Nasal challenge with allergen upregulates the local expression of vascular endothelial adhesion molecules

To understand the events involved in selective eosinophil migration into allergic inflammatory sites, we studied the expression of vascular endothelial adhesion molecules in the nasal mucosa. Ten subjects with asymptomatic seasonal allergic rhinitis and 13 nonallergic subjects underwent localized allergen challenge of one inferior turbinate. Twenty-four hours later, biopsy specimens were obtained from the inferior turbinates, bilaterally in the seasonally allergic subjects and unilaterally in the nonallergic control subjects. The specimens were divided, sectioned, and either stained for identification of eosinophils or analyzed immunohistochemically for intercellular adhesion molecule-1, E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and von Willebrand's factor. Intercellular adhesion molecule-1 expression was observed in all mucosal specimens, with no significant difference among groups. E-selectin showed minimal baseline expression, and low levels were significantly induced on the challenged mucosa of the allergic compared with nonallergic subjects (p < 0.05). VCAM-1 was expressed basally and was significantly upregulated by allergen challenge, compared with the nonchallenged side and nonallergic control subjects (p < 0.05). Submucosal eosinophils increased significantly in allergic subjects 24 hours after antigen challenge, compared with nonallergic control subjects and weakly correlated with VCAM-1 expression (rs = 0.33, p = 0.06). Our results suggest that endothelial activation accompanies allergic inflammation. Furthermore, because the counterligand for VCAM-1, very late activation antigen-4, is present on eosinophils, VCAM-1 upregulation may contribute to the selective recruitment of these cells to the nasal mucosa.

The human nasal response to capsaicin

Airway sensory nerves play a role in reactions to inhaled allergens, irritants, and physical stimuli. Capsaicin, the pungent principle of hot peppers, stimulates a subcategory of sensory nerves. To study the consequences of selective activation of airway sensory nerves in the human nose, we administered capsaicin nasal challenges to eight volunteers (four normal subjects and four subjects with perennial allergic rhinitis). Capsaicin (20 mumol/L), when sprayed into the nose, induced burning, rhinorrhea, and lacrimation. Capsaicin also induced a significant increase in total protein content of nasal lavage fluid after challenge compared with vehicle (increase from before challenge to 1 minute after challenge, 172 +/- 55 vs 46 +/- 29 micrograms/ml, p < 0.001). In contrast to many animal studies, capsaicin did not increase vascular permeability in the airway, because albumin content of nasal lavage fluid was not increased (p = 0.86). On the other hand, lactoferrin, a marker of glandular secretion, was increased (p < 0.005). Repetitive capsaicin challenge every 10 minutes led to tachyphylaxis of symptoms, total protein secretion, and lactoferrin secretion. Compared with vehicle, unilateral capsaicin (6 mmol/L) disk challenge induced significant secretion both ipsilateral (21.3 +/- 4.2 vs 4.9 +/- 2.1 mg, p < 0.01) and contralateral (18.2 +/- 4.4 vs 7.4 +/- 1.9 mg, p < 0.04) to challenge. Thus we have shown that capsaicin challenge to the human nose leads to airway sensory nerve activation. Further, we have demonstrated that capsaicin stimulates a predominantly central neuronal response and that the induced secretory response is of glandular rather than vascular origin.

Unilateral choanal atresia masquerading as chronic sinusitis

Choanal atresia is a congenital anomaly usually diagnosed at birth. This case involves bilateral choanal atresia in a newborn with respiratory difficulties in whom there is an inability to pass a #8 French catheter through the nose. In contrast, unilateral choanal atresia causes a variable degree of nasal obstruction that may delay the diagnosis. We report a case of unilateral choanal atresia in a 9-year-old boy diagnosed as having chronic sinusitis with allergic rhinitus. Initial interpretation of a computerized, tomographic (CT) examination confirmed the diagnosis of chronic sinusitis. The definitive diagnosis, however, was made by endoscopic evaluation. A review is presented of the epidemiology, clinical presentation, differential diagnosis, and contemporary surgical management for unilateral choanal atresia.

