Peak flow variability and sputum eosinophilia in allergic rhinitis

Risk factors associated with comorbid asthma in patients with chronic rhinosinusitis with nasal polyps: a cross-sectional study

Background

Although 20–60% of patients with chronic rhinosinusitis with nasal polyps (CRSwNP) have asthma, the risk factors associated with comorbid asthma are not clear. The aim of the study was to investigate the factors associated with asthma, and develop a practical scoring system to screen asthma comorbidity in CRSwNP patients.

Methods

This report describes a cross-sectional study with consecutive CRSwNP patients. Two cohorts of CRSwNP patients named “modelling” group and “validation” group were investigated respectively. Logistic regression analysis was performed based on demographic and clinical data collected from patients in the modelling group to determine the risk factors associated with asthma, and establish a scoring system for screening comorbid asthma. Receiver operating characteristic curve was constructed to evaluate the screening system; the optimal cut-off point was established by means of the Yoden Index. The consistency between the diagnosis of asthma by the Global Initiative for Asthma (GINA) criteria and by the screening system was assessed by Kappa value in the validation group.

Results

Totally 150 patients in modelling group and 78 patients in validation group were enrolled. Female gender (odds ratio [OR] = 6.4; P < 0.001), allergic rhinitis (OR = 2.9; P = 0.021), serum total (T)-immunoglobulin (Ig) E ≥ 69.0kU/L (OR = 12.0; P < 0.001), and blood eosinophil count  ≥ 0.35 × 10⁹/L (OR = 4.0; P = 0.001) were shown to be independent risk factors for asthma in patients with CRSwNP. Based on these variables, a scoring system (FAIE) ranging from 0(no risk) to 6(high risk); was developed. The area under the receiver operating characteristic curve of the system was 0.823, and the optimal cut-off value was 3 points, with sensitivity 83.8% and specificity 68.6% for screening asthma. The asthma comorbidity determined with FAIE score ≥ 3 points in the validation group, was moderately consistent with that defined by GINA (Kappa = 0.513, P < 0.001), with sensitivity 76.9% and specificity 74.4%.

Conclusions

Female gender, allergic rhinitis, serum T-IgE level, and blood eosinophil count are independent risk factors for asthma comorbidity in patients with CRSwNP, and the FAIE system may be practical for screening comorbid asthma in these patients.

Association of nasal inflammation and lower airway responsiveness in schoolchildren based on an epidemiological survey

BACKGROUND/AIMS

We sought to increase our understanding of the rhinitis-asthma relationship and improve strategies for the treatment of patients with these diseases. The aim of this study was to identify a connection between upper airway inflammation and lower airway responsiveness.

METHODS

We counted eosinophils on nasal smears, and performed spirometry, allergic skin tests, and methacholine challenge tests in 308 schoolchildren plus a questionnaire on respiratory symptoms. The methacholine concentration causing a 20% fall in forced expiratory volume in 1 second (PC20 < 25 mg/mL) was used as the threshold of bronchial hyperresponsiveness (BHR).

RESULTS

In total, 26% of subjects had positive nasal eosinophils on a smear, and 46.2% of subjects had BHR at < 25 mg/mL methacholine PC20. Nasal symptoms were higher in subjects with than without nasal eosinophils (p = 0.012). Asthma symptoms did not differ between subjects with and without nasal eosinophils. Nasal eosinophils were higher in subjects with atopy than those without (p = 0.006), and there was no difference in PC20 methacholine according to atopy (15.5 ± 1.07 vs. 17.5 ± 0.62; p > 0.05). No difference in BHR was detected when comparing subjects with and without nasal eosinophils. There were significant differences in the PC20 between subjects with greater than 50% nasal eosinophils and without nasal eosinophils (11.01 ± 2.92 mg/mL vs. 17.38 ± 0.61 mg/mL; p < 0.001).

CONCLUSIONS

These findings demonstrated that nasal eosinophilic inflammation might contribute to lower airway responsiveness in schoolchildren, based on an epidemiological survey.

