Sensitivity and maximal response to methacholine in perennial and seasonal allergic rhinitis

Different clinical effect of several types of airborne allergens on the severity of bronchial hyperreactivity

BACKGROUND

Atopic sensitization belongs to the most common risk factors for bronchial asthma. However, in clinical practice, it is not clear whether sensitization against pollen and perennial allergens is differently associated with the severity of bronchial hyperresponsiveness (BHR).

AIM

To find out whether patients sensitized to perennial allergens differ in severity of bronchial hyperresponsiveness from patients sensitized to pollen allergens.

METHODS

The study includes 109 patients. Based on the results of skin prick tests, patients were divided into three groups: sensitivity to pollen allergens - group A; sensitivity to perennial allergens - group B; sensitivity to both pollen and perennial allergens - group C. Based on the histamine bronchoprovocation test, we compared the values of histamine provocative concentration causing a 20% drop in FEV₁ (PC₂₀) among particular groups of patients. Mild bronchial hyperresponsiveness was determined if the value of PC₂₀ was >4 mg/ml, while if the value of PC₂₀ was <4 mg/ml, the bronchial hyperresponsiveness was considered as moderate/severe.

RESULTS

A statistically significant difference was found in the degrees of bronchial hyperresponsiveness between the three groups of patients, namely, group A with the patients sensitized only to the pollen allergens, group B comprising patients sensitized to the perennial allergens only, and group C, involving patients sensitized to the combination of both pollen and perennial allergens. The PC₂₀ values were higher among the patients from the group A (7.46 mg/ml) compared to group B (4.25 mg/ml) and C (4.52 mg/ml). The odds ratio for moderate/severe BHR was 5.21 and 5.04 in group B and group C, respectively.

CONCLUSION

Severity of bronchial hyperresponsiveness shows differences according to sensitization to particular allergens. Perennial allergens are more often associated with serious forms of bronchial hyperresponsiveness which also have an impact on the severity and prognosis of bronchial asthma.

Comorbidities of asthma and the unified airway

BACKGROUND

Asthma is a comorbid condition that may be seen by otolaryngic allergists when treating their patients with allergic rhinitis (AR). Often asthma is overlooked when aggressive treatment could prevent the development or progression of early disease.

METHODS

This article is a retrospective review of the current literature on asthma as a comorbidity of the unified airway. The unified airway and asthma are clearly defined. The epidemiology, morbidity, mortality, pathophysiologic mechanisms, and the chronicity of asthma are reviewed.

RESULTS

The otolaryngic allergist will become familiar the unified airway concept and the close relationships between AR, chronic rhinosinusitis, and asthma.

CONCLUSION

Otolaryngologists should be aware of the unified airway in order to most effectively treat their patients with AR. Knowledge of the close relationships between asthma and AR will help prevent progression of disease, identify early asthma, and improve the outcomes and quality of life for our patients.

