Induced sputum in children: feasibility, repeatability, and relation of findings to asthma severity

Prognostic Factors in Severe Eosinophilic Asthma in a Pediatric Population: A Prospective Cohort Study in Spain

Background/Objectives: The objective of this study was to provide real-world data on prognostic factors in children with severe eosinophilic asthma and to assess biomarkers of outcome. Methods: Fifty-nine children (aged 6-17 years) were included in a prospective cohort attended in a Severe Asthma Unit of a tertiary care teaching hospital in Badalona (Barcelona, Spain) and visited at baseline and at 1-year follow-up. Study variables included asthma control using the Asthma Control Test (ACT), forced expiratory volume in one second (FEV1), exacerbation episodes, fractional exhaled nitric oxide (FeNO), and inflammatory biomarkers (blood tests, sputum cells, immunoallergic tests, and levels of cytokines and effector cells in blood and sputum). Results: There were 36 boys and 23 girls, with a mean (SD) age of 11.9 (2.8) years. Uncontrolled severe asthma was diagnosed in 83.1% of cases, with poor symptom control (ACT score < 20) in 52.5%, obstructive pattern (FEV1 < 80% predicted) in 35.6%, and more than one exacerbation in the previous year in 30.5%. The mean duration of asthma was 9.2 (3.6) years. Positive prick tests were recorded in 55 patients, with polysensitization in 6. The mean percentage of sputum eosinophils was 2.5% (3.1%), and the mean eosinophil blood count 543.4 (427.7) cells/µL. Ten patients (32%) showed sputum eosinophilia (>3% eosinophils). Sputum eosinophils did not correlate with blood eosinophils, FeNO, and serum periostin. At 12 months, 13 (22%) children had uncontrolled asthma and 46 (78%) had controlled asthma. Variables significantly associated with uncontrolled asthma were duration of asthma (OR = 1.23, 95% CI 1.01-1.49, p = 0.04) and an ACT score < 20 (OR = 0.80, 95% CI 0.69-0.93, p = 0.004). Lower serum levels of IL-9 appeared to be related with uncontrolled asthma, but statistical significance was not reached. Conclusions: Pediatric severe eosinophilic asthma showed a predominant allergic phenotype with symptomatic disease as a main contributor of uncontrolled asthma at 1 year. Predictive biomarkers of outcome were not identified. Further studies are needed to confirm the present findings especially considering additional variables for a better phenotypic characterization of severe eosinophilic asthma in children and to study in-depth the role of inflammatory biomarkers.

Severe acute asthma at the pediatric intensive care unit: can we link the clinical phenotypes to immunological endotypes?

INTRODUCTION

The clinical phenotype of severe acute asthma at the pediatric intensive care unit (PICU) is highly heterogeneous. However, current treatment is still based on a 'one-size-fits-all approach'.

AREAS COVERED

We aim to give a comprehensive description of the clinical characteristics of pediatric patients with severe acute asthma admitted to the PICU and available immunological biomarkers, providing the first steps toward precision medicine for this patient population. A literature search was performed using PubMed for relevant studies on severe acute (pediatric) asthma.

EXPERT OPINION

Omics technologies should be used to investigate the relationship between cellular molecules and pathways, and their clinical phenotypes. Inflammatory phenotypes might guide bedside decisions regarding the use of corticosteroids, neutrophil modifiers and/or type of beta-agonist. A next step toward precision medicine should be inclusion of these patients in clinical trials on biologics.

The Predictive Role of Biomarkers and Genetics in Childhood Asthma Exacerbations

Asthma exacerbations are associated with significant childhood morbidity and mortality. Recurrent asthma attacks contribute to progressive loss of lung function and can sometimes be fatal or near-fatal, even in mild asthma. Exacerbation prevention becomes a primary target in the management of all asthmatic patients. Our work reviews current advances on exacerbation predictive factors, focusing on the role of non-invasive biomarkers and genetics in order to identify subjects at higher risk of asthma attacks. Easy-to-perform tests are necessary in children; therefore, interest has increased on samples like exhaled breath condensate, urine and saliva. The variability of biomarker levels suggests the use of seriate measurements and composite markers. Genetic predisposition to childhood asthma onset has been largely investigated. Recent studies highlighted the influence of single nucleotide polymorphisms even on exacerbation susceptibility, through involvement of both intrinsic mechanisms and gene-environment interaction. The role of molecular and genetic aspects in exacerbation prediction supports an individual-shaped approach, in which follow-up planning and therapy optimization take into account not only the severity degree, but also the risk of recurrent exacerbations. Further efforts should be made to improve and validate the application of biomarkers and genomics in clinical settings.

Cost-utility of use of sputum eosinophil counts to guide management in children with asthma

BACKGROUND

Tailoring asthma interventions based on sputum eosinophils are beneficial in reducing the frequency of asthma exacerbations. The routine use of sputum eosinophils in asthma in children is not uniformly adopted. The main barriers to policymakers adopting new technologies are always doubts about their cost-utility in scenarios with scarce health resources. This study aimed to evaluate the cost-utility of sputum eosinophil counts to guide management in children with asthma, from a societal perspective.

METHODS

A Markov simulation with three mutually exclusive nonabsorbent states was used. The intervention evaluated was adjustment of asthma therapy based on sputum eosinophils to adjusting therapy based on clinical symptoms with or without spirometry/peak flow in children between 4 and 18 years of age (EO). The group comparison was adjusting therapy based on clinical symptoms with or without spirometry/peak flow (SC). The analysis was carried out from a societal perspective. The analytic horizon was 12 months.

RESULTS

The model showed that EO was associated with lower cost than SC (US $1375 vs US $1454 average annual cost per patient), and higher QALYs (0.95 vs 0.92 average per patient); showing dominance. The probability that EO provides a more cost-effective use of resources compared with standard therapy exceeds 99% for all willingness to pay thresholds.

CONCLUSION

EO was cost-effective for infants with asthma to guide asthma management in Children. Our study provides evidence that should be used by decision-makers to improve clinical practice guidelines and should be replicated to validate their results in other middle-income countries.

Randomized trial of physiotherapy and hypertonic saline techniques for sputum induction in asthmatic children and adolescents

OBJECTIVES

This study aimed to analyze the efficiency of physiotherapy techniques in sputum induction and in the evaluation of pulmonary inflammation in asthmatic children and adolescents. Although hypertonic saline (HS) is widely used for sputum induction (SI), specific techniques and maneuvers of physiotherapy (P) may facilitate the collection of mucus in some asthmatic children and adolescents.

METHODS

A randomized crossover study was performed in patients with well-controlled asthma, and 90 sputum samples were collected. Children and adolescents were assessed using spirometry and randomized at entry into one of three sputum induction techniques: (i) 3% hypertonic saline - HS technique; (ii) physiotherapy (oscillatory positive expiratory pressure, forced expiration, and acceleration of expiratory flow) - P technique; and (iii) hypertonic saline + physiotherapy - HSP technique. ClinicalTrials.gov: NCT03136042.

RESULTS

The total cells (mL) and the percentage (%) of differential inflammatory cells were similar in all techniques. The sputum weight (g) in the HSP technique was significantly higher than that in the HS technique. In all techniques, the percentage of viable cells was >50%, and there was no difference between the HS and P techniques. Moreover, sputum induction did not cause any alterations in the pulmonary function of patients.

CONCLUSION

The physiotherapy sputum collection technique was effective in obtaining viable cells from mucus samples and yielded the same amount of sputum as the gold standard technique (hypertonic saline). In addition, the physiotherapy maneuvers were both safe and useful for sputum induction in asthmatic children and adolescents with well-controlled asthma.

Exploring the Utility of Noninvasive Type 2 Inflammatory Markers for Prediction of Severe Asthma Exacerbations in Children and Adolescents

BACKGROUND

Noninvasive markers of type 2 inflammation are needed to identify children and adolescents who might benefit from personalized biologic therapy.

OBJECTIVE

We hypothesized that blood eosinophil counts would predict 1 or more acute visits for asthma and that prediction could be improved with the addition of a second, noninvasive type 2 inflammatory biomarker.

METHODS

Children and adolescents 5 to 21 years (N = 589) with an asthma exacerbation necessitating systemic corticosteroid treatment in the previous year completed a characterization visit and telephone calls at 6 and 12 months. The primary outcome was an acute visit for asthma with receipt of systemic corticosteroids. Acute visits were verified by medical record review. Exploratory outcomes included time to first acute visit and hospitalization.

