Antigen-provoked increase in histamine reactivity. Observations on mechanisms

T Cell-Mediated Nasal Hyperresponsiveness in Allergic Rhinitis

Allergic rhinitis patients suffer various symptoms such as sneezing, runny nose, and nasal congestion. As disease severity and chronicity progress, nasal hyperresponsiveness (NHR) develops in those patients. During the generation of a mouse allergic rhinitis model, we discovered that immunized mice developed NHR upon repeated nasal antigen challenge. Using genetically modified mice and an originally developed T cell-transferred mouse model, we confirmed the critical role of CD4⁺ T cells after differentiation into several helper subsets in NHR. On the other hand, immunoglobulin E/mast cell-dependent responses that are critical for evoking nasal symptoms and eosinophils that accumulate in allergic inflammation sites were dispensable. A steroid, but not drugs targeting mast cell-derived mediators, was effective in alleviating NHR. The possible generation of a new means to treat allergic rhinitis by targeting T cell-derived NHR-inducing factors is suggested.

Sports activities enhance the prevalence of rhinitis symptoms in schoolchildren

BACKGROUND

To evaluate the association between sports activities and allergic symptoms, especially rhinitis, among schoolchildren.

METHODS

This longitudinal survey of schoolchildren collected data from questionnaires regarding allergic symptoms based on the International Study of Asthma and Allergies in Childhood (ISAAC) program and sports participation that were distributed to the parents of children at all 12 public primary schools in Ohmi-Hachiman City, Shiga Prefecture, Japan. Data were collected annually from 2011 until 2014, when the children reached 10 years of age. Blood samples were obtained in 2014, and the levels of immunoglobulin (Ig)E specific to four inhalant allergens were measured.

RESULTS

Data from 558 children were analyzed. At 10 years of age, prevalence of asthma and eczema did not differ significantly, while rhinitis was significantly higher (p = 0.009) among children who participated in sports. Prevalence of rhinitis increased as the frequency or duration of sports participation increased (p < 0.01). The prevalence of new-onset rhinitis increased significantly among 10-year-olds with increasing duration of participation in sports (p = 0.03). Among those who participated in continuous sports activities, the prevalence of rhinitis was significantly higher with prolonged eczema (p = 0.006). Sports activities did not increase sensitization to inhalant allergens.

CONCLUSION

Sports activities enhance the prevalence of rhinitis in schoolchildren. Prolonged eczema, together with sports participation, further promotes the symptoms. The mechanisms of these novel findings warrant further investigation.

Essential Contribution of CD4+ T Cells to Antigen-Induced Nasal Hyperresponsiveness in Experimental Allergic Rhinitis

Nasal hyperresponsiveness (NHR) is a characteristic feature of allergic rhinitis (AR); however, the pathogenesis of NHR is not fully understood. In this study, during the establishment of an experimental AR model using ovalbumin-immunized and -challenged mice, augmentation of the sneezing reaction in response to nonspecific proteins as well as a chemical stimulant was detected. Whether NHR is independent of mast cells and eosinophils was determined by using mast cell- and eosinophil-deficient mice. NHR was suppressed by treatment with anti-CD4 antibody, suggesting the pivotal contribution of CD4+ T cells. Furthermore, antigen challenge to mice to which in vitro-differentiated Th1, Th2, and Th17 cells but not naïve CD4+ T cells had been adoptively transferred led to the development of equivalent NHR. Since antigen-specific IgE and IgG were not produced in these mice and since antigen-specific IgE-transgenic mice did not develop NHR even upon antigen challenge, humoral immunity would be dispensable for NHR. CD4+ T cells play a crucial role in the pathogenesis of AR via induction of NHR, independent of IgE-, mast cell-, and eosinophil-mediated responses.

Clinical practice. Allergic rhinitis

A 35-year-old woman has a history of nasal congestion on most days of the year, dating back to her late teens. She has chronic nasal drainage, which is clear and thick. Her congestion is worst in the late summer and early fall and again in the early spring; at these times, she also has sneezing, nasal itching, and cough. Five years ago, she had an episode of shortness of breath with wheezing on a day when her nasal symptoms were severe, but this episode resolved spontaneously and has not recurred. Her eyes do not bother her. Over-the-counter oral antihistamines help her symptoms a little, as do nasal decongestants, which she uses occasionally. Her 6-year-old son has similar symptoms. How should this case be managed?

