Induced sputum cell counts in healthy adults

Age-related increase of airway neutrophils in older healthy nonsmoking subjects

BACKGROUND

Although an influence of advancing age on lung cellularity in healthy subjects has already been described, induced sputum reference values for cell counts in older healthy adults are not available. The aim of the present study was to evaluate the influence of age on the variation of sputum cell distribution in a considerable number of healthy subjects. A total of 70 nonatopic, nonsmoker healthy subjects aged ≥50 years underwent sputum induction and blood cell count. Sputum samples were processed and then were analyzed by optical microscopy. Differential cell counts were reported as percentages and amount of cells/mg.

RESULTS

Sputum cell distribution of healthy subjects aged ≥50 years was mainly composed of neutrophils. Both the percentage and the amount of sputum neutrophils correlated with the subjects' age, r=0.5, p=0.00001 and r=0.32, p=0.007, respectively. This correlation was more evident in women (n=35) than in men (n=35). No correlation was found between blood neutrophils and age. The increase in sputum neutrophils was not secondary to an increase in blood neutrophils.

CONCLUSIONS

In the studied subjects, aging was associated, particularly in women, with an increase in sputum neutrophils not related to an increase of blood neutrophils. These results could be useful in clinical and experimental settings as reference values to compare with data from subjects aged over 50 years. These data showed that sputum neutrophila can be dissociated from airway symptoms and could create a favorable background for the development of age-related lung diseases.

Expiratory flows and airway inflammation in elderly asthmatic patients

Asthma in the elderly is often underrecognized and suboptimally treated, resulting in an increased morbidity and mortality. The characteristics of asthma-related bronchitis and its optimal treatment remain to be determined in this population. We aimed to compare lung function and airway inflammation in elderly and younger asthmatic subjects. Data from two induced sputum databases were analyzed in three groups of asthmatic subjects (18-30 y, n = 136; 31-59 y, n = 385; 60-72 y, n = 172) and one group of healthy elderly subjects (60-89 y, n = 16). Expiratory flows and induced sputum cell counts were analyzed. Airway obstruction was more marked in elderly asthmatics compared with healthy elderly or younger asthmatic subjects (p < 0.01). An increase in sputum neutrophils and a decrease in macrophages and lymphocytes were observed in elderly asthmatics (p < 0.0001). Neutrophil percentages significantly increased with asthma severity in the young and the middle-aged groups, while they remained similar in elderly asthmatics regardless of asthma severity (p < 0.05). Neutrophil percentages weakly correlated with the dose of ICS in all asthmatics (r = 0.17, p < 0.0001). Age and dose of ICS were independent predictors of neutrophil percentage in asthmatic subjects in a regression model (R(2) = 0.12). Asthma in the elderly is associated with a more marked airway obstruction and sputum neutrophilia. Both age and the dose of corticosteroids need to be considered in the interpretation of the clinical relevance of sputum neutrophil count.

Simplified detection of eosinophils in induced sputum

OBJECTIVE AND DESIGN

The induction of sputum is a safe, noninvasive method of studying airway inflammation in asthma, but the method of analyzing the samples is laborious and requires well-trained technicians using highly specialized laboratory equipment. We introduce a shorter and simpler modification of the process for identifying eosinophilic inflammation from induced sputum (IS) samples.

MATERIAL

Samples of 81 patients referred for IS assessment of respiratory diseases were studied. Four different assessment approaches were studied in comparison with the conventional method of selecting plugs proposed by the European Respiratory Society/American Thoracic Society task force.

RESULTS

One modification of the conventional method of IS processing emerged as simpler to execute and less technologically demanding than the original one (13.0 ± 18.2 vs. 15.4 ± 22.4% eosinophils, P = 0.19).

CONCLUSION

The simpler approach should now encourage the use of IS as a convenient procedure for evaluating eosinophilic inflammation in less sophisticated laboratories.

Bronchial inflammation, respiratory symptoms and lung function in Primary Sjögren's syndrome

INTRODUCTION

There is no information available regarding the relationship between the respiratory symptoms or lung function and bronchial inflammation, measured by induced sputum.

OBJECTIVES

Description of the clinical characteristics, radiographic images and lung function of patients suffering from Primary Sjögren Syndrome (PSS), and to assess the relationship with the inflammatory airway profile.

METHODS

We analysed clinical, radiology, lung function tests, bronchial hyperresponsiveness and inflammatory data in the induced sputum from 36 consecutive patients with PSS.

RESULTS

A total of 58% of patients had hoarseness and 42% had cough and dispnea. No lung dysfunction was observed, although 46% (n=16) had a positive bronchial response. Lymphocytosis >2.6% in induced sputum was observed in 69% of all sputa. There was chronic cough in 29% of patients with lymphocytosis (n=24), whereas 73% were normal (n=11) (P=.02). The duration time of cough was less for the former (P=.02). On the contrary a positive bronchial response was associated with lymphocytosis >2.6% (P=.02). Lipophages were present in 55% of pathological sputa (n=22) (index >15) versus 18% of the non-pathological ones (n=11) (P=.05).

CONCLUSION

Hoarseness, cough and dyspnea are frequent respiratory symptoms in PSS, although there is a wide variation in the relationship with bronchial responsiveness and airway inflammation. Lymphocytosis in the airways is another site of the infiltrative process in PSS, and the induced sputum is a complementary tool in the identification of active inflammatory process.

Experimental rhinovirus infection as a human model of chronic obstructive pulmonary disease exacerbation

RATIONALE

Respiratory virus infections are associated with chronic obstructive pulmonary disease (COPD) exacerbations, but a causative relationship has not been proven. Studies of naturally occurring exacerbations are difficult and the mechanisms linking virus infection to exacerbations are poorly understood. We hypothesized that experimental rhinovirus infection in subjects with COPD would reproduce the features of naturally occurring COPD exacerbations and is a valid model of COPD exacerbations.

OBJECTIVES

To evaluate experimental rhinovirus infection as a model of COPD exacerbation and to investigate the mechanisms of virus-induced exacerbations.

METHODS

We used experimental rhinovirus infection in 13 subjects with COPD and 13 nonobstructed control subjects to investigate clinical, physiologic, pathologic, and antiviral responses and relationships between virus load and these outcomes.

MEASUREMENTS AND MAIN RESULTS

Clinical data; inflammatory mediators in blood, sputum, and bronchoalveolar lavage; and viral load in nasal lavage, sputum, and bronchoalveolar lavage were measured at baseline and after infection with rhinovirus 16. After rhinovirus infection subjects with COPD developed lower respiratory symptoms, airflow obstruction, and systemic and airway inflammation that were greater and more prolonged compared with the control group. Neutrophil markers in sputum related to clinical outcomes and virus load correlated with inflammatory markers. Virus load was higher and IFN production by bronchoalveolar lavage cells was impaired in the subjects with COPD.

CONCLUSIONS

We have developed a new model of COPD exacerbation that strongly supports a causal relationship between rhinovirus infection and COPD exacerbations. Impaired IFN production and neutrophilic inflammation may be important mechanisms in virus-induced COPD exacerbations.