RESULTS

Acute visits occurred in 106 (35.5%) children and 72 (24.8%) adolescents. Elevated blood eosinophils were associated with increased odds and shorter time to first acute visit, but optimal cut-points differed by age (≥150 vs ≥300 cells/μL for children vs adolescents, respectively). The addition of a second marker of type 2 inflammation did not improve prediction in children, but increased the odds and hazard of an acute visit up to 16.2% and 11.9%, respectively, in adolescents. Similar trends were noted for hospitalizations.

CONCLUSIONS

Blood eosinophils and other noninvasive markers of type 2 inflammation may be useful in the clinical assessment of children and adolescents with asthma. However, features of type 2 inflammation vary by age. Whether children and adolescents also respond differently to management of type 2 inflammation is unclear and warrants further evaluation.

Biomarkers and asthma management: analysis and potential applications

PURPOSE OF REVIEW

Asthma features a high degree of heterogeneity in both pathophysiology and therapeutic response, resulting in many asthma patients being treated inadequately. Biomarkers indicative of underlying pathological processes could be used to identify disease subtypes, determine prognosis and to predict or monitor treatment response. However, the newly identified as well as more established biomarkers have different applications and limitations.

RECENT FINDINGS

Conventional markers for type 2-high asthma, such as blood eosinophils, fraction of exhaled nitric oxide, serum IgE and periostin, feature limited sensitivity and specificity despite their significant correlations. More distinctive models have been developed by combining biomarkers and/or using omics techniques. Recently, a model with a positive predictive value of 100% for identification of type 2-high asthma based on a combination of minimally invasive biomarkers was developed.

SUMMARY

Individualisation of asthma treatment regimens on the basis of biomarkers is necessary to improve asthma control. However, the suboptimal properties of currently available conventional biomarkers limit its clinical utility. Newly identified biomarkers and models based on combinations and/or omics analysis must be validated and standardised before they can be routinely applied in clinical practice. The development of robust biomarkers will allow development of more efficacious precision medicine-based treatment approaches for asthma.

Effect of CPAP on airway reactivity and airway inflammation in children with moderate-severe asthma

BACKGROUND AND OBJECTIVE

Asthma is characterized by airway hyperreactivity and airway inflammation. We previously demonstrated that adults with mild well-controlled asthma exhibited a marked decrease in airway reactivity (PC20 increased >2-fold) after using nocturnal continuous positive airway pressure (CPAP) for 1 week. If CPAP produces a similar suppression of airway reactivity in children with moderate-severe asthma, who require chronic use of corticosteroids, then this non-pharmacological therapy might provide a beneficial alternative or supplemental therapy in these subjects.

METHODS

Children aged 8-17 years with moderate-severe asthma were treated with 4 weeks of nocturnal CPAP (8-10 cm H2 O) or sham CPAP (<2 cm H2 O). Adherence was monitored with a modem installed in the equipment or by memory cards. Airway reactivity, assessed by methacholine bronchial challenge, was measured prior to and following treatment.

RESULTS

The percentage of subjects adherent to treatment was similar in both groups (19/27 CPAP vs 19/28 sham, ~70%). There was a tendency for PC20 to increase with treatment in both groups (3.0-5.3 mg/mL CPAP vs 3.2 to 4.3 mg/mL sham, P = 0.083); however, the change did not differ significantly between groups (P = 0.569).

CONCLUSION

We found that the 4-week treatment with nocturnal CPAP did not produce a twofold suppression of airway reactivity in children with moderate-severe asthma.

Measuring Airway Inflammation in Asthmatic Children

Asthma is the most common chronic respiratory disease in children characterized by airways inflammation, bronchial hyperresponsiveness, recurrent reversible airways obstruction, and respiratory symptoms. The diagnosis of the disease is based on clinical history, airways obstruction at spirometry, and bronchial reversibility. Asthma treatment is aimed to disease control, through the use of controller treatment and monitoring lung function. However, lung function and symptoms not always reflect the underlying airways inflammation and response to the therapy. Objective parameters of asthma inflammation could be important for the clinician in the management of patients with asthma. In the last years, some studies were focused on biomarkers to identify phenotype, inflammation, and pathobiological pathways to help the clinician in the diagnosis and in personalizing the management. Accordingly, clinically feasible tests are represented by the collection of exhaled breath condensate (EBC) and measurement of exhaled nitric oxide (FeNO). Other-methods such as the evaluation of volatile organic compound (VOCs), that reflect airways inflammation and treatment efficacy, are currently used for research purposes For some of these methods, The lack of standardization in pre-collection, collection, post-collection of samples, and interpretation of the results may a problem in clinical practice. Improved these limitations, several biomarkers will be useful to distinguish patients with a different disease condition to personalize the treatment.

Tailored interventions based on sputum eosinophils versus clinical symptoms for asthma in children and adults

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. Using sputum analysis to adjust or tailor asthma medications is potentially superior to traditional methods based on symptoms and spirometry.

OBJECTIVES

To evaluate the efficacy of tailoring asthma interventions based on sputum analysis in comparison to traditional methods (usually symptom-based with or without spirometry/peak flow) for asthma-related outcomes in children and adults.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, trials' registries, and reference lists of articles. The last search was conducted in February 2017.

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. In this update, two reviewers selected relevant studies, independently assessed trial quality and extracted the data. We contacted authors for further information when relevant. We analysed data as 'treatment received' and performed sensitivity analyses.

MAIN RESULTS

Three new studies were added in this update, resulting in a total of six included studies (five in adults and one involving children/adolescents). These six studies were clinically and methodologically heterogeneous (use of medications, cut-off for percentage of sputum eosinophils and definition of asthma exacerbation). Of 374 participants randomised, 333 completed the trials. In the meta-analysis, there was a significant reduction in the occurrence of any exacerbations when treatment was based on sputum eosinophil counts, compared to that based on clinical symptoms with or without lung function; pooled odds ratio (OR) was 0.57 (95% confidence interval (CI) 0.38 to 0.86). The risk of having one or more exacerbations over 16 months was 82% in the control arm and 62% (95% CI 49% to 74%) in the sputum strategy arm, resulting in a number needed to treat to benefit (NNTB) of 6 (95% CI 4 to 13).There were also differences between the groups in the rate of exacerbation (any exacerbation per year) and severity of exacerbations defined by requirement for use of oral corticosteroids and hospitalisations: the risk of one or more hospitalisations over 16 months was 24% in controls compared to 8% (95% CI 3% to 21%) in the sputum arm. Data for clinical symptoms, quality of life and spirometry were not significantly different between groups. The mean dose of inhaled corticosteroids per day was also similar in both groups. However sputum induction was not always possible. The included studies did not record any adverse events.One study was not blinded and thus was considered to have a high risk of bias. However, when this study was removed in a sensitivity analysis, the difference between the groups for the primary outcome (exacerbations) remained statistically significant between groups. The GRADE quality of the evidence ranged from moderate (for the outcomes 'Occurrence of any exacerbation' and 'Hospitalisation' ) to low (for the outcome 'Mean dose of inhaled corticosteroids per person per day') due to the inconsistency in defining exacerbations and the small number of hospital admissions.

AUTHORS' CONCLUSIONS

In this updated review, tailoring asthma interventions based on sputum eosinophils is beneficial in reducing the frequency of asthma exacerbations in adults with asthma. Adults with frequent exacerbations and severe asthma may derive the greatest benefit from this additional monitoring test, although we were unable to confirm this through subgroup analysis. There is insufficient data available to assess tailoring asthma medications based on sputum eosinophilia in children.Further robust RCTs need to be undertaken and these should include participants with different underlying asthma severities and endotypes.

Correlation of induced sputum eosinophil levels with clinical parameters in mild and moderate persistent asthma in children aged 7-18 years

BACKGROUND

Treatment decisions in asthma are currently based on clinical assessment and spirometry. Sputum eosinophil, being a marker of airway inflammation, can serve as a tool for assessing severity and response to treatment in asthma patients.

OBJECTIVES

To measure eosinophil percentage in induced sputum in children with asthma and correlate it with clinical asthma parameters.

METHODS

A prospective observational study was performed at tertiary care hospital on 91 children aged 7-18 years with newly diagnosed mild or moderate persistent asthma. Theinduced sputum eosinophil percentage was obtained at the time of enrollment and three months after treatment with inhaled budesonide. Patients were specifically evaluated for five clinical parameters of asthma, i.e., days of acute exacerbations, use of salbutamol as rescue medication, emergency visits, nighttime cough and days of school absence.