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.

Characterization of phospholipase A2 from human nasal lavage

A secreted form of phospholipase A2 (PLA2) has been implicated in inflammatory disorders such as rheumatoid arthritis and sepsis. To determine if PLA2 may also play a role in allergic rhinitis, we have measured enzymic activity in nasal lavage from allergic subjects. Enhanced activity of PLA2 in the lavage was observed following nasal challenge with antigen or histamine. The PLA2 in the nasal lavage was partially purified by acid extraction, size exclusion chromatography, and ion exchange chromatography. The partially purified enzyme from nasal lavage was subsequently compared to a recombinant form of human PLA2 identified in synovial fluid from arthritic patients. The two enzymes showed similar molecular weights (15 to 16 kD) on SDS-PAGE, and both reacted with a rabbit polyclonal antiserum raised to a galactokinase-PLA2 fusion protein. The enzymatic activities of the two PLA2s were indistinguishable when compared for ionic dependence, substrate selectivity, and sensitivity to inhibitors. These results suggest that the PLA2 induced in nasal lavage in response to challenge by antigen is very similar to the extracellular PLA2 found in synovial fluid from subjects with rheumatoid arthritis and may play a role in the inflammatory processes associated with allergic rhinitis.

Physiologic responses and histamine release after nasal antigen challenge. Effect of atropine

We enrolled nine allergic subjects in a double blind, placebo-controlled study to examine the effect of premedication with 0.6 mg of atropine on nasal antigen challenge. The challenge consisted of unilaterally stimulating the nasal septum with diluent followed by three increasing doses of antigen and recording responses bilaterally. Sneezes, symptoms, and nasal airway resistance (NAR) were recorded. Secretions were collected using preweighed filter paper discs and histamine was measured. Antigen challenge with the subjects on placebo led to significant dose-dependent increases in sneezes, symptom scores, ipsilateral and contralateral secretion weights, ipsilateral NAR, and total amount of ipsilateral histamine (p < 0.05 versus diluent). Bilaterally applied atropine led to significant inhibition of ipsilateral and contralateral nasal secretions as well as rhinorrhea scores (p < 0.05 versus placebo) but had no significant effect on other parameters. Challenge after atropine premedication led to higher increases in histamine concentration than placebo (p < 0.01). These results suggest that parasympathetically stimulated fluids did not contain histamine and diluted the histamine released by mast cells. To support this hypothesis, we challenged the same subjects with methacholine. The concentration of histamine decreased and was significantly lower than after challenge with antigen (p < 0.01). The data suggest that: (1) histamine is released locally at the site of antigen challenge, (2) the volume of glandular secretions is primarily controlled by parasympathetic stimulation, and (3) the total amount of a mediator recovered in a fixed time interval best reflects the underlying pathophysiologic events.

The effect of terfenadine on unilateral nasal challenge with allergen

To investigate the role of H1 receptor-mediated effects in allergic rhinitis, we challenged 12 allergic volunteers with allergen 2 hours after administration of either placebo or 60 mg of terfenadine. Filter paper discs were used for the unilateral administration of allergen and the collection of nasal secretions. Secretion weights, levels of histamine in recovered nasal secretions, and nasal airway resistance (NAR) were measured for each nostril separately, and the number of sneezes was counted. After placebo treatment, allergen challenge led to significant increases in ipsilateral and contralateral secretion weights, ipsilateral histamine levels, ipsilateral NAR, and sneezing. Contralateral histamine levels were not elevated. H1 antagonism with terfenadine markedly reduced the number of sneezes and partially decreased ipsilateral and contralateral secretion weights, without affecting the increase in NAR. Terfenadine premedication also lowered the amount of histamine in ipsilateral secretions after allergen challenge. Performing identical nasal challenges with a 10-fold lower dose of antigen produced similar results. Previous studies showed that terfenadine had no effect on methacholine provocation and completely abolished ipsilateral and contralateral secretion weights after histamine challenge. We conclude that sneezing after allergen challenge is caused almost exclusively by a reflex initiated through H1 receptors and that H1 antagonism has no influence on allergen-induced increases in NAR. Unilateral allergen challenge leads to bilateral increases in secretion weights, which are only partially inhibited by terfenadine, suggesting the involvement of mediators other than histamine in the nasonasal reflex. As reported earlier, terfenadine also decreases allergen-induced histamine release after challenge with the highest dose of antigen.

