Inflammatory Cells In Induced Sputum Research Articles

The Role of Chitinases in Chronic Airway Inflammation Associated with Tobacco Smoke Exposure

Chitinases and chitinase-like proteins are thought to play a role in innate inflammatory responses. Our study aimed to assess whether chitinase concentration and activity in induced sputum (IS) of patients exposed to tobacco smoke are related to the level of airway inflammation including the level and activity of chitinases and chitinase-like proteins. The study included 22 patients with chronic obstructive pulmonary disease (COPD), 12 non-COPD smokers, and nine nonsmoking subjects. Sputum CHIT1 and YKL-40 levels and chitinolytic activity were compared with sputum IL-6, IL-8, IL-18, and MMP-9 levels. A hierarchical cluster analysis was also performed. Sputum YKL-40 was higher in COPD patients than in the control groups. Sputum CHIT1 and YKL-40 levels correlated with IS inflammatory cell count as well as with MMP-9 and IL-8 levels. Two main clusters were revealed: Cluster 1 had lower chitinase levels and activity, lower IS macrophage and neutrophil count, and lower IS IL-8, IL-18, and MMP-9 than Cluster 2. Comparison of COPD patients from both clusters revealed significant differences in the IS inflammatory profile despite comparable clinical and functional data. Our findings seem to confirm the involvement of chitinases in smoking-associated chronic airway inflammation and show that airway chitinases may be a potential novel marker in COPD phenotyping.

Airway Hyperresponsiveness to Inhaled Mannitol Identifies a Cluster of Noneosinophilic Asthma Patients with High Symptom Burden

Patients with asthma are heterogeneous in clinical presentation and in response to treatment. Despite this, tools to guide treatment are limited and include mainly measures of eosinophilic inflammation and symptoms. Airway hyperresponsiveness (AHR) to mannitol is present in patients across inflammatory phenotypes and improve with inhaled corticosteroids. To investigate whether measuring AHR to mannitol in addition to eosinophilic inflammation and symptoms adds information to the phenotypic characterization of patients with asthma. A total of 317 patients with asthma from 6 different cohorts were included in the analysis. All patients had measures of AHR to mannitol, blood eosinophils, and Asthma Control Questionnaire 5 available. A cluster analysis using Ward minimum variance method was performed. The distribution of fraction of exhaled nitric oxide, immunoglobulin E, lung function, induced sputum inflammatory cell count, age of onset, and severity of disease was compared between clusters. Four clusters were identified. Three of the clusters had proportionate levels of AHR, eosinophilic inflammation, and symptoms, but 1 cluster presented with low levels of eosinophilic inflammation and a significant symptom burden. Half of the subjects in this cluster presented with AHR to inhaled mannitol. Lung function, fraction of exhaled nitric oxide, body mass index, and immunoglobulin E were normal. Information on AHR to mannitol in addition to blood eosinophils and symptoms identifies a subgroup of asthma patients with symptomatic, noneosinophilic disease. Airway hyperresponsiveness to mannitol may provide a treatable trait in a subgroup of patients with noneosinophilic asthma.

Subphenotypes of nonsteroidal antiinflammatory disease-exacerbated respiratory disease identified by latent class analysis.

