Determining asthma treatment by monitoring sputum cell counts: effect on exacerbations

Management of asthma in pregnancy guided by measurement of fraction of exhaled nitric oxide: a double-blind, randomised controlled trial

BACKGROUND

Asthma exacerbations during pregnancy are common and can be associated with substantial maternal and fetal morbidity. Treatment decisions based on sputum eosinophil counts reduce exacerbations in non-pregnant women with asthma, but results with the fraction of exhaled nitric oxide (F(E)NO) to guide management are equivocal. We tested the hypothesis that a management algorithm for asthma in pregnancy based on F(E)NO and symptoms would reduce asthma exacerbations.

METHODS

We undertook a double-blind, parallel-group, controlled trial in two antenatal clinics in Australia. 220 pregnant, non-smoking women with asthma were randomly assigned, by a computer-generated random number list, before 22 weeks' gestation to treatment adjustment at monthly visits by an algorithm using clinical symptoms (control group) or F(E)NO concentrations (active intervention group) used to uptitrate (F(E)NO >29 ppb) or downtitrate (F(E)NO <16 ppb) inhaled corticosteroid dose. Participants, caregivers, and outcome assessors were masked to group assignment. Longacting β2 agonist and minimum dose inhaled corticosteroid were used to treat symptoms when F(E)NO was not increased. The primary outcome was total asthma exacerbations (moderate and severe). Analysis was by intention to treat. This study is registered with the Australian and New Zealand Clinical Trials Registry, number 12607000561482.

FINDINGS

111 women were randomly assigned to the F(E)NO group (100 completed) and 109 to the control group (103 completed). The exacerbation rate was lower in the F(E)NO group than in the control group (0·288 vs 0·615 exacerbations per pregnancy; incidence rate ratio 0·496, 95% CI 0·325-0·755; p=0·001). The number needed to treat was 6. In the F(E)NO group, quality of life was improved (score on short form 12 mental summary was 56·9 [95% CI 50·2-59·3] in F(E)NO group vs 54·2 [46·1-57·6] in control group; p=0·037) and neonatal hospitalisations were reduced (eight [8%] vs 18 [17%]; p=0·046).

INTERPRETATION

Asthma exacerbations during pregnancy can be significantly reduced with a validated F(E)NO-based treatment algorithm.

FUNDING

National Health and Medical Research Council of Australia.

New perspectives in pharmacological treatment of mild persistent asthma

Until the relationship between symptoms, lung function tests, airway inflammation, airway hyper-responsiveness (AHR), exacerbations and remodelling is clarified, regular treatment seems to enable a greater disease control than on-demand therapy in most patients with mild persistent asthma. Current guideline classification based on disease severity remains a cornerstone in asthma management. However, the heterogeneity of asthma, the growing emphasis on subphenotypes, including molecular phenotypes identified by -omics technologies, and their possible implications in terms of different asthma severity, progression and therapeutic response, are changing current asthma treatment mainly based on disease severity classification to a pharmacological strategy more focused on the individual patient.

Asthma phenotypes in adults and clinical implications

It is becoming increasingly recognized that asthma is a heterogeneous disease, whether based on clinical factors, including the patient's age at diagnosis, symptom spectrum and treatment response, triggering factors, or the level and type of inflammation. Attempts to analyze the importance of these characteristics to the clinical presentation of asthma have led to the appreciation of numerous separate and overlapping asthma phenotypes. However, these approaches are 'biased' and based on the clinician/scientist's own experience. Recently, unbiased approaches have also been attempted using both molecular and statistical tools. Early results from these approaches have supported and expanded on the clinician's concepts. However, until specific biologic markers are identified for any of these proposed phenotypes, the definitive nature of any phenotype will remain speculative.

The Asthma Control Scoring System: translation and cross-cultural adaptation for use in Brazil

OBJECTIVE

The translation and cross-cultural adaptation of a specific scoring instrument for the comprehensive control of asthma, the Asthma Control Scoring System (ACSS), for use in Brazil.

METHODS

The protocol included ten steps: acquisition of written permission from the author of the ACSS; translation of the instrument to Brazilian Portuguese, carried out by three separate translators; analysis and comparison of the three versions by a review committee; literal back-translation to English; review and harmonization of the back-translation; acquisition of the approval of the original author; review of the translation by specialists; cognitive debriefing: test of clarity to, understanding by, and acceptance of the target population (evaluation of the translation by 10 health care workers); second cognitive debriefing: review of the revised version by a second group of health care workers; and reconciliation and preparation of the final version by the review committee.

RESULTS

The Brazilian Portuguese-language version of the ACSS showed clarity, understandability, and acceptability. The instrument was considered to be comprehensive because it includes the clinical manifestations of asthma, as well as the functional and inflammatory aspects of the disease.

CONCLUSIONS

With the use of this careful methodology in the translation and cross-cultural adaptation of the ACSS, we have ensured its cultural adequacy for Brazil. The use of this instrument could facilitate future studies on asthma control.

Alcohol fixation of induced sputum samples for applications in rural communities

BACKGROUND

Sputum induction is a tool recommended for the assessment of airway inflammation and disease management. Currently, its use is limited because samples need to be processed within 3 h of induction (ie, while cells are viable); therefore, this procedure is unavailable to most clinicians.

OBJECTIVE

To develop a fixation method for induced sputum samples that allows for a delay in processing while maintaining sample integrity and not altering the standard processing method.

METHODS

Sputum samples were collected and split into three portions: a fresh sample processed using the routine method (within 3 h, using dithiothreitol); fixation in alcohol followed by delayed processing using the routine method (within 48 h to 72 h, using dithiothreitol); and fixation in formaldehyde followed by delayed processing using an alternative method (within 48 h to 72 h, using proteolysis). For each method, cytospins were prepared and differential cell counts were performed.

RESULTS

Fixation in alcohol provides accurate measures of eosinophils and macrophages, but not neutrophils. Formaldehyde fixation provides accurate measures of neutrophils and macrophages, but not eosinophils.

DISCUSSION

Alcohol fixation is a superior method for eosinophil quantification. It requires alteration of standardized methods for sputum sample processing and should be recommended for monitoring eosinophilic airway disease in settings where immediate processing of a sputum sample is not possible.