Nasal allergen challenge generates 1-0-hexadecyl-2-lyso-sn-glycero-3-phosphocholine

We studied antigen-induced platelet activating factor and the 1-0-hexadecyl-2-lyso-sn-glycero-3-phosphocholine (lyso-PAF) in nasal lavage fluids (NLF) by combined gas chromatography/mass spectrometric analysis (GC/MS). During the early allergic reaction, there was a dramatic increase in the levels of lyso-PAF that peaked at 15 min (2.6 +/- 5.2 ng/ml, mean +/- SEM, n = 6). Increasing doses of antigen produced a dose-dependent increase in the levels of lyso-PAF that peaked at the highest dose. Levels of lyso-PAF correlated strongly with those of N-alpha-tosyl-L-arginine methyl ester (TAME)-esterase activity (rs = 0.82, p = 0.0001) and histamine (rs = 0.57, p = 0.002). There was a no significant increase in the quantity of lyso-PAF found in NLF from allergic individuals challenged with diluent or nonallergic individuals challenged with antigen. In subjects showing a late phase reaction, as indicated by symptoms and histamine release, we detected lyso-PAF along with TAME-esterase activity and histamine during the late phase reaction. In contrast to lyso-PAF, PAF levels were near or below the detection limit of the assay in NLF and remained unchanged after antigen challenge. We also investigated the potential pathways for lyso-PAF generation from 2-acetylated phospholipids. We found that the time required for deacetylation of 50% of [3H]PAF (t1/2) to lyso-PAF was 50 min in baseline secretions and 10 and 22 min in NLF obtained 10 min and 24 h after antigen challenge, respectively. These data suggested that catabolic pathways were present in NLF.(ABSTRACT TRUNCATED AT 250 WORDS)

Onset and duration of inhibition of ipratropium bromide nasal spray on methacholine-induced nasal secretions

We performed a randomized, double-blind, placebo-controlled cross-over study with two different concentrations of ipratropium bromide (Atrovent) nasal spray to evaluate its onset and duration of inhibition. Twenty-four subjects with perennial rhinitis participated in the trial. Fifteen minutes to 12 hours after administration of ipratropium bromide (42 or 168 micrograms/nostril) or placebo nasal spray, methacholine challenges were performed and nasal secretion weights measured. After placebo administration the effect of methacholine remained unchanged over the 12-h-period. Both the 42 and 168 micrograms/nostril doses significantly inhibited the nasal hypersecretions induced by methacholine challenge within 15 min of treatment (P < 0.05). The 168 micrograms dose of ipratropium bromide continued to significantly reduce secretion weights through 6 hours, but the effectiveness of the 42 micrograms dose disappeared within 3 h. In addition to having a longer duration, the 168 micrograms/nostril dose produced approximately twice the inhibitory effect of the 42 micrograms dose.