BackgroundInduced sputum (IS) allows to measure mediators of asthmatic inflammation in bronchial secretions. NSAID‐exacerbated respiratory disease (NERD) is recognized as a distinct asthma phenotype, usually with a severe course, eosinophilic airway inflammation, and increased production of pro‐inflammatory eicosanoids. A more insightful analysis of NERD patients has shown this phenotype to be nonhomogeneous.ObjectiveWe aimed to identify possible subphenotypes in a cohort of NERD patients with the means of latent class analysis (LCA).MethodsA total of 95 asthma patients with aspirin hypersensitivity underwent sputum induction. High‐performance liquid chromatography or gas chromatography coupled with mass spectrometry was used to profile eicosanoids in induced sputum supernatant (ISS). Sixteen variables covering clinical characteristics, IS inflammatory cells, and eicosanoids were considered in the LCA.ResultsThree classes (subphenotypes) were distinguished within the NERD cohort. Class 1 subjects had mild‐to‐moderate asthma, an almost equal distribution of inflammatory cell patterns, the lowest concentrations of eicosanoids, and logLTE4/logPGE2 ratio. Class 2 represented severe asthma with impaired lung function despite high doses of steroids. High sputum eosinophilia was in line with higher pro‐inflammatory LTE4 in ISS and the highest logLTE4/logPGE2 ratio. Class 3 subjects had mild‐to‐moderate asthma and were also characterized by eosinophilic airway inflammation, yet increased production of pro‐ (LTE4, PGD2 and 11‐dehydro‐TBX2) was balanced by anti‐inflammatory PGE2. The value of logLTE4/logPGE2 was between values calculated for classes 1 and 3, similarly to disease control and severity.ConclusionsLCA revealed three distinct NERD subphenotypes. Our results support a more complex pathobiology of aspirin hypersensitivity. Considering NERD heterogeneity, the relationship between inflammatory pathways and clinical manifestations of asthma may lead to more individualized treatment in difficult to treat patients in the future.

Analysis of clinical features and inflammatory factors in induced sputum in common phenotypes of COPD with frequent exacerbations

Objective To compare the clinical characteristics of chronic bronchitis (CB), emphysema (EM), asthma - chronic obstructive pulmonary disease overlapping syndrome (ACOS) with frequent exacerbations (FE) or infrequent exacerbations (iFE)and induced sputum inflammatory cells and the heterogeneity of the transmitter. Methods Ninety-one cases of chronic obstructive pulmonary disease(COPD)with acute exacerbation were divided into CB, EM or ACOS phenotype, among which 44 were frequent, and 47 were non frequent.The clinical data, induced sputum inflammatory cells, interferon-γ(IFN-γ), tumor necrosis factor-α(TNF-α), interleukin(IL)-4, IL-13 were analyzed. Results The FEV1% was (47±13.1)%, significantly lower than that of non frequent episodes ((56.2±10.2)%), and the difference was statistically significant(P=0.049). The FEV1/FVC% was (54.3±9.3)%, significantly lower than that of non frequent episodes (60.1±7.3)%, and there was a significant difference between them (P=0.001). The proportion of patients with GOLD III and IV, the percentage of neutrophils in induced sputum, tumor necrosis factor -α(TNF-α) and interferon -γin the patients with frequent episodes were significantly higher than those with non frequent episodes (P<0.05). Among them, FEV1/FVC% and TNF-αwere independent risk factors for COPD patients (P=0.032, 0.021). The FEV1% of patients with CB phenotypic frequent episodes were (47.9±14.9)%, significantly lower than that of non frequent episodes ((57.2±10.9)% )(P=0.000), and FEV1/FVC% was (53.4±9.5)% in patients with CB frequent episodes, significantly lower than that of non frequent episodes ((60.3±6.9)%), and the difference was statistically significant (P=0.022), while the level of N%, TNF-α in induced sputum were significantly higher in CB phenotype subjects with FE than those in subjects with iFE(P<0.01). Patients with frequent episodes of emphysema had longer duration of disease (P<0.05), lower FEV1% and FEV1/FVC%(P<0.05), the proportion of GOLD III patients and the induced sputum TNF-αwere higher, but there was no significant difference in the number and proportion of phlegm inflammatory cells, interferon -γ, interleukin 4 and interleukin 3.The level of GOLD III and the IL-13 level of induced sputum in patients with frequent ACOS phenotype were significantly higher than those in patients with non frequent episodes (P<0.05). Conclusion The lung function, the severity of the disease, the course of the disease, and the percentage of sputum neutrophils, tumor necrosis factor -α, or interleukin 13 are helpful in diagnosing patients with high risk of frequent episodes. Key words: Chronic obstructive pulmonary disease; chronic bronchitis; emphysema; asthma-COPD overlap syndrome