Diseases of the nose and paranasal sinuses in child

Diseases of the pediatric nose and nasal sinuses as well as neighboring anatomical structures encompass a variety of pathologies, especially of inflammatory nature. Congenital disease, such as malformations and structural deviations of the nasal septum, as well as systemic metabolic pathologies affecting the nose and sinuses, rarely require medical therapy from an Otolaryngologist. The immunological function of the mucosa and genetic factors play a role in the development of disease in the pediatric upper airway tract, especially due to the constantly changing anatomy in this growth phase. Disease description of the nose and nasal sinuses due to mid-facial growth must also take developmental age differences (infant, toddler, preschool, and school age) into account. Epidemiological examinations and evidence based studies are often lacking in the pediatric population. The wide range of inflammatory diseases of the nose and paranasal sinuses, such as the acute and chronic rhinosinusitis, the allergic rhinitis, and adenoid disease, play a role in the susceptibility of a child to infection. The susceptibility to infection depends on the pediatric age structure (infant, young child) and has yet to be well defined. The acute rhinosinusitis in children develops after a viral infection of the upper airways, also referred to as the "common cold" in the literature. It usually spontaneously heals within ten days without any medical therapy. Antibiotic therapy is prudent in complicated episodes of ARS. The antibiotic therapy is reserved for children with complications or associated disease, such as bronchial asthma and/or chronic bronchitis. A chronic rhinosinusitis is defined as the inflammatory change in the nasal mucosa and nasal sinus mucosa, in which the corresponding symptoms persist for over 12 weeks. The indication for CT-imaging of the nasal sinuses is reserved for cases of chronic rhinosinusitis that have been successfully treated with medication. A staged therapeutic concept is followed in CRS based on conservative and surgical methods. Nasal sinus surgery is considered nowadays as effective and safe in children. Based on the assumption that adenoids are a reservoir for bacteria, from which recurrent infections of the nose and nasal sinus originate, the adenoidectomy is still defined as a cleansing procedure in rhinosinusitis. 69.3% of the children had benefit from adenoidectomy. Comorbidities, such as pediatric bronchial asthma, presently play an even more important role in the therapy of rhinosinusitis; therefore, it is often wise to have the support of pediatricians. In western European countries 40% of children presently suffer from allergic rhinitis, in which pronounced nasal obstruction can cause disturbed growth in facial bones. An early therapy with SIT may prevent the development of bronchial asthma and secondary sensitization to other allergens. Therefore, SIT is recommended in treatment of allergic rhinitis whenever, if possible. The assessment of diagnostic tools is for the examiner not often possible due to the lack of evidence. Rhinosurgical approaches are often described in study reports; however, they lack the standard prospective randomized long-term study design required nowadays and can only be evaluated with caution in the literature.

Why otolaryngologists and asthma are a good match: the allergic rhinitis-asthma connection

Consideration of the unified airway model when managing patients with rhinitis and or asthma allows a more comprehensive care plan and therefore improved patient outcomes. Asthma is linked to rhinitis both epidemiologically and biologically, and this association is even stronger in individuals with atopy. Rhinitis is not only associated with but is a risk factor for the development of asthma. Management of rhinitis improves asthma control. Early and aggressive treatment of allergic rhinitis may prevent the development of asthma. In patients with allergic rhinitis that is not sufficiently controlled by allergy medication, allergen-directed immunotherapy should be considered.

Allergic rhinitis and chronic rhinosinusitis: their impact on lower airways

Anatomy, pathophysiology, epidemiology, and disease characteristics link the upper and lower airways. Nonspecific symptoms such as cough, congestion, shortness of breath, and recurrent infection may be related to the upper airway, lower airway, or both. Patients with the most severe disease often exhibit symptoms and findings of inflammation at both sites. Recent literature suggests that medical treatment and, when appropriate, surgical therapy directed at the upper airway can yield improvements in the lower airway. An understanding of the diagnosis and management of diseases at both sites will afford patients the best possible outcomes.

Rhinitis in children: co-morbidities and phenotypes

Rhinitis and its co-morbidities affect quality of life; and in children, little is known. We therefore aimed to describe the co-morbidities and phenotypes of current rhinitis in 10-yr-old Norwegian children. We used information on rhinitis, asthma, allergic sensitization, anaphylaxis, and lung function tests from clinical examinations and structured parental interviews of 1019 children included in the birth cohort study, the Environment and Childhood Asthma Study, in Oslo. Current rhinitis was reported in 254 (25.0%) of the children, and 87.4% had at least one allergy-related co-morbidity of rhinitis, with conjunctivitis the most prevalent (75.6%). Overall, 11.8% of the children had conjunctivitis combined with current asthma and atopic eczema. Children with rhinitis were also more likely to have severe bronchial hyperresponsiveness (BHR) (PD(20) <or= 1 micromol methacholine) than children without rhinitis (17.5% and 5.8%, respectively, p < 0.001), as well as BHR (PD(20) <or= 8 micromol). The children with rhinitis and allergic sensitization (72.8%) had more frequently BHR, severe BHR, and conjunctivitis, but did not differ with respect to any other co-morbidity from children with rhinitis without allergic sensitization. Children with symptoms reported by exposure to both pollen and furry pets had more often asthma, wheeze, and BHR compared to the children who reported rhinitis symptoms only when exposed to pollen (91.9% of these had symptoms in spring/summer only). In conclusion, current rhinitis is closely associated with conjunctivitis, asthma, atopic eczema, and BHR in childhood. Conjunctivitis and BHR were most strongly linked to rhinitis with allergic sensitization.