Reflex activation of nasal secretion by unilateral inhalation of cold dry air

Exposure to cold dry air induces rhinorrhea and other nasal symptoms in many persons. To evaluate whether this response involves a neurogenic component, we delivered a unilateral cold dry air (UniCDA) nasal challenge to volunteers with previously documented reactivity to cold dry air. We measured their nasal secretory responses bilaterally using small filter paper discs to absorb secretions from the nasal mucosa. UniCDA increased nasal secretion both ipsilateral (p < 0.001) and contralateral (p < 0.001) to the challenge when compared with control challenge. Topical atropine (0.225 mg), a muscarinic antagonist, inhibited ipsilateral secretion (p < 0.002) when given ipsilateral to UniCDA. When atropine was given contralateral to UniCDA, there was a trend toward reduction of contralateral secretion but no effect on ipsilateral secretion. Topical anesthesia with lidocaine given ipsilateral to UniCDA inhibited ipsilateral (p < 0.02) and contralateral (p < 0.05) secretion immediately after challenge. Topical anesthesia did not inhibit methacholine-induced nasal secretion. Thus, UniCDA stimulates reflex secretion both ipsilateral and contralateral to challenge which is inhibitable by interrupting either the efferent or the afferent arm of the reflex arc. This human in vivo model supports the importance of neural mechanisms in airway responsiveness to an environmental stimulus.

Intranasal steroids inhibit seasonal increases in ragweed-specific immunoglobulin E antibodies

We performed two seasonal studies to evaluate the effect of continuous treatment with intranasal steroids, beginning approximately 1 week before the appearance of ragweed pollen, on the level of ragweed-specific IgE antibodies in serum. In both studies the control groups showed the anticipated rise in ragweed-specific IgE antibodies after the ragweed season. In the first study, employing aqueous beclomethasone dipropionate (168 micrograms twice daily), no rise occurred in serum ragweed IgE after seasonal exposure and the level actually decreased in eight of 12 treated subjects. In the second study, with triamcinolone acetonide (220 micrograms twice daily), the expected rise in ragweed IgE antibody was also reduced, although less dramatically, probably as a result of the lower potency of the dose delivered. Our studies not only support the benefits of intranasal steroids in the treatment of seasonal allergic rhinitis but also suggest that specific IgE production may be down-regulated by their continuous use, which may alter the subsequent clinical course of the disease.

Coronal CT scan abnormalities in children with chronic sinusitis

Coronal computed tomography (CT) scans are currently the optimal study to display the normal and abnormal anatomy in children with chronic and recurrent acute sinusitis after failure of medical therapy. To assess the extent and distribution of disease as well as associated anatomic abnormalities in this pediatric population, 74 coronal CT scans of children with continued symptoms of sinusitis after failure of extensive medical therapy were reviewed retrospectively. Twelve children with cystic fibrosis showed the characteristic features of medial displacement of the lateral nasal wall in the middle meatus and uncinate process demineralization, creating the appearance of a maxillary sinus mucocele. Nine of these 12 children had increased attenuation in the maxillary sinus on soft-tissue windows. In the remaining 62 children, a significantly greater frequency of disease, when compared with that reported for adults, was seen in the maxillary, anterior ethmoid, posterior ethmoid, and frontal sinuses. Children with asthma (n = 33) had more extensive disease. Bony anatomic abnormalities were similar to those reported for adults, except for a lower incidence of septal deformity.

Effects of antihistamines on inflammatory mediators

The nasal antigen challenge model has proved useful in assessing the roles of inflammatory mediators in the clinical allergic response. Studies using this model have revealed that the acute allergic response is associated with increased concentrations of histamine, prostaglandin D2 (PGD2), leukotrienes, tryptase, and kinins, and with increased TAME-esterase activity. The effects of antihistamines on the clinical response and inhibition of mediator release have also been examined with this model. Premedication with terfenadine caused a marked reduction in sneezing as well as decreased histamine release, kinin levels, and TAME-esterase activity. Levels of PGD2 also decreased, although not significantly. Release of leukotriene C4 (LTC4) was not affected by this agent. Terfenadine also reduced vascular permeability as reflected in decreased albumin levels. In this model, cetirizine reduced sneezing, TAME-esterase activity, and albumin levels, whereas histamine release and PGD2 levels remained unaffected. Pretreatment with cetirizine resulted in significantly reduced levels of LTC4. Loratadine markedly, but not significantly, inhibited the sneezing response and reduced release of histamine, PGD2, and LTC4. Albumin and kinin levels were significantly diminished. The clinical significance of the inhibitory effects of antihistamines on mediator release has yet to be determined.