The role of rhinosinusitis in severe asthma

The prevalence of asthma is approximately 5% to 10% in the general population. Of these, approximately 5% to 10% are severe asthmatics who respond poorly to asthmatic drugs, including high-dose inhaled steroids. Severe asthmatics have persistent symptoms, frequent symptom exacerbation, and severe airway obstruction even when taking high-dose inhaled steroids. The medical costs of treating severe asthmatics represent ~50% of the total healthcare costs for asthma. Risk factors for severe asthma are genetic and environmental, including many kinds of aeroallergens, β-blockers, and anti-inflammatory drugs. Gastroesophageal reflux disease and factors such as denial, anxiety, fear, depression, socioeconomic status, and alcohol consumption can exacerbate asthma. Rhinitis and asthma usually occur together. There is increasing evidence that allergic rhinitis and rhinosinusitis may influence the clinical course of asthma. This review discusses the role of rhinosinusitis in severe asthma.

Rhinitis patients with sputum eosinophilia show decreased lung function in the absence of airway hyperresponsiveness

Purpose

Sputum eosinophilia is observed frequently in patients with rhinitis. Sputum eosinophilia in patients with non-asthmatic allergic rhinitis has been suggested to be related to nonspecific airway hyperresponsiveness (AHR). However, the clinical significance of sputum eosinophilia in patients with non-asthmatic rhinitis without AHR has not been determined. We conducted a retrospective study examining the influence of sputum eosinophilia in patients with non-asthmatic rhinitis without AHR on pulmonary function and expression of fibrosis-related mediators.

Methods

Eighty-nine patients with moderate-to-severe perennial rhinitis without AHR were included. All underwent lung function tests (forced expiratory volume in 1 second [FEV1] and forced vital capacity [FVC]), skin tests to inhalant allergens, methacholine bronchial challenge tests, and hypertonic saline-induced sputum to determine eosinophil counts. Sputum mRNA levels for transforming growth factor-β (TGF-β), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase-1 (TIMP-1) were also examined. Patients were divided into two groups according to the presence of sputum eosinophilia (≥3%, eosinophilia-positive [EP] and <3%, eosinophilia-negative [EN] groups).

Results

FEV1 was significantly lower (P=0.04) and FEV1/FVC tended to be lower (P=0.1) in the EP group than in the EN group. In sputum analyses, the MMP-9 mRNA level (P=0.005) and the ratio of MMP-9 to TIMP-1 expression (P=0.01) were significantly higher in the EP group than in the EN group. There was no significant difference in TGF-β mRNA expression between the two groups.

Conclusions

Sputum eosinophilia in patients with moderate-to-severe perennial rhinitis without AHR influenced FEV1 and the expression pattern of fibrosis-related mediators.

Asthmatics without rhinitis have more fixed airway obstruction than those with concurrent rhinitis

PURPOSE

Rhinitis and asthma usually occur together. There are increasing evidences that allergic rhinitis (AR) may influence the clinical course of asthma. The aim of this study is to evaluate clinical parameters and therapeutic response in patients with between asthma and asthma with AR.

METHODS

Four-hundred eighty-five patients with asthma and 428 asthmatics with AR, who had lesser than 50 years old and smoked less than 10 pack-years were recruited. We compared FEV1 and FEV1/FVC following bronchodilator, atopy, IgE, emphysema on HRCT, and aspirin intolerance between two groups. Also we compared physiologic fixed airway obstruction defined using FEV1/FVC and FEV1 less than 75% following anti-asthmatic drug for 1 year.

RESULTS

46.8% (428/913) asthmatics suffered from AR. There were no differences of total IgE, body mass index, PC20, sputum eosinophils and emphysema on HRCT between two groups. The age in asthmatics was higher than that in those with AR. FEV1/FVC was lower in asthmatics than in those with AR. The prevalence of atopy was higher in asthmatics with AR than in asthmatics. Aspirin intolerance was higher in asthmatics with AR than in asthmatics (42/218 vs 13/109, P=0.001). Fixed airway obstruction were more observed in asthmatics than in those with AR (39/319 vs 28/355, P=0.001) after anti-asthmatic drug for 1 year.

CONCLUSIONS

Asthmatics with AR had more atopy and aspirin intolerance than asthmatics, and asthmatics had poor response to anti-inflammatory drugs than those with concurrent rhinitis, indicating that asthmatics have more fixed airway obstruction than those with concurrent rhinitis.