Animal studies supporting the inhibition of mast cell activation by Eriobotrya japonica seed extract

Objectives

The potent antioxidant activity of Eriobotrya japonica seed extract (ESE) and its usefulness in the prevention and treatment of various disorders has been reported previously. Its antioxidant activity associated with β-sitosterol and polyphenols contained in the extract was also validated. In this study, anti-allergic activity of Eriobotrya japonica seed extract was investigated.

Methods

The inhibition of histamine release-mediated type 1 allergy by Eriobotrya japonica seed extract was used as an index.

Key findings

The administration of this extract inhibited histamine release from rat mast cells, suggesting its usefulness in allergic disease treatment. In an experiment using a guineapig allergic rhinitis model, this extract reduced the frequency of sneezing and nose-scratching.

Conclusions

These results suggest that Eriobotrya japonica seed extract may contribute to the relief of allergic disease-related symptoms.

EAACI position paper on occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and non-European countries on Occupational Rhinitis (OR), a disease of emerging relevance which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored on that of occupational asthma, as well as a diagnostic algorithm based on steps allowing for different levels of diagnostic evidence are proposed. The needs for future research are pointed out. Key messages are issued for each item.

Occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and nonEuropean countries on Occupational Rhinitis (OR), a disease of emerging relevance, which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored to that of occupational asthma, as well as a diagnostic algorithm based on steps allowing different levels of diagnostic evidence, are proposed. The needs for future research are pointed out. Key messages are issued for each item.

Objective monitoring of nasal patency and nasal physiology in rhinitis

Nasal obstruction can be monitored objectively by measurement of nasal airflow, as evaluated by nasal peak flow, or as airways resistance/conductance as evaluated by rhinomanometry. Peak flow can be measured during inspiration or expiration. Of these measurements, nasal inspiratory peak flow is the best validated technique for home monitoring in clinical trials. The equipment is portable, relatively inexpensive, and simple to use. One disadvantage, however, is that nasal inspiratory peak flow is influenced by lower airway as well as upper airway function. Rhinomanometry is a more sensitive technique that is specific for nasal measurements. The equipment, however, requires an operator, is more expensive, and is not portable. Thus, it is applicable only for clinic visit measures in clinical trials. Measurements require patient cooperation and coordination, and not all can achieve repeatable results. Thus, this objective measure is best suited to laboratory challenge studies involving smaller numbers of selected volunteers. A nonphysiological measure of nasal patency is acoustic rhinometry. This sonic echo technique measures internal nasal luminal volume and the minimum cross-sectional area. The derivation of these measures from the reflected sound waves requires complex mathematical transformation and makes several theoretical assumptions. Despite this, however, such measures correlate well with the nasal physiological measures, and the nasal volume measures have been shown to relate well to results obtained by imaging techniques such as computed tomography scanning or magnetic resonance imaging. Like rhinomanometry, acoustic rhinometry is not suitable for home monitoring and can be applied only to clinic visit measures or for laboratory nasal challenge monitoring. It has advantages in being easy to use, in requiring little patient cooperation, and in providing repeatable results. In addition to nasal obstruction, allergic rhinitis is recognized to be associated with impaired mucociliary clearance and altered nasal responsiveness. Measures exist for the monitoring of these aspects of nasal dysfunction. Although measures of mucociliary clearance are simple to perform, they have a poor record of reproducibility. Their incorporation into clinical trials is thus questionable, although positive outcomes from therapeutic intervention have been reported. Measures of nasal responsiveness are at present largely confined to research studies investigating disease mechanisms in allergic and nonallergic rhinitis. The techniques are insufficiently standardized to be applied to multicenter clinical trials but could be used in limited-center studies to gain insight into the regulatory effects of different therapeutic modalities.

Antigen stimulation of TH2 cells augments acute bacterial sinusitis in mice

BACKGROUND

Previously, we showed that an ongoing nasal allergic response augmented bacterial sinusitis in mice. In those experiments mice were sensitized to ovalbumin (OVA) by means of intraperitoneal injections of OVA-alum and then exposed to OVA intranasally before being infected with Streptococcus pneumoniae.

OBJECTIVE

We sought to study the importance of TH2 cells and to eliminate potential alum effects.

METHODS

In this study we sensitized mice by adoptively transferring OVA-specific TH2- or TH1-skewed cells.

