Studies on the allergic and nonallergic nasal inflammation

PDE3 Inhibition Reduces Epithelial Mast Cell Numbers in Allergic Airway Inflammation and Attenuates Degranulation of Basophils and Mast Cells

Epithelial mast cells are generally present in the airways of patients with allergic asthma that are inadequately controlled. Airway mast cells (MCs) are critically involved in allergic airway inflammation and contribute directly to the main symptoms of allergic patients. Phosphodiesterase 3 (PDE3) tailors signaling of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are critical intracellular second messenger molecules in various signaling pathways. This paper investigates the pathophysiological role and disease-modifying effects of PDE3 in mouse bone marrow-derived MCs (bmMCs), human LAD2- and HMC1 mast cell lines, human blood basophils, and peripheral blood-derived primary human MCs (HuMCs). In a chronic house dust mite (HDM)-driven allergic airway inflammation mouse model, we observed that PDE3 deficiency or PDE3 inhibition (PDE3i) therapy reduced the numbers of epithelial MCs, when compared to control mice. Mouse bone marrow-derived MCs (bmMCs) and the human HMC1 and LAD2 cell lines predominantly expressed PDE3B and PDE4A. BmMCs from Pde3^−/− mice showed reduced loss of the degranulation marker CD107b compared with wild-type BmMCs, when stimulated in an immunoglobulin E (IgE)-dependent manner. Following both IgE-mediated and substance P-mediated activation, PDE3i-pretreated basophils, LAD2 cells, and HuMCs, showed less degranulation than diluent controls, as measured by surface CD63 expression. MCs lacking PDE3 or treated with the PDE3i enoximone exhibited a lower calcium flux upon stimulation with ionomycine. In conclusion PDE3 plays a critical role in basophil and mast cell degranulation and therefore its inhibition may be a treatment option in allergic disease.

Allergic rhinitis is associated with complex alterations in high-density lipoprotein composition and function

Despite strong evidence that high-density lipoproteins (HDLs) modulate the immune response, the role of HDL in allergies is still poorly understood. Many patients with allergic rhinitis (AR) develop a late-phase response, characterized by infiltration of monocytes and eosinophils into the nasal submucosa. Functional impairment of HDL in AR-patients may insufficiently suppress inflammation and cell infiltration, but the effect of AR on the composition and function of HDL is not understood. We used apolipoprotein (apo) B-depleted serum as well as isolated HDL from AR-patients (n = 43) and non-allergic healthy controls (n = 20) for detailed compositional and functional characterization of HDL. Both AR-HDL and apoB-depleted serum of AR-patients showed decreased anti-oxidative capacity and impaired ability to suppress monocyte nuclear factor-κB expression and pro-inflammatory cytokine secretion, such as interleukin (IL)-4, IL-6, IL-8, tumor necrosis factor alpha and IL-1 beta. Sera of AR-patients showed decreased paraoxonase and cholesteryl-ester transfer protein activities, increased lipoprotein-associated phospholipase A2 activity, while lecithin-cholesterol acyltransferase activity and cholesterol efflux capacity were not altered. Surprisingly, apoB-depleted serum and HDL from AR-patients showed an increased ability to suppress eosinophil effector responses upon eotaxin-2/CCL24 stimulation. Mass spectrometry and biochemical analyses showed reduced levels of apoA-I and phosphatidylcholine, but increased levels of apoA-II, triglycerides and lyso-phosphatidylcholine in AR-HDL. The changes in AR-HDL composition were associated with altered functional properties. In conclusion, AR alters HDL composition linked to decreased anti-oxidative and anti-inflammatory properties but improves the ability of HDL to suppress eosinophil effector responses.

Inflammatory Cells and Mediators in Nasal Secretions during Early Response to Ragweed Challenge: Correlation between Type of Cellular Influx and Mediator Release

The early and late phase responses in nasal tissues exhibit release of lipid-derived mediators, granule-associated mediators, and a mixed cellular influx in separate nasal challenges. To explore this phenomenon further, concentrations of inflammatory mediators were measured along with characterization of cell influx during dose-dependent ragweed challenges. Ten allergic rhinitis subjects underwent two unilateral nasal lavages using incremental 3-fold concentrations of short ragweed antigen. Low doses of ragweed (0.016–0.114 units Amb a I) rarely induced cell influx (1/18 challenges), whereas moderate doses (0.432–1.3 units Amb a I) caused cell influxes in 7/18, and high doses (3.39–11.7 units Amb a I) resulted in cell influxes in 8/17. The eluent contained >50% neutrophils in 7 challenges; >50% eosinophils in 3; and a mixed pattern in 6. There was a significant association between the dose of antigen and the level of histamine, prostaglandin D2 (PGD2), and leukotriene C4/D4/E4 (LTC4/D4/E4). Challenges with an eosinophilic influx tended to be associated with higher concentrations of mediators than neutrophilic influxes. Similar to the immediate skin response, the early allergic response in the nose demonstrated a cell influx with release of histamine, PGD2, and LTC4/D4/E4. Nasal cellular inflammation, therefore, can occur within minutes of allergen exposure.

Persistent nasal symptoms and mediator release after continuous pollen exposure in an environmental challenge chamber

BACKGROUND

Immediate- and late-phase reactions are associated with nasal symptoms of patients with allergic rhinitis.

OBJECTIVE

To examine the symptoms and mediators released after continuous allergen exposure in an environmental challenge chamber (ECC).

METHODS

Fifteen patients with Japanese cedar pollinosis were enrolled in this study and continuously exposed to cedar pollen at a concentration of 8,000 grains/m(3) for 3 hours in an ECC. Nasal function tests were performed, and nasal secretions were collected before pollen exposure (0 hour), immediately after exiting the ECC (3 hours), and 6 hours after exiting the ECC (9 hours). Symptom scores were recorded every 30 minutes in the ECC and every 3 hours after exiting the ECC. The frequency of sneezing and nose blowing also was monitored.

RESULTS

The severity of symptoms in the ECC peaked approximately 2 hours after the beginning of pollen exposure and continued more than 6 hours after leaving the ECC. Concentrations of histamine, tryptase, interleukins 5, 3, 33, and 31, and substance P increased over time, whereas that of nasal fractional exhaled nitric oxide decreased.

CONCLUSION

Various mediators are released during continuous allergen exposure, which subsequently induce persistent nasal symptoms. Effective treatment is required to control the intense inflammation observed after allergen exposure.