Pharmacotherapy of patients with mild persistent asthma: strategies and unresolved issues

In studies comparing regular versus on-demand treatment for patients with mild persistent asthma, on-demand treatment seems to have a similar efficacy on clinical and functional outcomes, but it does not suppress chronic airway inflammation or airway hyper-responsiveness (AHR) associated with asthma. Data on the efficacy of a continuous treatment with inhaled corticosteroids (ICS) in preventing the progression of asthma are conflicting. There is the possibility that patients without a regular treatment with ICS may develop a more severe asthma associated with airway structural changes (remodeling) and a progressive loss of lung function. However, the possible clinical and functional consequences of persistent, not controlled, airway inflammation in patients with asthma have to be established. Assessment of asthma control should include inflammatory outcomes, such as fraction of exhaled nitric oxide and sputum eosinophil counts. Until the relationships between symptoms, lung function tests, AHR, airway inflammation, exacerbations, and airway remodeling are clarified, regular treatment seems to be generally more appropriate than on-demand treatment to warrant a greater control of asthma. Select subgroups of patients with mild asthma who are well controlled by regular treatment might adopt the on-demand treatment plan as an intermediate step toward the suspension of controller medication. The increasing evidence for heterogeneity of asthma, the growing emphasis on asthma subphenotypes, including molecular phenotypes identified by omics technologies, and their possible implications for different asthma severity and progression and therapeutic response, are changing the paradigm of treating patients with asthma only based on classification of their disease severity to a pharmacological strategy more focused on the individual asthmatic patient. Pharmacological treatment of asthma is going toward a personalized approach.

WHO universal definition of severe asthma

PURPOSE OF REVIEW

In 2009, an expert panel met to propose a WHO definition of asthma severity and control, and criteria for describing exacerbations and their severity, which would be globally applicable. This review addresses their findings in the context of recent literature, and assesses the usefulness of these definitions in children in particular.

RECENT FINDINGS

Severe asthma was defined by the level of current clinical control and risks as: 'Uncontrolled asthma which can result in risk of frequent severe exacerbations (or death) and/or adverse reactions to medications and/or chronic morbidity (including impaired lung function or reduced lung growth in children)'. Severe asthma includes three groups, with different public health messages and challenges: untreated severe asthma, due to undiagnosed asthma or unavailability of therapy, difficult-to-treat severe asthma (due to adherence issues, inappropriate or incorrect use of medicines, environmental triggers or co-morbidity), and treatment-resistant severe asthma, including asthma for which control is not achieved despite the highest level of recommended treatment or asthma which is controlled only with the highest level of recommended treatment.

SUMMARY

These definitions will enable more precise measurement of the burden of severe childhood asthma globally. International collaborations in epidemiological and mechanistic studies, and randomized controlled trials of treatment, will be facilitated. However, both pathophysiology and severity are influenced by a number of factors with wide global variation; international comparisons should be interpreted with caution.

Asthma translational medicine: report card

Over the last 30 years, scientific research into asthma has focused almost exclusively on one component of the disorder - airway inflammation - as being the key underlying feature. These studies have provided a remarkably detailed and comprehensive picture of the events following antigen challenge that lead to an influx of T cells and eosinophils in the airways. Indeed, in basic research, even the term "asthma" has become synonymous with a T helper 2 cell-mediated disorder. From this cascade of cellular activation processes and mediators that have been identified it has been possible to pinpoint critical junctures for therapeutic intervention, leading experimentalists to produce therapies that are very effective in decreasing airway inflammation in animal models. Many of these compounds have now completed early Phase 2 "proof-of-concept" clinical trials so the translational success of the basic research model can be evaluated. This commentary discusses clinical results from 39 compounds and biologics acting at 23 different targets, and while 6 of these drugs can be regarded as a qualified success, none benefit the bulk of asthma sufferers. Despite this disappointing rate of success, the same immune paradigm and basic research models, with a few embellishments to incorporate newly identified cells and mediators, continue to drive target identification and drug discovery efforts. It is time to re-evaluate the focus of these efforts.

Composição celular do escarro induzido em adultos saudáveis

OBJETIVO: Estabelecer valores de referência para a celularidade de amostras de escarro induzido coletadas de indivíduos adultos saudáveis. MÉTODOS: O escarro induzido foi obtido de 88 adultos saudáveis que nunca fumaram (39 homens) com média de idade de 36 anos (variação: 18-68 anos) residentes há pelo menos dois anos em Florianópolis, uma cidade brasileira não industrial e de tamanho médio. As amostras foram processadas, e foi realizada a contagem total e diferencial das células. RESULTADOS: A média da contagem celular total foi de 4,8 ± 4,2 × 10(6) células/g. Houve predomínio de macrófagos (média de 77,5 ± 14,7%) e de neutrófilos (média de 23,4 ± 14,3%). Os eosinófilos estiveram virtualmente ausentes (média de 0,1 ± 0,3%). A proporção de linfócitos e de células broncoepiteliais foi pequena. Não houve efeito da idade ou de atopia sobre a contagem celular total ou diferencial. CONCLUSÕES: Nesta população de indivíduos saudáveis, macrófagos e neutrófilos foram as células predominantes no escarro induzido. Contudo, a proporção de neutrófilos foi inferior à previamente relatada, sugerindo que os valores de normalidade podem variar de acordo com o local onde ele é amostrado

Using biomarkers in the assessment of airways disease

A biomarker provides a window on underlying disease activity. This is helpful when the pathology, treatment response, or both are heterogeneous or when trying to interpret nonspecific respiratory symptoms in patients with comorbidities. The successful application of a biomarker result is critically dependent on the specific question being addressed and the performance characteristics of the biomarker in relation to that question in the context of pretest probabilities. Negative prediction might be the best way to use a biomarker, such as a D-dimer, pro-brain natriuretic peptide, and exhaled nitric oxide. In this review the role of biomarkers in airways disease (notably induced sputum eosinophils and exhaled nitric oxide) is considered in relation to risk stratification, identification of treatment responders, identification of a clinical phenotype, monitoring of disease, and new drug development.

Cytokine/anti-cytokine therapy - novel treatments for asthma?