Association of bronchial reactivity to occupational agents with methacholine reactivity, sputum cells and immunoglobulin E-mediated reactivity

BACKGROUND

Bronchial responsiveness and IgE-mediated reactivity are associated with specific bronchial reactivity to allergens.

OBJECTIVE

Our aim was to examine whether airway inflammation also plays a role.

METHODS

Retrospective analysis of all subjects who underwent specific inhalation challenges in the investigation of occupational asthma (OA) since 2000. Responsiveness to methacholine (PC(20) ) and levels of eosinophils and neutrophils in induced sputum on the control day were associated with the presence of OA (positive-specific inhalation challenge). In a sample of subjects exposed to wheat flour, we also examined the role of specific IgE- mediated reactivity (skin reactivity, specific IgE).

RESULTS

PC(20) level was significantly more often normal in subjects with OA (35 of 129, 27% instances) by comparison with non-OA (15 of 189, 8% instances), but the positive predictive value of responsiveness to methacholine for OA was low (35%). Coupling information on the level of eosinophils to responsiveness to methacholine increased positive predictive values for OA from 39% to 69% depending on the thresholds used. The best balance of positive (69%) and negative (60%) predictive values was obtained in the case of normal PC(20) and eosinophils ≥3%. In a multivariate analysis carried out in 34 subjects exposed to wheat flour, responsiveness to methacholine, sputum eosinophils, skin weal size and levels of specific IgE were all significantly associated with OA to wheat flour.

CONCLUSION AND CLINICAL RELEVANCE

Information on the level of sputum eosinophils in addition to PC(20) provides a better association with OA vs. non-OA when PC(20) is normal. Levels of sputum eosinophils in addition to PC(20) and IgE-mediated reactivity increase the likelihood of OA due to wheat flour.

Eosinophils, bronchitis and asthma: pathogenesis of cough and airflow obstruction

Eosinophilic airway inflammation is commonly observed in chronic cough in patients with asthma and non-asthmatic eosinophilic bronchitis. Indeed asthma and non-asthmatic eosinophilic bronchitis are amongst the commonest causes of chronic cough accounting for about 25 and 10% of cases respectively. In most cases the trigger that causes the cough is uncertain; however removal of potential triggers is important to consider in particular with respect to occupational exposure to known sensitizers. In both conditions the cough improves subjectively and objectively following treatment with corticosteroids. This improvement is associated with the presence of an airway eosinophilia, but whether eosinophilic inflammation is the cause of cough or an epiphenomenon is uncertain. The success of anti-IL5 to reduce eosinophilic inflammation and asthma exacerbations contrasts with the lack of efficacy to modify cough in asthma and therefore challenges a causal association. Both asthma and non-asthmatic eosinophilic bronchitis can lead onto airway remodeling and result in persistent airflow obstruction. However, response to corticosteroid therapy in both conditions is generally very good and the limited long term data available suggests that both usually have a benign course. Interestingly, improvement in airway remodeling in response to anti-IL5 observed using CT imaging and analysis of sub-epithelial matrix deposition does suggest that the eosinophil may play a causal role in airway remodeling.

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.

Increases in airway eosinophilia and a th1 cytokine during the chronic asymptomatic phase of asthma

BACKGROUND

Studies using allergen challenge models have suggested Th2 cytokines promote airway inflammation in asthma. We assessed mediators of airway inflammation during the chronic asymptomatic phase of asthma.

METHODS

Nine non-atopic asthma (NAA) patients, 19 atopic asthma (AA) patients, 20 atopic controls (AC), and 38 normal controls (NC) underwent sputum induction while asymptomatic. Sputum total cell counts and differentials were determined; levels of cytokines IL-4, IL-5, IL-13, GM-CSF, and IFN-gamma, and chemokines eotaxin (CCL11) and RANTES (CCL5) were measured by ELISA; and levels of eosinophil-derived neurotoxin (EDN) were measured by radioimmunoassay.

RESULTS

NAA patients showed higher % eosinophils and total eosinophils compared to AA. NAA and AA patients showed higher IFN-gamma and EDN levels compared to AC and NC, with no differences in IL-4, IL-5, or IL-13 levels among the four groups. GM-CSF levels were higher in AA patients compared to AC or NC. In NAA, AA, and AC patients, % eosinophils and EDN levels correlated positively with IFN-gamma, GM-CSF, eotaxin, and RANTES, but not with IL-5 levels.

CONCLUSIONS

Baseline airway inflammation of intrinsic and extrinsic asthma is characterized by eosinophilic inflammation and the Th1 cytokine, IFN-gamma. GM-CSF, instead of IL-5, and chemokines may coordinate airway eosinophilia during the chronic asymptomatic phase of asthma.

Can AMP induce sputum eosinophils, even in subjects with complete asthma remission?

Background

The definition of "clinical asthma remission" is based on absence of symptoms and use of medication. However, in the majority of these subjects airway inflammation is still present when measured. In the present study we investigated whether "complete asthma remission", additionally defined by the absence of bronchial hyperresponsiveness (BHR) and the presence of a normal lung function, is associated with the absence of airway inflammation.

Methods

Patients with a former diagnosis of asthma and a positive histamine provocation test were re-examined to identify subjects with complete asthma remission (no asthma symptoms or medication, PC₂₀ histamine > 32 mg/ml, FEV₁ > 90% predicted). Patients with PC₂₀ histamine ≤ 32 mg/ml were defined as current asthmatics and were divided in two groups, i.e. asthmatics with and without BHR to adenosine 5'monophoshate (AMP). Sputum induction was performed 1 week before and 1 hour after AMP provocation. Sputum induction and AMP provocation were previously shown to be sensitive markers of airway inflammation.

Results

Seven patients met criteria for complete asthma remission. Twenty-three were current asthmatics, including twelve without hyperresponsiveness to AMP. Subjects with complete asthma remission showed no AMP-induced sputum eosinophilia (median (range) 0.2 (0 - 4.6)% at baseline and 0.2 (0 - 2.6)% after AMP). After AMP, current asthmatics had a significant increase in sputum eosinophils (0.5 (0 - 26.0)% at baseline and 2.6 (0 - 32.0) % after AMP), as had the subgroup of current asthmatics without hyperresponsiveness to AMP (0.2 (0 - 1.8)% at baseline and 1.3 (0 - 6.3)% after AMP).

Conclusions

Subjects with complete asthma remission, in contrast to subjects with current asthma, do not respond with eosinophilic inflammation in sputum after AMP provocations. These data lend support to the usefulness of the definition of complete asthma remission.

Associations of airway inflammation and responsiveness markers in non asthmatic subjects at start of apprenticeship

Background

Bronchial Hyperresponsiveness (BHR) is considered a hallmark of asthma. Other methods are helpful in epidemiological respiratory health studies including Fractional Exhaled Nitric Oxide (FENO) and Eosinophils Percentage (EP) in nasal lavage fluid measuring markers for airway inflammation along with the Forced Oscillatory Technique measuring Airway resistance (AR). Can their outcomes discriminate profiles of respiratory health in healthy subjects starting apprenticeship in occupations with a risk of asthma?