Airway hyperresponsiveness: a comparative study of methacholine and exercise challenges in seasonal allergic rhinitis with or without asthma

BACKGROUND

Asymptomatic airway hyperreactivity in allergic rhinitis is a risk factor for later development of asthma. Although non-specific bronchial hyperresponsiveness (BHR) has been measured by several stimuli, the most appropriate measurement technique still remains unclear.

OBJECTIVE

To investigate whether an exercise challenge can be used to predict BHR in seasonal allergic rhinitis patients with or without asthma and to compare this bronchial reactivity with a methacholine challenge technique.

METHODS

Forty-six consecutive patients with seasonal allergic rhinitis only (n = 31) and with both seasonal allergic rhinitis and asthma (n = 15) were included in the study during the pollination period. Subjects underwent first methacholine (mch) and then exercise challenge testing (ECT). There was a 1-week interval between the tests. ECT was performed on a bicycle ergometer. Positive result was defined as a 15% decrease in forced expiratory volume in 1 second (FEV(1)) post-exercise. A patient's bronchial reactivity to methacholine was considered as hyperresponsive if PC(20) was less than 8 mg/mL.

RESULTS

Mch PC(20) values were significantly lower in patients with both rhinitis and asthma (p < 0.062). Among the 46 patients, mch PC(20) values were significantly different between patients who had positive and negative exercise challenge tests (p = 0.007). All patients with rhinitis alone had a negative ECT and 10 had a positive mch challenge. Change in FEV(1) values after ECT was significantly higher in patients with both rhinitis and asthma compared to those with rhinitis alone (p = 0.009). There was a significant relation between positivity of mch and exercise challenges (p = 0.025). ECT positivity was found to be a significant confounding factor in the diagnosis of asthma (p = 0.001). Specificity and sensitivity values were 100% and 24% for ECT and 68% and 100% for mch, respectively.

CONCLUSION

Exercise challenge presents poor diagnostic value for detecting bronchial responsiveness in individuals with allergic rhinitis alone during the pollen season.

Modifications in forced vital capacity during adenosine monophosphate-induced bronchoconstriction in asthma: relationship with the response to methacholine and the effect of inhaled corticosteroids

BACKGROUND

The effect of adenosine monophosphate (AMP) on forced vital capacity (FVC) has never been systematically investigated.

OBJECTIVE

To compare methacholine- and AMP-induced changes in FVC, as a marker of air trapping, in asthmatic patients treated and not treated with inhaled corticosteroids (ICSs).

METHODS

Airway responsiveness to equipotent concentrations of AMP and methacholine was obtained in asthmatic patients treated (n = 32) and not treated (n = 18) with ICSs. The response was expressed by the provocation concentration of agonist that caused a decrease in forced expiratory volume in 1 second (FEV1) of 20% (PC20) and by the slope of the FVC values recorded at each step of the challenge against the corresponding FEV1 values (sFVC).

RESULTS

Although methacholine and AMP PC20 values were similar in patients treated and not treated with ICSs, the mean (95% confidence interval) methacholine sFVC (but not AMP sFVC) was higher in those treated with ICSs (0.91; 0.77-1.06) than in those not taking ICSs (0.69; 0.57-0.81; P = .03). No significant correlation was found between sFVC and PC20 values obtained with either methacholine or AMP. Methacholine and AMP sFVC values were significantly related, but only in the group treated with ICSs (r = 0.60, P < .001).

CONCLUSIONS

Although the AMP-induced decline in FVC in asthmatic patients is similar to that observed with equipotent concentrations of methacholine, the apparently different effect of ICSs on changes in FVC induced by each agonist suggests that the information provided by the 2 bronchoconstrictor agents is not interchangeable and that the information generated by the analysis of the effect of each agonist on FEV1 and FVC may be complementary.

Asthma and rhinitis: comorbidities

The connection between asthma and rhinitis is not a new discovery. Significant progress has been made in understanding the relationship of these two conditions, however, and the implications of the asthma-rhinitis link make it increasingly important. Patients who have asthma and rhinitis tend to have more severe disease with higher treatment costs. Treatment of rhinitis may improve asthma control, and early treatment of allergies may prevent the development of asthma. This article more fully explores the epidemiologic, pathophysiologic, and clinical relationships between asthma and rhinitis.