Asthma is a chronic inflammatory disease of the airways and there are no preventions or cures. Inflammatory cells through the secretion of cytokines and pro-inflammatory molecules are thought to play a critical role in pathogenesis. Type 2 CD4(+) lymphocytes (Th2 cells) and their cytokines predominate in mild to moderate allergic asthma, whereas severe steroid-resistant asthma has more of a mixed Th2/Th1 phenotype with a Th17 component. Other immune cells, particularly neutrophils, macrophages and dendritic cells, as well structural cells such as epithelial and airway smooth muscle cells also produce disease-associated cytokines in asthma. Increased levels of these immune cells and cytokines have been identified in clinical samples and their potential role in disease demonstrated in studies using mouse models of asthma. Clinical trials with inhibitors of cytokines such as interleukin (IL)-4, -5 and tumour necrosis factor-α have had success in some studies but not others. This may reflect the design of the clinical trials, including treatments regimes and the patient population included in these studies. IL-13, -9 and granulocyte-macrophage colony-stimulating factor are currently being evaluated in clinical trials or preclinically and the outcome of these studies is eagerly awaited. Roles for IL-25, -33, thymic stromal lymphopoietin, interferon-γ, IL-17 and -27 in the regulation of asthma are just emerging, identifying new ways to treat inflammation. Careful interpretation of results from mouse studies will inform the development and application of therapeutic approaches for asthma. The most effective approaches may be combination therapies that suppress multiple cytokines and a range of redundant and disconnected pathways that separately contribute to asthma pathogenesis. Astute application of these approaches may eventually lead to the development of effective asthma therapeutics. Here we review the current state of knowledge in the field.

Therapeutic strategies to reduce asthma exacerbations

Asthma exacerbations can occur in patients with all degrees of asthma severity. They generally develop over 5 to 7 days and are most often initiated by an upper respiratory tract infection (usually with human rhinovirus) or by environmental allergen exposure in atopic subjects. Inhaled corticosteroids (ICSs) taken on a regular basis are very effective in reducing the risk of asthma exacerbations, and the combination of ICSs and long-acting inhaled β₂-agonists further reduces this risk. In addition, use of the combination of the ICS budesonide and the long-acting inhaled β₂-agonist formoterol, both as maintenance asthma treatment and also as rescue treatment (instead of a short-acting inhaled β₂-agonist), has a significant further beneficial effect on asthma exacerbation risk. Other therapies that have been demonstrated to reduce severe asthma exacerbations are leukotriene receptor antagonists, which have been demonstrated to be effective most consistently in this regard in children, and anti-IgE mAbs, which are effective in subjects with difficult-to-treat allergic asthma. Approximately 50% of severe asthma exacerbations are eosinophilic in nature, whereas many of the remaining are neutrophilic. Several studies have demonstrated that making asthma treatment decisions based on minimizing airway eosinophil numbers (measured in induced sputum) can reduce the risks of severe exacerbations. In addition, treatment of patients with severe asthma with an anti-IL-5 mAb also reduces the number of severe asthma exacerbations, demonstrating a central role of eosinophils in many exacerbations.

Can inhaled corticosteroids prevent asthma exacerbations?

PURPOSE OF REVIEW

asthma exacerbations occur unpredictably, are a cause of morbidity and mortality, and contribute significantly to increased healthcare costs. Inhaled corticosteroids reduce exacerbations and improve quality of life.

RECENT FINDINGS

the aetiopathology of asthma exacerbations is heterogeneous. Attempts to phenotype the heterogeneity of the pattern of airway inflammation by noninvasive monitoring of airway inflammation has identified a subgroup of patients with eosinophilic inflammation who are most likely to respond to steroid therapy. Strategies directed to normalize eosinophilic airway inflammation with corticosteroids have consistently led to a marked reduction in exacerbations. In contrast, their role in modulating the natural history of disease is less certain.

SUMMARY

in the near future, improvements in our understanding of the mechanisms of exacerbations may identify therapeutic targets. While we await these developments, inhaled corticosteroids remain the first choice anti-inflammatory therapy for asthma.

Early interventions with inhaled corticosteroids in asthma: benefits and risks

PURPOSE OF REVIEW

the present review examines the effects of early intervention with inhaled corticosteroids (ICSs) on clinical efficacy and natural history of asthma based on two recent clinical trials: the Inhaled Steroid Treatment as Regular Therapy in Early Asthma (START) and Prevention of Early Asthma in Kids (PEAK) trials, and a comparison of the effect of regular vs. intermittent therapy based on the Improving Asthma Control Trial (IMPACT).

RECENT FINDINGS

in most patients, both adults and children, who have a new diagnosis of asthma and whose symptoms are mild but persistent, treatment with ICS should be recommended as soon as the diagnosis is made. This is a cost-effective and well tolerated treatment. However, symptoms may recur and lung function may decline again if treatment is discontinued.

SUMMARY

ICS is the most cost-effective initial treatment for both adults and children with a new diagnosis of asthma. If patients are reluctant to use ICS daily for long periods, it would be reasonable to delay the onset of treatment with ICS. Initial therapy with leukotriene receptor antagonist is not likely to be as effective as initial therapy with ICS. Biomarkers of airway inflammation such as sputum cell counts and exhaled nitric oxide are probably not necessary to treat patients with mild intermittent asthma.

Assessment of synthetic glucocorticoids in asthmatic sputum

Nonadherence with anti-inflammatory treatment is a frequent cause of continued symptoms in asthmatic patients. Clinical assessments including patient-reported medication administration may provide the asthma specialist incomplete information regarding actual adherence to anti-inflammatory medications. The objective of this report was to describe the first case where adherence to inhaled asthma therapy was assessed by direct analysis of glucocorticoids in induced sputum. The patient's blood, urine, and sputum were tested for synthetic corticosteroids using mass spectrometry. To evaluate a clinical suspicion of poor adherence, sputum, urine, and blood were used to assess for current compliance to medication use. We report a case where asthma specialists attributed poorly controlled asthma to nonadherence to medical therapy. After modification of the medical regimen, adherence with oral and inhaled steroids was assessed-via examination of the urine, blood, and sputum. Direct analysis of glucocorticoids in sputum is feasible and in theory could provide a novel tool to document current medication adherence. Concomitant assessment of glucocorticoids and eosinophils in the same induced sputum specimen could provide insight into possible steroid resistance in select referral patients with difficult asthma.