Nasal histamine responses in nonallergic rhinitis with eosinophilic syndrome

Background:

Nonallergic rhinitis with eosinophilic syndrome (NARES) is persistent, without atopy, but with ≥25% nasal eosinophilia. Hypereosinophilia seems to contribute to nasal mucosa dysfunction.

Objectives:

This analytical case-control study aimed at assessing the presence and severity of nonspecific nasal hyperactivity and at finding out whether eosinophilia may be correlated with the respiratory and mucociliary clearance functions.

Materials:

The symptom score was assessed in 38 patients and 15 controls whose nasal smear was also tested for eosinophils and mucociliary transport (MCT). Nonspecific nasal provocation tests (NSNPT) with histamine were also carried out, and total nasal resistance (TNR) was determined.

Results:

The symptom score of NARES after NSNPT were not significantly different from the control group, and there was poor or no correlation among the single symptoms and the differences studied for every nasal reactivity class. This correlation improved when using the composite symptom score. The most severe eosinophilia was observed in high reactivity groups, and it was correlated with an increase in TNR. MCT worsened as eosinophilia and nasal reactivity increased. Unlike controls, a significant correlation was observed between the increase in MCT and TNR.

Conclusions:

In NARES, nonspecific nasal hyperreactivity is the result of epithelial damage produced by eosinophilic inflammation, which causes MCT slow down, an increase in TNR, and nasal reactivity classes, with possible impact on classification, prognosis, and treatment control.

Nasal lavage levels of granulocyte-macrophage colony-stimulating factor and chronic nasal hypereosinophilia

BACKGROUND

The aim of the present study was to measure levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) in nasal lavage of patients affected by chronic eosinophilic sinonasal inflammation to clarify the relationship with eosinophilic tissue infiltration and clinical features.

METHODS

Between November 2012 and June 2013, we selected 70 patients with chronic eosinophilic inflammation (average age 41.8 years) who were classified into the following groups: persistent allergic rhinitis (group 1), noninfectious non-allergic rhinitis with eosinophilia syndrome (group 2) and chronic rhinosinusitis with polyps (group 3). Finally, we enrolled 20 healthy subjects as controls (group 4). All patients underwent symptoms score questionnaire based on a visual analogue scale, nasal endoscopy and/or computed tomography (CT) scan, and allergy testing. Nasal cytology by scraping of the mucosa and GM-CSF assays in nasal lavage were performed in all subjects.

RESULTS

Detectable levels of GM-CSF were found in 34 of 70 (48.57%) patients, with an average concentration of 2.67 ± 0.8 pg/mL, whereas in controls only 1 of 20 individuals showed detectable GM-CSF levels. Eosinophil infiltration was significantly higher in patients with detectable GM-CSF compared to those with undetectable levels (49.4% vs 39.2%, respectively; p < 0.05). Furthermore, significant weakly-moderate correlation was found between GM-CSF levels and percentage of eosinophil infiltration in tissue (p < 0.05). Correlation between symptom scores and GM-CSF levels was significant only in group 2, which showed higher average concentrations of GM-CSF compared to groups 1 and 3 (2.9 pg/mL vs 1.6 pg/mL and 1.8 pg/mL, respectively; p < 0.05).

CONCLUSION

Our data confirm that GM-CSF is more frequently detectable in nasal lavages of patients affected by chronic sinonasal eosinophilic inflammation than in controls. Statistical analyses revealed a significant weakly-moderate correlation between GM-CSF levels in nasal lavage of all patients and percentage of eosinophil infiltration of nasal mucosa.

Allergic rhinoconjunctivitis: the role of histamine

Allergic rhinoconjunctivitis is the most common atopic condition encountered in clinical practice. Analysis of the pathogenesis of this condition permits identification of optimal therapeutic targets. The increased knowledge of the underlying pathophysiology suggests that multiple inflammatory mediators are involved in the pathogenesis of the allergic reaction in the ocular and nasal mucosa. However, despite the presence of a wide range of different mediators, it would appear that histamine plays a key role. Experimental allergen challenge studies have demonstrated that histamine is the only mediator which produces the full spectrum of clinical manifestations of the acute allergic reaction when applied to the mucosal surface. While both H₁- and H₂-receptors are present in the nasal and ocular mucosa, only H₁-receptor antagonists are capable of inhibiting histamine-induced symptoms of allergic rhinoconjunctivitis. Furthermore, although the exact role of histamine in the immediate and prolonged allergic reaction has not yet been fully elucidated, these findings do not exclude the possibility that histamine is involved in these processes. The available evidence therefore supports current clinical practice for use of H₁-receptor antagonist as a first-line therapy in patients with this atopic condition.

Functional variant in the autophagy-related 5 gene promotor is associated with childhood asthma

RATIONALE AND OBJECTIVE

Autophagy is a cellular process directed at eliminating or recycling cellular proteins. Recently, the autophagy pathway has been implicated in immune dysfunction, the pathogenesis of inflammatory disorders, and response to viral infection. Associations between two genes in the autophagy pathway, ATG5 and ATG7, with childhood asthma were investigated.

METHODS

Using genetic and experimental approaches, we examined the association of 13 HapMap-derived tagging SNPs in ATG5 and ATG7 with childhood asthma in 312 asthmatic and 246 non-allergic control children. We confirmed our findings by using independent cohorts and imputation analysis. Finally, we evaluated the functional relevance of a disease associated SNP.

MEASUREMENTS AND MAIN RESULTS

We demonstrated that ATG5 single nucleotide polymorphisms rs12201458 and rs510432 were associated with asthma (p = 0.00085 and 0.0025, respectively). In three independent cohorts, additional variants in ATG5 in the same LD block were associated with asthma (p<0.05). We found that rs510432 was functionally relevant and conferred significantly increased promotor activity. Furthermore, Atg5 expression was increased in nasal epithelium of acute asthmatics compared to stable asthmatics and non-asthmatic controls.

CONCLUSION

Genetic variants in ATG5, including a functional promotor variant, are associated with childhood asthma. These results provide novel evidence for a role for ATG5 in childhood asthma.

Nasal eosinophilia can predict bronchial hyperresponsiveness in persistent rhinitis: evidence for united airways disease concept

BACKGROUND

Nasal eosinophils may be indicative of bronchial hyperresponsiveness (BHR) in rhinitis concerning the "united airways disease" theory. This study was designed to evaluate the relationship between nasal eosinophilia and BHR in persistent perennial rhinitis patients.