RESULTS

Sputum eosinophil percentage was high (3.1 ± 0.515%) at the time of enrollment which reduced significantly after three months of inhaled budesonide therapy [0.06 ± 0.164% (p < 0.0005)]. Children with moderate persistent asthma had significantly higher values of sputum eosinophil levels than children with mild persistent asthma at the time of enrollment (3.38 ± 0.64% vs. 2.99 ± 0.42%, p  =  0.001) but the difference was not significant after three months of inhaled steroid therapy (0.07 ± 0.18 vs. 0.04 ± 0.12, p  =  0.5104). A significant negative correlation was found between reduction in sputum eosinophil levels and improvement in FEV1 (r = -0.400, p = 0.0001). All the clinical asthma parameters also correlated significantly with the reduction in sputum eosinophil levels after three months of inhaled steroid therapy.

CONCLUSION

Eosinophil levels in induced sputum correlate well with clinical asthma parameters and asthma severity in children. It is a simple, noninvasive and cheap method which can be used for the monitoring of asthma in a resource-limited setting.

Infection and inflammation in induced sputum from preschool children with chronic airways diseases

BACKGROUND

We hypothesized airway inflammation can be detected non-invasively by induced sputum (IS) or peripheral blood eosinophilia, and IS can detect bacterial and viral infection in preschool children with airway disease, with results comparable to broncho-alveolar lavage (BAL).

METHODS

Preschool children with cystic fibrosis, recurrent wheeze, or wet cough underwent IS with nebulized hypertonic saline, chest physiotherapy, and oropharyngeal suction. Samples were analyzed for inflammation by cytology and bacterial culture, viral detection by PCR. Results were compared to BAL and blood in a sub-group undergoing clinically indicated bronchoscopy.

RESULTS

64 children (median age 33 [7-76] months) underwent IS without adverse events. IS was obtained from 61/64. Twenty out of sixty-four underwent BAL and IS, no IS was obtained in 2/23. Thirteen out of twenty-one (62%) had matching bacteria and viruses, 4/21 had positive BAL bacterial growth with negative IS, and 3/21 had negative BAL growth with positive IS. 67% of sputum samples were processed for cytology, 46% had <80% squamous cells; the proportion of squamous cells reduced with increasing age (r = -0.55, P < 0.01). IS was significantly more neutrophilic and less eosinophilic than BAL; 2/21 IS samples contained eosinophils compared to 17/23 BAL. There was a positive correlation between blood and BAL eosinophilia (r = 0.75, P < 0.01).

CONCLUSION

IS from preschool children can be used to assess infection. BAL and IS culture concurred in approximately two-thirds. However, inflammation was measureable in only one-third of IS samples and the cell differential was predominantly neutrophilic compared to BAL. Blood eosinophils may provide a better reflection of lower airway eosinophilia in this age group. Pediatr Pulmonol. 2016;51:778-786. © 2015 WileyPeriodicals, Inc.

The Value of Induced Sputum in the Diagnosis and Management of Children with Bronchial Asthma

Background

Induced sputum in children with bronchial asthma represents a non-invasive method of bronchial inflammation assessment. The main objective of our study was to analyze the cellularity of sputum in patients with bronchial asthma according to the level of disease control and the controlling therapy (with/without inhaled glucocorticoids). The second objective was to establish the correlation between sputum cellularity and other indirect parameters used to evidence bronchial inflammation (exhaled nitric oxide) and obstruction (forced expiratory volume in 1 second).

Methods

The study included children with bronchial asthma that were assessed clinically (physical exam, questionnaire on the control of bronchial asthma in children) and by medical tests (induced sputum, exhaled nitric oxide, spirometry).

Results

In patients with partially controlled asthma and those with uncontrolled asthma, the eosinophils percentage in the sputum was higher than in patients with controlled asthma (19.8±26.4% respectively 9.2±20.5% versus 4.5±14.6%, p<0.001). Higher percentage of neutrophils in the sputum was found in the partially controlled and uncontrolled asthma than in the controlled asthma (43.9±20.1% respectively 51.6±38.3% versus 35±19.7%, p=0.009). We also evidenced a direct and statistically significant correlation between the exhaled nitric oxide and the neutrophils percentage in the sputum (r=0.67, p=0.0003). Also, an indirect, moderate to good correlation (r=−0.56, p=0.005) was evidenced between the values of the forced expiratory volume in 1 second and the high eosinophils percentage in the sputum.

Conclusions

In partially controlled and uncontrolled bronchial asthma the eosinophils and neutrophils count in the sputum is significantly higher than in patients with controlled asthma. There is an indirect correlation between the high eosinophils count in the sputum and the forced expiratory volume in 1 second, as well as a direct correlation between the neutrophils count and the exhaled nitric oxide, suggesting that induced sputum should be used in combination with other indirect parameters for the evidence of bronchial inflammation.

Pulmonary function testing in children and infants

Pulmonary function testing is performed in children and infants with the aim of documenting lung development with age and making diagnoses of lung diseases. In children and infants with an established lung disease, pulmonary function is tested to assess the disease progression and the efficacy of therapy. It is difficult to carry out the measurements in this age group without disturbances, so obtaining results of good quality and reproducibility is challenging. Young children are often uncooperative during the examinations. This is partly related to their young age but also due to the long testing duration and the unpopular equipment. We address a variety of examination techniques for lung function assessment in children and infants in this review. We describe the measuring principles, examination procedures, clinical findings and their interpretation, as well as advantages and limitations of these methods. The comparability between devices and centres as well as the availability of reference values are still considered a challenge in many of these techniques. In recent years, new technologies have emerged allowing the assessment of lung function not only on the global level but also on the regional level. This opens new possibilities for detecting regional lung function heterogeneity that might lead to a better understanding of respiratory pathophysiology in children.

Will symptom-based therapy be effective for treating asthma in children?

Traditionally, symptoms are important patient-oriented outcomes in asthma treatment, and assessment of symptoms is an essential component of assessing asthma control. However, variable airways obstruction, airways hyperresponsiveness and chronic inflammation are key components of the asthma syndrome, and correlations among these hallmarks and symptoms are weak or even absent. Therefore, it might be questioned if symptom-based therapy is effective for treating asthma in (all) children. To date, there is no firm indication that monitoring asthma based on repetitive lung function measurement or markers of airway inflammation is superior to monitoring based on symptoms only. In the majority of patients, symptom-based asthma management may well be sufficient, and in preschool children, symptoms are presently the only feasible outcome. Nevertheless, there is some evidence that selected groups might benefit from an approach that takes into account individual phenotypic characteristics. In patients with poor perception, those with a discordant phenotype and those with persistent severe asthma, considering lung function, airways hyperresponsiveness and inflammatory markers in treatment decisions might improve outcomes.

Airway inflammation and bronchial hyperreactivity in steroid naive children with intermittent and mild persistent asthma

BACKGROUND

Intermittent and mild persistent asthma are defined according to symptom frequency and spirometry and treated differently. To our knowledge, there is no study comparing airway inflammation between intermittent and mild persistent asthmatic children.

MATERIALS AND METHODS

Children aged 7-16 years, referred to our pediatric allergy clinic for recurrent respiratory complaints underwent a detailed clinical history and spirometry with reversibility. None of the subjects had been using regular anti-inflammatory treatment. After a 2-week run-in period during which asthma symptoms were recorded, exhaled NO measurement, bronchial provocation test with adenosine monophosphate and methacholine and sputum induction were performed. Data of patients with intermittent and mild persistent asthma and a control group were compared.

RESULTS

Thirty intermittent, 26 mild persistent asthmatic children, and 21 control subjects were studied. Sputum was obtained from 19 of intermittent asthmatics (63.3%), 18 of mild persistent asthmatics (69.2%), and 13 of control subjects (61.9%). Eosinophil count and exhaled nitric oxide were not different between asthmatic groups. Neutrophil count of children with mild persistent asthma was higher than the intermittent asthmatic group (P = 0.003). Geometric mean of PC20 methacoline values were not different between groups (P = 0.058). Geometric mean of PC20 AMP was lower among patients with mild persistent asthma (P = 0.102).

CONCLUSION

Eosinophilic airway inflammation and direct BHR may not be significantly different in intermittent asthmatic children from their peers with mild persistent disease. Neutrophilic airway inflammation and BHR to an indirect stimuli are more pronounced in the mild persistent group.

Researching asthma across the ages: insights from the National Heart, Lung, and Blood Institute's Asthma Network

Clinical asthma studies across different age groups (ie, cross-age studies) can potentially offer insight into the similarities, differences, and relationships between childhood and adult asthma. The National Institutes of Health's Asthma Research Network (AsthmaNet) is unique and innovative in that it has merged pediatric and adult asthma research into a single clinical research network. This combination enhances scientific exchange between pediatric and adult asthma investigators and encourages the application of cross-age studies that involve participants from multiple age groups who are generally not studied together. The experience from AsthmaNet in the development of cross-age protocols highlights some of the issues in the evaluation of cross-age research in asthma. The aim of this review is to summarize these challenges, including the selection of parallel cross-age clinical interventions, identification of appropriate controls, measurement of meaningful clinical outcomes, and various ethical and logistic issues.