Immunologic changes after nasal provocation with allergen

The high prevalence of allergic rhinitis requires all physicians and surgeons to have a fundamental understanding of this disease. Fortunately, patients with allergic rhinitis can be diagnosed accurately and prescribed effective treatment for symptoms. In the future, as the natural history of allergic rhinitis is appreciated and the pathophysiology better understood, additional points for therapeutic intervention will emerge. Research efforts should focus not solely on acquiring additional symptomatic therapies but also on altering the natural course of the illness.

Inflammatory diseases of the sinuses: an overview of immunology

We have provided an overview of the immune system and its components. These components--cell-mediated and humoral immunity, the complement system and the different phagocytic cells--all function in concert to protect the body from foreign invaders. When this powerful immune system behaves in a misdirected fashion, however, disease states develop from its injurious effects. One such disease process, intimately related to sinus disease, is allergic rhinitis, which starts as an IgE-mediated response and evolves into an extensive reaction with the contribution of several inflammatory cells and mediators (Fig. 5).

The effect of antihistamines on the immediate allergic response: a comparative review

Antihistamines are believed to reduce the sneezing and rhinorrhea associated with allergic rhinitis, primarily by competitive antagonism of histamine for H1 cellular receptors, but additional mechanisms of action may contribute to their clinical efficacy. To improve our understanding of H1 antihistamine action, we studied the effects of pretreatment with terfenadine, cetirizine, ketotifen, azatadine, diphenhydramine, and azelastine on increases in vascular permeability, mast cell activation, and sneezing induced by nasal challenge with antigen. All studied antihistamines reduced sneezing, indicating that they all effectively antagonize histamine after its release. In addition, terfenadine and topically administered azatadine blocked the release of histamine. Studies with cetirizine and azelastine revealed that these antihistamines significantly reduced sulfidopeptide leukotriene levels. Terfenadine and azelastine also reduced kinin production. These results confirm that antihistamines are effective in reducing sneezing and, in some cases, vascular permeability. The findings of these studies also illustrate that the various antihistamines have multiple and different mechanisms of action that may have implications for their clinical uses.

Comparison of the secretory response of the nasal mucosa to methacholine and histamine

To better understand the secretory response of the nasal mucosa, we must be able to accurately measure its physiological response. To this end, we developed a localized challenge technique using paper disks to stimulate the mucosa on one side and measure secretions from both sides to study both direct and reflex responses. Both methacholine and histamine induced a dose-dependent increase in secretion weights on the challenge side, whereas only histamine induced a contralateral reflex. Repeated stimulation with histamine, but not methacholine, resulted in tachyphylaxis. Pretreatment with atropine resulted in inhibition of the contralateral secretory response to histamine and the ipsilateral response to methacholine with only partial inhibition of the ipsilateral histamine response. Terfenadine pretreatment resulted in the complete inhibition of both the ipsilateral and contralateral responses to histamine with no effect on methacholine-induced secretions. Ipsilaterally applied lidocaine had no effect on the histamine response but, when applied contralaterally, partially inhibited that response. Topical diphenhydramine applied ipsilaterally led to significant inhibition of the ipsilateral and contralateral secretory responses to histamine but had no effect when applied contralaterally. We conclude that methacholine and histamine have different effects on the nasal mucosa. We speculate that methacholine stimulates glands directly, whereas histamine includes both direct and neurogenic stimulation.