New therapies and management strategies in the treatment of asthma: patient-focused developments

It is increasingly recognized that large proportions of patients with asthma remain poorly controlled with daily symptoms, limitation in activities, or severe exacerbations despite traditional treatment with inhaled corticosteroids and other agents. This suggests that there is considerable scope for the refinement of traditional guidelines on the use of inhaled therapies in asthma and also a need for the development of novel therapeutic agents, particularly for the treatment of severe asthma. This review aims to discuss a range of emerging treatment approaches in asthma. Firstly, we will set the scene by highlighting the importance of achieving good asthma control in a patient-focused manner and discussing recent work that has furthered our understanding of asthma phenotypes and paved the way for patient-specific treatments. Secondly, we will review new strategies to better use the existing therapies such as inhaled corticosteroids and long-acting β(2)-agonists that remain the mainstay of treatment for most patients. Finally, we will review the novel therapies that are becoming available, both pharmacological and interventional, and discuss their likely place in the management of this complex disease.

Respiratory viruses, eosinophilia and their roles in childhood asthma

With the advent of highly sensitive and specific screening of respiratory specimens for viruses, new viruses are discovered, adding to the growing list of those associated with wheezing illness and asthma exacerbations. It is not known whether early childhood infections with these viruses cause asthma, and, if so, what exactly are the pathophysiologic mechanisms behind its development. The current consensus is that respiratory viral infection works together with allergy to produce the immune and physiologic conditions necessary for asthma diasthesis. One link between viruses and asthma may be the eosinophil, a cell that plays a prominent role in asthma and allergy, but can also be found in the body in response to viral infection. In turn, the eosinophil and its associated products may be novel therapeutic targets, or at the very least, used to elucidate the complex pathophysiologic pathways of asthma and other respiratory illnesses. Together or separately, they can be used for diagnosis, treatment and monitoring. Not only symptoms, but also the underlying disease mechanisms must be taken into consideration for the optimal care of a patient.

Exhaled NO and exhaled breath condensate pH in the evaluation of asthma control

BACKGROUND

Asthma is a chronic inflammatory airways disorder. However, no biomarker of airways inflammation has been included in the assessment of asthma control.

OBJECTIVE

To evaluate exhaled NO (FeNO) and exhaled breath condensate (EBC) pH in patients with asthma according to the level of control, and their performance in the identification of not well-controlled patients.

METHODS

FeNO and EBC pH after Argon deaeration were measured in 274 consecutive patients. Asthma control was evaluated by two asthma specialists blinded to FeNO and pH measurements according to GINA guidelines, as well as by asthma control test (ACT) and asthma control questionnaire (ACQ).

RESULTS

FeNO was higher and EBC pH was lower in patients with not well-controlled compared to controlled asthma. In ROC analysis, FeNO presented an AUC of 0.790 for the identification of not well-controlled asthma performing better in non-smokers; EBC pH presented an AUC of 0.791 for the identification of not well-controlled asthma, performing better in smokers. The performance of both biomarkers was inferior to that of ACT and ACQ. FeNO values >30 ppb presented positive predictive values (PPV) > 0.85 with the exception of smokers treated with inhaled corticosteroids. EBC pH values ≤7.20 presented PPV >0.80 in all groups. The presence of FeNO >30 ppb and/or EBC pH ≤7.20 was indicative of not well-uncontrolled asthma in 88.3% of the patients.

CONCLUSION

FeNO and EBC pH levels may identify patients with not well-controlled asthma. However, their performance was inferior to clinical judgment and may be limited to selected subgroups of asthmatic patients.

Quantitative analysis of high-resolution computed tomography scans in severe asthma subphenotypes

Background

Severe asthma is a heterogeneous condition. Airway remodelling is a feature of severe asthma and can be determined by the assessment of high-resolution computed tomography (HRCT) scans. The aim of this study was to assess whether airway remodelling is restricted to specific subphenotypes of severe asthma.

Methods

A retrospective analysis was performed of HRCT scans from subjects who had attended a single-centre severe asthma clinic between 2003 and 2008. The right upper lobe apical segmental bronchus (RB1) dimensions were measured and the clinical and sputum inflammatory characteristics associated with RB1 geometry were assessed by univariate and multivariate regression analyses. Longitudinal sputum data were available and were described as area under the time curve (AUC). Comparisons were made in RB1 geometry across subjects in four subphenotypes determined by cluster analysis, smokers and non-smokers, and subjects with and without persistent airflow obstruction.

Results

Ninety-nine subjects with severe asthma and 16 healthy controls were recruited. In the subjects with severe asthma the RB1 percentage wall area (%WA) was increased (p=0.009) and lumen area (LA)/body surface area (BSA) was decreased (p=0.008) compared with controls but was not different across the four subphenotypes. Airway geometry was not different between smokers and non-smokers and RB1 %WA was increased in those with persistent airflow obstruction. RB1 %WA in severe asthma was best associated with airflow limitation and persistent neutrophilic airway inflammation (model R²=0.27, p=0.001).

Conclusions

Airway remodelling of proximal airways occurs in severe asthma and is associated with impaired lung function and neutrophilic airway inflammation.

Measuring bronchitis in airway diseases: clinical implementation and application: Airway hyperresponsiveness in asthma: its measurement and clinical significance

Airway inflammation is fundamental to the cause and persistence of asthma and other airway conditions. It contributes to symptoms, variable airflow limitation, airway hyperresponsiveness, and the structural changes (remodeling) associated with asthma. However, the presence and type of airway inflammation can be difficult to detect clinically, delaying the introduction of appropriate treatment. Cellular inflammation in the airway can be accurately and reliably assessed by examining spontaneous or, when not available, induced sputum. Induced sputum cell counts are relatively noninvasive, safe, and reliable. They can accurately discriminate eosinophilic airway inflammation from noneosinophilic airway inflammation and, thus, help to guide therapy. Eosinophilic airway inflammation is steroid responsive, whereas noneosinophilic (usually neutrophilic) inflammation generally is not. Monitoring of airway inflammation using sputum cell counts helps to identify the impending loss of asthma control and, thus, the need to adjust antiinflammatory medications in patients with a variety of airway diseases, such as asthma, smoker's COPD, and chronic cough. Other noninvasive, indirect measurements of airway inflammation, such as exhaled nitric oxide, do not help to identify the cellular nature of airway inflammation associated with exacerbations of airway diseases, particularly in patients who are already on corticosteroids. Thus, although they can be a predictor of steroid responsiveness, these measures do not help to reduce asthma exacerbations when used in clinical practice. The clinical usefulness of measurements in exhaled breath condensate has not yet been established.