METHODS

Thirty-seven patients (12 males and 25 females, mean age: 33.3 ± 10.4 years) were included in the study. Skin-prick test, nasal symptom score, nasal smears, methacholine bronchial challenge test, and nasal rhinometry were obtained in all patients. Eosinophil count in nasal smears was expressed as a percentage of the total cells. None of the patients had asthma.

RESULTS

There was no difference between the number of atopic and nonatopic patients having BHR (4/20 versus 4/17; chi-squared = 0.07; p > 0.05). Total nasal flow was lower and percentage of nasal eosinophils was higher in the patients with BHR than in patients without BHR (p = 0.012 and p = 0.009, respectively). A cutoff point of 68% nasal eosinophils yielded a sensitivity of 100% (63.1-100) and a specificity of 58.6% (38.9-76.5) to determine the presence of BHR. Positive likelihood ratio for the value of eosinophils above cutoff value was 2.42 (1.8-3.3).

CONCLUSION

This study shows the relationship between nasal eosinophils and BHR in persistent perennial rhinitis patients. Nasal eosinophil percentage below cutoff value indicates that a patient does not have BHR.

Efficacy and Safety of Once Daily Fluticasone Furoate Nasal Spray for Treatment of Irritant (Non-allergic) Rhinitis

INTRODUCTION

The safety and efficacy of fluticasone furoate nasal spray (FFNS) for the symptoms of seasonal and perennial allergic rhinitis have been previously demonstrated in several clinical studies. The objective of this pilot study was to compare the efficacy and safety of FFNS 110 mcg once daily with placebo in patients with irritant (non-allergic) rhinitis triggered predominantly by air pollution.

METHODS

This was a randomized, double-blind, placebo-controlled, 4-week study of subjects in Thailand with irritant rhinitis who received either FFNS 110 mcg (N=53) or placebo (N=49) once-daily. Subjects with a ≥2 year history of air pollution as their predominant rhinitis trigger, negative skin test to local seasonal/perennial allergens, positive histamine skin test, and normal sinus radiograph were enrolled if they met minimum reflective total nasal symptom score (rTNSS) ≥4.5 (maximum=9) and a nasal congestion score of ≥2 (maximum =3). All were assessed for nasal eosinophilia at study entry and completion. Air quality was monitored throughout the study. The primary efficacy endpoint was the mean change from baseline over the treatment period in daily rTNSS, the average of the morning and evening rTNSS. The key secondary measure was the mean change from baseline over the entire treatment period in morning pre-dose instantaneous total nasal symptom score (iTNSS).

RESULTS

The Air Quality Index (AQI) during the study generally did not reach unhealthy levels. Baseline daily rTNSS scores were similar between treatment groups (FFNS=6.7; placebo=6.4). The least square mean change from baseline in rTNSS was -2.17 and -2.10 for FFNS and placebo, respectively, with a difference of -0.065 (p=0.845). Gradual improvements were seen in both treatment groups for iTNSS; however, the treatment difference (-0.075) was not statistically significant (p=0.827). Additionally, there were no statistically significant differences between treatment groups for AM and PM rTNSS, individual nasal symptoms, daily reflective, AM and PM reflective and AM pre-dose instantaneous total ocular symptom scores (TOSS) or individual ocular symptom scores. Nasal cytology at baseline found more than two-thirds of subjects had <20% eosinophils. Adverse events were few and similar between groups and noted as mild in intensity.

CONCLUSION

Subjects receiving FFNS had similar improvement to placebo in their rhinitis symptoms. The lack of a treatment effect may be in part due to the overall good air quality present throughout the study or an insufficient dose or duration of FFNS. The safety findings showed FFNS 110 mcg once daily to be well tolerated.

Human basophils and cytokines/chemokines

Basophils comprise the smallest population in human peripheral blood leukocytes. The role of basophils in the pathogenesis of allergic diseases has long been obscure, although their accumulation and activation in tissues have suggested their potential importance. Recent advances in the field of basophil biology have indicated that cytokines and chemokines are the primary regulators of basophil functions. In addition, various functions of these cells seem differently modulated. The evidence strongly supports the notion that basophils exposed to these substances and allergens will behave as unique effector cells that presumably play proinflammatory roles in type I allergic reactions.

Allergic rhinitis

Allergic rhinitis is common malady with a significant impact on quality of life. It can affect 25% to 35% of people, depending on the population studied. Costs for physicians' visits and medications, and indirect costs of missed school and work and lost productivity, are estimated to be $2 billion annually in the United States. Pharmacotherapy is the most used therapeutic modality. Topical corticosteroids are the preferred method of treatment for seasonal and perennial allergic rhinitis. Antihistamines and antileukotrienes may be beneficial add-ons to topical steroids. Allergen avoidance is recommended, but may be difficult. Allergen immunotherapy is effective and should be considered with poor response to pharmacotherapy and avoidance.

Nonallergic rhinitis with eosinophilia syndrome

Nonallergic rhinitis with eosinophilia syndrome (NARES) is a clinical syndrome comprising symptoms consistent with allergic rhinitis in which an absence of atopy has been demonstrated by allergen skin testing, and nasal cytology analysis demonstrates more than 20% eosinophils. Anosmia is a prominent feature not shared with allergic rhinitis. The pathophysiology of NARES is poorly understood, but a key component involves a self-perpetuating, chronic eosinophilic nasal inflammation with development of nasal micropolyposis and polyposis. Mast cells likely play an important role as well. NARES is a risk factor for the development of nasal polyposis and aspirin sensitivity, as well as obstructive sleep apnea. Treatment consists mainly of intranasal corticosteroids with or without the addition of second-generation antihistamines and/or leukotriene-receptor antagonists.

Haemopoietic mechanisms in murine allergic upper and lower airway inflammation

Eosinophil recruitment to the airways, including involvement of haemopoietic eosinophil-basophil progenitors (Eo/B-CFU), is primarily regulated by interleukin-5 (IL-5) and eotaxin. In this study, we investigated the haemopoietic mechanisms in upper and lower airway eosinophilic inflammation. Ovalbumin (OVA) sensitized and challenged BALB/c mice were used to establish isolated upper (UAC), isolated lower (LAC), or combined upper and lower airway (ULAC) inflammation. Airway, blood and bone marrow responses were evaluated in each model. Numbers of airway eosinophils and CD4(+) cells were increased significantly in the nasal mucosa in UAC and ULAC mice, and in the lung tissue in LAC and ULAC groups. Levels of IL-5 and eotaxin were increased significantly in the nasal lavage fluid (NL) in UAC and ULAC mice, and in the bronchoalveolar lavage fluid (BAL) in LAC and ULAC groups. The proportion of IL-5-responsive bone marrow Eo/B-CFU was significantly higher than the control in all treatment groups, but peaked much earlier in the ULAC group. Kinetic studies revealed that IL-5 and eotaxin in NL, BAL and serum peaked between 2 and 12 hr after OVA challenge in ULAC mice, and at 24 hr in UAC mice, related to the timing of maximal progenitor responses. These data support the concept that the systemic mechanisms linking rhinitis to asthma depend on the location and extent of airway allergen exposure.