BSACI guidelines for the management of allergic and non-allergic rhinitis

This guidance for the management of patients with allergic and non‐allergic rhinitis has been prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI). The guideline is based on evidence as well as on expert opinion and is for use by both adult physicians and paediatricians practicing in allergy. The recommendations are evidence graded. During the development of these guidelines, all BSACI members were included in the consultation process using a web‐based system. Their comments and suggestions were carefully considered by the SOCC. Where evidence was lacking, consensus was reached by the experts on the committee. Included in this guideline are clinical classification of rhinitis, aetiology, diagnosis, investigations and management including subcutaneous and sublingual immunotherapy. There are also special sections for children, co‐morbid associations and pregnancy. Finally, we have made recommendations for potential areas of future research.

Contribution of prostaglandin D2 via prostanoid DP receptor to nasal hyperresponsiveness in guinea pigs repeatedly exposed to antigen

We examined the role of prostanoid DP receptor in nasal blockage in an experimental allergic rhinitis model in guinea pigs. Local inhalation of prostaglandin D(2) (PGD(2)) to the nasal cavity resulted in an increase in intranasal pressure in guinea pigs actively sensitized by repeated antigen exposure but not in non-sensitized guinea pigs. Nasal hyperresponsiveness was observed when the guinea pigs were exposed to histamine and U-46619 (11alpha, 9alpha-epoxymethano-PGH(2); a thromboxane (TX) A(2) mimetic) after repeated antigen exposure. S-5751 ((Z)-7-[(1R,2R,3S,5S)-2-(5-hydroxybenzo[b]thiophen-3-ylcarbonylamino)-10-norpinan-3-yl]hept-5-enoic acid), a prostanoid DP receptor antagonist, inhibited not only PGD(2)-induced nasal blockage but also nasal hyperresponsiveness to histamine and U-46619 in sensitized guinea pigs. Combined exposure of the nasal cavity of guinea pigs to an aerosol of PGD(2) with histamine or U-46619 at sub-threshold concentrations synergistically caused a marked increase in intranasal pressure. These responses were significantly suppressed by S-5751. These results suggest that PGD(2) plays a critical role in the increase in intranasal pressure via prostanoid DP receptor, probably through synergistically enhancing the nasal response with other chemical mediators released from mast cells and other inflammatory cells activated by allergens.

Asthma and the unified airway

Inflammatory processes of the upper and lower airway commonly co-exist. Patients with upper respiratory illnesses such as allergic rhinitis and acute and chronic rhinosinusitis often present to both otolaryngologists and primary care physicians for treatment of their symptoms of nasal and sinus disease. These patients often have concurrent lower respiratory illnesses such as asthma that may be contributing to their overall symptoms and quality of life. Unfortunately, asthma frequently remains undiagnosed in this population. It was the objective of this paper to examine the relationship between upper respiratory illnesses such as rhinitis and rhinosinusitis and lower respiratory illnesses such as asthma, and to provide a framework for primary care and specialty physicians to approach these illnesses as a spectrum of inflammatory disease. The present manuscript was developed by a multidisciplinary workgroup sponsored by the American Academy of Otolaryngic Allergy. Health care providers in various specialties contributed to the manuscript through preparation of written materials and through participation in a panel discussion held in August 2006. Each author was tasked with reviewing a specific content area and preparing a written summary for inclusion in this final document. Respiratory inflammation commonly affects both the upper and lower respiratory tracts, often concurrently. Physicians who are treating patients with symptoms of allergic rhinitis and rhinosinusitis must be vigilant to the presence of asthma among these patients. Appropriate diagnostic methods should be used to identify individuals with concurrent respiratory illnesses, and comprehensive treatment should be instituted to reduce symptoms and improve quality of life.

Nonspecific provocation of target organs in allergic diseases: EAACI-GA(2)LEN consensus report

It is widely accepted that nonspecific tissue reactivity is a distinct pathophysiological hallmark of allergic diseases, influenced by genetic and environmental factors different from those involved in causing sensitization and allergen response of target organs. This consensus document aims at reviewing procedures currently used for nonspecific provocation of the bronchi, nose and eye and for measuring their responsiveness to nonspecific stimuli.