The connection between allergic rhinitis and bronchial asthma

PURPOSE OF REVIEW

The relationship between allergic rhinitis and asthma has intrigued practicing physicians since the turn of the century. Investigations during the past two decades have led to an increased understanding of this relationship.

RECENT FINDINGS

A growing body of evidence clearly demonstrates that patients with allergic rhinitis, in the absence of asthma, have distinct abnormalities of lower airway function, including alterations in physiology, histology and biochemistry. In addition, epidemiologic surveys have consistently shown allergic rhinitis as an independent risk factor for developing asthma, and that preexisting abnormalities in lung function may predispose to lower airway disease development. Clinical trials show that specific allergen immunotherapy for children and adults with seasonal allergic rhinitis reduces the risk of developing asthma. In patients with established asthma and concomitant allergic rhinitis, several medications have significant effects upon the upper and lower airways, including intranasal corticosteroids, oral antihistamines, and leukotriene receptor antagonists.

SUMMARY

Our understanding of the natural history of allergic rhinitis could lead to improvements in early intervention, potentially preventing the progression of allergic rhinitis to asthma. Aggressive treatment of rhinitis in patients with concomitant asthma may enhance asthma outcomes and quality of life for all patients with these chronic diseases.

Peak expiratory flow variability and exercise responsiveness in methacholine-hyperresponsive adolescents with asthma remission

The aim of this study was to investigate whether bronchial hyperresponsiveness in adolescents with long-term asthma remission is associated with increased peak expiratory flow (PEF) variability and/or increased bronchial response to exercise (BRE). Twenty-nine adolescents with asthma remission (neither symptoms nor any medication used during the previous two years), but with persistent methacholine hyperresponsiveness (PC20 < 18 mg/mL; remission group), 29 methacholine PC20-matched adolescents with symptomatic asthma (symptomatic group), and 20 healthy subjects (control group) were studied. Subjects recorded PEF twice daily for 14 days and PEF variability, expressed as amplitude % mean, was calculated. Subjects also underwent a standardized exercise challenge; BRE was defined as a maximal % fall in FEV1 within 30 min after exercise. The mean (+/- SD) PEF variations in the symptomatic group and in the remission group were 12.10 +/- 6.35% and 10.02 +/- 4.73%, respectively, which were significantly higher than that (5.94 +/- 2.44%) of the control group. On the other hand, the degree of BRE (7.36 +/- 3.85%) in the remission group was significantly lower than that (22.31 +/- 10.50%) of the symptomatic group, and similar to that (5.98 +/- 2.70%) of the control group. Methacholine hyperresponsiveness in asthma remission during adolescence is associated with increased PEF variability but not with increased BRE.

An evaluation of peripheral blood eosinophil/basophil progenitors following nasal allergen challenge in patients with allergic rhinitis

OBJECTIVE

To evaluate the effect of a single nasal allergen challenge on peripheral blood eosinophil/basophil (Eo/B) progenitor cells and induced sputum eosinophil counts in subjects with allergic rhinitis.

METHODS

Sixteen adults entered a sequential nasal control and allergen challenge study, outside the pollen season. Blind assessment of peripheral blood Eo/B progenitor colony forming units (CFU), induced sputum and nasal lavage cell counts was made before and 24 h after both challenges. Subjects recorded their rhinitis symptoms and nasal peak inspiratory flow, hourly at home, following both challenges.

RESULTS

When comparing the values 24 h after the control vs. the allergen challenge, there were no significant differences in Eo/B progenitor CFU (control (mean, SD): 3.6 (1.0)/10(6) cells; allergen: 4.4 (1.1)/10(6) cells) or sputum eosinophils (control (median, inter-quartile range): 1.0 (0.3-1.7)%; allergen: 0.7 (0.0-1.3)%) despite a significant increase in the percentage (median (inter-quartile range) of eosinophils in nasal lavage (control: 0.6 (0.1-0.9)%; allergen; 1.9 (0.9-8.1)% and significant worsening of nasal peak inspiratory flow and rhinitis symptoms.

CONCLUSIONS

Despite a significant increase in nasal symptoms and lavage eosinophil counts, a single nasal allergen challenge was not sufficient to elicit a measurable haemopoietic response in circulation, or an increase in sputum eosinophil counts.