The allergic march in pollinosis: natural history and therapeutic implications

BACKGROUND

That specific immunotherapy (SIT) can slow the march of allergy has been confirmed in controlled clinical trials. However, an assessment of its effects in everyday life, in a large cohort of patients, might provide further useful information.

METHODS

This observational study comprised 3,643 patients allergic to pollens; 1,620 with pure allergic rhinitis or rhinitis and intermittent or mild-persistent bronchial asthma, responding poorly to standard pharmacological therapy (SPT), were treated for 3 years with SPT alone (pure rhinitis, n = 890), or combined with continuous SIT (rhinitis and asthma, n = 730). Symptom/drug scores were recorded, respiratory function and skin tests were done, and methacholine challenge was scheduled at the beginning and end of the study. A series of 2,023 patients with pure rhinitis, responsive to SPT, were asked to 'self-medicate' as needed, serving as a control group to check the incidence of asthma.

RESULTS

The incidence of rhinitis-asthma co-morbidity was highest in the self-medication group (50.8%). Persistent rhinitis was associated with asthma more often than the intermittent form, regardless of the severity of the symptoms that led to progression to asthma in patients with intermittent rhinitis. Treatment with SIT combined with SPT always slowed the allergic march which, however, was not influenced by drugs alone.

CONCLUSIONS

In routine clinical practice, SIT is effective in preventing the allergic march. Patients with persistent rhinitis, who are at greatest risk of progression to asthma, appear to be the most logical candidates.

In vitro diagnosis of chronic nasal inflammation

BACKGROUND

Differential diagnosis of chronic nasal inflammation is insufficient when based solely on clinical examination and radiography of paranasal sinuses. Patients complain about more or less similar symptoms. Activation of mast cells and eosinophils is pivotal in nasal inflammation.

OBJECTIVE

To compare tryptase and eosinophilic cationic protein (ECP) in nasal secretions in different forms of chronic nasal inflammation and to establish norm values.

METHODS

The study included 1710 patients presenting with nasal complaints. Nasal secretions were gained by the cotton wool method and analysed for tryptase, as a marker of mast cell activation, and for ECP, as a marker of tissue eosinophilia and activation. Patients were grouped according to their diagnosis: chronic, non-allergic rhinosinusitis (sinusitis, n=194), non-allergic nasal polyposis (polyposis, n=138), non-allergic rhinitis with eosinophilia syndrome (NARES, n=198), isolated perennial allergic rhinitis (AR) (n=126), isolated seasonal AR (n=132), and patients allergic to both, seasonal and perennial allergens (n=193). Seven hundred and twenty-nine patients with nasal complaints due to a deviated septum and without any nasal inflammation served as controls.

RESULTS

Nasal tryptase was highly significantly (P<0.001) elevated in polyposis, NARES, and in AR. ECP was highly significantly (P<0.001) elevated in all groups of patients suffering from chronic nasal inflammation. Based on our data and method we established norm values (95% confidence interval of mean value) for nasal tryptase in healthy adults, ranging from 12.0 to 18.7 ng/mL and for ECP ranging from 84.4 to 102.6 ng/mL.

CONCLUSION

Mast cells and eosinophils are involved in non-allergic and allergic forms of chronic nasal inflammation. We established an in vitro assay for tryptase and ECP in nasal secretions and defined norm values based on our data and method. In vitro measurement of biological markers in nasal secretions provides important information for differential diagnosis and therapeutic strategies of chronic nasal inflammation.

Lysozyme levels in the nasal secretions of patients with perennial allergic rhinitis and recurrent sinusitis

BACKGROUND

The association of perennial allergic rhinitis (PAR) with recurrent sinusitis (RS) is well recognized. Anatomic abnormalities at the osteomeatal complex or ciliary dysfunction may play a significant role in some patients. However, for most patients with allergy, the determinants of RS are unknown.

OBJECTIVE

To determine whether altered concentrations of antimicrobial peptides and proteins, such as lysozyme, lactoferrin, human beta-defensin-2 (HBD-2), and human neutrophil peptides 1 to 3 (HNP-1 to 3), contribute to the development of RS in patients with PAR.

METHODS

Nasal secretions were collected by vacuum aspiration from 15 individuals with PAR+RS, 16 with PAR alone, and 16 controls. Lysozyme and lactoferrin levels were determined in nasal secretions by using quantitative enzyme-linked immunosorbent assay, and HBD-2 and HNP-1 to 3 levels were determined in nasal secretions by using semiquantitative Western blot analysis. Eosinophil-derived neurotoxin (EDN) levels were measured by using enzyme-linked immunosorbent assay as a marker of nasal eosinophilia in all 3 groups.

RESULTS

Levels of EDN were elevated significantly in patients with PAR+RS compared with controls. Lysozyme levels were decreased significantly in patients with PAR+RS compared with PAR alone or controls. Mean lysozyme levels were significantly lower in patients with EDN levels greater than 1,000 ng/mL vs those with levels of 1,000 ng/mL or less in the PAR+RS group. There were no statistically significant differences in lactoferrin, HBD-2, and HNP-1 to 3 levels among the 3 groups.

CONCLUSIONS

The presence of eosinophils and their products and reduced lysozyme concentrations may be critical factors that predispose the airways of patients with PAR to RS.

A role for neutrophils in intermittent allergic rhinitis

OBJECTIVE

In patients with intermittent allergic rhinitis, allergen challenge may induce both early- and late-phase responses. The aim of this study was to examine the correlation between inflammatory cells in the nasal lavage fluid and clinical parameters following pollen challenge.

MATERIAL AND METHODS

Nasal lavage fluids were obtained from 29 patients with intermittent allergic rhinitis before and 1 and 6 h after allergen provocation, representing the control, early and late phases, respectively. Symptom and rhinoscopic scores were registered on the same occasions. Inflammatory cells were determined in the nasal fluid.

