401
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Flood-Page P, Swenson C, Faiferman I, Matthews J, Williams M, Brannick L, Robinson D, Wenzel S, Busse W, Hansel TT, Barnes NC. A study to evaluate safety and efficacy of mepolizumab in patients with moderate persistent asthma. Am J Respir Crit Care Med 2007; 176:1062-71. [PMID: 17872493 DOI: 10.1164/rccm.200701-085oc] [Citation(s) in RCA: 535] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Accumulation of eosinophils in the bronchial mucosa of individuals with asthma is considered to be a central event in the pathogenesis of asthma. In animal models, airway eosinophil recruitment and airway hyperresponsiveness in response to allergen challenge are reduced by specific targeting of interleukin-5. A previous small dose-finding study found that mepolizumab, a humanized anti-interleukin-5 monoclonal antibody, had no effect on allergen challenge in humans. OBJECTIVES To investigate the effect of three intravenous infusions of mepolizumab, 250 or 750 mg at monthly intervals, on clinical outcome measures in 362 patients with asthma experiencing persistent symptoms despite inhaled corticosteroid therapy (400-1,000 mug of beclomethasone or equivalent). METHODS Multicenter, randomized, double-blind, placebo-controlled study. MEASUREMENTS AND MAIN RESULTS Morning peak expiratory flow, forced expiratory volume in 1 second, daily beta(2)-agonist use, symptom scores, exacerbation rates, and quality of life measures. Sputum eosinophil levels were also measured in a subgroup of 37 individuals. Mepolizumab was associated with a significant reduction in blood and sputum eosinophils in both treatment groups (blood, P < 0.001 for both doses; sputum, P = 0.006 for 250 mg and P = 0.004 for 750 mg). There were no statistically significant changes in any of the clinical end points measured. There was a nonsignificant trend for decrease in exacerbation rates in the mepolizumab 750-mg treatment group (P = 0.065). CONCLUSIONS Mepolizumab treatment does not appear to add significant clinical benefit in patients with asthma with persistent symptoms despite inhaled corticosteroid therapy. Further studies are needed to investigate the effect of mepolizumab on exacerbation rates, using protocols specifically tailored to patients with asthma with persistent airway eosinophilia.
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402
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403
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D'silva L, Cook RJ, Allen CJ, Hargreave FE, Parameswaran K. Changing pattern of sputum cell counts during successive exacerbations of airway disease. Respir Med 2007; 101:2217-20. [PMID: 17606366 DOI: 10.1016/j.rmed.2007.05.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 05/15/2007] [Accepted: 05/15/2007] [Indexed: 11/21/2022]
Abstract
BACKGROUND Exacerbations of airway disease are eosinophilic, neutrophilic, both or neither, and this determines the treatment needed. We examined changes in the cellular nature of airway inflammation between consecutive exacerbations and their predictors in individual patients. METHODS In a retrospective survey of 1786 consecutive sputum cell counts from 1139 patients with airway disease, we identified 79 patients with two or more exacerbations at an interval of >or=6 weeks. The patients were divided into those who demonstrated a change in the type of airway inflammation and those who did not. RESULTS There were 186 exacerbations of airway disease over 22 months. The cellular nature of inflammation was eosinophilic in 43%, neutrophilic in 40%, combined eosinophilic and neutrophilic in 5% and unclassified in 12%. A change in the type of airway inflammation was seen in 38 patients (48%). Patients, whose previous exacerbation was eosinophilic or neutrophilic were twice or nearly three times more likely, respectively, to have a subsequent exacerbation of the same type. There was no significant difference in the time to the second exacerbation or the inflammatory type of the second exacerbation in relation to the first exacerbation, irrespective of the cellular nature of the first exacerbation. CONCLUSIONS Quantitative sputum cell counts during successive exacerbations identify that they are commonly of different type, reflecting different causes and the need for different treatment. Their use, when available, helps to optimize therapy.
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Affiliation(s)
- Liesel D'silva
- Firestone Institute for Respiratory Health, St. Joseph's Healthcare and Department of Medicine, McMaster University, 50 Charlton Avenue East, Hamilton, Ontario, Canada L8N 4A6.