Predicting intermediate phenotypes in asthma using bronchoalveolar lavage-derived cytokines

An important problem in realizing personalized medicine is the development of methods for identifying disease subtypes using quantitative proteomics. Recently we found that bronchoalveolar lavage (BAL) cytokine patterns contain information about dynamic lung responsiveness. In this study, we examined physiological data from 1,048 subjects enrolled in the US Severe Asthma Research Program (SARP) to identify four largely separable, quantitative intermediate phenotypes. Upper extremes in the study population were identified for eosinophil- or neutrophil-predominant inflammation, bronchodilation in response to albuterol treatment, or methacholine sensitivity. We evaluated four different statistical ("machine") learning methods to predict each intermediate phenotype using BAL A-cytokine measurements on a 76 subject subset. Comparison of these models using area under the ROC curve and overall classification accuracy indicated that logistic regression and multivariate adaptive regression splines produced the most accurate methods to predict intermediate asthma phenotypes. These robust classification methods will aid future translational studies in asthma targeted at specific intermediate phenotypes.

Eosinophil protein in airway macrophages: a novel biomarker of eosinophilic inflammation in patients with asthma

BACKGROUND

Noneosinophilic asthma is common across asthma severities. However, in patients with moderate-to-severe disease, the absence of sputum eosinophilia cannot distinguish between asthmatic subjects with eosinophilic inflammation controlled by corticosteroids versus those in whom eosinophilic inflammation is not a component of the disease.

OBJECTIVES

We sought to develop a method to quantify eosinophil proteins in airway macrophages as a novel biomarker of eosinophilic airway inflammation.

METHODS

Eosinophil proteins in airway macrophages were assessed by means of flow cytometry, immunofluorescence, and cytoplasmic hue change after ingestion of apoptotic eosinophils. Airway macrophage median percentage of red-hued area in stained sputum cytospin preparations was assessed by means of image analysis from (1) subjects with mild-to-severe asthma, subjects with nonasthmatic eosinophilic bronchitis, and healthy control subjects; (2) subjects with eosinophilic severe asthma after treatment with prednisolone; and (3) subject with noneosinophilic asthma before corticosteroid withdrawal.

RESULTS

Eosinophil proteins were detected in airway macrophages, and cytoplasmic red hue increased after ingestion of apoptotic eosinophils. Airway macrophage percentage redhued area was increased in subjects with moderate-to-severe asthma compared with that seen in subjects with mild asthma and healthy control subjects, was similar in those with or without a sputum eosinophilia, and was increased after corticosteroid therapy. In asthmatic subjects without sputum eosinophilia, the airway macrophage percentage red-hued area was increased in subjects who did versus those who did not have sputum eosinophilia after corticosteroid withdrawal.

CONCLUSIONS

Eosinophil proteins can be reliably measured in airway macrophages. In combination with sputum eosinophilia, the macrophage eosinophil protein content might further define the asthma phenotype and provide an additional tool to direct therapy.

Monitoring asthma therapy using indirect bronchial provocation tests

OBJECTIVES

Bronchial provocation tests that assess airway hyperresponsiveness (AHR) are known to be useful in assisting the diagnosis of asthma and in monitoring inhaled corticosteroid therapy. We reviewed the use of bronchial provocation tests that use stimuli that act indirectly for monitoring the benefits of inhaled corticosteroids.

DATA SOURCE

Published clinical trials investigating the effect of inhaled corticosteroids on bronchial hyperresponsiveness in persons with asthma were used for this review.

STUDY SELECTION

Studies using indirect stimuli to provoke airway narrowing such as exercise, eucapnic voluntary hyperventilation, cold air hyperventilation, hypertonic saline, mannitol, or adenosine monophosphate (AMP) to assess the effect of inhaled corticosteroids were selected.

RESULTS

Stimuli acting indirectly result in the release of a variety of bronchoconstricting mediators such as leukotrienes, prostaglandins, and histamine, from cells such as mast cells and eosinophils. A positive response to indirect stimuli is suggestive of active inflammation and AHR that is consistent with a diagnosis of asthma. Persons with a positive response to indirect stimuli benefit from daily treatment with inhaled corticosteroids. Symptoms and lung function are not useful to predict the long-term success of inhaled corticosteroid dose as they usually resolve rapidly, and well before inflammation and AHR has resolved. Following treatment, AHR to indirect stimuli is attenuated. Further, during long-term treatment, asthmatics can become as non-responsive as non-asthmatic healthy persons, suggesting that asthma is not active.

CONCLUSIONS

Non-responsiveness to indirect bronchial provocation tests following inhaled corticosteroids occurs weeks to months following the resolution of symptoms and lung function. Non-responsiveness to indirect stimuli may provide a goal for adequate therapy with inhaled corticosteroids.

Inflammatory phenotypes in adult asthma: clinical applications

BACKGROUND

The pattern of granulocyte infiltration can be used to identify different inflammatory phenotypes in asthma. Recognized granulocyte phenotypes using induced sputum are eosinophilic (EA), neutrophilic, mixed granulocytic and paucigranulocytic asthma.

METHODS

The recognition and importance of inflammatory phenotype analysis using induced sputum in adult asthma are reviewed using published literature.

RESULTS

Knowledge of inflammatory phenotype is useful because it relates to treatment response, mechanistic pathways involved in disease pathogenesis and future disease risk. The population attributable risk of asthma because of eosinophilic inflammation is about 50%, and conversely, this means that up to 50% of asthma cannot be attributed to eosinophilic inflammation, and represents asthma associated with non-eosinophilic processes. In these patients, bronchial biopsy shows significantly fewer eosinophils in the bronchial mucosa than subjects with EA. This confirms that non-eosinophilic asthma is a consistent pattern/phenotype in the airway lumen and the airway mucosa. A key aspect of asthma inflammatory phenotype analysis is that it can be applied to individual patients. The underlying principle relates to the association between a clinical response to corticosteroids and the presence of a selective sputum eosinophilia.

CONCLUSIONS

Clinically useful applications of induced sputum analysis are the detection of non-adherence to corticosteroid therapy, assessment of adequacy of inhaled corticosteroid therapy, long-term therapy management in asthma, oral corticosteroid dose adjustment in refractory asthma and assessment of occupational asthma.