RESULTS

TH2 passive sensitization followed by intranasal OVA showed a robust local eosinophilic response (5-fold increase) compared with that seen in mice with only TH2 passive sensitization alone (P <.001). Mice with TH2 passive sensitization and intranasal OVA exposure followed by infection showed an increase in the number of recovered S pneumoniae (P <.05) and an increase in sinus inflammation compared with that seen in those with infection alone (P <.01). In contrast, mice passively sensitized with TH1 followed by intranasal OVA exposure and infection showed no significant increase in the recovery of S pneumoniae and sinus inflammation compared with those with infection alone.

CONCLUSIONS

These data support the importance of antigen-stimulated TH2 cells in the augmented response to infection in allergic mice. Whether the increased infection is related to the direct effect of TH2 cells and their cytokines or subsequent recruitment of other cells, such as eosinophils, will be determined in further studies.

Kinins are involved in the development of allergic nasal hyperresponsiveness in guinea pigs

We evaluated roles of kinins in allergen-induced nasal blockage and sneezing, and development of nasal hyperresponsiveness to leukotriene D4 in a Japanese cedar pollen-induced allergic rhinitis model of guinea pigs. Sensitised guinea pigs were repeatedly challenged by pollen inhalation once every week. Neither a bradykinin B1 receptor antagonist, des-Arg9-[Leu8]bradykinin nor a bradykinin B2 receptor antagonist, icatibant suppressed allergen-induced sneezing and nasal blockage. However, development of nasal hyperresponsiveness to leukotriene D4 was significantly suppressed by them. The amount of bradykinin in nasal cavity lavage fluid was immediately increased after the challenge. In non-sensitised animals, hyperresponsiveness to leukotriene D4 was developed by a bradykinin B2 receptor agonist, bradykinin, but not by a bradykinin B1 receptor agonist, des-Arg10-kallidin, while in the sensitised-challenged animal, both agonists developed hyperresponsiveness. In conclusion, the nasal hyperresponsiveness appeared to be induced by kinins produced in response to the antigen challenge through activation of not only bradykinin B2 but also B1 receptors.

Hot, humid air increases cellular influx during the late-phase response to nasal challenge with antigen

BACKGROUND

Inhalation of hot, humid air (HHA: 37 degrees C, > 95% relative humidity (RH)) partially inhibits the early response to nasal challenge with antigen.

OBJECTIVE

To investigate whether HHA inhibited the late-phase response to nasal challenge with antigen and increased hyper-responsiveness of the nasal mucosa to histamine.

METHODS

Twenty subjects with seasonal allergic rhinitis, outside of their allergy season, participated in a randomized, 2-way cross-over study. The subjects continuously breathed room air (25 degrees C, 30% RH) or HHA delivered via a face mask during the entire experiment. Subjects were challenged intranasally with antigen 1 h after beginning conditioning. The response was monitored by symptoms and nasal lavage at 2-h intervals after the last antigen challenge. Eight hours after antigen challenge, nasal challenge with histamine was performed.

RESULTS

Exposure to HHA significantly increased nasal mucosal temperature from baseline without affecting nasal secretion osmolality. HHA significantly inhibited antigen-induced sneezes, congestion, pruritus, and human serum albumin levels during the early response to antigen challenge. HHA exposure, however, was associated with an 8-fold increase in the eosinophil influx and a 15-fold increase in the levels of eosinophil cationic protein during the late-phase response compared to room air. There were no significant differences in nasal hyper-responsiveness to histamine during either exposure.

CONCLUSION

HHA partially decreases the early response to nasal challenge with antigen, but dramatically increases eosinophil influx. Increasing eosinophil number had no effects on the hyper-responsiveness to histamine. We speculate that the physical conditions of air differentially impact the stages of allergic inflammation.