Eosinophil-derived neurotoxin levels at 3 months post-respiratory syncytial virus bronchiolitis are a predictive biomarker of recurrent wheezing

OBJECTIVE

To determine whether eosinophil-derived neurotoxin (EDN) is a predictive marker of recurrent wheezing episodes in post-respiratory syncytial virus (RSV) bronchiolitis.

METHODS

EDN levels and recurrent wheezing episodes were serially measured in 200 infants hospitalized with RSV bronchiolitis.

RESULTS

Serum EDN levels at 3 months correlated significantly with total wheezing episodes at 12 months in the RSV-PLC (n  = 71; r = 0.720, p < 0.0001) and RSV-MONT groups (n = 79; r = 0.531, p < 0.001). Positive predictive value of 3-mo EDN level for total wheezing episodes was 57%; negative predictive value, 76%; sensitivity, 72%; specificity, 62%.

CONCLUSION

EDN levels have predictive value for the development of recurrent wheezing post-RSV bronchiolitis.

Association between eosinophilic airway inflammation and persistent airflow limitation

OBJECTIVE

We aimed to evaluate the association between eosinophilic inflammation in induced sputum and pulmonary function and persistent airflow limitation in children.

METHODS

A total of 92 asthmatic children and 72 controls were enrolled in this study. Eosinophil count (%) and eosinophil cationic protein (ECP) levels were measured in induced sputum. We performed spirometry and a methacholine challenge test, and measured total eosinophil count, total serum IgE, and serum ECP in all subjects.

RESULTS

Asthmatic children had significantly higher levels of sputum eosinophils (9% vs. 0%; P < 0.001) and sputum ECP (2.3 ± 0.7 vs. 1.6 ± 0.6 log µg/L, p < .001) than controls. Sputum ECP levels showed a significant negative correlation with post-bronchodilator (post-BD) FEV(1) (r = -0.307; p = .001) and post-BD FEV(1)/FVC (r = -0.286; p = .002), whereas sputum eosinophils showed no correlation with post-BD FEV(1) and post-BD FEV(1)/FVC. However, no significant differences in sputum ECP and sputum eosinophil counts were observed in asthmatic children with and without persistent airflow limitation.

CONCLUSIONS

Our findings suggest that sputum eosinophilic inflammation, especially ECP, is associated with pulmonary function and persistent airflow limitation, which is manifested by low post-BD FEV(1)/FVC.

Eosinophil-derived neurotoxin: a novel biomarker for diagnosis and monitoring of asthma

Asthma is associated with increased levels of eosinophils in tissues, body fluids, and bone marrow. Elevated levels of eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) have been noted in asthma patients. Higher levels of EDN and ECP are also associated with exacerbated asthmatic conditions. Thus, EDN, along with ECP, may aid the diagnosis and monitoring of asthma. Several groups have suggested that EDN is more useful than ECP in evaluating disease severity. This may partially be because of the recoverability of EDN (not sticky, 100% recovery rate), as ECP is a sticky and more highly charged protein. In terms of clinical utility, EDN level is a more accurate biomarker than ECP when analyzing the underlying pathophysiology of asthma. As a monitoring tool, EDN has shown good results in children with asthma as well as other allergic diseases. In children too young to fully participate in lung function tests, EDN levels may be useful as an alter native measurement of eosinophilic inflammation. EDN can also be used in adult patients and in multiple specimen types (e.g., serum, sputum, bronchoalveolar lavage fluid, and nasal lavage fluid). These results are repeatable and reproducible. In conclusion, EDN may be a novel biomarker for the diagnosis, treatment, and monitoring of asthma/allergic disease.

Inflammatory markers in induced sputum of school children born before 32 completed weeks of gestation

OBJECTIVE

To test whether chronic bronchial inflammation may be a contributing risk factor for persistent airflow limitation in children born before 32 weeks of gestation in later life.

STUDY DESIGN

Thirty-six of 160 children born before 32 completed weeks of gestation who were born between 1988 and 1992 were recruited at a median age of 11 years. Eighteen age-matched children born at term were controls; 47% of the premature infants and 61% of the term born children produced sputum of sufficient quality for interleukin (IL)-8, cell numbers, and differential counts.

RESULTS

Compared with term born children, sputum from the premature group had a higher proportion of neutrophils (62% vs 3.8%; P < .001) and higher IL-8/protein values (1.93 μg/g vs 0.64 μg/g; P = .008). Forced expiratory flow 25%-75% and forced expiratory volume in 1 second/vital capacity were significantly lower (73.4 % vs 116% predicted, P = .002 and 97% vs 101%, P = .012, respectively). Lung function values and sputum indices did not correlate. IL-8/protein and neutrophil percentages correlated significantly with decreasing gestational age (Spearman rank coefficient = -0.58, P = .020 and -.70, P =.03 respectively).

CONCLUSION

A significant proportion of school children born very preterm demonstrate persistent peripheral airway obstruction that is accompanied by neutrophilic lower airway inflammation.

Genetic and epigenetic variations in inducible nitric oxide synthase promoter, particulate pollution, and exhaled nitric oxide levels in children

BACKGROUND

Inducible nitric oxide synthase (iNOS; encoded by nitric oxide synthase isoform 2 [NOS2]) is the major enzyme for nitric oxide synthesis in airways. As such, measurement of fractional concentration of exhaled nitric oxide (Feno) provides an in vivo assessment of iNOS activity. Short-term exposure to air pollution, haplotypes, and DNA methylation in the NOS2 promoter has been associated independently with iNOS expression, Feno levels, or both.

OBJECTIVE

We aimed to examine the effects of ambient air pollutants, NOS2 promoter haplotypes, and NOS2 promoter methylation on Feno levels in children.

METHODS

We selected 940 participants in the Children's Health Study who provided buccal samples and had undergone Feno measurement on the same day. DNA methylation was measured with a bisulfite-PCR Pyrosequencing assay. Seven single nucleotide polymorphisms captured the haplotype diversity in the NOS2 promoter. Average particulate matter with an aerodynamic diameter of 2.5 μm or less (PM(2.5)) and 10 μm (PM(10)) or less and ozone and nitrogen dioxide levels 7 days before Feno measurement were estimated based on air pollution data obtained at central monitoring sites.

RESULTS

We found interrelated effects of PM(2.5), NOS2 promoter haplotypes, and iNOS methylation on Feno levels. Increased 7-day average PM(2.5) exposure was associated with lower iNOS methylation (P = .01). NOS2 promoter haplotypes were globally associated with NOS2 promoter methylation (P = 6.2 × 10(-8)). There was interaction among 1 common promoter haplotype, iNOS methylation level, and PM(2.5) exposure on Feno levels (P(interaction) = .00007).

CONCLUSION

Promoter variants in NOS2 and short-term PM(2.5) exposure affect iNOS methylation. This is one of the first studies showing contributions of genetic and epigenetic variations in air pollution-mediated phenotype expression.

Does asthma control as assessed by the asthma control test reflect airway inflammation?

BACKGROUND AND AIMS

The treatment of asthmatic patients is particularly focused on the control of symptoms as well as functional and inflammatory parameters. In our study, we investigated the relationship between the asthma control test (ACT) which evaluates symptoms and airway inflammation and functional parameters.

MATERIALS AND METHODS

Stable asthmatic patients admitted to our pulmonary outpatient clinic were enrolled in the study consecutively and underwent the ACT, pulmonary function tests and methacholine bronchial provocation test (MBPT). Additionally, fractional exhaled nitric oxide level (FeNO) and induced sputum cell distribution were assessed. All these parameters were re-evaluated at the third month after adjusting medications of the patients according to baseline ACT scores.

RESULTS

Of the 101 patients screened, we analyzed 83 who proceeded to the follow up visit. At the baseline visit, 8 were totally controlled, 36 partially controlled and 39 uncontrolled according to ACT. At the follow up visit, 10 were totally controlled, 39 partially controlled and 34 uncontrolled. Comparison of the two visits in terms of all parameters revealed significant reductions only in the percentages of patients with MBPT positivity (p = 0.029) and FeNO levels > 20 ppb (p = 0.025) at follow up. The percentages of patients with FeNO > 20 ppb, MBPT positivity, induced sputum eosinophilia or induced sputum neutrophilia did not show significant differences between totally controlled, partially controlled and uncontrolled groups at both baseline and follow up visits.