Biological markers in diagnosing, monitoring, and treating asthma: a focus on noninvasive measurements

Asthma is a major concern for society, healthcare professionals, and individuals and families directly affected by asthma due to rising morbidity rates and costs associated with the disease. The pathological hallmark of asthma is airway inflammation that is considered to be a major cause of exacerbations and persistent structural alterations of the airways. Assessing airway inflammation is important for investigating the underlying mechanisms of the disease and possibly for following the progression and resolution of the disease. The presence and type of airway inflammation can be difficult to detect clinically, and may result in delays in initiating appropriate therapy. The purpose of this article is to review noninvasive methods for assessing biological markers of airway inflammation and their potential role in the future for diagnosing, monitoring, and treating asthma. The article reviews the noninvasive measurements of induced sputum and exhaled nitric oxide as indicators of airway inflammation.

The development of asthma in patients with allergic rhinitis

PURPOSE OF REVIEW

We will review data supporting the link between allergic rhinitis and asthma, examine recent progress made towards understanding the influence of allergic rhinitis on asthma regarding future development or progression of asthma, and discuss possible mechanisms through which this occurs and potential preventive measures.

RECENT FINDINGS

Several recent reviews have concluded that a close relationship exists between allergic rhinitis and asthma. It has even been proposed that allergic rhinitis and asthma are manifestations of the same disease entity and that they represent a continuum of disease. Allergic rhinitis often precedes the onset of clinical asthma and is a risk factor for the development of asthma. Recognition of this relationship between allergic rhinitis and asthma is highlighted by the recent development of guidelines for the diagnosis and treatment of these disorders by the international Allergic Rhinitis and Its Impact on Asthma workshop. The mechanisms by which allergic rhinitis may be a risk factor for asthma are not entirely understood, although a few recent studies have addressed this question. Some clues in regard to the identification of subjects at risk of developing asthma have been provided by recent studies. Several recent reports support the belief that early introduction of immunotherapy in patients with allergic rhinitis reduces subsequent development of asthma, whereas it remains to be studied whether timely pharmacotherapy for allergic rhinitis may prevent the progression to asthma.

SUMMARY

Because asthma is generally permanent at the time of diagnosis, it would be of great benefit to identify individuals at increased risk of developing asthma in order to provide a window of opportunity in which the progression to asthma could be prevented. As recognition and early treatment of allergic rhinitis could have important consequences in terms of reducing the prevalence and severity of asthma, there is a need to perform further clinical studies that address this issue.

Effect of cigarette smoking on airway responsiveness to adenosine 5'-monophosphate in subjects with allergic rhinitis

STUDY OBJECTIVES

The objective of this study was to determine differences in airway responsiveness to adenosine 5'-monophosphate (AMP) between smokers and nonsmokers with allergic rhinitis.

METHODS

A total of 41 adults with allergic rhinitis (16 smokers and 25 nonsmokers) were challenged with increasing concentrations of methacholine and AMP. 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 in FEV(1) (PC(20)).

RESULTS

The geometric mean PC(20) AMP values were significantly lower in smokers than in nonsmokers: 72.4 mg/mL (95% confidence interval [CI], 33.9 to 154.9) vs 204.2 mg/mL (95% CI, 120.2 to 346.7) [p = 0.021]. The proportion of subjects with bronchoconstriction in response to AMP was higher in smokers (12 of 16 subjects) than in nonsmokers (7 of 25 subjects) [p = 0.005].

CONCLUSIONS

We conclude that smokers with allergic rhinitis have a greater AMP sensitivity than nonsmokers.

Concentrations of exhaled nitric oxide in asthmatics and subjects with allergic rhinitis sensitized to the same pollen allergen

BACKGROUND

Some studies have reported that the levels of exhaled nitric oxide (ENO) in asthmatics are similar to those in subjects with allergic rhinitis, and it has been postulated that atopic status might be the determinant of enhanced nitric oxide production in asthma.

OBJECTIVES

The aim of this study was to determine differences in ENO levels between asthmatics and subjects with allergic rhinitis sensitized to the same allergen, and to correlate these levels with airway responsiveness.