Comparison of cedar pollen-induced allergic rhinitis in passively and actively sensitized guinea pigs

We have developed an allergic rhinitis model in guinea pigs using Japanese cedar pollen as antigen. In the present study, we examined whether provocation by pollen induces similar magnitudes of rhinitis symptoms in passively and actively sensitized guinea pigs. One group of animals was actively sensitized by intranasal application of pollen extract, and another was passively sensitized by intraperitoneal injection with anti-pollen serum. Actively and passively sensitized groups were then challenged by repeated and a single pollen inhalation, respectively. In both groups, sneeze was induced immediately after the challenge. The actively sensitized animals developed not only early but also late nasal blockage, whereas the passively sensitized animals showed only early nasal blockage. In both groups, an H1 antagonist, mepyramine, inhibited the occurrence of sneezing but did not inhibit nasal blockage. Nasal hyperresponsiveness to intranasal instillation of leukotriene D4 was obvious only in the actively sensitized animals. We thus conclude that although early nasal blockage is induced by a single antigen-antibody reaction, repetitive anaphylactic reaction is required for occurrence of late nasal blockage and hyperresponsiveness to stimuli. Furthermore, histamine plays a central role in induction of sneezing but not in nasal blockage, irrespective of whether animals are actively or passively sensitized.

Natural and induced allergic responses increase the ability of the nose to warm and humidify air

BACKGROUND

We have previously shown that subjects with seasonal allergic rhinitis out of season had a reduced ability to warm and humidify air compared with normal subjects.

OBJECTIVE

We sought to investigate whether allergic reactions induced by either seasonal exposure or nasal challenge with antigen would decrease the capacity of the nose to condition cold, dry air.

METHODS

We performed two prospective studies comparing the effects of allergic inflammation, induced by either seasonal exposure or nasal challenge with antigen, on nasal conditioning capacity (NCC). The total water gradient (WG) across the nose was used to represent the NCC. In the first study, the NCC was measured and compared before and during the allergy season in 10 subjects with seasonal allergic rhinitis. In the second study, 20 subjects with seasonal allergic rhinitis were recruited outside of the allergy season. NCC was measured and compared before and 24 hours after challenge with antigen.

RESULTS

In the first study, seasonal allergic subjects in season showed a significant increase in NCC when compared with their preseason baseline (total WG in season: 2050 +/- 138 mg vs total WG preseason: 1524 +/- 100 mg; P <.01). In the second study, antigen challenge led to early-phase and late-phase responses. There was a statistically significant increase in NCC 24 hours after antigen challenge compared with that before antigen challenge (total WG after antigen challenge: 1938 +/- 101 mg vs total WG before antigen challenge: 1648 +/- 84 mg; P =.01).

CONCLUSION

Allergic reactions induced by either seasonal exposure or antigen challenge increase the ability of the nose to condition inspired air. We speculate that allergic inflammation increases this ability by changing the perimeter of the nasal cavity.

Induction by inhibitors of nitric oxide synthase of hyperresponsiveness in the human nasal airway

1. The effects of inhibitors of nitric oxide synthase (NOS) on the responsiveness of the human nasal airway were investigated, by measuring the nasal response to histamine and bradykinin. 2. Repeated intranasal administration of N(G)-nitro-L-arginine methyl ester (L-NAME) or N(G)-monomethyl-L-arginine (L-NMMA), 1 micromol per nostril every 30 min for 6 h, increased the nasal obstruction induced by histamine, 50 - 500 microg, and bradykinin, 200 microg per nostril. A single administration of L-NAME, 1 micromol per nostril did not induce hyperresponsiveness to histamine. 3. Pretreatment with L-arginine, 30 micromol, abolished the hyperresponsiveness to histamine caused by L-NAME, 1 micromol. Pretreatment with N(G)-nitro-D-arginine methyl ester (D-NAME), 1 micromol, did not induce hyperresponsiveness to histamine. 4. Repeated administration of L-NAME, 1 micromol, caused a significant reduction in the amount of nitric oxide measured in the nasal cavity. 5. Neither L-NMMA, 1 micromol, nor L-arginine, 30 micromol, altered the nasal hyperresponsiveness induced by platelet activating factor (PAF), 60 microg. PAF did not alter the levels of nitric oxide in the nasal cavity. 6. The results suggest that inhibition of nitric oxide synthase induces a hyperresponsiveness in the human nasal airway, and that this occurs by a mechanism different from that involved in PAF-induced hyperresponsiveness.