CONCLUSION

Although the ACT scores did not show significant correlations with the airway inflammation parameters tested in this study, a marked reduction in the percentage of patients with MBPT positivity and FeNO > 20 ppb at follow up may suggest the importance of the control concept in the management of asthma.

Clinical study of multiple breath biomarkers of asthma and COPD (NO, CO(2), CO and N(2)O) by infrared laser spectroscopy

Breath analysis is a powerful non-invasive technique for the diagnosis and monitoring of respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD). Exhaled nitric oxide (NO) and carbon monoxide (CO) are markers of airway inflammation and can indicate the extent of respiratory diseases. We have developed a compact fast response quantum cascade laser system for analysis of multiple gases by tunable infrared absorption spectroscopy. The ARI breath analysis instrument has been deployed in a study of exhaled breath from patients with asthma or COPD. A total of 173 subjects participated, including both adult and pediatric patients. Patients in asthma or COPD exacerbations were evaluated twice-during the exacerbation and at a follow-up visit-to compare variations in breath biomarkers during these events. The change in exhaled NO levels between exacerbation and 'well' visits is consistent with spirometry data collected. Respiratory models are important for understanding the exchange dynamics of nitric oxide and other species in the lungs and airways. At each patient's visit, tests were conducted at four expiratory flow rates. We have applied a trumpet model with axial diffusion to the multi-flow exhaled nitric oxide data, obtaining NO alveolar concentrations and airway fluxes. We found higher airway fluxes for those with more severe asthma and during exacerbation events. The alveolar concentrations from the model were higher in adults with asthma and COPD, but this trend was less clear among the pediatric subjects.

Inflammatory markers in childhood asthma

The major characteristic of asthma is persistent airway inflammation that fails to resolve spontaneously. Dysregulation of pro- and anti-inflammatory mechanisms is responsible for the development of chronic inflammation. The inflammatory reaction is mediated by numerous cells and their mediators. Detection and quantification of airway inflammation in children are subject to many requirements, e.g., use of biologic samples obtained in a non-invasive way; use of standardized analytical methods to determine biomarkers that can identify inflammation processes (inflammation itself, oxidative stress, apoptosis and remodelling); determining the role of systemic inflammation; assessment of correlation of various biomarkers of inflammation with clinical parameters and their diagnostic efficacy; providing a tool(s) to monitor diseases, and to evaluate adequacy of therapy; and predicting the clinical course of inflammation and prognosis of asthma. Using standardized analyses, it is now possible to determine direct markers of local inflammation, i.e., fractional nitric oxide (marker of oxidative stress) in exhaled breath, pH (marker of acid stress) in breath condensate, and indirect markers in blood/serum, i.e., eosinophil granulocytes (indicating migration), eosinophil cationic protein (marker of activated eosinophil granulocytes) and C-reactive protein (marker of systemic inflammation). However, none of these biomarkers are specific for asthma. Further standardization of the known pulmonary biomarkers of local inflammation and identification of new ones will allow for longitudinal follow-up of inflammation in children with asthma.

[Sputum induction in children: Technical development]

OBJECTIVE

To compare low and high flow nebulizers performance (total of samples) and its side effects on sputum induction in asthmatic children.

PATIENTS AND METHODS

Sputum induction was performed by inhalation of a hypertonic saline solution at increasing concentrations (3%, 4% and 5%) using low flow (OMRON NE-U07; flow rate 1ml/min), or high flow (OMRON NE-U12; flow rate 3ml/min, and DeVilbiss Ultraneb 3000; flow rate 2.5ml/min) ultrasonic nebulizers.

RESULTS

We performed 49 inductions in 49 patients from 7 to 15 years old (in 15 children we used a low flow nebulizer (Omron NE-U07) and in 34 children a high flow nebulizer (OMRON NEU12, 6 patients, and DeVilbiss Ultraneb 3000, 28 patients). We obtained 37 samples of which 36 had less than 20% of squamous cells, and 26 had a viability > or =60%. The test performance was higher with high-flow nebulizers, obtaining 85.3% of samples compared to 53% (p=0.04). A total of 69% of samples obtained with the high flow nebulizer were valid, compared to 62.5% (p=0.7) with the low flow nebulizers. With high flow rate nebulizers the incidence of cough (17.6%, p=0.08) and itchy eyes (0%, p=0.02) decreased with the low flow nebulizer (47% and 20% respectively), but bad taste (82.3%, p <0.001) and salivation (14.7%, p=0.3) increased.

CONCLUSIONS

With high flow rate ultrasonic nebulizers we obtain a higher performance of the technique without an increase in significant side effects.

[Feasibility of FeNO measurement in asthmatic children in the primary care setting. CANON Study]

AIM

Asses the feasibility of exhaled nitric oxide (FeNO) measurement in asthmatic children using a hand-held device in the primary care setting.

METHODS

Multicentre study performed in the paediatric clinics in seven Spanish primary health care centres. Each centre consecutively included 6-14 year-old children with doctor-diagnosed asthma. Children were asked to obtain two valid measurements of FeNO with the hand-held device NIOX MINO (Aerocrine AB, Solna, Sweden). Feasibility analysis included: (a) percentage of children able to perform the manoeuvre, (b) time required to obtain a successful determination, (c) number of attempts needed, and (d) acceptability of the technical procedure by clinical personnel involved in their guidance.

RESULTS

The Study enrolled 151 children. A total of 149 (98.7%) were able to perform the FeNO manoeuvre. The majority (55%) of children had previous experience of using the hand-held device. The Overall median (and Interquartile Range, IQR) of attempts needed to reach a first valid measurement was 2 (1-3) and median (IQR) of time taken was 4 min (3-5). Nurses considered the overall procedure was very easy or easy in 87.8% (teaching) and 86.5% (performing) of children. Children with previous experience performed the manoeuvre in less attempts, less time and more easily than children without experience.

CONCLUSIONS

Measurement of FeNO using NIOX MINO device is technically feasible and acceptable for children and staff in the clinical context of asthma management in primary health care. Previous experience had a positive, learning effect, in teaching and performing the FeNO manoeuvre.

Partitioned exhaled nitric oxide to non-invasively assess asthma

Asthma is a chronic inflammatory disease of the lungs, characterized by airway hyperresponsiveness. Chronic repetitive bouts of acute inflammation lead to airway wall remodeling and possibly the sequelae of fixed airflow obstruction. Nitric oxide (NO) is a reactive molecule synthesized by NO synthases (NOS). NOS are expressed by cells within the airway wall and functionally, two NOS isoforms exist: constitutive and inducible. In asthma, the inducible isoform is over expressed, leading to increased production of NO, which diffuses into the airway lumen, where it can be detected in the exhaled breath. The exhaled NO signal can be partitioned into airway and alveolar components by measuring exhaled NO at multiple flows and applying mathematical models of pulmonary NO dynamics. The airway NO flux and alveolar NO concentration can be elevated in adults and children with asthma and have been correlated with markers of airway inflammation and airflow obstruction in cross-sectional studies. Longitudinal studies which specifically address the clinical potential of partitioning exhaled NO for diagnosis, managing therapy, and predicting exacerbation are needed.

Exhaled nitric oxide measurement is useful for the exclusion of nonasthmatic eosinophilic bronchitis in patients with chronic cough

BACKGROUND

Nonasthmatic eosinophilic bronchitis (NAEB) is an important cause of chronic cough, and it can be diagnosed by an induced-sputum (IS) examination. However, an IS examination is a complex and time-consuming procedure, and it has limited clinical application. This study aimed to evaluate the role of exhaled nitric oxide (NO) for the investigation of chronic cough, especially of NAEB.

METHODS

Two hundred eleven nonsmoking patients with a cough lasting > 3 weeks were enrolled in the study. The patients were examined and investigated with conventional diagnostic tools, including an IS examination. Exhaled NO was measured by a chemoluminescent analyzer.

RESULTS

One hundred seventeen patients with adequate IS results were analyzed: asthma, n = 14; NAEB, n = 21; and "others," n = 82. Exhaled NO and IS eosinophils were significantly higher in the asthma group and NAEB group than in the others group. Exhaled NO and IS eosinophils were significantly correlated in the asthma and NAEB groups. In the nonasthmatic group, the sensitivity and specificity of exhaled NO for detecting NAEB, using 31.7 parts per billion as the exhaled NO cutoff point, were 86% and 76%, respectively. Positive and negative predictive values were 47% and 95%, respectively, and positive and negative likelihood ratios were 3.51 and 0.19, respectively.