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404
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Maneechotesuwan K, Essilfie-Quaye S, Kharitonov SA, Adcock IM, Barnes PJ. Loss of Control of Asthma Following Inhaled Corticosteroid Withdrawal Is Associated With Increased Sputum Interleukin-8 and Neutrophils. Chest 2007; 132:98-105. [PMID: 17550933 DOI: 10.1378/chest.06-2982] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND The role of neutrophils in exacerbations of asthma is poorly understood. We examined the effect of withdrawal of inhaled corticosteroids on sputum inflammatory indexes in a double-blind study in patients with moderate, stable asthma. METHODS Following a 2-week run in period, 24 subjects were randomized to receive either budesonide (400 microg bid) or placebo, and the study was continued for another 10 weeks. RESULTS Loss of asthma control developed in 8 of 12 patients over the 10-week period of steroid withdrawal, whereas only 1 of 10 patients with budesonide treatment had exacerbations. Those with an exacerbation had increased sputum interleukin (IL)-8 (p < 0.0001) and increased sputum neutrophil numbers (p < 0.0001) compared to those without an exacerbation. The significant elevation in sputum IL-8 and neutrophil counts initially occurred 2 weeks prior to an exacerbation. Sputum neutrophilia correlated positively with changes in IL-8 levels (r(2) = 0.76, p = 0.01). CONCLUSIONS Rapid withdrawal of inhaled corticosteroids results in an exacerbation of asthma that is preceded by an increase in sputum neutrophils and IL-8 concentrations, in contrast to an increase in eosinophils reported in previous studies in which inhaled steroids are slowly tapered.
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405
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Siddiqui S, Brightling CE. Airways disease: phenotyping heterogeneity using measures of airway inflammation. ALLERGY, ASTHMA, AND CLINICAL IMMUNOLOGY : OFFICIAL JOURNAL OF THE CANADIAN SOCIETY OF ALLERGY AND CLINICAL IMMUNOLOGY 2007; 3:60-9. [PMID: 20525145 PMCID: PMC2873624 DOI: 10.1186/1710-1492-3-2-60] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
: Despite asthma and chronic obstructive pulmonary disease being widely regarded as heterogeneous diseases, a consensus for an accurate system of classification has not been agreed. Recent studies have suggested that the recognition of subphenotypes of airway disease based on the pattern of airway inflammation may be particularly useful in increasing our understanding of the disease. The use of non-invasive markers of airway inflammation has suggested the presence of four distinct phenotypes: eosinophilic, neutrophilic, mixed inflammatory and paucigranulocytic asthma. Recent studies suggest that these subgroups may differ in their etiology, immunopathology and response to treatment. Importantly, novel treatment approaches targeted at specific patterns of airway inflammation are emerging, making an appreciation of subphenotypes particularly relevant. New developments in phenotyping inflammation and other facets of airway disease mean that we are entering an era where careful phenotyping will lead to targeted therapy.
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406
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Menzies D, Nair A, Fardon T, Barnes M, Burns P, Lipworth B. An in vivo and in vitro comparison of inhaled steroid delivery via a novel vortex actuator and a conventional valved holding chamber. Ann Allergy Asthma Immunol 2007; 98:471-9. [PMID: 17521032 DOI: 10.1016/s1081-1206(10)60762-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Valved holding chambers improve delivery of inhaled corticosteroids to the lung but are bulky in design. A novel compact vortex actuator device has therefore been developed. OBJECTIVES To compare the in vitro and in vivo performance of a novel compact vortex actuator (the Neohaler [NH]) vs a conventional small-volume valve holding chamber (the AeroChamber Plus [AP]. METHODS Seventeen asthmatic patients completed the study per protocol, receiving 4 weeks each of 100 microg/d (50-microg formulation) or 400 microg/d (100-microg formulation) of hydrofluoroalkane beclomethasone dipropionate via the NH or AP devices in a randomized crossover, double-blind, double-dummy, placebo-controlled design. The doubling dilution (dd) shift in methacholine provocation concentration that caused a decrease in forced expiratory volume in 1 second of 20% (primary outcome) was used to evaluate anti-inflammatory effects and adrenal function to measure systemic exposure. The fine particle (<4.7 tm) dose was evaluated using an Andersen Cascade Impactor. RESULTS A total of 100 microg of hydrofluoroalkane beclomethasone dipropionate via the NH and AP produced 0.95-dd (95% confidence interval [CI], 0.44-1.45; P = .006) and 0.45-dd (95% CI, -0.16 to 1.06; P = .83) improvements from baseline in methacholine provocation concentration that caused a decrease in forced expiratory volume in 1 second of 20%, respectively, with no statistically significant difference between devices: 0.50 dd (95% CI, -0.25 to 1.24; P = .18). At 400 microg/d, 1.08-dd (95% CI, 0.49-1.67; P = .006) and 0.85-dd (95% CI, 0.32-1.39; P = .02) improvements were found for the NH and AP, respectively, with a 0.23-dd difference (95% CI, -0.28 to 0.74; P = .36) between devices. No adrenal suppression occurred with either device. The in vitro fine particle dose was 39.1 microg for the NH and 39.0 microg for the AP with the 100-microg formulation and 26.0 g and 25.2 microg, respectively, with the 50-microg formulation. CONCLUSIONS Delivering hydrofluoroalkane beclomethasone dipropionate via the NH and AP attenuates asthmatic airway inflammation to a comparable degree and produces a similar in vitro fine particle dose profile.