Methods

Rhinoconjunctivitis, asthma-like symptoms, FEV1 and AR post-Methacholine Bronchial Challenge (MBC) test results, FENO measurements and EP were all investigated in apprentice bakers, pastry-makers and hairdressers not suffering from asthma. Multiple Correspondence Analysis (MCA) was simultaneously conducted in relation to these groups and this generated a synthetic partition (EI). Associations between groups of subjects based on BHR and EI respectively, as well as risk factors, symptoms and investigations were also assessed.

Results

Among the 441 apprentice subjects, 45 (10%) declared rhinoconjunctivitis-like symptoms, 18 (4%) declared asthma-like symptoms and 26 (6%) suffered from BHR. The mean increase in AR post-MBC test was 21% (sd = 20.8%). The median of FENO values was 12.6 ppb (2.6-132 range). Twenty-six subjects (6.7%) had EP exceeding 14%. BHR was associated with atopy (p < 0.01) and highest FENO values (p = 0.09). EI identified 39 subjects with eosinophilic inflammation (highest values of FENO and eosinophils), which was associated with BHR and atopy.

Conclusions

Are any of the identified markers predictive of increased inflammatory responsiveness or of development of symptoms caused by occupational exposures? Analysis of population follow-up will attempt to answer this question.

The roles of a Th2 cytokine and CC chemokine in children with stable asthma: potential implication in eosinophil degranulation

Th2 cytokine IL-5 and CC chemokine eotaxin are thought to be key regulators of eosinophils in bronchial asthma. However, their involvement in children with stable asthma (SA) has not been determined. We investigated the roles of IL-5 and eotaxin in eosinophil degranulation in children with SA. Induced sputum was obtained from 30 SA, 21 allergic rhinitis (AR), and 22 non-atopic healthy control (HC) children. We measured sputum levels of IL-5, eotaxin, and eosinophil indices [percentage eosinophils, eosinophil-derived neurotoxin (EDN), and eosinophil-cationic protein (ECP)]. We also examined correlations of IL-5 and eotaxin with eosinophil indices. Sputum percentage eosinophils and EDN and ECP levels were significantly higher in the SA group than in the HC group, while only the sputum EDN and ECP levels were significantly higher in the AR group than in the HC group. Unexpectedly, sputum levels of IL-5 were not significantly different among the three groups; however, the levels of eotaxin were higher in the SA group when compared to the HC group. No significant correlations were found between IL-5 and percentage eosinophils, EDN, or ECP levels; in contrast, eotaxin levels correlated significantly with percentage eosinophils (R(s) = 0.638; p = 0.0001), EDN (R(s) = 0.522; p = 0.003), and ECP levels (R(s) = 0.630 and p = 0.0002). The elevated levels and good correlations of eotaxin with sputum eosinophil indices, and no elevation or correlation of IL-5 with these indices, suggest that CC chemokine eotaxin may play a more important role in eosinophil degranulation in children with SA.

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.

Noninvasive methods for assessment of airway inflammation in occupational settings

The present document is a consensus statement reached by a panel of experts on noninvasive methods for assessment of airway inflammation in the investigation of occupational respiratory diseases, such as occupational rhinitis, occupational asthma, and nonasthmatic eosinophilic bronchitis. Both the upper and the lower airway inflammation have been reviewed and appraised reinforcing the concept of 'united airway disease' in the occupational settings. The most widely used noninvasive methods to assess bronchial inflammation are covered: induced sputum, fractional exhaled nitric oxide (FeNO) concentration, and exhaled breath condensate. Nasal inflammation may be assessed by noninvasive approaches such as nasal cytology and nasal lavage, which provide information on different aspects of inflammatory processes (cellular vs mediators). Key messages and suggestions on the use of noninvasive methods for assessment of airway inflammation in the investigation and diagnosis of occupational airway diseases are issued.

Exhaled nitric oxide and exhaled breath condensate pH in severe refractory asthma

BACKGROUND

Distinct inflammatory cellular phenotypes of severe refractory asthma (SRA) have been reported. Fractional exhaled nitric oxide (FeNO) primarily is related to eosinophilic inflammation. Exhaled breath condensate (EBC) pH has been suggested as a noninvasive tool in the assessment of patients with asthma. We sought to determine whether FeNO and EBC pH could identify the presence and type of the underlying cellular inflammation in patients with SRA.

METHODS

Twenty-nine patients with SRA, 27 patients with moderate asthma, and 17 healthy subjects underwent FeNO measurement, EBC collection for pH measurement, and sputum induction for cell count identification.

RESULTS

FeNO was significantly higher and pH significantly lower in patients with SRA than in the other groups. In SRA, FeNO levels of > 19 parts per billion were associated with a sensitivity of 0.78 and a specificity of 0.73 for sputum eosinophilia, whereas FeNO levels of < 19 parts per billion were associated with a sensitivity of 0.63 and a specificity of 0.9 for sputum neutrophilia irrespective of the presence of eosinophils. The pH failed to predict the cellular profile in SRA, but a cutoff value of < 7.37 could predict sputum eosinophilia in moderate asthma.

CONCLUSIONS

In patients with SRA, different FeNO threshold values can identify those with predominant eosinophilia as well as those with neutrophilia. FeNO levels were reduced in patients with predominant neutrophilia regardless of the concomitant presence of eosinophilia. Although pH could not identify the cellular profile in SRA, it seemed to be a better index for predicting eosinophilia in moderate asthma.

[Asthma: a disease of the whole bronchial tree]

Inflammation and remodelling are constant features of asthma. They are present throughout the whole bronchial tree, even in the small airways (less than 2 mm). The inflammatory cell infiltrate and structural changes are, in most cases, identical. However, in severe asthma, nocturnal asthma and fatal asthma, the cellular infiltrate in the distal airways is more intense and the number of activated cells is increased. In fatal asthma there are major alterations in the distal airways involving the smooth muscle and the bronchial epithelium, and mucus hypersecretion leading to distal airway plugging. Thus the histopathological changes in the distal airways contribute to the most severe stages of asthma and should be targeted by treatment. Currently the non-invasive tools that reflect inflammation are unable to assess these changes in the distal airways.

Airway inflammation in Michigan pleasure horses: prevalence and risk factors

REASONS FOR PERFORMING STUDY

Although subclinical airway inflammation is thought to be common in horses, there is little information on its prevalence and none on risk factors.

OBJECTIVE

To determine the prevalence and risk factors for an increased number of inflammatory cells and for mucus accumulation in the trachea of pleasure horses.

METHODS

Horses (n = 266) in stables (n = 21) in Michigan were examined endoscopically, once in winter and once in summer 2004. Visible tracheal mucoid secretions were graded 0-5 and inflammatory cell numbers counted in a tracheal lavage sample. Information collected about each horse included age, gender, presence of cough, percent time indoors and source of roughage. The repeated measures were analysed by generalised estimating equations and linear mixed models.

RESULTS

Horses eating hay, especially from round bales, had the most neutrophils, whereas horses feeding from pasture had the fewest. Being female and being outdoors in winter were associated with increased numbers of inflammatory cells. Older horses had fewer macrophages than young horses. More than 70% of horses had >20% neutrophils in tracheal lavage. Twenty percent of horses had a mucus accumulation score >1; 17% had both a mucus score >1 and >20% neutrophils. The significant risk factors for mucus accumulation >1 were age >15 years, feeding on hay as compared to pasture, and being outdoors for more than 80% time in winter. Even though mucus accumulation score >1 was a risk factor for cough, only half of such horses coughed. Cough and mucus accumulation were associated with increased number of neutrophils.