Effect of systemic corticoid and antihistamine alone or in combination on elements of the response to a two dose nasal allergen challenge

This study examined the effects of low dose systemic corticoid (methylprednisolone, MP), standard dose antihistamine (terfenadine, TF) or the combination on response to out-of-season acute allergen challenge. We feel that a single dose challenge delivered to the nose may represent real disease imperfectly and in this study used two doses given 1 hour apart, hoping to approximate better the circumstances of natural allergen stimulation. The study used clinical endpoints only: measured nasal airway resistance (NAR), sneeze count, and weight of blown nasal secretions. Subjects showed similar NAR, sneezing, and secretion response to both challenges. With placebo treatment, NAR rose after the first allergen provocation and returned to baseline about 30 minutes later. Antihistamine pretreatment appeared to delay but did not prevent this rise; low dose corticoid partially inhibited it, and the combination totally ablated the response. All active treatments suppressed sneezing and secretion better than placebo. Combination corticoid/antihistamine treatment showed no greater effect on sneeze/ secretion than did antihistamine alone; this differs from our findings in separate studies comparing analogous drug combinations in naturally-acquired ragweed hayfever.

Challenge tests in nose and bronchi: pharmacological modulation of rhinitis and asthma

In order to study the pathophysiology of allergic airway disease and its response to pharmacotherapy, allergic and non-allergic provocation challenge techniques can be employed. Lower airway challenge has been used widely, but the use of nasal challenge is becoming more widespread as its advantages are realized. New measurement techniques are also being used (e.g. acoustic rhinometry), along with more classical methods such as spirometry, peak airflow rate and symptom scores, to determine the response to challenge. In the lungs, allergen challenge produces a biphasic response, which is less clearly defined in the nose. Topical histamine challenge closely resembles the effects of an allergic reaction and acts by stimulating sensory nerve endings. Methacholine is also often used for nasal challenge (often in addition to histamine), due to its effects on glandular sensitivity. Exercise induces bronchoconstriction in asthmatics and can be imitated by inhalation of cold, dry air. Cold air induces glandular hypersecretion and nasal discharge in normal subjects, which is increased in severity in rhinitic patients. Drug effect investigations using antihistamines have shown that histamine is important in producing the symptom of sneezing, whereas nasal blockage is due to vasodilatation rather than plasma exudation and oedema. Beta 2-agonists reduce allergen-induced symptoms by stabilizing mast cells, whereas cholinoceptor antagonists reduce watery nasal secretion. Increased responsiveness of sensory nerves and nasal glands is a characteristic clinical feature of asthma and rhinitis, which is responsible for the symptomatology. These effects can be reduced by topical corticosteroids.

Selective recruitment of eosinophils by substance P after repeated allergen exposure in allergic rhinitis

We have investigated the nasal response to substance P after pollen exposure in seasonal allergic rhinitic patients. Seven patients with strictly seasonal allergic rhinitis were studied during the pollen season, 24 h after nasal challenge with pollen. They received increasing doses of nebulized substance P (0 to 80 nmol) in each nostril. Responses were assessed by measurement of nasal airway resistance by posterior rhinomanometry and quantification of albumin, histamine, and inflammatory cells in the nasal lavage fluid. Nasal airway resistance increased in a dose-dependent manner after substance P challenge. Protein and albumin in nasal lavage fluids increased after administration of substance P: from 2.6 +/- 0.3 to 6.8 +/- 1.1 mg for protein (P < 0.01) and from 0.2 +/- 0.1 to 3.1 +/- 0.6 mg for albumin (P < 0.02). Expressed as a percentage of total protein, albumin increased from 10.5 +/- 3.6% to 39.9 +/- 3.5% (P < 0.02), suggesting occurrence of plasma leakage. No histamine release was observed after challenge with substance P. Total cell counts significantly increased from 11.4 +/- 2.4 to 41.8 +/- 17.3 x 10(3) cells/ml after substance P (P < 0.05). Eosinophils were already numerous before substance P challenge (2.1 +/- 0.7 x 10(3) cells/ml), and the number of eosinophils markedly increased in all patients after substance P (for the whole group, 25.8 +/- 13.3 cells/ml, P < 0.05). In contrast, the number of neutrophils only slightly increased in five patients, and changes did not reach significance for the group as a whole. Our results show that substance P induces nasal obstruction and albumin extrusion in allergic rhinitic patients after repeated pollen exposure. These vascular phenomena are associated with recruitment of eosinophils. Since substance P is known to be released after nasal allergen challenge, our data suggest a role for substance P in the chronic eosinophilic inflammation of the nasal mucosa observed in symptomatic allergic rhinitis.