METHODS

Nineteen patients with asthma and 18 subjects with allergic rhinitis monosensitized to Parietaria pollen were enrolled in the study. ENO values and airway responsiveness to methacholine and adenosine 5'-monophosphate (AMP) were measured during the pollen season. The response to each bronchoconstrictor agent was measured by the provocative concentration required to produce a 20% fall in FEV1 (PC20). ENO was measured with the single-exhalation method.

RESULTS

The geometric mean (95% confidence interval) ENO values were significantly higher in asthmatics than in subjects with allergic rhinitis: 72.4p.p.b. (54.9-93.3p.p.b) vs. 44.7p.p.b. (30.9-64.6p.p.b., P = 0.03). In asthmatics, a significant correlation was found between ENO and PC20 AMP values (p = -0.57, P=0.02), whereas no correlation was detected between ENO and PC20 methacholine (p = -0.35, P = 0.14).

CONCLUSIONS

Our results suggest that atopy is not the only determinant of increased ENO levels detected in subjects with asthma, and that responsiveness to AMP may be a more sensitive marker for assessing airway inflammation in asthma compared to methacholine.

Lower airway inflammatory responses to repeated very-low-dose allergen challenge in allergic rhinitis and asthma

BACKGROUND

Low-dose allergen challenge (LDAC) may be a useful tool for studying the capacity of allergens to induce airway inflammation in atopic subjects.

OBJECTIVE

To evaluate lower airway inflammatory changes following repeated inhalation of very low doses of allergen (VLDAC) in non-asthmatic subjects with allergic rhinitis (NAAR) compared with mild allergic asthmatic subjects (AA).

METHODS

Fourteen NAAR and 11 AA were seen out of the pollen season and had skin prick tests with common aeroallergens. Baseline spirometry (S) and methacholine challenge (MC) were done and blood and induced sputum (IS) differential cell counts were obtained. Each subject underwent VLDAC on four consecutive mornings with a relevant allergen. S, MC, and blood and IS samplings were repeated 6 h after the second and fourth VLDAC and one week later.

RESULTS

Although there were, as expected, no changes in FEV1 or PC20 in either group, mean percentage eosinophils on IS were significantly increased in NAAR on day 2 of VLDAC and decreased in all but one subject on day 4, with a tendency to return to baseline levels one week later. In AA, there was a non-significant trend for sputum eosinophils to increase on day 2; four subjects showed a decrease of eosinophils on day 4 of VLDAC. There was a correlation between eosinophil cationic protein (ECP) levels and eosinophil counts in NAAR throughout the study. There were no variations in other sputum cells or blood inflammatory cells.

CONCLUSION

VLDAC can increase the percentage of eosinophils in IS of NAAR subjects without associated respiratory symptoms nor physiological modifications. A reduction in eosinophilic response despite repeated exposure, more common in NAAR subjects, suggests an adaptation process that needs to be further evaluated.

Modifications of airway responsiveness to adenosine 5'-monophosphate and exhaled nitric oxide concentrations after the pollen season in subjects with pollen-induced rhinitis

STUDY OBJECTIVE

s: To determine the effect of cessation of exposure to pollen on airway responsiveness to adenosine 5'-monophosphate (AMP) in subjects with pollen-induced rhinitis, and to explore the relationship between changes in airway responsiveness and changes in exhaled nitric oxide (ENO) levels.

STUDY DESIGN

Subjects were studied during the pollen season and out of season.

SETTING

Specialist allergy unit in a university hospital.

PATIENTS

Fourteen subjects without asthma with pollen-induced rhinitis who showed bronchoconstriction in response to methacholine and AMP during the pollen season and 10 healthy nonatopic control subjects.

MEASUREMENTS AND RESULTS

In subjects with pollen-induced rhinitis, ENO concentrations, provocative concentration of agonist causing a 20% fall in FEV(1) (PC(20)) methacholine, and PC(20) AMP were determined during the pollen season and out of season. Healthy control subjects were studied during the pollen season. In subjects with allergic rhinitis, PC(20) AMP increased from a geometric mean of 79.4 mg/mL (95% confidence interval [CI], 31.6 to 199.5 mg/mL) during the pollen season to 316.2 mg/mL (95% CI, 158.5 to 400.0 mg/mL) out of season (p = 0.004). The ENO concentrations decreased from 63.1 parts per billion (ppb) [95% CI, 50.1 to 79.4 ppb] during the pollen season to 30.2 ppb (95% CI, 23.4 to 38.0 ppb) out of season (p < 0.001). The ENO concentrations out of pollen season were still significantly increased in subjects with pollen-induced rhinitis when compared with healthy control subjects. There was no relationship between individual changes in ENO levels and changes in either PC(20) methacholine or PC(20) AMP.