CONCLUSIONS

In comparison to pasture feeding, hay feeding, particularly from round bales, was associated with an increased number of neutrophils in the airway. Being outdoors in winter was associated with increased numbers of inflammatory cells and with mucus accumulation. Because 70% of horses have >20% neutrophils, this value should not be used as the sole indicator of airway inflammation.

POTENTIAL RELEVANCE

The study reinforces the importance of hay feeding and older age as risk factors for inflammatory airway disease. Horses that do not have 'heaves' may be best kept indoors when winters are cold.

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.

Association between asthma control and bronchial hyperresponsiveness and airways inflammation: a cross-sectional study in daily practice

BACKGROUND

The primary end-point in the management of asthma is to obtain optimal control. The aim of this study was to assess the relationships between the markers of airway inflammation (sputum eosinophilia and exhaled nitric oxide), bronchial hyperresponsiveness (BHR) and asthma control.

METHODS

One hundred and thirty-four patients were recruited from our asthma clinic between January 2004 and September 2005 [mean age: 42 years, mean forced expiratory volume in 1 s (FEV(1)): 86% predicted]. Eighty-six of them were treated by inhaled corticosteroids, 99 were atopic and 23 were current smokers. They all underwent detailed investigations including fractional-exhaled nitric oxide (FE(NO)) measurement, sputum induction and methacholine challenge when FEV(1) was >70% predicted, and filled in a validated asthma control questionnaire (ACQ6 Juniper).

RESULTS

When dividing patients into the three groups according to their level of asthma control determined by ACQ [well-controlled asthma (ACQ score <or=0.75), borderline (0.75<ACQ score <1.5) and uncontrolled asthma (ACQ score >or=1.5)], it appeared that uncontrolled asthmatics had a greater BHR to methacholine and sputum eosinophilia than controlled asthma (P<0.05, P<0.001, respectively). By contrast, we failed to show significant differences in the FE(NO) levels between the groups. With receiver-operating characteristic curves for differentiating uncontrolled (ACQ>or=1.5) from controlled and borderline (ACQ<1.5) asthma, sputum eosinophilia and methacholine responsiveness were found to be more accurate than FE(NO) (area under the curve: 0.72, 0.72 and 0.59, respectively).

CONCLUSION

In a broad spectrum of asthmatics encountered in clinical practice, sputum eosinophilia and methacholine bronchial hyperresponsiveness, but not FE(NO), are associated with uncontrolled asthma.

Cough due to asthma and nonasthmatic eosinophilic bronchitis

Asthma and nonasthmatic eosinophilic bronchitis are among the most common causes of chronic cough, accounting for about 25 and 10% of cases, respectively. Chronic cough due to asthma may present in isolation in which case it is known as cough-variant asthma. Nonasthmatic eosinophilic bronchitis is characterized by the presence of eosinophilic airway inflammation in the absence of variable airflow obstruction or airway hyperresponsiveness. Both conditions share many immunopathological features with the exceptions to date of mast cell infiltration into the airway smooth muscle, increased IL-13 expression, and narrowing and thickening of the airway wall, which are features reserved to asthma. In most cases the trigger that causes the cough is uncertain. However, removal of potential triggers is important to consider, in particular with respect to occupational exposure to known sensitisers. In both conditions there is subjective and objective improvement following treatment with inhaled corticosteroids, which is associated with the presence of an airway eosinophilia. Whether eosinophilic inflammation is the cause of cough or an epiphenomenon is uncertain, but the failure of anti-IL-5 to modify cough in asthma has questioned a causal association. In asthma, beta-agonist theophylline, leukotriene receptor antagonist, and oral corticosteroid therapy improve cough. In noneosinophilic bronchitis, some patients require oral corticosteroids but the benefit of other additional therapies is unknown. In general, 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 persistent airflow obstruction may occur.

The validity of induced sputum and bronchoalveolar lavage in childhood asthma

There are a number of useful direct airway sampling procedures to help diagnose and monitor asthma in patients. However, non-invasive techniques are the ideal, especially in children, given the necessity of safe and repeatable measurements to monitor treatment efficacy and disease progression. Bronchoalveolar lavage (BAL) may be too invasive for clinical use in children, while questions still surround the utility of induced sputum (IS). More novel techniques, such as fractional exhaled nitric oxide (FE(NO)) and exhaled breath condensate (EBC), are still unproven. Eosinophilic airway inflammation is a major feature of childhood asthma, and it has been revealed as a major treatment target with inhaled corticosteroids. Moreover, treatment protocols governed by sputum eosinophil counts may be more efficacious - by reducing the frequency and severity of exacerbations - than treatment based on clinical symptoms and other traditional objective measures of lung function. The selection of an appropriate airway inflammation monitoring technique must take everything into consideration, including safety, reproducibility, repeatability, sensitivity to treatment, and the overall clinical/research goals.

[Phenotypic characterization and course of chronic obstructive pulmonary disease in the PAC-COPD Study: design and methods]

BACKGROUND AND OBJECTIVES

The Phenotype and Course of Chronic Obstructive Pulmonary Disease (PAC-COPD) study aims to improve our understanding of the phenotypic heterogeneity of this disease and the extent to which this heterogeneity is related to clinical course. The main objectives are a) to characterize the phenotypic variability in first-time hospitalizations for exacerbation of COPD and to propose a classification into subtypes and b) to ascertain the association between the defined subtypes and the clinical and functional course of COPD.

PATIENTS AND METHODS

This is a cross-sectional and cohort study of 342 patients with COPD from 9 tertiary hospitals in 3 autonomous communities. The minimum follow-up period is 5 years. The main variables of interest are respiratory symptoms, smoking, alcohol use, physical activity, use of health care services, medical care, treatment received, activities of daily living, comorbid conditions, sleepiness, anxiety and depression, quality of life, forced spirometry and bronchodilation tests, lung volume and inspiratory capacity measured by body plethysmography, carbon monoxide diffusing capacity, baseline arterial blood gas values, respiratory and peripheral muscle function, electrocardiogram, body weight and composition measured by bioelectric impedance, chest radiograph, skin prick test, capacity for exercise measured in the 6-minute walk test and cardiopulmonary exercise test, induced sputum (for quantitative microbiological culture and determination of inflammatory markers), nighttime pulse oximetry, chest computed tomography scan, and echocardiography. Serum and plasma samples are also taken to measure levels of inflammatory markers and oxidative stress, for genetic analysis, and for other possible measurements that might be required in the future. The statistical analysis combines factor analysis and survival models such as Cox regression analysis. This project will enable us to reconsider the definition and classification of COPD and to better understand the factors associated with its natural history.