Response of nasal mucosa to histamine or methacholine challenge: use of a quantitative method to examine the modulatory effects of atropine and ipratropium bromide

We have developed a new technique for the direct local administration of test solutions to the nasal mucosa and for quantification of nasal secretory responses. This technique, a variation on several published reports of filter paper use, allows simple and rapid determination of drug effects and facilitates the analysis of ipsilateral and contralateral responses to local challenge of the nasal mucosa. We have used this technique to investigate the secretory responses of the nasal mucosa to methacholine and histamine and to determine the effects of atropine and ipratropium bromide (Atrovent nasal spray) on these secretory responses.

Inhibition of mediator release during the early reaction to antigen

A nasal lavage model and a new filter paper disk model have been used to measure biologic and physiologic responses to antigen challenge in patients with allergic rhinitis. Pretreatment of subjects with cetirizine reduced the number of sneezes induced by antigen challenge but did not significantly reduce levels of histamine or prostaglandin D2 in a double-blind, placebo-controlled trial with the lavage model. Pretreatment with 60 or 300 mg of terfenadine did significantly reduce levels of histamine, kinin, albumin, and TAME-esterase activity in a double-blind, placebo-controlled study with this model. Again with the nasal lavage model, a double-blind, placebo-controlled comparison of pretreatment with 60 mg of terfenadine or 10 mg of loratadine showed that both agents significantly reduced sneezing. Both drugs also lowered levels of antigen-induced histamine and TAME-esterase, but only terfenadine did so significantly. In a double-blind, placebo-controlled study, the new disk method showed that terfenadine reduced sneezing but not nasal congestion in eight patients with allergic rhinitis. Terfenadine significantly reduced the weight of nasal secretions on both sides of the nose and significantly reduced histamine on the ipsilateral side.

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.

Anatomic and physiologic considerations in sinusitis

The anatomy and physiology of the nose, the paranasal sinuses, and related structures are of major importance in understanding sinusitis. A brief description of the airflow, blood flow, nasal cycle, histology and the developmental anatomy are given. These elements combine to condition inhaled air by warming, humidifying, and filtering it. An important mechanism for understanding sinusitis is mucociliary clearance. The nasal cavity and the paranasal sinuses are covered by a pseudostratified, columnar, ciliated epithelium with a thin mucous layer on top of it. In the sinuses the beat of the cilia is directed toward their natural ostia. The ostia of most of the paranasal sinuses lead into the region of the middle meatus and the anterior ethmoid, the osteomeatal complex. Obstruction in this area reduces clearance and plays a major role in the pathophysiology of sinusitis.

Respiratory compromise after adenotonsillectomy in children with obstructive sleep apnea

A retrospective study of pediatric patients with obstructive sleep apnea who underwent adenotonsillectomy between 1987 and 1990 was undertaken to determine the frequency of postoperative respiratory compromise and to determine if risk factors for its development could be identified. Sixty-nine patients less than 18 years old had polysomnographically documented obstructive sleep apnea and were observed postoperatively in the pediatric intensive care unit. Of these, 16 (23%) had severe respiratory compromise, defined as intermittent or continuous oxygen saturation of 70% or less, and/or hypercapnia, requiring intervention. Compared with patients without respiratory compromise, these patients were younger (3.4 +/- 4 vs 6.1 +/- 4 years) and had more obstructive events per hour of sleep on the polysomnogram (49 +/- 41 vs 19 +/- 30). They were more likely to weight less than the fifth percentile for age (odds ratio [OR], 5.1; 95% confidence interval [CI], 1.4 to 18.7), to have an abnormal electrocardiogram and/or echocardiogram (OR, 4.5; 95% CI, 1.3 to 15.1), and to have a craniofacial abnormality (OR, 6.2; 95% CI, 1.5 to 26). Multiple logistic regression analysis revealed the most significant risk factors were age below 3 years and an obstructive event index greater than 10. Children with obstructive sleep apnea are at risk for respiratory compromise following adenotonsillectomy; young age and severe sleep-related upper airway obstruction significantly increase this risk. We recommend in-hospital postoperative monitoring for children undergoing adenotonsillectomy for obstructive sleep apnea.