CONCLUSION

We concluded that exhaled NO measurement may be useful as part of the initial evaluation for chronic cough, especially for the exclusion of NAEB. A low level of exhaled NO suggested little likelihood of NAEB for the nonasthmatic patients with chronic cough.

Neutrophil but not eosinophil inflammation is related to the severity of a first acute epidemic bronchiolitis in young infants

Acute bronchiolitis is the main cause of emergency visits and hospitalizations in infants. Recent data suggest that neutrophil- and eosinophil-mediated inflammations were part of bronchiolitis pathophysiology. Apart from the defined risk factors, few was known on the underlying pathophysiology, which might point out the differences observed in the severity of the disease. The aim of this study was to assess whether the clinical severity of acute epidemic bronchiolitis in young infants might be related to a specific underlying inflammatory process. Total and differential cell counts, IL-8, eotaxin, eosinophil cationic protein (ECP) and albumin levels were assessed at the time of admission in bronchial secretions from 37 infants (median age 17 wk) with acute bronchiolitis. Outcome severity variables were: hypoxemia, Silverman score, tachypnea, feeding alteration, and duration of hospitalization. Neutrophils predominated, and eosinophils were present in 54% of the infants. IL-8 levels strongly correlated with ECP and albumin levels. Albumin levels were correlated with ECP and eotaxin levels. IL-8 levels were higher in infants with hypoxemia and inversely related with SaO(2) levels. IL-8 and albumin levels significantly rose with respiratory rate, and Silverman score. IL-8, albumin and ECP levels were significantly higher in infants hospitalized >/=7 days. Furthermore, IL-8 levels were correlated with the duration of hospitalization. Neither cell counts nor eotaxin levels were related to the severity criteria studied. This study suggests that IL-8-associated airway inflammation significantly contributed to the severity of acute epidemic bronchiolitis.

Exhaled nitric oxide for monitoring childhood asthma inflammation compared to sputum analysis, serum interleukins and pulmonary function

The level of fractional exhaled nitric oxide (FENO) is significantly elevated in uncontrolled asthma and decreases after anti-inflammatory therapy. The aim of this prospective study was to analyze the behavior of FENO in the follow-up and management of the inflammation in asthmatic pediatric patients treated with inhaled corticosteroids (ICS), compared to sputum cellularity, serum interleukins (IL), and pulmonary function. Twenty-six clinically stable asthmatic children aged from 6 to 18 years, previously treated or not with ICS were included. Following an international consensus (GINA), the patients were submitted to standard treatment with inhaled fluticasone for 3 months according to the severity of the disease. During this period, each patient underwent three assessments at intervals of approximately 6 weeks. Each evaluation consisted of the measurement of FENO, determination of serum interleukins IL-5, IL-10, IL-13, and interferon gamma (INF-gamma), spirometry and cytological analysis of spontaneous or induced sputum. A significant reduction in mean FENO and IL-5, without concomitant changes in FEV1, was observed along the study. There was no significant correlation between FeNO and FEV1 in the three assessments. A significant correlation between FeNO and IL-5 levels was only observed in the third assessment (r = 0.499, P = 0.025). In most patients, serum IL-10, IL-13, and INF-gamma concentrations were undetectable throughout the study. Sputum samples were obtained spontaneously in 11 occasions and in 56 by induction with 3% hypertonic saline solution (success rate: 50.8%), with 39 (69.9%) of them adequate for analysis. Only two of the 26 patients produced adequate samples in the three consecutive evaluations, which impaired the determination of a potential association between sputum cellularity and FeNO levels throughout the study. In conclusion, among the parameters of this study, it was difficult to perform and to interpret the serial analysis of spontaneous or induced sputum. Serum interleukins, which remained at very low or undetectable levels in most patients, were not found to be useful for therapeutic monitoring, except for IL-5 that seems to present some correlation with levels of FeNO exhaled. Monitoring of the mean FEV1 indicated no significant variations during the treatment, demonstrating that functional stability or the absence of obstruction may not reflect the adequate management of asthma. Serial measurement of FeNO seemed to best reflect the progressive anti-inflammatory action of ICS in asthma.

Exhaled nitric oxide after a single dose of intramuscular triamcinolone in children with difficult to control asthma

In a previous study, we reported that intramuscular (IM) triamcinolone improves symptoms in children with difficult asthma. In 2005, we revised our difficult asthma protocol to include assessment of airway inflammation, both directly using sputum induction and indirectly by measurement of exhaled nitric oxide (eNO). In this retrospective review, we aimed to describe (i) the changes in eNO and symptoms after a single 60 mg dose of IM triamcinolone and (ii) the changes in inflammatory markers in the subgroup with non-eosinophilic asthma (i.e., an induced sputum eosinophil differential count <2.0%). Seven children received IM triamcinolone during the study period. In all children, symptom scores fell in the week following the IM injection (P < 0.01 vs. the pre-treatment week), and remained reduced for up to 6 weeks. eNO also fell within a week after IM therapy (P < 0.01), and remained reduced for up to 4 weeks. Non-eosinophilic asthma was definitively identified in three children, and in this group, eNO and symptoms fell after the IM injection. We conclude that IM triamcinolone therapy reduces both eNO and symptoms for up to 4 weeks in children with difficult asthma. Our data provide preliminary evidence that IM triamcinolone is an effective anti-inflammatory therapy in children with induced sputum non-eosinophilic asthma.

Tailored interventions based on sputum eosinophils versus clinical symptoms for asthma in children and adults

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.

Quality of life and inflammatory markers in mild asthma

STUDY OBJECTIVES

The aim of this study was to explore the relationship between quality of life and measures of asthma, such as lung function, reversibility to bronchodilation, exhaled nitric oxide (NO), and bronchial responsiveness to direct and indirect stimulus in patients with mild asthma in a primary care setting.

PATIENTS AND MEASUREMENTS

Seventy-seven asthmatic patients not treated with glucocorticosteroids completed the Asthma Quality of Life Questionnaire. Spirometry was performed before and after bronchodilation, and bronchial challenges with methacholine and eucapnic dry air hyperventilation were conducted on separate days. NO in exhaled air and serum IgE were also analyzed.

RESULTS

We found no correlation between quality of life and any of the other parameters. There was a significant covariation between exhaled NO and bronchial responsiveness to methacholine and dry air, and also between FEV(1) (percentage of predicted) and reversibility to a bronchodilator. The levels of exhaled NO were higher in the asthmatic subjects with atopy than in the nonatopic asthmatics.

CONCLUSIONS

The measures used in our study do not reflect health-related quality of life in subjects with mild asthma. We conclude that in the clinical situation, quality of life and other measures of asthma provide complementary information.

Comparison of induced sputum inflammatory profiles between childhood and adult-onset asthma

The aim of this study was to investigate differences in airway inflammation between childhood and adult-onset asthma. A total of 47 asthmatic subjects were recruited from patients attending outpatient clinic. A group of 32 adults, mean age 42.8 years (yrs) and a group of 15 children, mean age 11.7 yrs were included. The two groups did not differ in respect to gender, dose of inhaled corticosteroids, atopy status or duration of asthma (mean duration 7.75 yr). Lung function tests, and sputum induction were performed. Flowcytometry was used to study cell population and interleukin-8, eosinophilic cationic protein (ECP) and granulocyte-macrophage colony stimulating factor were measured by enzyme-linked immunosorbent assay (ELISA). Three out of 15 (20%) of the children and 6 out of 32 (19%) of the adult patients were unable to produce a sufficient sputum sample. However, all individuals tolerated the procedure well. The viability of induced sputum cells did not differ among adult-onset asthmatics and children with asthma. Children had greater number of total cells in induced sputum compared with adult subjects (P=0.02). No statistical difference in T-lymphocytes subsets was found between the two groups, except for CD25 (P=0.04). A negative correlation was found between forced expiratory volume (FEV1) values and ECP levels (r=0.338, P=0.04) in the whole population (children and adults). Our study showed that the immunopathology of pediatric and adult asthma is similar and sputum induction provides opportunities for comparison of airway inflammation in childhood and adult asthma safely.

Induced sputum in cystic fibrosis: within-week reproducibility of inflammatory markers

Analysis of induced sputum has provided significant insight into the inflammatory response in chronic respiratory diseases such as asthma. The thick, tenacious nature of cystic fibrosis (CF) sputum presents certain challenges to such evaluation. We describe the development of a methodology to assess CF sputum, and the within-week reproducibility (to limit the possibility of any change in clinical status) of cellular and inflammatory markers.