CONCLUSIONS

In pollen-sensitive subjects with allergic rhinitis, the cessation of exposure to pollen is associated with a significant reduction of airway responsiveness to inhaled AMP. However, no association was found between allergen-induced changes in ENO values and in airway responsiveness to either direct or indirect bronchoconstrictors. These findings suggest that modifications in ENO and in airway responsiveness are the consequence of different alterations induced by allergen exposure on the lower airways.

Exhaled nitric oxide and bronchial responsiveness to adenosine 5'-monophosphate in subjects with allergic rhinitis

STUDY OBJECTIVES

To determine differences in exhaled nitric oxide (ENO) between subjects with allergic rhinitis with and without increased responsiveness to direct and indirect bronchoconstrictor agents.

STUDY DESIGN

Cross-sectional study with the order of challenge tests randomized.

SETTING

Specialist allergy unit in a university hospital.

PATIENTS

Thirty-eight subjects without asthma with allergic rhinitis and 10 healthy nonatopic control subjects.

MEASUREMENTS AND RESULTS

Participants were challenged with increasing concentrations of adenosine 5'monophosphate (AMP) and methacholine. ENO was measured with the single-exhalation method. A positive response to both bronchoconstrictor agents was detected in nine subjects with allergic rhinitis, whereas four subjects showed increased responsiveness to AMP but not to methacholine. The geometric mean (range) ENO values were significantly higher in subjects with allergic rhinitis with increased responsiveness to either methacholine or AMP than in subjects with normal responsiveness to both agonists: 51.3 parts per billion (ppb) [22.0 to 108.5 ppb] vs 25.1 ppb (5.7 to 102.9 ppb, respectively; p = 0.007) and healthy control subjects (11.2 ppb [5.0 to 31.9 ppb], p < 0.001). Subjects with allergic rhinitis with normal responsiveness to both agonists also had higher concentrations of ENO than healthy control subjects (p = 0.007). No correlation was found between ENO and either of the provocative concentrations of methacholine or AMP causing a 20% fall in FEV(1).

CONCLUSIONS

In subjects without asthma but with allergic rhinitis, the presence of bronchoconstriction in response to methacholine or AMP is associated with increased ENO concentrations. However, elevated concentrations of ENO are detected even in subjects with allergic rhinitis without airway hyperresponsiveness. These results suggest that the presence of airway hyperresponsiveness is not the only factor that determines the increased NO levels detected in subjects with allergic rhinitis.

Eosinophilic bronchitis: clinical manifestations and implications for treatment

Airway inflammation with eosinophils is now reported to occur not only in asthma but in other airway diseases such as cough variant asthma, chronic cough, atopic cough, episodic symptoms without asthma, allergic rhinitis, and COPD. Although the prevalence of eosinophilic bronchitis (EB) is less than in asthma, the causes, mechanisms and treatment of EB in these conditions appears to be similar to asthma where allergen induced IL-5 secretion and symptoms are readily responsive to inhaled corticosteroids. The prognosis of EB without asthma is not known but it may be a precursor for asthma and, if so, recognition of this syndrome may permit effective treatment and reduction in the rising prevalence of asthma. Induced sputum analysis allows recognition of EB in clinical practice. The place of the asthma treatment paradigm with early and sustained corticosteroid treatment needs to be defined in EB without asthma. Airway wall remodelling can occur in rhinitis, COPD, and cough variant asthma with EB. The mechanisms and long term implications of this complication in EB without asthma need to be clarified.

Changes in sputum cell counts after exposure to occupational agents: what do they mean?

BACKGROUND

Exposure to occupational agents can induce eosinophilic inflammation in subjects with occupational asthma (OA). It might also induce nonspecific changes in airway inflammation in subjects without OA.