RESULTS

The early phase was characterized by increased symptom scores, rhinoscopic signs of oedema and secretion and neutrophilia. In the late phase, symptom scores had diminished, but the signs of ongoing secretion remained. Both the total nasal symptom score and the secretion score correlated with the number of neutrophils in lavage fluids at 1 h. The eosinophil count did not increase during the early or late phases.

CONCLUSION

A single allergen provocation induces an early-phase response dominated by neutrophils, with secretion being the only clinical sign remaining during the late phase. The increase in neutrophil numbers correlated with the registration of secretory symptoms. The presented data indicate a role for neutrophils in intermittent allergic rhinitis and their relation with secretory parameters makes it intriguing to speculate that neutrophils may function as promoters of nasal secretion.

H1-receptors: localization and role in airway physiology and in immune functions

Histamine H(1)-receptors are involved in the pathologic processes of allergy. Clinical trials of H(1)-receptor antagonists have demonstrated the efficacy of these agents in reducing the sneezing, pruritus, and rhinorrhea associated with allergic rhinitis. In the lung, H(1)-receptors mediate the bronchoconstrictive effects of histamine and increase vascular permeability, which lead to plasma exudation. H(1)-receptors are present on T cells, B cells, monocytes, and lymphocytes, and stimulation of these receptors induces pro-inflammatory effects. It has been suggested that a signal from the H(1)-receptor contributes to the antigen receptor-mediated signaling pathways that induce proliferative responses and lead to the production of cytokines and antibodies by T cells and B cells, respectively. It would appear, therefore, that the H(1)-receptor has a wider role in inflammatory processes than simply mediating the actions of histamine.

Atypical nasal challenges in patients with idiopathic rhinitis: more evidence for the existence of allergy in the absence of atopy?

BACKGROUND

The pathophysiology of idiopathic rhinitis is unknown although evidence is accumulating to suggest that many patients may have a localized form of allergic rhinitis in the absence of other atopic symptoms and markers. This study compares detailed nasal challenge results obtained from patients with idiopathic rhinitis to those of atopic and normal controls.

METHODS

Patients with idiopathic rhinitis (n = 23), perennial allergic rhinitis (n = 8) and normal controls (n = 8) underwent a normal saline challenge to exclude hyper-reactivity and then bilateral nasal allergen challenges. Nasal patency was assessed by anterior active rhinomanometry.

RESULTS

All of the patients with atopic rhinitis demonstrated positive bilateral allergen challenges. All normal control subjects had bilateral negative challenges. Two patients in the idiopathic group tested positively to saline and were excluded from further study with 62% of the remainder testing positive to allergens. Of the idiopathic patients testing positive, 85% were sensitive to house dust mite.

CONCLUSION

A significant proportion of patients with idiopathic rhinitis have positive nasal challenges, the vast majority to house dust mite allergen. These findings add to the weight of evidence that suggests 'localized allergy' may exist in the absence of systemic atopic markers.

Neurology of allergic inflammation and rhinitis

Afferent nerves, derived from the trigeminal ganglion, and postganglionic autonomic nerves, derived from sympathetic and parasympathetic ganglia expressing many different neurotransmitters, innervate the nose. Reflexes that serve to optimize the air-conditioning function of the nose by altering sinus blood flow, or serve to protect the nasal mucosal surface by mucus secretion, vasodilatation, and sneezing, can be initiated by a variety of stimuli, including allergen, cold air, and chemical irritation. Activation of nasal afferent nerves can also have profound effects on respiration, heart rate, blood pressure, and airway caliber (the diving response). Dysregulation of the nerves in the nose plays an integral role in the pathogenesis of allergic rhinitis. Axon reflexes can precipitate inflammatory responses in the nose, resulting in plasma extravasation and inflammatory cell recruitment, while allergic inflammation can produce neuronal hyper-responsiveness. Targeting the neuronal dysregulation in the nose may be beneficial in treating upper airway disease.

Autoanti-IgE antibodies in patients with allergic and idiopathic rhinitis

The pathophysiology of idiopathic rhinitis is unknown although evidence is accumulating to suggest that, in a proportion of patients, it may be a more localized form of allergic rhinitis in the absence of other atopic symptoms and markers. Anti-IgE is thought to be a systemic marker of atopy. This study compared serum IgG autoanti-IgE levels in patients with idiopathic rhinitis, perennial allergic rhinitis and normal controls. Serum samples were obtained from 19 patients with idiopathic rhinitis, 17 patients with perennial allergic rhinitis and 10 normal non-rhinitic controls. The presence or absence of IgG1 and IgG4 anti-IgE antibodies was detected using enzyme-linked immunosorbent assays. Eighty-eight percent of the patients with perennial allergic rhinitis had raised levels of autoanti-IgE antibodies in their serum. None of the controls or patients with idiopathic rhinitis showed raised levels (P < 0.001). Although patients with idiopathic rhinitis may exhibit clinical and pathological features of allergy, they do not show raised levels of anti-IgE in their serum.

Repeatability and validity of cell and fluid-phase measurements in nasal fluid: a comparison of two methods of nasal lavage

BACKGROUND

There is little information on the repeatability of cell counts and fluid-phase measurements in nasal fluid obtained by different methods of nasal lavage.

OBJECTIVE

To compare the repeatability and validity of total and differential cell counts and eosinophil cationic protein (ECP) in nasal secretions obtained by two methods of nasal lavage.

PATIENTS AND METHODS

Twelve healthy subjects and twelve subjects with clinically stable allergic rhinitis were randomly assigned to two nasal lavages (separated by 48 h), by one of two methods in the first week and by the second method in the following week. One method was a modification of the method described by Greiff et al. and Grunberg and coworkers and the other was that described by Naclerio and coworkers.

RESULTS

Both methods of nasal lavage gave poorly repeatable eosinophil counts and ECP in normal subjects but better repeatability in subjects with rhinitis. The modified Greiff/Grunberg method gave higher and more repeatable total cell count and, in subjects with rhinitis, more reproducible ECP levels compared with the Naclerio

METHOD

Both methods were able to discriminate between healthy and rhinitic subjects: mean +/- SD eosinophil percentage count and eosinophil cationic protein differences were 4.5 +/- 4% (P < 0.05) and 24.5 +/- 46.9 microg/L (P < 0.05), respectively, with the modified method and 7.0 +/- 4% (P < 0.05) and 26.9 +/- 68 microg/L (P < 0.05), respectively, with the Naclerio method.