Asthma management by monitoring sputum neutrophil count

We report the utility of quantitative cell counts in sputum in monitoring therapy of a patient with poorly controlled asthma. Recurrent neutrophilic bronchitis without an eosinophilic bronchitis led to the identification of Chlamydophila pneumoniae as the cause of bronchitis and asthma exacerbation. Serial examination of blood and sputum by polymerase chain reaction for C pneumoniae helped to prevent exacerbations by prophylactic antibiotic therapy, reduce the dose of prednisone and inhaled corticosteroids, and improve asthma control.

Magnetic enrichment of bronchial epithelial cells from sputum for lung cancer diagnosis

BACKGROUND

Sputum is an easily accessible diagnostic material for lung cancer early detection by cytologic and molecular genetic analysis of exfoliated airway epithelial cells. However, the use of sputum is limited by its cellular heterogeneity, which includes >95% macrophages and neutrophils and only about 1% bronchial epithelial cells. We propose to obtain concentrated and purified bronchial epithelial cells to improve early detection of lung cancer in sputum samples.

METHODS

Sputum was collected from patients with stage I nonsmall-cell lung cancer, cancer-free smokers, and healthy nonsmokers. Magnetic-assisted cell sorting (MACS) with anti-CD14 and anti-CD16 antibody beads were used to enrich bronchial epithelial cells by depleting macrophages and neutrophils from sputum. Fluorescence in situ hybridization (FISH) analysis for detection of FHIT deletion and cytology were evaluated in the enriched specimens.

RESULTS

The bronchial epithelial cells were concentrated to 40% purity from 1.1% of the starting population, yielding an average of 36-fold enrichment and at least 2.3 x 10(5) cells per sample. Detecting FHIT deletions for lung cancer diagnosis produced 58% sensitivity in the enriched sputum, whereas there was 42% sensitivity in the unenriched samples (P = .02). Cytologic examination of the enriched sputum resulted in 53% sensitivity, as compared with 39% sensitivity in unenriched sputum (P = .03). Furthermore, only 2 cytocentrifuge slides of the unenriched sputum were needed for the analyses, as compared with up to 10 cytocentrifuge slides required from the unprocessed specimens.

CONCLUSIONS

The enrichment of bronchial epithelial cells could improve the diagnostic value of sputum and the efficiency of genetic and cytologic analysis of lung cancer.

Non-invasive biomarkers and pulmonary function in smokers

Limited information exists regarding measurement, reproducibility and interrelationships of non-invasive biomarkers in smokers. We compared exhaled breath condensate (EBC) leukotriene B₄ (LTB₄) and 8-isoprostane, exhaled nitric oxide, induced sputum, spirometry, plethysmography, impulse oscillometry and methacholine reactivity in 18 smokers and 10 non-smokers. We assessed the relationships between these measurements and within-subject reproducibility of EBC biomarkers in smokers. Compared to non-smokers, smokers had significantly lower MMEF % predicted (mean 64.1 vs 77.7, p = 0.003), FEV₁/FVC (mean 76.2 vs 79.8 p = 0.05), specific conductance (geometric mean 1.2 vs 1.6, p = 0.02), higher resonant frequency (mean 15.5 vs 9.9, p = 0.01) and higher EBC 8-isoprostane (geometric mean 49.9 vs 8.9 pg/ml p = 0.001). Median EBC pH values were similar, but a subgroup of smokers had airway acidification (pH < 7.2) not observed in non-smokers. Smokers had predominant sputum neutrophilia (mean 68.5%). Repeated EBC measurements showed no significant differences between group means, but Bland Altman analysis showed large individual variability. EBC 8-isoprostane correlated with EBC LTB₄ (r = 0.78, p = 0.0001). Sputum supernatant IL-8 correlated with total neutrophil count per gram of sputum (r = 0.52, p = 0.04) and with EBC pH (r = −0.59, p = 0.02). In conclusion, smokers had evidence of small airway dysfunction, increased airway resistance, reduced lung compliance, airway neutrophilia and oxidative stress.

Eosinophilic bronchitis without asthma

BACKGROUND

Eosinophilic bronchitis without asthma causes chronic coughs without the physiologic features of asthma. The aim of this study was to review the clinical features, pathogenesis, diagnosis, treatment and prognosis of this condition.

METHODS

The current literature was reviewed using Pubmed for all studies published in the English language using the search term 'eosinophilic bronchitis'.

RESULTS

Eosinophilic bronchitis presents as normal spirometry, without evidence of airway hyperresponsiveness, and normal peak expiratory flow variability. When compared with asthma, mast cell recruitment to the superficial airways and mast cell activation appear to be a feature of eosinophilic bronchitis. In contrast, mast cell infiltration in the smooth muscle is significantly higher in asthma patients than in either eosinophilic bronchitis patients or healthy control subjects. In this condition, the absence of high IL-13 expression can contribute to the normal airway reactivity. The cough usually responds well to inhaled corticosteroids but dose and duration of treatment remain unclear. The condition can be transient, episodic or persistent unless treated, and occasionally, patients may require long-term treatment with oral corticosteroids.

CONCLUSIONS

The condition is an important cause of chronic coughs which are corticosteroid responsive. The study of eosinophilic bronchitis suggests that eosinophil-dependent mechanisms are generally not important in the pathogenesis of asthma.

Asthma biomarkers in sputum

Several inflammatory cells are thought to contribute to the pathogenesis of asthma. Among these, the eosinophil appears to be a major effector cell. This review focuses primarily on the clinical utility of sputum eosinophil counts in asthma. Several studies have shown sputum eosinophils to be associated with both asthma severity and level of asthma control. In addition, the presence of sputum eosinophilia is strongly predictive of a favorable response to glucocorticoid therapy. Conversely, the absence of sputum eosinophilia is predictive of a poor response to glucocorticoid therapy. Sputum eosinophilia also predicts asthma relapse in subjects who have their inhaled glucocorticoid reduced or withdrawn. Lastly, inhaled glucocorticoid therapy can be titrated to keep the sputum eosinophil count at or below 2%.

Nitrative stress in refractory asthma

BACKGROUND

Most asthma is mild and moderate and can be well controlled by low-dose inhaled steroid with or without bronchodilators. However, 5% to 10% of patients with asthma have more troublesome disease despite using such medication. Recent reports showed that nitrative stress induced tissue remodeling in vitro, which is associated with a component of refractoriness in asthma. However, there is no report that nitrative stress is involved in refractory asthma.

OBJECTIVE

The aim of this study is to evaluate whether patients with refractory asthma have more nitrative stress.

METHODS

Ten healthy subjects, 10 patients with well-controlled asthma, and 8 patients with refractory asthma took part in the current study. Exhaled nitric oxide, xanthine oxidase activity in the supernatant of the sputum, immunostaining for the inducible type of nitric oxide synthase, and 3-nitrotyrosine in induced sputum from the subjects were assessed.

RESULTS

All nitrative markers including exhaled nitric oxide (P < .01), immunopositivities for inducible nitric oxide synthase (P < .01), xanthine oxidase activities (P < .01), and 3-nitrotyrosine (P < .01) in sputum from the refractory asthma group were enhanced compared with the well-controlled group. All these nitrative markers in the sputum had a significant negative correlation with the %FEV(1) values (P < .01).

CONCLUSION

These results suggested that patients with refractory asthma have more nitrative stress in their airways compared with patients with well-controlled asthma.