Utility of Induced Sputum in Routine Clinical Practice

ObjectiveTo determine the general and specific utility in diagnosis and/or treatment of induced sputum (IS) inflammatory cell counts in routine clinical practice. MethodsRetrospective study of 171 patients referred for clinical sputum induction over a 1-year period in the pulmonology department of a referral hospital. Independent observers established whether the information provided by IS inflammatory cell count was useful for making diagnostic and therapeutic decisions. ResultsThe most frequent reasons for determination of IS inflammatory cell count were: asthma 103 (59.20%); uncontrolled asthma 34 (19.54%); chronic cough 19 (10.9%), and gastroesophageal reflux 15 (8.6%). In 115 patients (67.3%) it was generally useful for diagnosis and/or treatment; in 98 patients (57.3%) it provided diagnostic information and in 85 patients (49.7%) it assisted in therapeutic decision-making. In asthma, uncontrolled asthma, chronic cough and gastroesophageal reflux, the results were useful in 71.8%, 67.6%, 47.4% and 60%, respectively. ConclusionThe information provided by IS inflammatory cell count is extremely useful in clinical practice, especially in asthma and chronic cough. These results may justify the inclusion of the IS technique in pulmonology departments and asthma units of referral centers.

Utilidad del esputo inducido en la práctica clínica habitual

ObjectiveTo determine the general and specific utility in diagnosis and/or treatment of induced sputum (IS) inflammatory cell counts in routine clinical practice. MethodsRetrospective study of 171 patients referred for clinical sputum induction over a 1-year period in the pulmonology department of a referral hospital. Independent observers established whether the information provided by IS inflammatory cell count was useful for making diagnostic and therapeutic decisions. ResultsThe most frequent reasons for determination of IS inflammatory cell count were: asthma 103 (59.20%); uncontrolled asthma 34 (19.54%); chronic cough 19 (10.9%), and gastroesophageal reflux 15 (8.6%). In 115 patients (67.3%) it was generally useful for diagnosis and/or treatment; in 98 patients (57.3%) it provided diagnostic information and in 85 patients (49.7%) it assisted in therapeutic decision-making. In asthma, uncontrolled asthma, chronic cough and gastroesophageal reflux, the results were useful in 71.8%, 67.6%, 47.4% and 60%, respectively. ConclusionThe information provided by IS inflammatory cell count is extremely useful in clinical practice, especially in asthma and chronic cough. These results may justify the inclusion of the IS technique in pulmonology departments and asthma units of referral centers.

Induced sputum supernatant bioactive lipid mediators can identify subtypes of asthma.

Induced sputum (IS) allows to measure mediators of asthmatic inflammation in bronchial secretions. The specific role of induced sputum supernatant (ISS) endogenous bioactive lipid mediators in subtypes of asthma is not well understood. To investigate the interactions between airway inflammation and clinical phenotypes of asthma, we integrated induced sputum supernatant (ISS) eicosanoids and quantitative assessment of infiltrating cells into new subtypes with the means of latent class analysis (LCA). One hundred and thirty-nine asthmatics with and without aspirin hypersensitivity underwent sputum induction. High-performance liquid chromatography or gas chromatography coupled with mass spectrometry was used to profile eicosanoids. Nineteen variables covering clinical characteristics, IS inflammatory cells and eicosanoids were considered in the LCA. Four phenotypic asthma classes were distinguished. Class 1 with mild-to-moderate asthma, chronic rhinosinusitis (CRS), high PGA2 in ISS and almost equal distribution of inflammation cell patterns. Class 3 subjects also had mild-to-moderate asthma but without upper airway symptoms. Induced sputum was often paucigranulocytic with low levels of lipid mediators. Classes 2 and 4 represented severe asthma with CRS and impaired lung function despite high doses of steroids. High blood and sputum eosinophilia was in line with high cysteinyl leukotrienes and PGD2 in ISS only in class 2. Class 4 subjects tended to have increased sputum neutrophilia and PGE2 in ISS. Aspirin hypersensitivity was most frequent among class 2 subjects. The LCA revealed four distinct asthma classes differing in eicosanoid pathways.