Epidermal growth factor receptor - but not histamine receptor - is upregulated in seasonal allergic rhinitis

BACKGROUND

We were interested in exploring the molecular mechanisms underlying the observed difference in histamine (H) responsiveness between seasonal allergic rhinitic (SAR) and nonrhinitic (NR) subjects. We hypothesized that SAR subjects express higher nasal mucosal histamine receptor 1 (H1R) and 2 (H2R) levels than do NR subjects. In addition, we examined expression of genes involved in regulating the glandular response, including epidermal growth factor (EGF), EGF receptor (EGFR), and mucins (Muc5Ac and Muc5B).

METHODS

Fourteen subjects, seven SAR and seven NR, were provoked during pollen season with doubling doses of H (0.125-8.0 mg/ml). Nasal airway resistance (NAR) was measured by active posterior rhinomanometry. Provocation was halted when NAR exceeded 150% of baseline. Prior to provocation, nasal scrapings were obtained and mRNA quantified using two-step real-time PCR.

RESULTS

The mean PD50 (concentration of H producing a 50% increase in NAR) was significantly lower in the SAR than NR group (0.36 vs 1.32 mg/ml; P < 0.05). The ratio of relative gene copy numbers between the SAR and NR groups were as follows: H1R, 0.85 (P = 0.52); H2R, 0.67 (P = 0.35); EGF, 1.02 (P = 0.93), and EGFR, 103.5 (P < 0.05).

CONCLUSIONS

There were no significant differences in H1R or H2R mRNA levels between SAR and NR subjects in-season, despite observed differences in H reactivity. SAR subjects, however, did show a significant elevation in EGFR expression, consistent with the observation of mucus hypersecretion in allergic rhinitis.

Markedly increased nasal blockage by intranasal leukotriene D4 in an experimental allergic rhinitis model: contribution of dilated mucosal blood vessels

We examined whether nasal hyperresponsiveness to leukotriene (LT) D4 is seen in our allergic rhinitis model, which showed sneezing and biphasic nasal blockage by repeated antigen inhalation challenge, and whether a dilatation of mucosal blood vessels contributes to this hyperresponsiveness. Nasal blockage [increase of specific airway resistance (sRaw)] was indexed as nasal (hyper)responsiveness. The sensitized-challenged guinea pig showed a remarkable dose-dependent increase in sRaw by intranasal instillation of LTD4 (10 microl/nostril) at 10(-10) to 10(-6) M 10 h and 2 days but not 7 days after the challenge. The increase in sRaw induced by LTD4 was largely blocked by pranlukast or naphazoline, and this was dose-dependently suppressed by N(omega)-nitro-L-arginine methyl ester. Sodium nitroprusside induced an elevation of sRaw in the sensitized-challenged animal in the hyperresponsiveness state, but the degree did not differ from that in the non-sensitized-non-challenged group. The amount of NO2- and NO3- in nasal cavity lavage fluid after LTD4 instillation in the sensitized-challenged animal in the hyperresponsiveness state was significantly greater than that before the instillation. These results demonstrate that the hyperresponsiveness to LTD4 acquired by repeated antigen challenge is mainly due to dilatation of nasal blood vessels, which can be related to hyperproduction of nitric oxide through cysteinyl LT1-receptor activation.

Relationship between airway sensitivity to adenosine 5' monophosphate and the shape of the concentration-response curve to methacholine in subjects with allergic rhinitis