Recent advances in the pathophysiology of asthma

There has been an increased understanding, over the past 2 decades, that asthma is a chronic, immunologically mediated condition with a disturbance of the normal airway repair mechanism, which results in inflammatory changes and airway remodeling. The airway inflammation and remodeling together likely explain the clinical manifestations of asthma. The mechanisms by which the external environmental cues, together with the complex genetic actions, propagate the inflammatory process that characterize asthma are beginning to be understood. There is also an evolving awareness of the active participation of structural elements, such as the airway epithelium, airway smooth muscle, and endothelium, in this process. In tandem with this has come the realization that inflammatory cells respond in a coordinated, albeit dysfunctional manner, via an array of complex signaling pathways that facilitate communication between these cells; these structural elements within the lung and the bone marrow serve as reservoirs for and the source of inflammatory cells and their precursors. Although often viewed as separate mechanistic entities, so-called innate and acquired immunity often overlap in the propagation of the asthmatic response. This review examines the newer information on the pathophysiologic characteristics of asthma and focuses on papers published over the past 3 years that have helped to improve current levels of understanding.

Will exhaled nitric oxide monitoring become routine in managing asthma?

In this editorial, we outline the rationale for a new approach to the assessment of airway disease based on measurement of airway inflammation using noninvasive markers (inflammometry). Our focus is on measurement of exhaled nitric oxide (FE(NO)), as this technique is simple and affordable, and is applicable in a wide variety of clinical settings. Studies have shown that raised FE(NO) is a useful marker of corticosteroid-responsive airway disease; low FE(NO) may identify patients who can safely reduce or withdraw corticosteroids. However, the optimum use of FE(NO) in clinical practice remains to be established.

Organ-specific eosinophilic disorders of the skin, lung, and gastrointestinal tract

Eosinophils are multifunctional leukocytes that increase in various tissues in patients with a variety of disorders. Locally, they can be involved in the initiation and propagation of diverse inflammatory responses. In this review the clinical association of eosinophils with diseases of the skin, lung, and gastrointestinal tract is summarized. An approach to determining the causal role of eosinophils in these diseases is presented. Recent findings concerning molecular diagnosis, cause, and treatment are discussed.

Resolution of cell-mediated airways diseases

"Inflammation resolution" has of late become a topical research area. Activation of resolution phase mechanisms, involving select post-transcriptional regulons, transcription factors, 'autacoids', and cell phenotypes, is now considered to resolve inflammatory diseases. Critical to this discourse on resolution is the elimination of inflammatory cells through apoptosis and phagocytosis. For major inflammatory diseases such as asthma and COPD we propose an alternative path to apoptosis for cell elimination. We argue that transepithelial migration of airway wall leukocytes, followed by mucociliary clearance, efficiently and non-injuriously eliminates pro-inflammatory cells from diseased airway tissues. First, it seems clear that numerous infiltrated granulocytes and lymphocytes can be speedily transmitted into the airway lumen without harming the epithelial barrier. Then there are a wide range of 'unexpected' findings demonstrating that clinical improvement of asthma and COPD is not only associated with decreasing numbers of airway wall inflammatory cells but also with increasing numbers of these cells in the airway lumen. Finally, effects of inhibition of transepithelial migration support the present hypothesis. Airway inflammatory processes have thus been much aggravated when transepithelial exit of leukocytes has been inhibited. In conclusion, the present hypothesis highlights risks involved in drug-induced inhibition of transepithelial migration of airway wall leukocytes. It helps interpretation of common airway lumen data, and suggests approaches to treat cell-mediated airway inflammation.

Effects of asthma treatment: the present and future

The increasing burden of asthma in both primary and secondary care has led to extensive research into its genetics, pathophysiology and treatment over the past few decades. Inhaled corticosteroids remain an integral component in all but the mildest disease, although despite a low-to-moderate dose, many individuals remain symptomatic. In patients with persistent symptoms despite inhaled corticosteroids, a variety of different nonsteroidal second-line therapies are available as add-on therapy. In this review, existing and potential future pharmacological strategies involved in the management of asthma will be highlighted.

Cough due to asthma, cough-variant asthma and non-asthmatic eosinophilic bronchitis

Among the most common causes of chronic cough are asthma (25%) and nonasthmatic eosinophilic bronchitis (10%). In asthma, cough may present as an isolated symptom, in which case it is known as cough variant asthma. Variable airflow obstruction and airway hyper-responsiveness are cardinal features of asthma, which are absent in nonasthmatic eosinophilic bronchitis. The presence of eosinophilic airway inflammation is a common feature of asthma and is a diagnostic criterion for nonasthmatic eosinophilic bronchitis. At a cellular level, mast cell infiltration into the airway smooth muscle bundle, narrowing of the airway wall, and increased interleukin-13 expression are features of asthma and not nonasthmatic eosinophilic bronchitis. In most cases, the trigger that causes the cough is uncertain, but occasionally occupational exposure to a sensitizer is identified, and avoidance is recommended. In both conditions, there is improvement following treatment with inhaled corticosteroids, which is associated with the presence of an airway eosinophilia and increased exhaled nitric oxide. Generally, response to therapy in both conditions is very good, and the limited long-term data available suggest that both usually have a benign course, although in some cases fixed airflow obstruction may occur.

Clinical patterns in asthma based on proximal and distal airway nitric oxide categories

BACKGROUND

The exhaled nitric oxide (eNO) signal is a marker of inflammation, and can be partitioned into proximal [J'awNO (nl/s), maximum airway flux] and distal contributions [CANO (ppb), distal airway/alveolar NO concentration]. We hypothesized that J'awNO and CANO are selectively elevated in asthmatics, permitting identification of four inflammatory categories with distinct clinical features.

METHODS

In 200 consecutive children with asthma, and 21 non-asthmatic, non-atopic controls, we measured baseline spirometry, bronchodilator response, asthma control and morbidity, atopic status, use of inhaled corticosteroids, and eNO at multiple flows (50, 100, and 200 ml/s) in a cross-sectional study design. A trumpet-shaped axial diffusion model of NO exchange was used to characterize J'awNO and CANO.