CONCLUSION

Both methods are valid and discriminate between normal and rhinitic subjects. In subjects with rhinitis, although the repeatability of eosinophil counts is similar by both methods, the modified Greiff/Grunberg method gives more reproducible ECP measurements, compared with the Naclerio method.

Systemic immunologic and inflammatory aspects of allergic rhinitis

Allergic rhinitis is a common chronic condition that is characterized by inflammation of the nasal mucosa. Although allergic rhinitis is a condition with upper respiratory symptoms, there is a growing body of evidence to suggest that allergic rhinitis may be linked to the development of systemic allergic manifestations that include allergic asthma. The evidence reveals that individuals with allergic rhinitis are sensitized to the eliciting allergens and exhibit cutaneous and respiratory hypersensitivity responses on exposure to the allergen. On exposure to a nasal allergen, circulating immunoglobulin E levels increased and remained elevated 2 weeks after the initial provocation. Patients with allergic rhinitis exhibit peripheral eosinophilia and basophilia, the magnitude of which correlates with the severity of symptoms. Additionally, there are several links between allergic rhinitis and asthma. First, 85% to 95% of patients with allergic asthma report rhinitis symptoms, and the severity of the 2 conditions increases in parallel on exposure to an allergen. Second, nasal administration of allergens can provoke impaired lower airway airflow in 25% to 30% of individuals and cause airway eosinophilia, as evidenced by increased numbers of eosinophils in sputum and mucosal biopsy specimens. Third, the treatment of seasonal allergic rhinitis with both systemic (eg, antihistamines) and local agents (eg, glucocorticosteroid analogues) can alleviate the symptoms of asthma. In summary, evidence that associates allergic rhinitis with systemic immunologic and inflammatory processes is growing, thereby warranting further in-depth investigation.

Eosinophils are a feature of upper and lower airway pathology in non-atopic asthma, irrespective of the presence of rhinitis

BACKGROUND

Asthma and rhinitis often co-exist and there are data to suggest that they may be two ends of the same disease spectrum. Immunohistochemical studies have shown that eosinophilia in the airways is a feature of rhinitic patients without asthma.

OBJECTIVE

The aim of our study was to examine whether cellular infiltration exists in the nasal mucosa of asthmatics even in the absence of symptoms and signs of rhinitis.

METHODS

Nasal mucosa biopsies were taken from 27 non-atopic subjects and comprised nine asthmatic rhinitic patients (AR), eight asthmatic non-rhinitic patients (ANR) and 10 healthy control subjects (N). Bronchial mucosa biopsies were also taken simultaneously from some of the patients (n = 10) to determine whether there was an association between cellular infiltration in the nose and the lungs. The alkaline phosphatase-anti-alkaline phosphatase (APAAP) method was used on 6 microm thick cryostat sections using monoclonal antibodies against T cells (CD4, CD8), eosinophils (EG2) and mast cells (mast cell tryptase). Slides were counted blind and results expressed as cells per field.

RESULTS

The results showed that eosinophil counts were higher in both asthma groups compared with control nasal biopsies (median values AR 8.3, ANR 9.2, N 2.1 cells per field, P < 0.01). Furthermore, there was a significant correlation between eosinophil cell counts in the nose and the airways (r = 0.851 P < 0.001). No differences in eosinophil numbers were detected between the two groups of asthmatics. Also, no differences were noted for any other cell type (i.e. CD4, CD8, tryptase) among the three study groups.

CONCLUSIONS

These results show that eosinophil infiltration was present in the nasal mucosa of asthmatic patients even in the absence of rhinitis, and add further support to the hypothesis that asthma and rhinitis are clinical expressions of the same disease entity.

Allergic inflammation in upper and lower airways

OBJECTIVE

The primary reason for this review is to discuss the relationship between upper and lower airways at various levels with the emphasis on common pathophysiologic mechanisms, and how treatment of the upper airways will benefit the lower airways.

DATA SOURCES

The main source of information is derived from original articles and books, with an extensive bibliography included.

STUDY SELECTION

Studies were derived almost exclusively from articles and reviews in peer-reviewed journals.

RESULTS

The prevalence of rhinitis and asthma are both increasing. Common to both the upper and lower airways are the triggers, many of the inflammatory cells and mediators, and the treatment modalities. By contrast, there are organ-specific differences in the reaction to various stimuli in the nose or lung, with each organ manifesting its own vocabulary of response.

CONCLUSIONS

There are meaningful relationships between upper and lower airways at various levels of our understanding. Differential responses to medications help us better understand pathogenic mechanisms in rhinitis and asthma. Further, treatment of the upper airways provides additional benefit to the lower airways.

Diagnosis and management of rhinitis

This article reviews the differential diagnoses for rhinitis, medications available for the treatment of rhinitis, and special circumstances (such as pregnancy or medication side-effects) that may influence a clinician's decision. Considering the economic impact of rhinitis, the cost of prescription medications, and quality-of-life issues that are affected by rhinitis, physicians dealing with managed care organizations should make their diagnosis and treatment decisions carefully.

Quantitative cytology of nasal secretions with perennial allergic rhinitis in children: comparison of noninfected and infected conditions

This study was performed to quantify the number of inflammatory cells in nasal secretions from pediatric patients with perennial allergic rhinitis under noninfected and infected conditions. Nasal secretions were obtained from seven children under both noninfected and infected conditions with perennial allergic rhinitis to house dust mites, and secondary quantitative cytology was performed on the secretions. The number of neutrophils under infected condition was significantly higher than that under noninfected condition (P < .05), whereas the number of eosinophils in infected condition was significantly lower than that in noninfected condition (P < .05). The ratio of eosinophil count to neutrophil count was more than 0.1 in noninfected condition. The ratio was significantly decreased in infected condition (P < .02). These results suggest that the distribution of inflammatory cells in the nasal mucus of children with allergic rhinitis would be modified under infected condition.