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Affiliation(s)
- Daniel Menzies
- Asthma & Allergy Research Group, Ninewells Hospital and Medical School, Dundee, Scotland
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407
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Abstract
Achieving and maintaining optimal asthma control is a major asthma management goal advocated by the Global Initiative for Asthma (GINA). Recent evidence suggests that while asthma control is clearly achievable in most asthmatics, not all asthmatics attain optimal asthma control. The difficulty is compounded further because patients, physicians and regulatory bodies have different perceptions of what is meant by asthma control. The challenge therefore remains as to how best to assess asthma control and define management strategies to ensure that this control is achieved and maintained. Despite the availability of several patient-based tools for assessing asthma control, these are mostly employed in a research setting or in selected specialist clinics. A symptom-based treatment approach also may have its limitations because patients can be poor judges of disease symptoms and severity and under-estimation may lead to inadequate treatment of airway inflammation and airway hyperresponsiveness (AHR) when treatment is administered as on-demand reliever therapy, since the effect of treatment on these underlying features occurs over a longer time course. The clinical benefits of sustained maintenance treatment for at least 3 months has been documented in recent studies of salmeterol/fluticasone propionate combination, which have demonstrated correlations between reduction in airway inflammation/AHR and reduction in exacerbation rates. In view of the putative limitations of a purely symptom-based asthma management plan, we suggest that treatment should be focussed on management of all aspects of the disease rather than management of symptoms alone, with a practical approach being treatment for a minimum of 3 months with an optimal dose to ensure maximal effects are seen on asthma control, airway inflammation, lung function, and remodelling.
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Affiliation(s)
- B Lundback
- Lung and Allergy Research, National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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408
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Lemiere C. Induced sputum and exhaled nitric oxide as noninvasive markers of airway inflammation from work exposures. Curr Opin Allergy Clin Immunol 2007; 7:133-7. [PMID: 17351465 DOI: 10.1097/aci.0b013e3280187584] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Noninvasive measures of airway inflammation are increasingly used in the investigation and management of asthma. Their role in the investigation of occupational lung diseases, however, is not as clearly established. The present article reviews the use of noninvasive methods - induced sputum and exhaled nitric oxide - in the assessment of airway inflammation during the investigation of occupational asthma and eosinophilic bronchitis, and reviews studies investigating the effect of exposure to various occupational agents on airway inflammation in healthy individuals. RECENT FINDINGS A number of studies have confirmed the association between exposure to occupational agents and the presence of eosinophilic airway inflammation after that exposure in individuals with occupational asthma. Individuals with positive specific inhalation challenges to occupational agents seem to show a greater increase in exhaled nitric oxide than those with negative specific inhalation challenges. Exposure to various agents associated with an increase in exhaled nitric oxide mainly induced a neutrophilic inflammation. SUMMARY Increasing evidence supports the use of induced sputum as an additional tool in the investigation of occupational asthma. The role of exhaled nitric oxide in the investigation of occupational asthma needs to be clarified due to conflicting evidence reported in the literature.
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Affiliation(s)
- Catherine Lemiere
- Department of Chest Medicine, Hôpital du Sacré-Coeur de Montréal, Université de Montréal, Quebec, Canada.
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409
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Shaw DE, Berry MA, Thomas M, Green RH, Brightling CE, Wardlaw AJ, Pavord ID. The use of exhaled nitric oxide to guide asthma management: a randomized controlled trial. Am J Respir Crit Care Med 2007; 176:231-7. [PMID: 17496226 DOI: 10.1164/rccm.200610-1427oc] [Citation(s) in RCA: 241] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Current asthma guidelines recommend adjusting antiinflammatory treatment on the basis of the results of lung function tests and symptom assessment, neither of which are closely associated with airway inflammation. OBJECTIVES We tested the hypothesis that titrating corticosteroid dose using the concentration of exhaled nitric oxide in exhaled breath (Fe(NO)) results in fewer asthma exacerbations and more efficient use of corticosteroids, when compared with traditional management. METHODS One hundred eighteen participants with a primary care diagnosis of asthma were randomized to a single-blind trial of corticosteroid therapy based on either Fe(NO) measurements (n = 58) or British Thoracic Society guidelines (n = 60). Participants were assessed monthly for 4 months and then every 2 months for a further 8 months. The primary outcome was the number of severe asthma exacerbations. Analyses were by intention to treat. MEASUREMENTS AND MAIN RESULTS The estimated mean (SD) exacerbation frequency was 0.33 per patient per year (0.69) in the Fe(NO) group and 0.42 (0.79) in the control group (mean difference, -21%; 95% confidence interval [CI], -57 to 43%; p = 0.43). Overall the Fe(NO) group used 11% more inhaled corticosteroid (95% CI, -17 to 42%; p = 0.40), although the final daily dose of inhaled corticosteroid was lower in the Fe(NO) group (557 vs. 895 microg; mean difference, 338 microg; 95% CI, -640 to -37; p = 0.028). CONCLUSIONS An asthma treatment strategy based on the measurement of exhaled nitric oxide did not result in a large reduction in asthma exacerbations or in the total amount of inhaled corticosteroid therapy used over 12 mo, when compared with current asthma guidelines. Clinical trial registered with www.controlled-trials.com (ISRCTN08067387).