METHODS

Seventeen young adults [9 males, 8 females, mean age 24 (5), median (quartile range) years, percentage of predicted FEV(1) = 64.0 (18.0%)] with CF underwent sputum inductions on the Monday and Thursday of the same week. Patients were pretreated with 400 microg salbutamol and subsequently inhaled 5% saline via a breath enhanced nebulizer. Every 3-min nebulization was interrupted to allow for expectoration of sputum into a polypropylene pot. Sputum samples were dispersed with a solution of dithiothreitol (DTT) and deoxyribonuclease to allow for analysis of total cell count (TCC) and percentage neutrophils (%Neut). Measurement of tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), and neutrophil elastase was performed on samples dispersed with DTT alone.

RESULTS

There were no significant differences between the measurements taken in the same week. Values for Day 1 versus Day 2 were as follows: TCC 20.8 (6.4) vs. 17.6 (2.5) x 10(6) cells/ml; %Neut: 94.1 (0.0) vs. 95.4 (0.5) %; TNF-alpha 7.5 (26.0) vs. 21.0 (44.0) pg/ml; IL-8 610.0 (422.0) vs. 524.0 (587.0) ng/ml and neutrophil elastase 110.0 (19.75) vs. 49.75 (60.75) microM. High intraclass correlation coefficients (ICC) for TCC, %Neut, TNF-alpha IL-8 and neutrophil elastase were found (ICC = 0.76, 0.82, 0.93, 0.82, 0.74, respectively).

CONCLUSIONS

The method developed here for the analysis of CF sputum shows good reproducibility and can be used to evaluate therapeutic interventions in patients with cystic fibrosis.

Sputum induction in children with difficult asthma: safety, feasibility, and inflammatory cell pattern

Difficult childhood asthma is defined by persistent symptoms despite maximal conventional therapy. We aimed to establish a safe method of sputum induction for these children and to study cytology and the relationship to exhaled nitric oxide (eNO). Sputum induction was performed in 38/40 children (aged 6-16 years) with difficult asthma, using 3.5% saline for four 5-min periods after bronchodilator pretreatment. Two children were excluded from sputum induction because postbronchodilator forced expired volume in 1 sec (FEV(1)) was <65% predicted. Seven of 38 children had symptoms (dyspnea and wheezing) during induction; of these, 3 experienced a fall in FEV(1) of >20% from postbronchodilator FEV(1), readily reversed with salbutamol. Sputum induction was successful in 28/38 children, with a higher success rate in children >/= 12 years than in younger children (87% vs. 50%, P = 0.02). Only 9/28 had abnormal sputum cytology; of these, 6 had predominant sputum eosinophilia (>2.5% eosinophils, </=54% neutrophils), while 3 had sputum neutrophilia (</=2.5% eosinophils, >54% neutrophils). Of 23 children with elevated eNO values, only 6 had sputum eosinophilia. In conclusion, sputum induction can be used to assess airway inflammation in children with difficult asthma, but abnormal sputum cytology is only present in a minority. Raised nitric oxide is only poorly predictive of sputum eosinophilia in these children.

Induced sputum in children with newly diagnosed mild asthma: the effect of 6 months of treatment with budesonide or disodium cromoglycate

BACKGROUND

There are few controlled studies on the effects of anti-inflammatory treatment on airway inflammation in newly diagnosed childhood asthma.

METHODS

Sixty children with newly diagnosed mild persistent asthma, 5-10 years of age, and 17 healthy control subjects were studied. Asthmatic children were randomized into an open study with two treatment groups: (1) budesonide 400 microg twice daily for 1 month, 200 microg twice daily for 5 months and (2) disodium cromoglycate (DSCG) 10 mg three-times daily for 6 months. All exacerbations were treated with budesonide 400 microg twice daily for 2 weeks. Symptoms and lung function were recorded throughout the study.

RESULTS

Sputum induction was safe and the overall success rate was 71%. This improved with age and decreased after treatment. At baseline, the asthmatic children had more eosinophils in blood (0.26 vs 0.18 x 10(9)/l, P = 0.03) and sputum (1.1 vs 0.0 %, P = 0.0001) than the control subjects. The numbers of sputum eosinophils correlated with bronchial responsiveness (R = -0.58, P = 0.0002). Eosinophils were higher in children with atopic asthma than with nonatopic asthma (P < 0.0001), and in children with a history wheezing than in children without wheezing (P = 0.02). Six months of budesonide treatment, but not of DSCG, improved lung function (P = 0.007), decreased symptoms (P = 0.007) and sputum eosinophils (P = 0.003). The effects of budesonide were pronounced in children with intense sputum eosinophilia (>3%).

CONCLUSION

Sputum eosinophilia is present in children with newly diagnosed mild persistent asthma. Treatment with inhaled budesonide, but not with DSCG, decreases sputum eosinophils along with clinical and functional improvement.

Exhaled NO and eosinophil markers in blood, nasal lavage and sputum in children with asthma after withdrawal of budesonide

BACKGROUND

There is a need for controlled trials among children with asthma to evaluate and compare different markers of inflammation.

OBJECTIVE

Our goal was to investigate the effect of withdrawal of inhaled budesonide on repeated measurements of exhaled NO (ENO), peripheral blood eosinophils (PBE), sputum/NAL/serum-eosinophil cationic protein (ECP), bronchial hyperresponsiveness (BHR) and forced expiratory volume in 1 s (FEV(1)) in children with allergic asthma.

METHODS

Eighteen asthmatic children were randomly allocated to continue or discontinue use of inhaled budesonide. They were followed up, at six visits for 4 months with regular blood, serum, sputum, and NAL samples. Sixteen age-matched healthy children served as controls.

RESULTS

ENO, PBE, and S-ECP increased significantly in the withdrawal group (p < 0.05) but not in the continuous treatment group. No trend could be observed during the study for markers in sputum or in NAL in either group.

CONCLUSION

The present data provide evidence for the clinical usefulness of measuring ENO, PBE, and S-ECP and when combined they could help to avoid over- and undertreatment with corticosteroids in the growing child.

Assessment of inhaled BDP-dose dependency of exhaled nitric oxide and local and serum eosinophilic markers in steroids-naive nonatopic asthmatics

The aim of the present study was to assess the dose-dependency from inhaled steroids of changes of airways inflammation [eosinophils count and eosinophil cationic protein (ECP)] measures in induced sputum and in serum, as well as that of exhaled nitric oxide. Twenty steroid-naive patients with nonatopic asthma of mild to moderate degree [forced expiratory volume in 1 s (FEV1) = 70% of predicted] and with negative response to the standard tests for allergy were selected; after a 1-week run-in period they were randomized to receive a 12-week treatment period of inhaled beclomethasone dipropionate dry powder given with the Pulvinal inhaler (Clenil P, Chiesi Farmaceutici S.p.A., Parma, Italy) in two different dose regimens, 400 microg bid (high dose) or 200 microg bid (low dose), over a double blind, parallel groups design. The following outcome measures were assessed in baseline and after 1, 6 and 12 weeks of treatment: FEV1 (l), eosinophils count in sputum (%), is ECP (microg/l), serum eosinophils count (%), serum ECP (microg/l) and exhaled NO (ppb). The results showed that all the considered parameters improved in both groups: the increase over baseline of FEV1 and the decrease of NO were significant at any time in the high-dose group and only at week 12 in the low-dose group (NS between groups), whereas the markers of eosinophilic activity showed more consistent reductions in the high-dose than in the low-dose group when measured in induced sputum (P < 0.05 between groups after 6 and 12 weeks for eosinophils count and after 12 weeks for ECP). Decreases over baseline of markers measured in serum were more rapid in the high-dose group, without differences between groups. A marked trend towards a negative correlation was found between FEV1 and ECP, (r = -0.72, P < 0.05), between FEV1 and eosinophils in sputum (r = -0.31, NS) and between FEV1 and exhaled NO (r = -0.38, NS), all of them only in the high-dose group. The results of the study demonstrate that changes of levels of eosinophilic activity in the airways are dependent from the daily dose of inhaled steroids when measured in induced sputum and that the local assessment can therefore represent a practical and noninvasive method to monitor the extent of airways inflammation.

Safety and success of exhaled breath condensate collection in asthma

BACKGROUND

Exhaled breath condensate (EBC) is a rapidly expanding area of research to study airway inflammation through the detection of volatile and non-volatile substances in the airways.

AIMS

To determine the safety and feasibility of EBC procedure in a group of children with asthma of varying severity.