Eosinophilic airway inflammation in COPD

Chronic obstructive pulmonary disease is a common condition and a major cause of mortality. COPD is characterized by irreversible airflow obstruction. The physiological abnormalities observed in COPD are due to a combination of emphysema and obliteration of the small airways in association with airway inflammation. The predominant cells involved in this inflammatory response are CD8+ lymphocytes, neutrophils, and macrophages. Although eosinophilic airway inflammation is usually considered a feature of asthma, it has been demonstrated in large and small airway tissue samples and in 20%–40% of induced sputum samples from patients with stable COPD. This airway eosinophilia is increased in exacerbations. Thus, modifying eosinophilic inflammation may be a potential therapeutic target in COPD. Eosinophilic airway inflammation is resistant to inhaled corticosteroid therapy, but does respond to systemic corticosteroid therapy, and the degree of response is related to the intensity of the eosinophilic inflammation. In COPD, targeting treatment to normalize the sputum eosinophilia reduced the number of hospital admissions. Whether controlling eosinophilic inflammation in COPD patients with an airway eosinophilia will modify disease progression and possibly alter mortality is unknown, but warrants further investigation.

Sputum eosinophils and the response of exercise-induced bronchoconstriction to corticosteroid in asthma

BACKGROUND

The relationship between eosinophilic airway inflammation and exercise-induced bronchoconstriction (EIB), and the response to inhaled corticosteroid (ICS) therapy was examined.

METHODS

Twenty-six steroid-naïve asthmatic patients with EIB were randomized to two parallel, double-blind, crossover study arms (13 subjects in each arm). Each arm compared two dose levels of inhaled ciclesonide that were administered for 3 weeks with a washout period of 3 to 8 weeks, as follows: (1) 40 vs 160 microg daily; and (2) 80 vs 320 microg daily. Baseline and weekly assessments with exercise challenge and sputum analysis were performed.

RESULTS

Data were pooled and demonstrated that 10 subjects had baseline sputum eosinophilia >or= 5%. Only high-dose ICS therapy (ie, 160 and 320 microg) significantly attenuated the sputum eosinophil percentage. Sputum eosinophil percentage significantly correlated with EIB severity, and predicted the magnitude and temporal response of EIB to high-dose therapy, but not to low-dose therapy (ie, 40 and 80 microg). Low-dose ICS therapy provided a significant reduction in EIB at 1 week, with little additional improvement thereafter, irrespective of baseline sputum eosinophil counts. In contrast, high-dose ICS therapy provided a significantly greater improvement in EIB in subjects with sputum eosinophilia compared to those with an eosinophil count of < 5%. The difference between the eosinophilic groups in the magnitude of improvement in EIB was evident after the first week of high-dose ICS therapy and increased with time.

CONCLUSIONS

These results suggest that eosinophilic airway inflammation may be important in modifying the severity of EIB and the response to ICS therapy. Measurements of sputum eosinophil percentage may, therefore, be useful in predicting the magnitude and temporal response of EIB to different dose levels of ICSs.

TRIAL REGISTRATION

clinicaltrial.gov; Identifier: NCT00525772.

Sputum neutrophilia can mask eosinophilic bronchitis during exacerbations

BACKGROUND

Exacerbations of airway disease are eosinophilic, neutrophilic, both or neither. The primary objective of the present study was to identify whether the treatment of a neutrophilic bronchitis can unmask an associated eosinophilia.

METHODS

A retrospective survey of 2160 consecutive sputum cell counts from 1343 patients with airway disease was conducted to identify patients with an isolated neutrophilic bronchitis, which was defined as a sputum total cell count of greater than or equal to 12 x 10(6) cells/g of sputum and a proportion of neutrophils of 80% or greater. The characteristics of the patients who subsequently demonstrated sputum eosinophilia (3% or greater) within eight weeks of resolving the neutrophilia were compared with the patients who subsequently did not have sputum eosinophilia.

RESULTS

Two hundred thirty-seven patients had 273 neutrophilic exacerbations. The sputum was re-examined within eight weeks in 65 patients (27.4%), of whom 38 (58.5%) had resolution of the neutrophilic bronchitis after treatment with an antibiotic. Of these 38 patients, 13 (34%) showed eosinophilia.

CONCLUSIONS

A neutrophilic exacerbation of airway disease was observed to mask sputum eosinophilia in one-third of patients who had sputum cell counts available before and after antibiotic therapy. Hence, the absence of sputum eosinophilia during an infective exacerbation should not be used as an indication to reduce the dose of corticosteroids. To optimize therapy, repeat sputum cell count measurements are recommended after antibiotic treatment before changing corticosteroid treatment.

Association between neutrophilic airway inflammation and airflow limitation in adults with asthma

BACKGROUND

There is debate about the mechanisms of persistent airflow limitation in patients with asthma. Chronic inflammation is assumed to be important, although there is limited and contradictory information about the relationship between airway inflammation and postbronchodilator FEV1.

METHODS

We have assessed the cross-sectional relationship between prebronchodilator and postbronchodilator FEV1 and measures of airway inflammation after allowing for the effects of potential confounding factors. Multivariate analysis was performed on data collected from 1,197 consecutive patients with asthma seen at the respiratory outpatient clinic at Glenfield Hospital between 1997 and 2004. Relationships between induced sputum total neutrophil and differential eosinophil cell counts, and prebronchodilator and postbronchodilator lung function were examined.

RESULTS

Sputum total neutrophil but not differential eosinophil count was associated with lower postbronchodilator FEV1. Both differential eosinophil and total neutrophil count were associated with lower prebronchodilator FEV1. These effects were independent after adjustment for age, smoking, ethnicity, asthma duration, and inhaled corticosteroid use. A 10-fold increase in neutrophil count was associated with a 92 mL reduction (95% confidence interval, 29 to 158; p = 0.007) in postbronchodilator FEV1.

CONCLUSIONS

In this large heterogeneous population of adults with asthma, we have shown that prebronchodilator FEV1 is associated with neutrophilic and eosinophilic airway inflammation, whereas sputum total neutrophil counts alone are associated with postbronchodilator FEV1. This supports the hypothesis that neutrophilic airway inflammation has a role in the progression of persistent airflow limitation in asthma and raises the possibility that this progression and the development of COPD share a common mechanism.

Airway inflammation in the elite athlete and type of sport

BACKGROUND

The prevalence of asthma and bronchial hyper-responsiveness is greater in elite athletes than in the general population, and its association with mild airway inflammation has recently been reported.

OBJECTIVE

To study the relationship between the type of sport practised at the highest levels of competition (on land or in water) and sputum induction cell counts in a group of healthy people and people with asthma.

MATERIAL AND METHODS

In total, 50 athletes were enrolled. Medical history, results of methacholine challenge tests and sputum induced by hypertonic saline were analysed

RESULTS

Full results were available for 43 athletes, who were classified by asthma diagnosis and type of sport (land or water sports). Nineteen were healthy (10 land and 9 water athletes) and 24 had asthma (13 land and 11 water athletes). Although the eosinophil counts of healthy people and people with asthma were significantly different (mean difference 3.1%, 95% CI 0.4 to 6.2, p = 0.008), analysis of variance showed no effect on eosinophil count for either diagnosis of asthma or type of sport. However, an effect was found for neutrophil counts (analysis of variance: F = 2.87, p = 0.04). There was also a significant correlation between neutrophil counts and both duration of training and bronchial hyper-responsiveness among athletes exposed to water (Spearman's rank correlations, 0.36 and 0.47, p = 0.04 and 0.04, respectively).