Characteristics of histamine-induced leukocyte rolling in the undisturbed microcirculation of the rat mesentery

1. The main objective of this study was to analyse the role and mode of action of the mast cell mediator histamine in leukocyte-endothelium interactions in small venules in vivo. For this purpose, we used a histological approach (combined with intravital microscopy) that allows studies of rapid mediator-induced venular leukocyte accumulation, reflecting leukocyte rolling, in the undisturbed microcirculation of the rat mesentery where rolling is normally absent. 2. We first examined the relative importance of histamine and 5-hydroxytryptamine (5-HT) in acute mast cell-dependent leukocyte recruitment. The mast cell secretagogue compound 48/80 (i.p. for 15 min) induced a marked venular accumulation of polymorphonuclear leukocytes (PMNL) which was almost abolished by combined histamine1 (H1)- and histamine2 (H2)-receptor blockade. In contrast, the 5-HT-receptor antagonist methysergide was inactive in this regard. Moreover, exogenous 5-HT was less active than exogenous histamine in evoking venular PMNL accumulation (histamine response dose-dependent; 5-HT response bell shaped). Prostaglandin D2 did not cause PMNL accumulation. 3. The venular PMNL response to exogenous histamine peaked between 15 min and 1 h, was still significantly elevated at 2 h, and then returned to prechallenge values after 3 h. At all time points, the histamine-induced PMNL accumulation was nearly abolished by i.v. treatment with the polysaccharide fucoidin (which blocks rolling but not firm adhesion per se), suggesting that the PMNL response to histamine was due to rolling rather than firm adhesion over the entire 3 h period. At no time point did histamine trigger accumulation of mononuclear leukocytes (MNL). 4. To examine the role of histamine-receptors in the histamine-induced PMNL accumulation (i.e. rolling), the animals were pretreated with diphenhydramine (H1-receptor antagonist), cimetidine, or ranitidine (H2-receptor antagonists). Diphenhydramine alone inhibited the venular PMNL response to histamine by 52%, while both H2-receptor antagonists were completely inactive. However, the combination of cimetidine and diphenhydramine reduced the histamine-induced PMNL rolling by 82%. Furthermore, in contrast to an H3-receptor agonist, challenge with either the H1-receptor agonist 2-thiazolylethylamine or two different H2-receptor agonists (impromidine, dimaprit) was sufficient to provoke significant venular PMNL accumulation. 5. Treatment with the nitric oxide-synthase inhibitor L-NAME did not affect the histamine-induced PMNL rolling. On the other hand, 3 h pretreatment with dexamethasone reduced the PMNL response to histamine by 73%, and flow cytometric analysis showed that the dexamethasone treatment almost completely inhibited binding of soluble P-selectin to rat isolated PMNLs. 6. We conclude that initial leukocyte recruitment after mast cell activation in the rat mesentery is critically dependent on histamine release. The cellular response to histamine was specifically due to PMNL rolling, involved activation of both H1- and H2-receptors, and lasted for 2 3 h. Moreover, the histamine-induced PMNL rolling was not dependent on nitric oxide synthesis, but was sensitive to glucocorticoid treatment, possibly via inhibition of expression or function of leukocytic P-selectin ligand(s).

Effect of immunotherapy on serum levels of eosinophil cationic protein in perennial allergic rhinitis

Eosinophil cationic protein (ECP) levels in the serum of clotted blood could reflect the rate of activation of circulating eosinophils. We investigated the serum ECP levels in patients with perennial allergic rhinitis, with special reference to the effect of immunotherapy on the serum ECP levels. Serum ECP levels in untreated patients with perennial allergic rhinitis are significantly higher than those of nonatopic volunteers. Therefore, this elevation in the untreated patients represents an ongoing inflammation occurring in allergic rhinitis. The mean serum ECP level of a 1-year immunotherapy group was significantly higher than that of the nonatopic group, and was not different from that of the untreated group. In contrast, the mean serum ECP level in patients who had more than 2 years of immunotherapy was significantly lower than that of the untreated group, and was not different from that of the nonatopic group. Additionally, serum ECP levels were significantly correlated with the duration of immunotherapy. These findings suggest that activation of circulating eosinophils decreases gradually during immunotherapy, but this inhibition becomes apparent only after 2 years of immunotherapy. The control of circulating eosinophil activation might be one of the important working mechanisms behind the clinical effect of immunotherapy.

Intranasal capsaicin is efficacious in non-allergic, non-infectious perennial rhinitis. A placebo-controlled study

BACKGROUND

Several authors described capsaicin, the pungent substance in red pepper, as an efficacious therapy for non-allergic non-infectious perennial rhinitis (NANIPER). Repeated capsaicin application induces peptide depletion and specific degeneration of the unmyelinated sensory C-fibres in the nasal mucosa.

METHODS

We performed a placebo-controlled (NaCl 0.9%) study with 25 NANIPER patients. Daily record charts and visual analogue scales (VAS) were used for clinical evaluation. Nasal lavages were obtained before, during, and after treatment.

RESULTS

There was a significant and long-term reduction in the VAS scores in the capsaicin group. No significant difference was found between the placebo and capsaicin treated groups for the mean group concentrations of leukotriene (LT) C4/D4/E4, prostaglandin D2 (PGD2), and tryptase. The levels of mast cell mediators, tryptase and PGD2, and leukotrienes, mediators derived from a variety of inflammatory cells, were low at baseline and comparable with levels observed in nasal lavages obtained from normals.

CONCLUSION

As involvement of inflammation could not be demonstrated, it is not surprising that capsaicin has no effect on inflammatory mediators. This suggests that inflammatory cells do not play a major part in the pathogenesis of NANIPER.

Pathogenesis of allergic rhinitis

Allergic rhinitis is an increasing problem for which new and exciting therapies are being developed. These can be understood through an appreciation of the newer concepts of pathogenesis of allergic rhinitis. Allergen induces Th2 lymphocyte proliferation in persons with allergies with the release of their characteristic combination of cytokines including IL-3, IL-4, IL-5, IL-9, IL-10, and IL-13. These substances promote IgE and mast cell production. Mucosal mast cells that produce IL-4, IL-5, IL-6, and tryptase proliferate in the allergic epithelium. Inflammatory mediators and cytokines upregulate endothelial cell adhesion markers, such as vascular cell adhesion molecule-1. Chemoattractants, including eotaxin, IL-5, and RANTES, lead to characteristic infiltration by eosinophils, basophils, Th2 lymphocytes, and mast cells in chronic allergic rhinitis. As our understanding of the basic pathophysiologic features of allergic rhinitis continues to increase, the development of new diagnostic and treatment strategies may allow more effective modulation of the immune system, the atopic disease process, and the associated morbidity.