RESULTS

J'awNO was not correlated with CANO, and thus asthmatic subjects were grouped into four eNO categories based on upper limit thresholds of non-asthmatics for J'awNO (>or= 1.5 nl/s) and CANO (>or= 2.3 ppb): Type I (normal J'awNO and CANO), Type II (elevated J'awNO and normal CANO), Type III (elevated J'awNO and CANO) and Type IV (normal J'awNO and elevated CANO). The rate of inhaled corticosteroid use (lowest in Type III) and atopy (highest in Type II) varied significantly amongst the categories influencing J'awNO, but was not related to CANO, asthma control or morbidity. All categories demonstrated normal to near-normal baseline spirometry; however, only eNO categories with increased CANO (III and IV) had significantly worse asthma control and morbidity when compared to categories I and II.

CONCLUSIONS

J'awNO and CANO reveal inflammatory categories in children with asthma that have distinct clinical features including sensitivity to inhaled corticosteroids and atopy. Only categories with increase CANO were related to poor asthma control and morbidity independent of baseline spirometry, bronchodilator response, atopic status, or use of inhaled corticosteroids.

A review of treatment with mepolizumab, an anti-IL-5 mAb, in hypereosinophilic syndromes and asthma

The hypereosinophilic syndromes (HESs) are a heterogeneous group of diseases characterized by peripheral blood eosinophilia with end-organ damage and varying in severity from nonspecific symptoms to life-threatening. Treatment objectives are a safe reduction of blood and tissue eosinophil levels and prevention of eosinophil-mediated tissue damage. Current treatment of patients with HESs, who lack the FIP-1-like 1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) fusion gene, is mainly systemic corticosteroid therapy. Eosinophil development from hematopoietic progenitor cells is regulated by IL-5, which influences maturation, differentiation, mobilization, activation, and survival. Consequently, inhibiting IL-5 is a logical therapeutic objective for patients with HESs or selected patients with asthma. Mepolizumab is a fully humanized anti-IL-5 monoclonal IgG(1) antibody that binds to free IL-5 with high affinity and specificity to prevent IL-5 from associating with the IL-5 receptor complex alpha-chain on the surface of eosinophils. In clinical trials with patients with HESs, mepolizumab reduced blood eosinophil counts and the maintenance corticosteroid dose and had no major safety concerns. Mepolizumab reduced airway and blood eosinophils and prevented asthma exacerbations. Thus, mepolizumab may be effective for long-term treatment of patients with selected eosinophilic disorders.

Inhaled Corticosteroids

Inhaled corticosteroids (ICS) are the most effective controllers of asthma. They suppress inflammation mainly by switching off multiple activated inflammatory genes through reversing histone acetylation via the recruitment of histone deacetylase 2 (HDAC2). Through suppression of airway inflammation ICS reduce airway hyperresponsiveness and control asthma symptoms. ICS are now first-line therapy for all patients with persistent asthma, controlling asthma symptoms and preventing exacerbations. Inhaled long-acting β₂-agonists added to ICS further improve asthma control and are commonly given as combination inhalers, which improve compliance and control asthma at lower doses of corticosteroids. By contrast, ICS provide much less clinical benefit in COPD and the inflammation is resistant to the action of corticosteroids. This appears to be due to a reduction in HDAC2 activity and expression as a result of oxidative stress. ICS are added to bronchodilators in patients with severe COPD to reduce exacerbations. ICS, which are absorbed from the lungs into the systemic circulation, have negligible systemic side effects at the doses most patients require, although the high doses used in COPD has some systemic side effects and increases the risk of developing pneumonia.

Section 3. A discussion of flexible dosing and patient-centered therapy: highlights of the asthma summit 2009: beyond the guidelines

Despite positive clinical experience and the published clinical benefits of monotherapy with low-or medium-dose inhaled corticosteroids or combination therapy with ICS + long-acting beta-agonist to treat asthma, many patients remain suboptimally controlled. Alternative approaches are needed, and 3 options that have had some success are: 1) using the patient's level of inflammation by established biomarkers to set treatment; 2) self-management incorporating flexible dosing; and 3) using a single inhaler for rescue and maintenance therapy. Which strategy for which patient depends ultimately on the individual patient's disease burden, life-style, comorbidities, preferences, and his or her ability to self-manage the disease, including assessing symptoms and adhering with therapy.

Overall asthma control: the relationship between current control and future risk

BACKGROUND

Asthma guidelines emphasize both maintaining current control and reducing future risk, but the relationship between these 2 targets is not well understood.

OBJECTIVE

This retrospective analysis of 5 budesonide/formoterol maintenance and reliever therapy (Symbicort SMART Turbuhaler(*)) studies assessed the relationship between asthma control questionnaire (ACQ-5) and Global Initiative for Asthma-defined clinical asthma control and future risk of instability and exacerbations.

METHODS

The percentage of patients with Global Initiative for Asthma-defined controlled asthma over time was assessed for budesonide/formoterol maintenance and reliever therapy versus the 3 maintenance therapies; higher dose inhaled corticosteroid (ICS), same dose ICS/long-acting beta(2)-agonist (LABA), and higher dose ICS/LABA plus short-acting beta(2)-agonist. The relationship between baseline ACQ-5 and exacerbations was investigated. A Markov analysis examined the transitional probability of change in control status throughout the studies.

RESULTS

The percentage of patients achieving asthma control increased with time, irrespective of treatment; the percentage Controlled/Partly Controlled at study end was at least similar to budesonide/formoterol maintenance and reliever therapy versus the 3 maintenance therapies: higher dose ICS (56% vs 45%), same dose ICS/LABA (56% vs 53%), and higher dose ICS/LABA (54% vs 54%). Baseline ACQ-5 score correlated positively with exacerbation rates. A Controlled or Partly Controlled week predicted at least Partly Controlled asthma the following week (>or=80% probability). The better the control, the lower the risk of an Uncontrolled week. The probability of an exacerbation was related to current state and was lower with budesonide/formoterol maintenance and reliever therapy.

CONCLUSIONS

Current control predicts future risk of instability and exacerbations. Budesonide/formoterol maintenance and reliever therapy reduces exacerbations versus comparators and achieves at least similar control.

Use of exhaled nitric oxide measurement to identify a reactive, at-risk phenotype among patients with asthma

RATIONALE

Exhaled nitric oxide (Fe(NO)) is a biomarker of airway inflammation in mild to moderate asthma. However, whether Fe(NO) levels are informative regarding airway inflammation in patients with severe asthma, who are refractory to conventional treatment, is unknown. Here, we hypothesized that classification of severe asthma based on airway inflammation as defined by Fe(NO) levels would identify a more reactive, at-risk asthma phenotype.