CONCLUSIONS

Elite athletes who practice water sports have mild neutrophilic inflammation, whether or not asthma is present, related to the degree of bronchial hyper-reactivity and the duration of training in pool water.

Diagnostic utility of inflammatory biomarkers in asthma: exhaled nitric oxide and induced sputum eosinophil count

BACKGROUND

Even though an inflammatory process is known to be the underlying cause of asthma, diagnosis is based on clinical history, reversible airway obstruction and bronchial hyperresponsiveness according to international guidelines. The fraction of exhaled nitric oxide (FE(NO)) and induced sputum eosinophil count (Eos%) have been used as non-invasive inflammatory biomarkers.

OBJECTIVES

The aim of this study was to compare the sensitivity and specificity of FE(NO), Eos% and spirometry and to assess whether their combined use in clinical practice would improve diagnostic yield.

METHODS

In 50 patients with asthma symptoms we performed spirometry, a methacholine challenge test, FE(NO) measurement and assessment of Eos% in induced sputum. The standard diagnosis of asthma followed the guidelines of the Global Initiative for Asthma.

RESULTS

Twenty-two of the 50 patients were diagnosed with asthma. The sensitivity and diagnostic accuracy were higher for FE(NO) measurement (77%; area under the receiver operating curve [AUC], 0.8) than for spirometry (22%; AUC, 0.63). The sensitivity and specificity of Eos% in induced sputum were 40% and 82%, respectively, and the diagnostic accuracy of Eos% was lower (AUC, 0.58). When both inflammatory biomarkers were used together specificity increased to 76%.

CONCLUSIONS

The diagnostic accuracy of FE(NO) measurement was superior to that of the standard diagnostic spirometry in patients with symptoms suggestive of asthma. The use of FE(NO) measurement and induced sputum Eos% together to diagnose asthma in clinical practice is more accurate than spirometry or FE(NO) assessment alone and easier to perform.

Induced sputum as a tool for early detection of airway inflammation in connective diseases-related lung involvement

BACKGROUND

Induced sputum (IS) sampling is a safe and validated approach to study bronchial inflammation in chronic obstructive lung diseases. Although promising results have also been reported in various diffuse interstitial lung disorders, the potential use of IS in the assessment of connective tissue diseases (CTD)-related lung involvement has not yet been investigated.

AIM OF THE STUDY

To evaluate the clinical usefulness of IS in the early management of patients suffering from rheumatoid arthritis (RA) and systemic sclerosis (SSc) at the onset of respiratory symptoms.

PATIENTS AND METHODS

The study population included 19 patients (RA=12; SSc=7) and 14 age- and sex-matched healthy volunteers. Lung function testing, high resolution computed tomography (HRCT) of the thorax and IS collection were performed in all cases. Broncho-alveolar lavage (BAL) was obtained in selected patients.

RESULTS

IS samples from patients contained a significantly higher percentage of neutrophils and a lower percentage of macrophages compared to healthy subjects (p=0.002 and 0.001, respectively), while the total cell number showed no differences. In addition, sputa yielded both higher cell counts and higher neutrophils than BAL samples (p=0.02 in all instances). No correlations were found between IS findings and lung function parameters, HRCT and BAL findings.

CONCLUSIONS

This is the first study investigating the inflammatory cell pattern in IS from CTD patients with early clinical evidence of lung involvement. Future studies are needed to determine whether the assessment of airway inflammation adds significant information that may result in a relevant improvement of disease management.

Effect of obesity on airway inflammation: a cross-sectional analysis of body mass index and sputum cell counts

BACKGROUND

Several observational studies have demonstrated an association between obesity and asthma. Studies evaluating exhaled nitric oxide levels and obesity have revealed that a higher body mass index (BMI) is associated with elevated exhaled nitric oxide levels. Airway inflammation using sputum cell counts has not been assessed in obese patients with airway diseases.

OBJECTIVE

The primary aim of this study was to determine whether obesity (based on BMI) is associated with eosinophilic or neutrophilic bronchitis.

METHODS

The results from a database of induced sputum cell counts were compared with BMI and analysed using correlation statistics, regression and parametric and non-parametric analysis.

RESULTS

Seven-hundred and twenty-seven adult participants with an equal number of sputum samples were included in the analysis. BMI varied from 14.5 to 55 kg/m(2). Sputum total cell count (mean+/-SD: 12.9 x 10(6) cell/g+/-21.5), eosinophil percent (median; min to max: 0.3%; 0-89.0), and neutrophil percent (mean+/-SD: 63.5+/-26.6%) were within normal limits. Participants with asthma had a higher percentage of sputum eosinophils than those without asthma (P=0.01). However, there was no difference in the total or differential cell counts among the obese and non-obese participants, when the data were analysed according to BMI category, gender, dose of inhaled corticosteroid, and presence or absence of asthma.

CONCLUSION

In this large sample of adult asthmatic and non-asthmatic participants, there was no association between BMI and airway inflammation measured by sputum cell counts. Other mechanisms to explain the relationship between obesity and asthma will need to be explored if this association is to be better understood.

Airways disease: phenotyping heterogeneity using measures of airway inflammation

: Despite asthma and chronic obstructive pulmonary disease being widely regarded as heterogeneous diseases, a consensus for an accurate system of classification has not been agreed. Recent studies have suggested that the recognition of subphenotypes of airway disease based on the pattern of airway inflammation may be particularly useful in increasing our understanding of the disease. The use of non-invasive markers of airway inflammation has suggested the presence of four distinct phenotypes: eosinophilic, neutrophilic, mixed inflammatory and paucigranulocytic asthma. Recent studies suggest that these subgroups may differ in their etiology, immunopathology and response to treatment. Importantly, novel treatment approaches targeted at specific patterns of airway inflammation are emerging, making an appreciation of subphenotypes particularly relevant. New developments in phenotyping inflammation and other facets of airway disease mean that we are entering an era where careful phenotyping will lead to targeted therapy.

Noneosinophilic asthma: A distinct clinical and pathologic phenotype

The use of induced sputum to assess airway inflammation in large and diverse populations with asthma has led to the recognition that significant numbers of patients do not have evidence of eosinophilic airway inflammation. The absence of a sputum eosinophilia has been noted in patients across the range of asthma severity; it has also been reported in patients presenting with an asthma exacerbation. However, whether noneosinophilic asthma represents a pathologically distinct and clinically important asthma phenotype remains unclear. In this review, we present recent evidence suggesting that noneosinophilic asthma represents a stable phenotype associated with a distinct lower airway pathology and structure. We suggest that this lower airway inflammation develops in response to etiologic factors acting through the innate immune pathway and that elements of this immune response contribute to airway dysfunction. Finally, we argue that noneosinophilic asthma is associated with clinically important differences in natural history and treatment response. We particularly highlight evidence that noneosinophilic asthma is associated with a reduced short-term and long-term response to corticosteroid therapy.