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Affiliation(s)
- Dominick E Shaw
- Institute for Lung Health, Department of Respiratory Medicine and Thoracic Surgery, Glenfield Hospital, Leicester, United Kingdom
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410
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Haldar P, Pavord ID. Noneosinophilic asthma: A distinct clinical and pathologic phenotype. J Allergy Clin Immunol 2007; 119:1043-52; quiz 1053-4. [PMID: 17472810 DOI: 10.1016/j.jaci.2007.02.042] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 02/26/2007] [Accepted: 02/26/2007] [Indexed: 11/18/2022]
Abstract
The use of induced sputum to assess airway inflammation in large and diverse populations with asthma has led to the recognition that significant numbers of patients do not have evidence of eosinophilic airway inflammation. The absence of a sputum eosinophilia has been noted in patients across the range of asthma severity; it has also been reported in patients presenting with an asthma exacerbation. However, whether noneosinophilic asthma represents a pathologically distinct and clinically important asthma phenotype remains unclear. In this review, we present recent evidence suggesting that noneosinophilic asthma represents a stable phenotype associated with a distinct lower airway pathology and structure. We suggest that this lower airway inflammation develops in response to etiologic factors acting through the innate immune pathway and that elements of this immune response contribute to airway dysfunction. Finally, we argue that noneosinophilic asthma is associated with clinically important differences in natural history and treatment response. We particularly highlight evidence that noneosinophilic asthma is associated with a reduced short-term and long-term response to corticosteroid therapy.
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Affiliation(s)
- Pranab Haldar
- Institute for Lung Health, Department of Respiratory Medicine, Glenfield Hospital, Leicester, UK
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411
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Petsky HL, Kynaston JA, Turner C, Li AM, Cates CJ, Lasserson TJ, Chang AB. Tailored interventions based on sputum eosinophils versus clinical symptoms for asthma in children and adults. Cochrane Database Syst Rev 2007:CD005603. [PMID: 17443604 DOI: 10.1002/14651858.cd005603.pub2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Asthma severity and control can be measured both subjectively and objectively. Sputum analysis for evaluation of percentage of sputum eosinophilia directly measures airway inflammation, and is one method of objectively monitoring asthma. Interventions for asthma therapies have been traditionally based on symptoms and spirometry. OBJECTIVES To evaluate the efficacy of tailoring asthma interventions based on sputum analysis in comparison to clinical symptoms (with or without spirometry/peak flow) for asthma related outcomes in children and adults. SEARCH STRATEGY We searched the Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and reference lists of articles. The last search was on 31 October 2006. SELECTION CRITERIA All randomised controlled comparisons of adjustment of asthma therapy based on sputum eosinophils compared to traditional methods (primarily clinical symptoms and spirometry/peak flow). DATA COLLECTION AND ANALYSIS Results of searches were reviewed against pre-determined criteria for inclusion. Three sets of reviewers selected relevant studies. Two review authors independently assessed trial quality extracted data. Authors were contacted for further information but none were received. Data was analysed as "treatment received" and sensitivity analyses performed. MAIN RESULTS Three adult studies were included; these studies were clinically and methodologically heterogenous (use of medications, cut off for percentage of sputum eosinophils and definition of asthma exacerbation). There were no eligible paediatric studies. Of 246 participants randomised, 221 completed the trials. In the meta-analysis, a significant reduction in number of participants who had one or more asthma exacerbations occurred when treatment was based on sputum eosinophils in comparison to clinical symptoms; pooled odds ratio (OR) was 0.49 (95% CI 0.28 to 0.87); number needed to treat to benefit (NNTB) was 6 (95% CI 4 to 32). There were also differences between groups in the rate of exacerbation (any exacerbation per year) and severity of exacerbations defined by requirement for use of oral corticosteroids but the reduction in hospitalisations was not statistically significant. Data for clinical symptoms, quality of life and spirometry were not significantly different between groups. The mean dose of inhaled corticosteroids per day was similar in both groups and no adverse events were reported. However sputum induction was not always possible. AUTHORS' CONCLUSIONS Tailored asthma interventions based on sputum eosinophils is beneficial in reducing the frequency of asthma exacerbations in adults with asthma. This review supports the use of sputum eosinophils to tailor asthma therapy for adults with frequent exacerbations and severe asthma. Further studies need to be undertaken to strengthen these results and no conclusion can be drawn for children with asthma.
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Affiliation(s)
- H L Petsky
- Royal Children's Hospital, Department of Respiratory Medicine, Herston Road, Brisbane, Queensland, Australia, 4029.