METHODS

Fe(NO) and major features of asthma, including airway inflammation, airflow limitation, hyperinflation, hyperresponsiveness, and atopy, were determined in 446 individuals with various degrees of asthma severity (175 severe, 271 non-severe) and 49 healthy subjects enrolled in the Severe Asthma Research Program.

MEASUREMENTS AND MAIN RESULTS

Fe(NO) levels were similar among patients with severe and non-severe asthma. The proportion of individuals with high Fe(NO) levels (>35 ppb) was the same (40%) among groups despite greater corticosteroid therapy in severe asthma. All patients with asthma and high Fe(NO) had more airway reactivity (maximal reversal in response to bronchodilator administration and by methacholine challenge), more evidence of allergic airway inflammation (sputum eosinophils), more evidence of atopy (positive skin tests, higher serum IgE and blood eosinophils), and more hyperinflation, but decreased awareness of their symptoms. High Fe(NO) identified those patients with severe asthma characterized by the greatest airflow obstruction and hyperinflation and most frequent use of emergency care.

CONCLUSIONS

Grouping of asthma by Fe(NO) provides an independent classification of asthma severity, and among patients with severe asthma identifies the most reactive and worrisome asthma phenotype.

The utility of sputum eosinophils and exhaled nitric oxide for monitoring asthma control with special attention to childhood asthma

The monitoring of sputum eosinophils has received certain attention as a tool for improving asthma management both in children and in adults. The present paper reviews the technique and also the usefulness of induced sputum in the diagnosis and assessment of asthma, together with its ability to predict the response to treatment and to anticipate asthma exacerbations. Special attention is addressed to childhood asthma. The authors conclude that due to cost-effectiveness reasons derived from high labour costs, together with the unpleasantness of the technique and the failure to obtain adequate samples in a non-negligible percentage of children, this technique should be only used for research purposes.

Pharmacological strategies for improving the efficacy and therapeutic ratio of glucocorticoids in inflammatory lung diseases

Glucocorticoids are widely used to treat various inflammatory lung diseases. Acting via the glucocorticoid receptor (GR), they exert clinical effects predominantly by modulating gene transcription. This may be to either induce (transactivate) or repress (transrepress) gene transcription. However, certain individuals, including those who smoke, have certain asthma phenotypes, chronic obstructive pulmonary disease (COPD) or some interstitial diseases may respond poorly to the beneficial effects of glucocorticoids. In these cases, high dose, often oral or parental, glucocorticoids are typically prescribed. This generally leads to adverse effects that compromise clinical utility. There is, therefore, a need to enhance the clinical efficacy of glucocorticoids while minimizing adverse effects. In this context, a long-acting beta(2)-adrenoceptor agonist (LABA) can enhance the clinical efficacy of an inhaled corticosteroid (ICS) in asthma and COPD. Furthermore, LABAs can augment glucocorticoid-dependent gene expression and this action may account for some of the benefits of LABA/ICS combination therapies when compared to ICS given as a monotherapy. In addition to metabolic genes and other adverse effects that are induced by glucocorticoids, there are many other glucocorticoid-inducible genes that have significant anti-inflammatory potential. We therefore advocate a move away from the search for ligands of GR that dissociate transactivation from transrepression. Instead, we submit that ligands should be functionally screened by virtue of their ability to induce or repress biologically-relevant genes in target tissues. In this review, we discuss pharmacological methods by which selective GR modulators and "add-on" therapies may be exploited to improve the clinical efficacy of glucocorticoids while reducing potential adverse effects.

Evaluation of diagnostic criteria for severe asthma described in a public health directive regulating the free distribution of medications for the maintenance treatment of asthma

OBJECTIVE

To evaluate the capacity of the criteria described in Complementary Directive SAS/MS 12, issued on November 12, 2002, to identify patients with severe asthma, describing and comparing clinical, functional and treatment data of such patients.

METHODS

This was a nested case-control study using a structured database for adult asthma outpatients. We defined cases as asthma patients who met the inclusion criteria described in the directive, defining controls as those who did not. We collected and compared data related to the following: demographic characteristics; history of asthma; medications in use; comorbidities; history of tobacco use; number of exacerbations within the last 12 months, asthma-related hospitalizations and intensive care unit admissions within the last 12 months; spirometry; and sputum cytology.

RESULTS

The case and control groups consisted of 29 and 31 patients, respectively. The number of asthma exacerbations and emergence room visits within the last 12 months, as well as the number of patients that received at least one pulse of oral corticosteroids, was significantly higher in the case group than in the control group. In addition, prebronchodilator FVC was lower among the cases than among the controls. Furthermore, cytology revealed that eosinophil counts were significantly higher in the induced sputum of cases than in that of controls.

CONCLUSIONS

The criteria described in the directive are suited to stratifying patients with severe asthma.

Effects of glucocorticoids on the neutrophil count: a cohort study among hospitalized patients

BACKGROUND

Systemic glucocorticoids are often used in clinical practice for a large variety of indications. Clinical observations have shown that patients using glucocorticoids often have higher neutrophil counts. Debate remains whether this observed neutrophilia is associated with glucocorticoid use or that other factors, like disease and severity of disease, should be considered. The objective of this study was to investigate the effect of systemic glucocorticoids on the absolute neutrophil count in hospitalized patients.

METHODS

A cohort study was conducted using data from the Utrecht Patient Oriented Database which comprises clinical data of patients of the University Medical Center Utrecht. We identified all adult patients, hospitalized in 2005 with at least two blood samples for hematological testing during admission and compared in-hospital glucocorticoid use with non-use.

RESULTS

A total of 809 glucocorticoid users and 2658 non-users were included in the study with comparable neutrophil counts at admission (8.2.10(9)/l for glucocorticoid users and 8.0.10(9)/l for non-users). Overall analysis showed a slight association between glucocorticoid use and an increase in neutrophil count (RR 1.3; 95% CI 1.1-1.5). However, within diagnostic subgroups there was no increase in neutrophil count in glucocorticoid users. Furthermore, among all no dose response relationship, no effect of time between the two samples, and no effect of anti-inflammatory/sodium retaining potency was found.

CONCLUSION

Observed neutrophilia in users of systemic glucocorticoids is probably associated with underlying disease, rather than glucocorticoid use itself.