflation tympanometric test before and immediately after each nasal challenge. Eustachian obstruction developed in 4 of 38 non-allergic ears during histamine nasal provocation. With ragweed nasal challenge, 9 of 42 allergic ears developed Eustachian tube obstruction. Four allergic ears gained Eustachian tube function despite being obstructed before the challenge. The observed changes in ear function for both groups were not significant due to variability in Eustachian response. At the concentrations which initiated symptoms of rhinitis, nasal provocation with histamine or ragweed did not consistently obstruct the Eustachian tube. We conclude that mild symptoms of allergic rhinitis may not cause significant Eustachian tube obstruction.     

A single nasal allergen challenge increases induced sputum inflammatory markers in non-asthmatic subjects with seasonal allergic rhinitis: correlation with plasma interleukin-5

BACKGROUND: Seasonal allergic rhinitis (SAR) is a risk factor for asthma in affected individuals. Nasal allergic inflammation enhances bone-marrow eosinophil production, mainly via IL-5, and rhinitis patients have increased airway inflammation during the pollen season. OBJECTIVE: To assess the impact of nasal allergy on sputum inflammatory markers. METHODS: In an open-labelled, randomized, placebo-controlled cross-over study with 16 non-asthmatic SAR patients (median age 25 years, 56% males), the effect of a single nasal allergen challenge performed out of season on induced sputum inflammatory parameters was evaluated. SAR patients were identified by history, skin-prick test and specific IgE. All patients had normal lung function/bronchial hyper-responsiveness out of season and a negative asthma/wheezing history. Sputum cells and supernatant levels of ECP, sICAM, IL-5 and IL-10, and plasma levels of IL-5 and ECP, were measured before and 24 h after nasal allergen challenge. After a washout period of at least 4 weeks, the procedure was repeated with placebo challenge (diluent). RESULTS: Nasal allergen challenge led to an increase in sputum ECP (pre = 60 +/- 12, post = 212 +/- 63 micro g/L, P = 0.02 vs. placebo), and sICAM (4.8 +/- 2.7 to 6.5 +/- 2.9 ng/mL, P = 0.02 vs. placebo), whereas IL-10 decreased after provocation (44 +/- 11 to 29 +/- 6 pg/mL, P = 0.06 vs. placebo). Sputum IL-5 was undetectable in all patients. The absolute number of blood and sputum eosinophils did not change significantly after allergen or placebo challenge (P > 0.07, both comparisons). Plasma levels of IL-5 increased after allergen challenge (8.7 +/- 2.9 to 14.5 +/- 3.9 pg/mL, P = 0.001), and the increase in plasma IL-5 was positively correlated with the rise in sputum ECP in a subgroup of 'responders' (n = 12, r = 0.71, P = 0.01). CONCLUSIONS: A single nasal allergen challenge in SAR patients increased markers of allergic inflammation in the lower respiratory tract, possibly via pronounced activation of inflammatory cells through circulating immediate-type reaction cytokines like IL-5. These findings may provide additional explanatory data for the high susceptibility of SAR patients to incident asthma.     

Allergen-Induced Release of Sulphidopeptide Leukotrienes (SRS-A) and LTB4 in Allergic Rhinitis

Leukotrienes are a recently discovered group of arachidonic acid-derived lipid mediators. Using radioimmunoassay and high pressure liquid chromatography (HPLC), we have identified the SRS-A sulphidopeptide leukotrienes (LTC4, LTD4 and LTE4) in nasal washings from patients with allergic rhinitis who underwent nasal challenge with specific allergen. Smaller, but significant, amounts of LTB4 were also detected. The concentrations of nasal leukotrienes were directly related to the dose of allergen, and were recovered in washings in a time-dependent fashion after challenge. When the patients were subjected to methacholine nasal challenge on a control day, we found only negligible amounts of either the sulphidopeptide leukotrienes or LTB4. These findings support the view that LTC4, LTD4 and LTE4 might contribute to the pathogenesis of allergic rhinitis as a result of their recognized effects on mucous hypersecretion and vasopermeability, and that the potent chemoattractant LTB4 might be involved in the subsequent infiltration of inflammatory cells.