The objective of this study was to determine differences in airway sensitivity to adenosine 5'-monophosphate (AMP) between allergic rhinitis subjects with plateau and those without evidence of plateau on the concentration response curves to methacholine. A total of 51 adults (38 subjects with allergic rhinitis and 13 healthy controls) were challenged with increasing concentrations of methacholine and AMP. The methacholine challenge was terminated when there was a 40% or more decrease in forced expiratory volume in 1 sec (FEV1), whereas the AMP challenge was stopped when FEV1 had fallen by more than 20%. A plateau for methacholine was detected in all 13 healthy controls and in 27 patients with allergic rhinitis (AR-plateau group), whereas 11 subjects with allergic rhinitis did not exhibit a plateau (AR-non-plateau group). The median (range) PC20 AMP (provocative concentration required to produce a 20% fall in FEV1) value for the AR-non-plateau group was 44.0 mg ml(-1) (3.3-400.0), compared with 400.0 mgml(-1) (12.1-400.0) in the AR-plateau group (P=0.03) and 400.0 mgml(-1) in the healthy control group (P=0.007). The proportion of subjects who showed bronchoconstriction in response to AMP was higher in the AR-non-plateau group (73%) than in the AR-plateau group (30%) (P=0.03). However, three subjects with allergic rhinitis who had normal sensitivity to methacholine and plateau showed bronchoconstriction in response to AMP. We conclude that, in subjects with allergic rhinitis, the absence of plateau on the concentration response curves to methacholine is associated with a higher prevalence and degree of bronchoconstriction in response to AMP. However, the two bronchoconstrictor stimuli were not identifying the same abnormalities of the airways.

Bronchoconstriction induced by inhaled adenosine 5'-monophosphate in subjects with allergic rhinitis

Adenosine and its related nucleotide, adenosine 5'-monophosphate (AMP) induce bronchoconstriction in asthmatics, probably caused by histamine release from airway mast cells. The objective of this study was to determine the effect of inhaled AMP on lung function in subjects with allergic rhinitis. A total of 52 adults (28 subjects with allergic rhinitis, 14 asthmatics and 10 healthy subjects) were challenged with increasing concentrations of AMP and methacholine. Airflow was assessed after each concentration and the response to each bronchoconstrictor agent was measured by the provocative concentration required to produce a 20% fall (PC20) in forced expired volume in one second (FEV1). All 14 asthmatics, 10 subjects with allergic rhinitis and none of the healthy controls were hyperresponsive to AMP. Subjects with allergic rhinitis had higher prevalence of hyperresponsiveness to AMP than healthy controls (p=0.038). Although the prevalence of hyperresponsiveness for methacholine and for AMP in subjects with allergic rhinitis was similar (39% and 36%, respectively), four subjects had hyperresponsiveness to methacholine but not to AMP, whereas three subjects had hyperresponsiveness to AMP but not to methacholine. To conclude, inhaled adenosine 5'-monophosphate causes airway narrowing in a significantly higher proportion of subjects with allergic rhinitis than healthy volunteers. Furthermore, methacholine and adenosine 5'-monophosphate hyperresponsiveness are not detected in the same individuals with allergic rhinitis, thus suggesting that responsiveness to the two bronchoconstrictor stimuli is not reflecting the same abnormalities of the airways.

The effect of regular salbutamol on lung function and bronchial responsiveness in patients with primary ciliary dyskinesia

STUDY OBJECTIVE

There is growing evidence that regular beta(2)-agonist use in patients with asthma is associated with decreased airway caliber and increased bronchial responsiveness. The aim of this study was to determine whether regular treatment with beta(2)-agonists induces changes in lung function and bronchial responsiveness in patients with primary ciliary dyskinesia.

DESIGN

A randomized, double-blind, placebo-controlled, crossover study.

PATIENTS

Nineteen children with primary ciliary dyskinesia.

INTERVENTIONS

Subjects received inhaled salbutamol or identical placebo (2 x 100 microg qid) for periods of 6 weeks with a wash-out period of 4 weeks.

MEASUREMENTS AND RESULTS

FEV(1) was measured before and 3 weeks and 6 weeks after salbutamol or placebo treatment. High-dose methacholine inhalation tests were performed before and 6 weeks after each treatment. The provocative concentration of methacholine producing a 20% fall in FEV(1) (PC(20)) and maximal airway narrowing (MDeltaFFEV(1)) was measured. No significant change in FEV(1) was observed during the salbutamol or placebo periods. No significant differences in the parameters of bronchial responsiveness (PC(20) and MDeltaFFEV(1)) were noted as the result of either salbutamol or placebo treatment.

CONCLUSION

Our data have shown that salbutamol, inhaled regularly for 6 weeks, did not cause either a decline in lung function or an increase in bronchial responsiveness in subjects with primary ciliary dyskinesia.