METHODS

In a cross sectional study of children aged 4-17 years, 18 healthy and 91 asthmatic children (69 in stable condition and 22 with asthma exacerbation) underwent the EBC procedure. Outcomes assessed included completion of the procedure, decrease in FEV1, change in fractional exhaled nitric oxide (FE(NO)), and adverse effects. No pretreatment with beta2 agonists was given. All children were able to successfully complete the EBC procedure.

RESULTS

Median fall in FEV1 after the procedure was -1% (IQR -3.5, 1.8) in asthmatics and was comparable to that observed in healthy children. In only one asthmatic child did the drop in FEV1 exceed 12%. No significant changes in FE(NO) were observed after EBC.

CONCLUSION

This study suggests that EBC is a simple and well tolerated method for evaluating biological samples from the lower airway. The procedure was safe in children with asthma exacerbation, and the success rate was 100% in children aged 4 years and above.

Relationship between induced sputum eosinophils and the clinical pattern of childhood asthma

BACKGROUND

The relationship between the clinical pattern of asthma and airway inflammation in childhood asthma is poorly characterised, yet underpins the treatment recommendations in current asthma guidelines. A study was undertaken to examine the relationship between airway inflammation and clinical asthma in children.

METHODS

Children with asthma (n=146) and healthy controls (C, n=37) were recruited from primary and specialist clinics. Sputum induction and hypertonic saline challenge were performed.

RESULTS

As the frequency of asthma episodes in the past 12 months increased, there were significant increases in sputum eosinophils (median; infrequent episodic (IE) 1.5%, frequent episodic (FE) 2.3%, persistent (P) 3.8%, control (C) 1.0%; p=0.002), sputum eosinophil cationic protein (ECP) (IE 113 ng/ml, FE 220, P 375, C 139; p=0.003), and desquamated bronchial epithelial cells (IE 2.0%, FE 6.0%, P 5.0%, C 2.5%; p=0.04). Treatment intensity was also associated with increased sputum eosinophils (p=0.005). The relationships between other severity markers (current symptoms, lung function) were less strong.

CONCLUSION

Children with more frequent episodes of clinical asthma exhibit increasing airway inflammation that is characterised by sputum eosinophilia and bronchial epithelial desquamation. The results support clinical assessment by frequency of wheezing episodes over the past 12 months when determining anti-inflammatory treatment requirements, and indicate that current symptoms are determined by mechanisms in addition to sputum eosinophilia.

Circadian variation of sputum inflammatory cells in mild asthma

BACKGROUND

Asthma, like many conditions, demonstrates a circadian rhythm with a worsening of lung function in the early morning hours compared with in the late afternoon.

OBJECTIVE

Because eosinophilic airway inflammation is a proposed mechanism for worsening asthma, we characterized circadian variation in airway eosinophils and determined its relationship to variability in airway function.

METHODS

Pulmonary function testing, sputum induction, and phlebotomy were performed at 7 am and 4 pm in 11 allergic subjects with mild asthma. Sputum was analyzed for cell viability, differential, and eosinophil-derived neurotoxin levels. IL-5 levels in serum were measured by means of ELISA.

RESULTS

Subjects had a significant decrease in FEV(1) (median [interquartile range] = 80% [70%-86%] vs 85% [82%-94%], P =.009) and a greater beta-agonist reversibility (median [interquartile range] = 13% [7%-32%] vs 8% [5%-14%], P =.024) in the early morning compared with in the late afternoon. Sputum analysis showed an increase in early morning total sputum leukocytes (median [interquartile range] = 4.3 x 10(6) [2.3 x 10(6) to 6.1 x 10(6)] vs 2.6 x 10(6) [1.7 x 10(6) to 3.6 x 10(6)], P =.044) and eosinophils (median [interquartile range] = 7.0 x 10(4) [2.7 x 10(4) to 18.7 x 10(4)] vs 3.6 x 10(4) [1.0 x 10(4) to 8.2 x 10(4)], P =.024). Furthermore, sputum eosinophils correlated with beta-agonist reversibility (R (s) = 0.665, P =.019). Finally, levels of IL-5 in serum and eosinophil-derived neurotoxin in sputum were significantly increased at 7 am.

CONCLUSION

These data suggest that circadian variability in pulmonary function in asthma could be related to changes in airway eosinophil recruitment and activation.

Induced sputum is a reproducible method to assess airway inflammation in asthma

To evaluate the reproducibility of induced sputum analysis, and to estimate the sample size required to obtained reliable results, sputum was induced by hypertonic saline inhalation in 29 asthmatic subjects on two different days. The whole sample method was used for analysis, and inflammatory cells were counted on cytospin slides. Reproducibility, expressed by intra-class correlation coefficients, was good for macrophages (+0.80), neutrophils (+0.85), and eosinophils (+0.87), but not for lymphocytes (+0.15). Detectable differences were 5.5% for macrophages, 0.6% for lymphocytes, 5.2% for neutrophils, and 3.0% for eosinophils. We conclude that analysis of induced sputum is a reproducible method to study airway inflammation in asthma. Sample sizes greater than ours give little improvement in the detectable difference of eosinophil percentages.

Non-eosinophilic asthma: importance and possible mechanisms

There is increasing evidence that inflammatory mechanisms other than eosinophilic inflammation may be involved in producing the final common pathway of enhanced bronchial reactivity and reversible airflow obstruction that characterises asthma. A review of the literature has shown that, at most, only 50% of asthma cases are attributable to eosinophilic airway inflammation. It is hypothesised that a major proportion of asthma is based on neutrophilic airway inflammation, possibly triggered by environmental exposure to bacterial endotoxin, particulate air pollution, and ozone, as well as viral infections. If there are indeed two (or more) subtypes of asthma, and if non-eosinophilic (neutrophil mediated) asthma is relatively common, this would have major consequences for the treatment and prevention of asthma since most treatment and prevention strategies are now almost entirely focused on allergic/eosinophilic asthma and allergen avoidance measures, respectively. It is therefore important to study the aetiology of asthma further, including the underlying inflammatory profiles.

Serum B12 tryptase level as a marker of allergic airway inflammation in asthma

Tryptase is a specific marker of mast-cell activation and plays a part in the pathophysiology of various allergic diseases including asthma, but little is known of the spillover of this enzyme into the systemic circulation. Therefore, we measured serum levels of mast-cell-derived tryptase in 21 patients with mild to moderate asthma and 20 healthy, subjects, using a B12 monoclonal antibody-based immunofluoroassay that detects both monomers and tetramers of alpha- and beta-tryptases. There was a good correlation between serum and sputum tryptase levels, and, compared with healthy subjects (1.68 +/- 0.31 ng/ml), asthma patients had higher concentrations of serum tryptase (atopic asthma, 4.18 +/- 0.95 ng/ml, p = 0.022; nonatopic asthma, 3.93 +/- 0.82 ng/ml, p = 0.031). Although serum tryptase levels did not correlate with asthma symptom scores, peak expiratory flow, or forced expiratory volume in 1 s, they positively correlated with mast-cell and eosinophil counts (p = 0.041 and p = 0.025, respectively) and eosinophil cationic protein contents (p = 0.029) in induced sputum. These results suggest that serum tryptase detected with B12 antibody is a marker of allergic airway inflammation in asthma.

Measurement of airway inflammation in asthma

Chronic airway inflammation is considered responsible for symptoms and disorders of airway function associated with asthma. This process is the target of anti-inflammatory therapy, so a number of standardized, noninvasive techniques have been developed to assess it. More recent approaches include the measurement of exhaled gases and nonvolatile substances in breath condensate. Results from studies using a wide variety of inflammatory markers have shown group differences between patients with asthma and healthy control subjects, but evidence for the diagnostic use of these markers in individual patients is scarce. Similarly, despite many studies demonstrating some correlation between markers of airway inflammation and a measure of disease control, none has yet convincingly shown a place for the use of these markers in an individual with corticosteroid-treated asthma. However, application of these markers continues to further our understanding of the disease process and provides the potential for more appropriate, customized therapy.

Categorizing asthma severity and monitoring control of chronic asthma

Asthma is a distressing disease, affecting up to 8% of the US population and causing considerable morbidity. Effective management of asthma requires accurate categorization of asthma severity and effective methods for monitoring the activity of the disease with treatment. Currently, symptoms, lung function, and requirements for corticosteroid treatment are the most accepted factors used for asthma severity categorization. Measures of airway hyperresponsiveness, particularly the use of methacholine, may provide additional information regarding the duration of asthma. Assessing airway inflammation using either sputum eosinophilia or exhaled nitric oxide levels has added little to clinical methods for determining asthma severity, but may be useful in monitoring the activity of the disease.