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412
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Chanez P, Wenzel SE, Anderson GP, Anto JM, Bel EH, Boulet LP, Brightling CE, Busse WW, Castro M, Dahlen B, Dahlen SE, Fabbri LM, Holgate ST, Humbert M, Gaga M, Joos GF, Levy B, Rabe KF, Sterk PJ, Wilson SJ, Vachier I. Severe asthma in adults: what are the important questions? J Allergy Clin Immunol 2007; 119:1337-48. [PMID: 17416409 DOI: 10.1016/j.jaci.2006.11.702] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 11/10/2006] [Accepted: 11/15/2006] [Indexed: 12/18/2022]
Abstract
The term severe refractory asthma (SRA) in adults applies to patients who remain difficult to control despite extensive re-evaluation of diagnosis and management following an observational period of at least 6 months by a specialist. Factors that influence asthma control should be recognized and adequately addressed prior to confirming the diagnosis of SRA. This report presents statements according to the literature defining SRA in order address the important questions. Phenotyping SRA will improve our understanding of mechanisms, natural history, and prognosis. Female gender, obesity, and smoking are associated with SRA. Atopy is less frequent in SRA, but occupational sensitizers are common inducers of new-onset SRA. Viruses contribute to severe exacerbations and can persist in the airways for long periods. Inflammatory cells are in the airways of the majority of patients with SRA and persist despite steroid therapy. The T(H)2 immune process alone is inadequate to explain SRA. Reduced responsiveness to corticosteroids is common, and epithelial cell and smooth muscle abnormalities are found, contributing to airway narrowing. Large and small airway wall thickening is observed, but parenchymal abnormalities may influence airway limitation. Inhaled corticosteroids and bronchodilators are the mainstay of treatment, but patients with SRA remain uncontrolled, indicating a need for new therapies.
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Affiliation(s)
- Pascal Chanez
- INSERM U454 and Clinique des Maladies Respiratoires, Montpellier, France.
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413
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Hargreave FE. Quantitative sputum cell counts as a marker of airway inflammation in clinical practice. Curr Opin Allergy Clin Immunol 2007; 7:102-6. [PMID: 17218819 DOI: 10.1097/aci.0b013e328013e3c2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW Bronchitis, meaning airway inflammation, is an important component of airway disease. Yet respirologists and allergists, who have stressed the importance of measurements of airway function, have been slow to introduce airway inflammation measurements into clinical practice. Of the measurements available, quantitative sputum cell counts have the most clinical value. This article provides additional information on this topic from studies published in 2005 and 2006. RECENT FINDINGS Airway diseases are heterogeneous within patients in terms of the disease present and the type of airway inflammation. Quantitative sputum cell counts (total cell count as well as the differential) identify noneosinophilic, mainly neutrophilic, probably infective exacerbations as common in patients with asthma and chronic obstructive pulmonary disease that may be unresponsive to corticosteroid treatment. In contrast, measurements of sputum eosinophils can be used to guide the minimum dose of corticosteroid required to control eosinophilic bronchitis and reduce eosinophilic exacerbations. SUMMARY Measurements of quantitative sputum cell counts need to be made available, initially by tertiary care centres, to diagnose bronchitis in airway disease and to optimize treatment. Examination of how these are complemented by indirect measures of airway inflammation, specifically exhaled nitric oxide and airway hyperresponsiveness to stimuli acting indirectly through mediator release, requires further investigation.
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414
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Boulet LP, Lemière C, Gautrin D, Cartier A. New insights into occupational asthma. Curr Opin Allergy Clin Immunol 2007; 7:96-101. [PMID: 17218818 DOI: 10.1097/aci.0b013e328013ccd8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW To examine recent publications on the types of agents involved in occupational asthma, the mechanisms by which they induce asthma, and how best to evaluate and treat workers suspected of this respiratory condition. RECENT FINDINGS High rates of occupational asthma and inhalation accidents were found in workers in crafts and related occupations in the manufacturing industries, and in plant and machine operatives; cleaners and construction workers may also be at risk. Further data support a role for CD4 T cells in low-molecular-weight agent-induced asthma, such as with isocyanates, and neurogenic mechanisms may also be involved. The use of noninvasive measures of airway inflammation in the diagnosis and management of occupational asthma such as sputum eosinophils monitoring is promising, although this is less obvious for exhaled nitric oxide. Finally, the persistence of troublesome asthma even after withdrawal from relevant exposure has been re-emphasized and surveillance programs have been proposed. SUMMARY Further data have been gathered on the prevalence of occupational asthma in various working populations, its mechanisms of development, the contribution of noninvasive measures of airway inflammation in the diagnosis and management of this condition, and its management and prevention.