Airway responsiveness to acetaldehyde in patients with asthma: relationship to methacholine responsiveness and peak expiratory flow variation

BACKGROUND

Although airway hyperresponsiveness to inhaled acetaldehyde has been documented in Japanese patients with asthma, the response to this bronchoconstrictor agent has never been studied in Caucasians.

OBJECTIVES

The objectives of the study were to determine differences in airway responsiveness to acetaldehyde between asthmatic and healthy subjects, and to examine the relationship between acetaldehyde responsiveness and the variability of peak expiratory flow (PEF).

METHODS

The response to methacholine and acetaldehyde challenges was measured in 81 non-smoking adults (61 asthmatics and 20 normal controls). Subjects recorded PEF morning and evening for 14 days. The response to both bronchoconstrictor agents was measured by the PC20 (provocative concentration required to produce a 20% fall in FEV1). PEF variation was expressed as amplitude percentage mean, and as low percentage best (lowest PEF expressed as a percentage of the best PEF recorded).

RESULTS

The two types of challenge yielded a similarly high level of sensitivity (100% for methacholine and 92% for acetaldehyde) and specificity (90 and 100%, respectively) to distinguish between asthma and controls. Asthmatic subjects were on average 265-fold less sensitive to acetaldehyde than to methacholine. PC20 acetaldehyde correlated weakly but significantly with both indices of PEF variation (amplitude percentage mean: rho = - 0.36, P = 0. 004; low percentage best: rho = 0.42, P = 0.001).

CONCLUSIONS

These results indicate that airway hyperresponsiveness to acetaldehyde is a sensitive and specific indicator for separating asthmatic and normal subjects. Airway responsiveness to methacholine or acetaldehyde and PEF variation are not reflecting the same pathophysiological process in the airways.

Variability of peak expiratory flow rate in allergic rhinitis and mild asthma: relationship to maximal airway narrowing

BACKGROUND

Previous studies have demonstrated a significant correlation between airway sensitivity to pharmacologic agents and daily peak expiratory flow rate (PEF) variation in asthmatic and nonasthmatic subjects.

OBJECTIVE

The aim of this study was to investigate, both in patients with asthma and in subjects with allergic rhinitis, differences in daily PEF variation between subjects with plateau on the concentration-response curves to methacholine and those without plateau.

METHODS

A total of 120 adults (50 with mild asthma, 52 with allergic rhinitis, and 18 healthy control subjects) were challenged with methacholine (up to 200 mg/mL) and, for the next 14 days, measured their PEF three times daily. The response to methacholine was measured by the percent decrease in FEV1. A maximal response plateau was considered if three or more of the highest concentrations fell within a 5% response range. Diurnal PEF variation was expressed as the amplitude percent mean.

RESULTS

A plateau response was detected in 11 (22%) asthmatic patients, in 33 (63%) subjects with allergic rhinitis, and in 17 (94%) healthy subjects. Diurnal PEF variation was significantly greater (P < .01) in the asthmatic group without a plateau (8.8 +/- 3.7%) compared with the three groups with a plateau (asthma = 5.5 +/- 2.9%; allergic rhinitis = 4.6 +/- 2.1%; healthy = 4.7 +/- 2.3%). Those three groups with a plateau were not significantly different from each other with respect to PEF variability. Diurnal PEF variation was significantly higher in allergic rhinitis patients without plateau (7.6 +/- 3.5%) than in allergic rhinitis patients with plateau (P < .01) and healthy subjects (P < .05). The rhinitic group without a plateau, however, was not significantly different from either the asthmatic group without plateau or the asthmatic group with plateau.

CONCLUSIONS

We conclude that in both asthmatic patients and subjects with allergic rhinitis, the shape of the concentration-response curve to methacholine provides new information on the relationship between airway responsiveness and PEF variability. Further, allergic rhinitis subjects without evidence of plateau have a degree of diurnal PEF variation similar to that found in patients with mild asthma. This could indicate that those subjects may have subclinical inflammatory changes in the airways.