Uteroglobin-Related Protein 1 and Clara Cell Protein in Induced Sputum of Patients With Asthma and Rhinitis

RATIONALE

Uteroglobin-related protein 1 (UGRP1) and Clara cell protein (CC16), members of the secretoglobin family, increasingly appear to play a role in airway inflammatory response.

OBJECTIVE

To explore levels of UGRP1 and CC16 in induced sputum of patients with asthma and rhinitis.

METHODS

Induced-sputum samples of patients with asthma or rhinitis (n = 32 each; atopic asthma, n = 24; atopic rhinitis, n = 20) and from 19 nonsmoking nonatopic control subjects were analyzed for cytology and levels of UGRP1, CC16, and albumin.

MEASUREMENTS AND MAIN RESULTS

Sputum UGRP1 increased in both asthma and rhinitis, most strikingly so in asthma, in which changes were most significant in atopic individuals. By contrast, sputum CC16 did not change significantly in either condition, although it was positively correlated with UGRP1 in patients and control subjects. Changes in sputum UGRP1 in atopic asthma were not linked to permeability changes reflected by increased albumin levels but correlated positively with sputum macrophages and negatively with eosinophils. The observed differences in UGRP1 and CC16 may be linked to different cell populations being responsible for their secretion; UGRP1 is mainly secreted in larger conducting airways, whereas CC16 is mainly secreted by the nasal and peripheral airways epithelium.

CONCLUSIONS

The increase in UGRP1 but not of CC16 in asthma and rhinitis suggests that UGRP1 may play a role in these inflammatory diseases.

Repeated sputum inductions induce a transient neutrophilic and eosinophilic response

INTRODUCTION

Sputum induction is a tool to monitor airway inflammation, yet it may induce by itself a neutrophilic response when repeated within 24 to 48 h. This limits its repeated use in clinical trials.

OBJECTIVE

We aimed to investigate the induction and resolution of inflammation generated by repeated sputum inductions.

SUBJECTS AND DESIGN

Sixteen healthy intermittent smokers participated in a study on the short-term effects of smoking. The nonsmoking arm consisted of seven successive sputum inductions with increasing time intervals (3, 6, 12, 24, 48, and 96 h). Inflammatory cellular characteristics and different soluble mediators were investigated.

MEASUREMENTS AND RESULTS

The median percentage of sputum neutrophils increased significantly from baseline to 6 h (58.9% [range, 31.8 to 94.2%] to 83.2% [range, 26.7 to 98.3%], respectively). Surprisingly, the percentage of eosinophils also increased significantly from baseline to 6, 12, 24, and 48 h, as follows: 0.3% (range, 0.0 to 1.2%) to 1.7% (range, 0.0 to 15.5%), 2.2% (range, 0.5 to 12.5%), 1.2% (range, 0.0 to 4.8%), and 0.8% (range, 0.0 to 2.8%), respectively. Interleukin-8 increased significantly from baseline to 24 h (1,553 pg/mL [range, 462 to 8,192 pg/mL] to 2,178 pg/mL [range, 666 to 128,544 pg/mL]).

CONCLUSIONS

Repeated sputum inductions should preferably be avoided within 48 h. It induces not only a short-lived neutrophilic response but also a prolonged eosinophilic inflammatory response in healthy subjects, possibly by local changes in osmolarity, and subsequent epithelial and/or mast cell activation.

Profiles of proinflammatory cytokines in sputum from different groups of severe asthmatic patients

BACKGROUND

Severe asthma represents a heterogeneous group of patients whose characteristics of airway inflammation are poorly known.

OBJECTIVE

To evaluate the sputum cytokine profiles of different phenotypes of severe asthma.

METHODS

Severe asthmatic patients (n = 45) were divided into 3 groups: frequent exacerbations, persistent bronchoconstriction, and both features. Two other groups (9 patients with untreated mild asthma and 10 control subjects) were also studied. Selected sputum portions were assayed for differential cell count, supernatant interleukin 5 (IL-5), granulocyte-macrophage colony-stimulating factor, IL-8, and eosinophil cationic protein.

RESULTS

There were no statistically significant differences among the 3 severe asthma groups in terms of sputum inflammatory cell percentages, IL-8 levels, and eosinophil cationic protein levels, although IL-8 levels tended to be higher in patients with persistent bronchoconstriction. Sputum concentrations of granulocyte-macrophage colony-stimulating factor and IL-5 were significantly higher in patients with frequent exacerbations compared with the other 2 groups. Levels of IL-5 and IL-8 were higher in severe asthmatic patients compared with mild asthmatic patients and controls, whereas sputum eosinophil percentages were intermediate between those of mild asthmatic patients and controls.

CONCLUSIONS

Proeosinophilic cytokine levels are increased in severe asthmatic patients with frequent exacerbations but not in severe asthmatic patients with persistent bronchoconstriction, suggesting that different cytokine profiles could be associated with different phenotypes of severe asthma.

[Use of induced sputum in the investigation of occupational asthma]

The diagnosis of occupational asthma relies mainly on the demonstration of changes in airway calibre and airway responsiveness after exposure to occupational agents in the laboratory or at the workplace. However, spirometry or peak expiratory flow measurements may be open to misinterpretation when they are not performed optimally. As in non-occupational asthma, airway inflammation is one of the main characteristics of occupational asthma. Induced sputum, a non invasive method to assess airway inflammation, has been successfully used in the management of asthma. This article reviews the studies that have investigated and characterized the changes in sputum cell counts occurring in subjects with occupational asthma after exposure to occupational agents in the laboratory or at the workplace in order to assess the place of induced sputum in the investigation of occupational asthma. It also reviews the use of induced sputum during the follow-up of workers with occupational asthma after removal from exposure. This article also describes a new condition identified thanks to the use of induced sputum : occupational eosinophilic bronchitis. In conclusion, induced sputum is a useful tool in the investigation of occupational asthma. Its use on a regular basis in the investigation of occupational asthma also allows for the possibility of diagnosis of overlooked conditions such as occupational eosinophilic bronchitis. Its role in the surveillance of workers at risk to develop occupational asthma remains to be determined.

Pharmacological management of mild or moderate persistent asthma

Patients with mild persistent asthma rarely see their doctor with symptoms of the disease. Partly as a result of this situation, mild asthma is generally undertreated. Findings of several large randomised clinical trials have shown benefits for this population of regular treatment with low doses of inhaled corticosteroids. Additional drugs are rarely needed, and although leukotriene modifiers are effective, they are less so than inhaled corticosteroids. People with moderate persistent asthma are not well controlled on low doses of inhaled corticosteroids. A combination of this drug and long-acting inhaled beta2 agonists provides improved control compared with doubling of the maintenance dose of inhaled corticosteroids. The combination of budesonide and formoterol has been assessed as both maintenance and reliever treatment. This approach further reduces the risk for severe exacerbations. With these strategies, most individuals can achieve good control of their asthma. For patients who do not achieve asthma control despite taking drugs, measurement of the inflammatory response in the airway in induced sputum could provide further information to guide treatment.