OBJECTIVES

We sought to investigate the changes in airway inflammation induced by exposure to occupational agents in subjects with and without OA and to determine which changes in sputum eosinophil numbers and bronchial responsiveness to methacholine should be regarded as clinically significant for predicting a 20% fall in FEV(1).

METHODS

We performed specific inhalation challenges (SICs) in 3 groups of subjects: subjects reporting a history consistent with OA with a positive SIC response (n = 17); subjects reporting a history consistent with OA with a negative SIC response (n = 14); and asthmatic subjects without any history of OA (n = 10). Induced sputum and methacholine challenges were performed at the end of the control day and again at the end of the last day of exposure; the last day of exposure was always performed in the laboratory.

RESULTS

There was an increase in median sputum eosinophil and neutrophil numbers in subjects with positive SIC responses. Cell counts remained unchanged after exposure in asthmatic subjects without OA. A combination of a greater than 0.26 10(6)/mL increase in sputum eosinophil numbers and a decrease in the concentration of methacholine inducing a 20% fall in FEV(1) of at least 1.8-fold compared with baseline values predicted a 20% fall in FEV(1) in 96% (95% CI, 70%-99%) of patients.

CONCLUSION

Exposure to occupational agents per se does not induce airway inflammation. Changes in both sputum eosinophil counts and methacholine responsiveness are satisfactory predictors of a significant bronchial responsiveness to occupational agents.

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.

The lack of the bronchoprotective and not the bronchodilatory ability of deep inspiration is associated with airway hyperresponsiveness

In healthy subjects, deep inspiration (DI) acts both as a bronchodilator and a bronchoprotector. The latter is impaired in asthmatics. We have now evaluated whether the lack of bronchoprotection is related to bronchial hyperresponsiveness (BHR), and whether the bronchodilatory effect is also lost in asthmatics. Ten healthy subjects (PC20 > 75 mg/ml), 12 asthmatics with moderate to severe BHR (PC20 < 1 mg/ml), 14 asthmatics with mild to borderline BHR (1 < PC20 < 25 mg/ml), and 10 rhinitics with mild to borderline BHR (1 < PC20 < 25 mg/ml) underwent single-dose methacholine provocations inducing at least 20% reduction in FEV1 after 20 min of DI inhibition. To measure the bronchodilatory effect, DIs were taken immediately after the postmethacholine spirometry, and lung function was again tested. To measure the bronchoprotective effect, DIs were taken before the administration of spasmogen. All four groups achieved the same reductions in FEV1 and FVC, in the absence of deep breaths (analysis of variance [ANOVA], p = 0.49). Only healthy subjects showed bronchoprotection (percent bronchoprotection, mean +/- SEM; healthy: 79 +/- 4.0; asthmatics with moderate to severe BHR: 12 +/- 14.5; asthmatics with mild to borderline BHR: -7 +/- 19.7; rhinitics with mild to borderline BHR: 2 +/- 14.0). In contrast, DIs were able to partially reverse bronchial obstruction in all four groups, albeit percent bronchodilation in healthy subjects was somewhat stronger. The dissociation between bronchoprotection and bronchodilation suggests that the two effects involve different mechanisms.

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.

Induced sputum, eosinophilic bronchitis, and chronic obstructive pulmonary disease

The application of sputum induction and refined methods of sputum examination has provided the opportunity to examine cell and molecular markers of airway inflammation in asthma, COPD, and other airway diseases. The measurements are relatively noninvasive and can be applied safely, with care, even in more severe exacerbations of asthma and severe COPD. Induced sputum examination can be applied at random and repeatedly and gives results that are reproducible, valid, and responsive to changes in treatment. An eosinophilic bronchitis, defined as sputum eosinophilia, is typical of asthma but can also occur in patients with a chronic cough without asthma, and in some patients with COPD in whom the classic inflammatory response is neutrophilic without eosinophilia. When eosinophilia occurs in COPD, it has been considered to be the result of cigarette smoking but it may be due to other causes. The clinical importance of eosinophilic bronchitis is that it responds to treatment with corticosteroid. In contrast, there is increasing evidence that an absence of sputum eosinophilia is associated with steroid resistance. Hargreave FE, Leigh R. Induced sputum, eosinophilic bronchitis, and chronic obstructive pulmonary disease.