Pathology of rhinitis and bronchial asthma

Studies of the pathology of rhinitis and asthma have identified similarities and differences between these two clinical conditions. With regard to symptoms, both the nose and the lower airways respond to neural stimulation by irritant substances, but a major difference is that engorgement of the capacitance vessels is the main cause of nasal obstruction in rhinitis, while muscle constriction is the major determinant of lower airway narrowing. There are also similarities and differences with respect to the role of inflammatory cells. In both conditions there is evidence of allergen-induced mast cell activation, with production of an array of mediators (some mast cell-derived and others originating from a variety of other cell types). Eosinophilia is also characteristic of both diseases--it is prominent even in mild forms of asthma, but is low in pollen-sensitive rhinitics outside of the season. T-cell activation and production of cytokines plays an important role in the development and maintenance of allergic disease, but the level of T-cell activation may differ between asthma and rhinitis. Further research into differences in cellular activity and response to treatment between these two diseases may help define factors which will determine whether atopic disease is expressed in the upper, lower, or both parts of the respiratory tract.

Anti-IgE-induced accumulation of leukocytes, mediators, and albumin in skin chamber fluid from healthy and atopic subjects

The aim of this study was to examine potential differences between healthy and atopic subjects with regard to IgE-mediated cutaneous inflammation. For this purpose, we analyzed histamine, tryptase, leukotriene B4, albumin, eosinophils, and total leukocytes in skin chamber fluid after challenge with anti-human IgE. We also measured gross skin reactivity (wheal, flare, and late-phase reactions), circulating IgE, and eosinophils, as well as the state of eosinophil activation. It was found that despite having more circulating IgE, the skin responsiveness of the atopic subjects did not differ significantly from that of the nonatopic subjects with respect to mediator release, albumin extravasation, or total recruitment of leukocytes. Moreover, the sizes of anti-IgE-induced wheal, flare, and late-phase reactions were very similar in the two groups. On the other hand, significant recruitment of eosinophils during the IgE-mediated reaction was more or less restricted to the atopic group. Yet the recruited eosinophils, of which the majority was in an early state of activation before degranulation, did not seem to contribute significantly to the IgE-mediated delayed skin edema. Furthermore, the eosinophil count in anti-IgE chambers of the atopic subjects did not correlate with any of the other parameters monitored. Thus because the anti-IgE-induced recruitment of eosinophils appeared to be unrelated to factors such as the number of peripheral blood eosinophils, the degree of mast cell activation, the intensity of inflammatory skin changes, and the level of circulating IgE, it is apparent that the mechanisms for and pathophysiologic role of IgE-mediated dermal eosinophil accumulation in atopic subjects require further investigation.

Nasal lavage cellularity, grain dust, and airflow obstruction

To evaluate the clinical utility of nasal lavage (NL), we performed post-work shift NL on 172 grain workers and 78 postal worker control subjects. The grain worker group included a higher percentage of current smokers (25.7% vs 16.7%) and a lower percentage of former smokers (21.15% vs 35.9%) compared with the postal workers. The control subjects included more female workers and were slightly older than the grain workers. Compared with the postal workers, the grain workers were exposed to significantly greater concentrations of total dust (0.1 +/- 0.0 vs 6.8 +/- 1.4 mg/m3; mean +/- SEM) and total endotoxin (4.3 +/- 0.8 vs 2,372.4 +/- 653.8 endotoxin units/m3). NL from gain workers showed a higher concentration of total cells (55,000 +/- 14,000 vs 25,000 +/- 5,000 cells per milliliter; p=0.03), a higher concentration of squamous epithelial cells (17,029.0 +/- 4,177 .0 vs 7,103.7 +/- 1,479.8 cells per milliliter; p=0.03), and a higher concentration of neutrophils (40,058.0 +/- 12,803.2 vs 17,891.0 +/- 3,822.3 cells per milliliter; p=0.10) compared with postal workers. Importantly, these differences in NL cellularity between grain workers and postal workers were observed within the three strata of smokers. To further assess the importance of total cells, squamous epithelial cells, and neutrophils in the NL fluid of grain workers, we investigated the relationship between these cell concentrations and (1) measures of dust and endotoxin exposure during the work shift. (2) spirometric measures of airflow obtained immediately before the NL, and (3) work-related respiratory symptoms. The concentration of total cells, the concentration of squamous epithelial cells, or the concentration of neutrophils in the NL was not associated with ambient levels of dust or endotoxin, with baseline or cross-shift changes in lung function, or with work-related respiratory symptoms. These findings suggest that increased NL cellularity may be seen in workers exposed to high dust levels. However, the NL cellularity does not appear to be associated with ambient concentrations of dusts or endotoxins, with signs of airflow obstruction, or with work-related respiratory symptoms.

Nasal lavage as tool for health effect assessment of photochemical air pollution

It is widely accepted that humans exposed to known concentrations of ozone under controlled conditions exhibit reversible changes that affect the large and small airways as well as the alveolar region of the lung. Among the reversible changes, the induction of inflammatory responses in the lung are of major concern. Many of the cell types found in the lining of the nasopharyngeal region are similar to cells of the tracheal and bronchial lining. therefore, it has been suggested that the cellular responses in the nose to toxicants are likely to be similar to the lower airway at the same dose of the agent. If these pollutants are respiratory irritants, capable of causing cellular damage, effects may therefore be detected in the nasal passage. Experimental studies have shown that the inflammatory response in the nose may be predictive for the situation in the lung. In this paper we described the results of a feasibility study on the use of nasal lavage for epidemiological studies. Nasal lavages were performed in 12 volunteers, 5-7 times per volunteer during 2 months. Polymorph nuclear leukocytes (PMN's), immune mediators and markers for exudation were monitored in the nasal lavage (NAL). It was found that the procedure of the nasal lavage technique was minimally invasive, very well tolerated and no adverse side effect were observed. The leukocytes, the proteins myeloperoxidase (MPO), eosinophil cationic proteins myeloperoxidase (MPO), eosinophil cationic protein (ECP) and interleukin-8 (IL-8) were detectable in NAL of most volunteers, while tryptase IgE and IL-6 were not detectable. Exudation markers albumin, urea and uric acid were also detectable. The coefficient of variance (CV) values of the various cells and mediators varied between 13% and 137%. It was calculated that, except for the number of leukocytes and the concentration of ECP, it should be possible to detect ozone effects with a study-protocol of 6 repeated measurements among 35 children and an assumed 26% increase in cells or mediators per 100 micrograms O3 per m3. To measure increase in leukocytes number or in ECP concentration more children are needed. In conclusion, this pilot study has shown that it is possible to measure relevant biomarkers in NAL, and that these assays can be easily incorporated in epidemiological studies.