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Affiliation(s)
- Louis-Philippe Boulet
- Unité de Recherche en Pneumologie, Institut de Cardiologie et de Pneumologie de l'Université Laval, Hôpital Laval, Québec, Canada
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415
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Green RH, Brightling CE, Bradding P. The reclassification of asthma based on subphenotypes. Curr Opin Allergy Clin Immunol 2007; 7:43-50. [PMID: 17218810 DOI: 10.1097/aci.0b013e3280118a32] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE OF REVIEW Despite asthma being widely regarded as a heterogeneous disease, a consensus for an accurate system of classification has not been agreed. Recent studies have suggested that the recognition of subphenotypes of asthma based on the pattern of airway inflammation may be particularly useful in increasing our understanding of the disease. The present review discusses the important literature in this field, placing current work in its historical context. RECENT FINDINGS The use of noninvasive markers of airway inflammation has suggested the presence of four distinct phenotypes: eosinophilic, neutrophilic, mixed inflammatory and paucigranulocytic asthma. Recent studies suggest that these subgroups may differ in their aetiology, immunopathology and response to treatment. Several studies have focused on refractory asthma as a distinct phenotype with evidence of a more distal pattern of airway inflammation and of upregulation of the tumour necrosis factor-alpha axis. Finally, novel treatment approaches targeted at specific patterns of airway inflammation are emerging, making an appreciation of subphenotypes particularly relevant. SUMMARY The present review will discuss limitations to current classification systems, identify key current studies based on identifying inflammatory subphenotypes and provide suggestions for a novel approach that may further improve our understanding in this area.
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Affiliation(s)
- Ruth H Green
- Department of Respiratory Medicine, Glenfield Hospital, Groby Road, Leicester, UK.
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416
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Menzies D, Nair A, Lipworth BJ. Portable exhaled nitric oxide measurement: Comparison with the "gold standard" technique. Chest 2007; 131:410-4. [PMID: 17296641 DOI: 10.1378/chest.06-1335] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND The measurement of fractional exhaled nitric oxide (FENO) can assist in the diagnosis of asthma and may also act as a useful surrogate inflammatory marker on which to base treatment decisions in asthma management algorithms. Until recently, this technique was confined to research facilities and secondary care institutions. A portable nitric oxide analyzer (MINO; Aerocrine AB; Smidesvägen, Sweden) has been developed, but few data exist comparing this device with established, larger laboratory-based analyzers (NIOX; Aerocrine AB). METHODS A total of 101 asthmatic patients (64 treated with regular inhaled corticosteroids) and 50 healthy volunteers had simultaneous FENO measurements undertaken using NIOX and MINO devices. RESULTS In both asthmatic patients and healthy volunteers, there was a good correlation between the measurements obtained using each device (r = 0.94 and 0.96, respectively). Altman-Bland plots confirmed this agreement. Receiver operating characteristic curves discriminating asthmatic patients from healthy volunteers obtained using the NIOX and MINO showed a sensitivity of 83.2% and a specificity of 72% using cutoff values of 13 and 12.5 parts per billion, respectively. CONCLUSION FENO values obtained using a portable analyzer correlate well with those obtained using an established laboratory analyzer and can be used to discriminate asthmatic from nonasthmatic patients. This may facilitate the measurement of asthmatic airway inflammation in primary care.
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417
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Abstract
In the first National Heart Lung and Blood Institute and Global Initiative for Asthma (GINA) guidelines, the level of symptoms and airflow limitation and its variability allowed asthma to be subdivided by severity into four subcategories (intermittent, mild persistent, moderate persistent, and severe persistent). It is important to recognize, however, that asthma severity involves both the severity of the underlying disease and its responsiveness to treatment. Thus, the first update of the GINA guidelines defined asthma severity depending on the clinical features already proposed as well as the current treatment of the patient. In addition, severity is not a fixed feature of asthma, but may change over months or years, whereas the classification by severity suggests a static feature. Moreover, using severity as an outcome measure has limited value in predicting what treatment will be required and what the response to that treatment might be. Because of these considerations, the classification of asthma severity is no longer recommended as the basis for treatment decisions, a periodic assessment of asthma control being more relevant and useful.
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Affiliation(s)
- M Humbert
- Service de Pneumologie, INSERM U764, Hôpital Antoine-Béclère, Assistance-Publique-Hôpitaux de Paris, Université Paris-Sud 11, Clamart, France
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418
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Abstract
Asthma exacerbations are common. They account for a significant morbidity and contribute a disproportionate amount to the cost of asthma management. The optimal strategies for the prevention of asthma exacerbations include the early introduction of anti-inflammatory treatment-most commonly, low dose inhaled corticosteroids. This should be coupled with a structured education programme which has a written action plan as an integral component. Where patients continue to be poorly controlled, the addition of a long acting beta agonist should be considered. The latter should not be used as monotherapy and should always be used with inhaled corticosteroids. Atopic patients with a history of repeated exacerbations, especially if they are steroid dependent and with a raised IgE, may be considered as potential candidates for omalizumab. In the early stages of an asthma exacerbation, doubling the dose of inhaled corticosteroids has been shown to be ineffective. The ideal strategy for the management of worsening asthma in patients on combination treatment, especially salmeterol and fluticasone, is uncertain. There is an emerging body of evidence for strategies on how to prevent progression to an exacerbation in patients taking a combination of budesonide and formoterol.