Nasal histamine challenge in nonallergic and allergic subjects evaluated by acoustic rhinometry

Nasal patency shows spontaneous variations but is influenced by a number of factors like exercise and allergic conditions. Nasal histamine challenge has been used to define nasal hypersensitivity. We have applied acoustic rhinometry as a new objective method to study the spontaneous variations of the nasal mucosa and its response to histamine challenge in 12 nonallergic subjects and 12 subjects with nasal allergy to pollen, but out of the pollen season. Measurements of the minimum cross-sectional area and the volume of the nasal cavities were done every 15 min for 6 h. More pronounced spontaneous variations, defined by the coefficient of variation of the measurements, were encountered in the allergic than in the nonallergic subjects, especially with regard to the minimum cross-sectional areas in the nasal cavities (P < 0.02). Allergic subjects showed increased sensitivity to histamine, as compared with nonallergic subjects, during low-concentration (0.1%) challenge (P < 0.05) and a prolonged effect of histamine challenge (P = 0.01). Antihistamine (cetirizine) had a significant effect on the histamine-induced symptoms and decrease of nasal dimensions during histamine challenge, but no significant effect on pollen-induced changes. In the allergic group, the decrease in minimum area during allergen provocation correlated with the level of specific IgE (r = 0.81; P = 0.0015).

Observations on the response of the nasal mucosa to allergens

Allergic rhinitis is the sixth most prevalent chronic health condition in the United States. To study the pathogenesis of the allergic response, we have used a model of nasal provocation with antigen. During the initial reaction of an allergic subject to allergen provocation, increases occur in the levels of histamine, tryptase, and prostaglandin D2. This pattern of mediator release, combined with histologic evidence of mast-cell degranulation, strongly supports the role of the mast cell in the acute allergic reaction. The response to antigen, however, does not end with mast-cell degranulation. Hours after challenge we observed the spontaneous recurrence of symptoms and increased responsiveness to antigenic and nonantigenic stimuli. Our central hypothesis is that cellular infiltration and activation after antigen challenge are responsible for the observed increase in nasal reactivity. The predominant cells in nasal lavage 24 hours after challenge are eosinophils and neutrophils, whereas the predominant cell in the mucosa is the CD4+ lymphocyte. An early step in the movement of cells from the peripheral blood involves adhesion between circulating leukocytes and the endothelium. Evidence suggests that vascular endothelial adhesion molecule may be responsible in part for the selective adherence of eosinophils to the endothelium.

Inhibitory effect of levocabastine on allergen-induced increase of nasal reactivity to histamine and cell influx

For evaluation of the effect of levocabastine pretreatment on allergen-induced rhinitis symptoms, changes in nasal washings, and nasal responsiveness to histamine, 12 asymptomatic patients with documented allergic rhinitis participated in a single-blind, placebo-controlled study. Eight-day treatment with levocabastine (twice in each nostril, four times a day) caused significant reduction in nasal symptoms and inflammatory cell influx after allergen challenge, as compared with placebo administration. Levocabastine inhibited increased nasal reactivity to histamine induced by allergen provocation, as controlled by rhinitis symptoms and albumin level in nasal washings. These data reveal a high effectiveness of levocabastine in the prevention of allergen-induced rhinitis symptoms. Moreover, its inhibitory effect on inflammatory cell influx and hyperresponsiveness to histamine suggest that levocabastine is more than a simple H1-receptor antagonist.

Intranasal beclomethasone inhibits antigen-induced nasal hyperresponsiveness to histamine

To determine whether intranasal steroid treatment inhibits the increased sensitivity to histamine that occurs 24 hours after nasal antigen challenge, 12 allergic volunteers were entered into a double-blind study comparing placebo or 164 micrograms of beclomethasone dipropionate twice a day for 7 days. Beclomethasone dipropionate partially reduced the early mediator response to antigen and the influx of eosinophils 24 hours later. Comparing the initial histamine challenge with that done 24 hours after antigen with the subjects on placebo, there was a significant increase in sneezes, TAME-esterase activity, and albumin. Pretreatment with intranasal beclomethasone dipropionate resulted in a reduced response to histamine 24 hours after antigen challenge. A positive correlation occurred between the number of eosinophils in the lavage before histamine challenge and the level of TAME-esterase activity (rs = 0.67, p = 0.03) during the histamine challenge that followed antigen with the subjects on placebo. We thus confirmed the increase in nonspecific nasal airway responsiveness 24 hours after antigen challenge, with a concomitant increase in eosinophils, and demonstrate its inhibition by pretreatment with intranasal steroids.