Differences in sensitivity, maximal response and position of the concentration-response curve to methacholine between asthmatics, patients with allergic rhinitis and healthy subjects

The aim of this study was to detect differences in maximal response and position of the concentration-response curves to methacholine between asthmatics and subjects with allergic rhinitis. A total of 228 adults (107 mild asthmatics, 96 allergic rhinitics and 25 healthy control subjects) were challenged with methacholine. The test was interrupted when FEV1 dropped by more than 40% or when the highest concentration of methacholine (200 mg ml-1) had been administered. Concentration-response curves were characterized by their PC20 (concentration of methacholine that produced 20% fall in FEV1 = airway sensitivity), and if possible, by their EC50 (concentration of methacholine that produced 50% of the maximal response = position) and level of plateau. The proportion of subjects with plateau was significantly lower in asthmatics (18.7%) than in either allergic rhinitics (57.3%) or healthy subjects (92%). It was also significantly lower in allergic rhinitics than in healthy subjects. The level of plateau for asthmatics was (means +/- SD) 31.5 +/- 5.5%, compared with 20.8 +/- 8.1% in allergic rhinitics and 13.7 +/- 6.7% in healthy subjects (P < 0.01). It was also higher in allergic rhinitics than in healthy subjects (P < 0.01). The EC50 values were decreased in asthmatics when they were compared with either allergic rhinitics or healthy subjects (geometric mean EC50: asthmatics = 2.7 mg ml-1, allergic rhinitics = 6.2 mg ml-1, healthy subjects = 8.7 mg ml-1; P < 0.01), but no significant differences were detected between allergic rhinitics and healthy subjects. These results demonstrate that in subjects with allergic rhinitis, the prevalence and level of the plateau on the methacholine concentration-response curve is intermediate between that of asthmatics and normals. Furthermore, while the asthmatic curves differ from normal in having both an increased maximal response and a leftward shift, the rhinitic curves differ only in terms of plateau level. These results suggest that airway responsiveness in asthma and allergic rhinitis may be a consequence of mechanisms that are at least partially different.

Non-specific airway hyperresponsiveness in mono-sensitive Sicilian patients with allergic rhinitis. Its relationship to total serum IgE levels and blood eosinophils during and out of the pollen season

BACKGROUND

Initial attempts to evaluate the association between allergic rhinitis and non-specific bronchial responsiveness has produced conflicting results. In fact, some studies showed a strong correlation and other failed to find an association. However, little is known about the effect of natural specific allergen exposure on the bronchial reactivity of mono-sensitive patients with rhinitis in the southern Mediterranean area, in relation to skin reactivity to allergens, total serum IgE levels and blood eosinophils.

OBJECTIVES

The significance of the association between allergic rhinitis, and abnormal airway responsiveness with regard to the pathogenesis of asthma is unclear. For this reason, we have studied non-specific bronchial hyperreactivity, in patients with seasonal allergic rhinitis, with reference to the responsible allergen. The aim of the study was to correlate the responsiveness to bronchoprovocation with methacholine in subjects a with allergic rhinitis during and out of the pollen season with total serum IgE and blood eosinophils.

METHODS

Fourty-nine non-smoking patients with clinical diagnosis of allergic rhinitis and mono-sensitive skin-prick tests to pollen allergens were enrolled in the study. Twenty patients suffered from seasonal rhinitis to Parietaria pollen, 15 patients to Gramineae pollen and 14 patients to Olea pollen. In all patients lung function measurements (assessed as response to methacholine), total serum IgE and blood eosinophil counts were measured during and out of the pollen season.

RESULTS

During pollen season, 16 out of 49 rhinitis patients demonstrated values of bronchial responsiveness measured as response to inhaled methacholine in the asthmatic range whereas out of the pollen season only eight patients were in the asthmatic range. By analysing the results with reference to the responsible allergen, during the pollen season 15 out of 16 patients were Parietaria-sensitive and out of the pollen season seven out of eight patients. Finally, in Parietaria-sensitive rhinitis bronchial responsiveness significantly correlated, during and out of the pollen season, with total serum IgE and with blood eosinophil counts.

CONCLUSIONS

Our results are consistent with the hypothesis that Parietaria is more important than Olea and Gramineae as a risk for developing non-specific bronchial hyperresponsiveness. On the whole, present observations provide further evidence that there is an interrelationship of allergen kind, total serum IgE, eosinophil and bronchial hyperresponsiveness suggesting that they may play a role in the development of bronchial asthma in rhinitis patients.