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Affiliation(s)
- J M FitzGerald
- Centre for Clinical Epidemiology and Evaluation, Vancouver Coastal Research Institute, Vancouver General Hospital, Vancouver, BC, V5Z 1L8, Canada.
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419
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Taylor DR, Pijnenburg MW, Smith AD, De Jongste JC. Exhaled nitric oxide measurements: clinical application and interpretation. Thorax 2006; 61:817-27. [PMID: 16936238 PMCID: PMC2117092 DOI: 10.1136/thx.2005.056093] [Citation(s) in RCA: 348] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The use of exhaled nitric oxide measurements (F(E)NO) in clinical practice is now coming of age. There are a number of theoretical and practical factors which have brought this about. Firstly, F(E)NO is a good surrogate marker for eosinophilic airway inflammation. High F(E)NO levels may be used to distinguish eosinophilic from non-eosinophilic pathologies. This information complements conventional pulmonary function testing in the assessment of patients with non-specific respiratory symptoms. Secondly, eosinophilic airway inflammation is steroid responsive. There are now sufficient data to justify the claim that F(E)NO measurements may be used successfully to identify and monitor steroid response as well as steroid requirements in the diagnosis and management of airways disease. F(E)NO measurements are also helpful in identifying patients who do/do not require ongoing treatment with inhaled steroids. Thirdly, portable nitric oxide analysers are now available, making routine testing a practical possibility. However, a number of issues still need to be resolved, including the diagnostic role of F(E)NO in preschool children and the use of reference values versus individual F(E)NO profiles in managing patients with difficult or severe asthma.
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Affiliation(s)
- D R Taylor
- Department of Medical and Surgical Sciences, Dunedin School of Medicine, University of Otago, P O Box 913, Dunedin, New Zealand.
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420
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Belda J, Parameswaran K, Lemière C, Kamada D, O’Byrne PM, Hargreave FE. Predictors of loss of asthma control induced by corticosteroid withdrawal. Can Respir J 2006; 13:129-33. [PMID: 16642226 PMCID: PMC2539017 DOI: 10.1155/2006/189127] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Asthma guidelines recommend reducing the dose of inhaled corticosteroids after establishing control. OBJECTIVE To identify predictors of loss of control and the kinetics of symptoms, and inflammatory and physiological measurements when inhaled corticosteroids are reduced in patients with stable asthma. PATIENTS AND METHODS In a single-blind study, the daily dose of inhaled corticosteroid was reduced by one-half at intervals of 20+/-2 days in 17 adults with controlled asthma until loss of asthma control occurred or until the corticosteroid was replaced with placebo for 20 days. The patients recorded symptoms and peak expiratory flow each day, and forced expiratory volume in 1 s (FEV1), the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20), exhaled nitric oxide, and eosinophils in sputum and blood were measured every 10 days. A loss of asthma control was defined as a worsening of the symptoms score of at least 20%, and either a decrease in FEV1 of at least 15% or a decrease in PC20 of at least fourfold. RESULTS Two patients had a respiratory infection and were withdrawn from the study. In eight patients, asthma became uncontrolled after a mean of 33 days (range 13 to 48 days). This was accurately reflected by a worsening of all parameters. The first parameter to change was the sputum eosinophil percentage (20 days before the loss of asthma control). Significant changes in exhaled nitric oxide, FEV1 and methacholine PC20 were observed only when the symptoms became uncontrolled. A high blood eosinophil count at baseline (risk ratio of 2.5, 95% CI 1.0 to 6.5) and an increase in sputum eosinophil count after the reduction of corticosteroids were predictors of loss of asthma control. CONCLUSION In patients whose asthma is controlled on inhaled corticosteroid, it is prudent not to reduce the dose further if the blood eosinophils are increased or if the sputum eosinophils increase by as little as 1% after the reduction of corticosteroids.
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Affiliation(s)
| | - Krishnan Parameswaran
- Correspondence: Dr K Parameswaran, Firestone Institute for Respiratory Health, St Joseph’s Healthcare, 50 Charlton Avenue East, Hamilton, Ontario L8N 4A6. Telephone 905-522-1155 ext 5044, fax 905-521-6183, e-mail
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421
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Abstract
Patients with mild persistent asthma rarely see their doctor with symptoms of the disease. Partly as a result of this situation, mild asthma is generally undertreated. Findings of several large randomised clinical trials have shown benefits for this population of regular treatment with low doses of inhaled corticosteroids. Additional drugs are rarely needed, and although leukotriene modifiers are effective, they are less so than inhaled corticosteroids. People with moderate persistent asthma are not well controlled on low doses of inhaled corticosteroids. A combination of this drug and long-acting inhaled beta2 agonists provides improved control compared with doubling of the maintenance dose of inhaled corticosteroids. The combination of budesonide and formoterol has been assessed as both maintenance and reliever treatment. This approach further reduces the risk for severe exacerbations. With these strategies, most individuals can achieve good control of their asthma. For patients who do not achieve asthma control despite taking drugs, measurement of the inflammatory response in the airway in induced sputum could provide further information to guide treatment.
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Affiliation(s)
- Paul M O'Byrne
- Firestone Institute for Respiratory Health, St Joseph's Healthcare and Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
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422
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Abstract
The common disease asthma is probably not a single disease, but rather a complex of multiple, separate syndromes that overlap. Although clinicians have recognised these different phenotypes for many years, they have remained poorly characterised, with little known about the underlying pathobiology contributing to them. Development of targeted therapies for asthma, and phenotype-specific clinical trials have raised interest in these phenotypes. Improved understanding of these phenotypes in complex diseases such as asthma will also improve our ability to link specific genotypes to their associated disease, which should help development of biomarkers. However, there is no standardised method to define asthma phenotypes. This Review analyses some of the methods that have been used to define asthma phenotypes and proposes an integrated method of classification to improve our understanding of these phenotypes.
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Affiliation(s)
- Sally E Wenzel
- Department of Medicine, National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206, USA.
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423
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Abstract
The development of standardized methods for sputum induction has improved the quality and reproducibility of sputum samples. This technique has been used to optimize samples in the investigation of pulmonary tuberculosis and lung cancer, but its clinical application as a noninvasive measure of airway inflammation has highlighted the enormous potential of this technique. Sputum induction has allowed researchers to characterize the inflammatory profiles of a variety of airway diseases including asthma, COPD, and chronic cough. To date, the identification of sputum eosinophilia has the greatest clinical value as this predicts a favorable response to corticosteroids and can therefore guide treatment. In asthma and COPD management, protocols aimed at normalizing the sputum eosinophil count have markedly reduced exacerbations without an overall increase in therapy. Currently, no other noninvasive measure of airway inflammation has demonstrated a benefit in reducing exacerbations. The value of sputum induction and analysis is not restricted to the recognition of sputum eosinophilia but also may be used to direct novel antineutrophilic therapies. Thus, it is time for sputum induction to move from the research laboratory to the clinic.
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Affiliation(s)
- Christopher E Brightling
- Institute for Lung Health, University of Leicester, Glenfield Hospital, Groby Rd, Leicester, LE3 9QP, UK.
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424
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Kelly MM, Leigh R, Jayaram L, Goldsmith CH, Parameswaran K, Hargreave FE. Eosinophilic bronchitis in asthma: a model for establishing dose-response and relative potency of inhaled corticosteroids. J Allergy Clin Immunol 2006; 117:989-94. [PMID: 16675323 DOI: 10.1016/j.jaci.2006.01.045] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Revised: 01/06/2006] [Accepted: 01/11/2006] [Indexed: 11/26/2022]
Abstract
BACKGROUND Newer generations and formulations of inhaled corticosteroids have necessitated the development of a clinically relevant model to compare their clinical potency. OBJECTIVE We evaluated whether sputum eosinophil counts could demonstrate a dose-response to inhaled corticosteroids, and compared the response with other inflammatory markers. METHODS Fourteen steroid-naive patients with asthma with an initial sputum eosinophilia of > or = 2.5% entered a 6-week sequential, placebo-controlled, patient-blinded, cumulative dose-response study. After 7 days of placebo, they received incremental doses of fluticasone propionate (FP), 50, 100, 200, and 400 microg/d, each for 7 days. Measurements were made of sputum and blood eosinophils, exhaled nitric oxide, spirometry, airway responsiveness to methacholine (methacholine PC20), and symptom scores before and after each dose. RESULTS Sputum eosinophils and exhaled nitric oxide were extremely sensitive to the effects of FP, and exhibited significant dose-dependent reductions of 99.4% and 99.8 parts per billion, respectively, where each variable was expressed per 100 microg/d FP. This compared with a 0.5 doubling dose increase of airway responsiveness to methacholine and a 0.3 decrease in symptom scores. Airway responsiveness to methacholine was the only variable that increased throughout the study. CONCLUSION These results suggest that the model of eosinophilic bronchitis could be used to compare the effect of cumulative doses of an inhaled corticosteroid delivered by different types of delivery systems or preparations using a relatively small number of patients. CLINICAL IMPLICATIONS Future clinical studies based on this model will allow clinicians to make informed decisions regarding the relative potencies of different inhaled corticosteroids.
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Affiliation(s)
- Margaret M Kelly
- Airways Research Group, Firestone Institute for Respiratory Health, Hamilton, Canada.
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425
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Affiliation(s)
- Krishnan Parameswaran
- McMaster University, Firestone Institute for Respiratory Health, St. Joseph's Healthcare.
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