S132 Sputum And Bronchial Biopsy Expression Of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodg) In Asthma Is Related To Neutrophilic Inflammation And Poor Asthma Control

Introduction and objectives Oxidative stress has been implicated in the pathogenesis of asthma. Validated sputum biomarkers are required to assess this and its relationship to other clinical variables. We sought to compare sputum and bronchial 8-oxodG expression in asthma and health; assess the sputum repeatability; and explore its relationship with induced sputum inflammatory cells counts and exacerbations. Methods Asthmatics and healthy controls were recruited from a single centre and underwent clinical characterisation including sputum induction (asthma n = 58, health n = 27) and bronchial biopsy (asthma n = 16, health n = 10). Sputum and epithelial 8-oxodG expression was measured by ELISA and Immunohistochemistry respectively. Sputum asthmatics were assessed at a repeat stable visit at 6 months. Results Between health and asthma, there were no significant differences in the median (IQR) sputum 8-oxodG levels [12 (16) ngml -1 vs. 11 (15) ngml -1 , p = 0.36] or the mean (SEM) percentage area of epithelium reaching threshold intensity for 8-oxodG [2.0 (0.7)% vs. 4.4 (1.0) %, p = 0.12]. Asthma sputum 8-oxodG correlated with the sputum total cell count ( r s =0.53, p r s =0.27, p = 0.04), sputum macrophages ( r s =-0.31, p = 0.02) and serum IgE ( r s =-0.27, p = 0.04). Epithelial 8-oxodG correlated to the number of exacerbations in the previous year (r s =0.70,p s =-0.52,p = 0.04). The upper 95th confidence interval of sputum 8-oxodG and epithelium 8-oxodG reaching threshold in healthy controls was used to split asthma patients into 8-oxodG high and low groups. The sputum 8-oxodG high group (n = 13) had significantly higher sputum total cells 8.08 [8.41] x10 6 g -1 vs. 2.25 [2.91] x10 6 g -1 , p -1 vs. 157 [212.90] KUL -1 , p high group (n = 8) had significantly more exacerbations 3.9 (0.3) vs. 0.5 (0.3) p In the asthmatic group, the intra-class correlation coefficient of sputum 8-oxodG between the 2 visits was 0.51 (p Conclusions 8-oxodG expression in sputum and bronchial biopsies was not different between asthma and health, although we did identify an 8-oxodG high group in asthma. Interestingly, expression in asthma was associated with neutrophilic inflammation and poor asthma control.

P87 Is fraction of exhaled nitric oxide (FeNO) in asymptomatic older teenagers related to preschool wheeze and chronic cough?

BackgroundMany children with preschool wheeze and chronic cough become asymptomatic in later childhood, only for asthma to be diagnosed in adulthood (1). A previous study found in individuals with apparently...

Fluticasone Induces Epithelial Injury and Alters Barrier Function in Normal Subjects.

ObjectiveThe airway epithelium has a number of roles pivotal to the pathogenesis of asthma, including provision of a physical and immune barrier to the inhaled environment. Dysregulated injury and repair responses in asthma result in loss of airway epithelial integrity. Inhaled corticosteroids are a corner stone of asthma treatment. While effective in controlling asthma symptoms, they fail to prevent airway remodeling. Direct cytopathic effects on the airway epithelium may contribute to this.MethodsThis study examined the effects of a 4-week treatment regimen of inhaled fluticasone 500 μg twice daily in healthy human subjects. Induced sputum was collected for cell counts and markers of inflammation. Barrier function was examined by diethylenetriaminepentacetic acid (DTPA) clearance measured by nuclear scintillation scan, and albumin concentration in induced sputum.ResultsSteroid exposure resulted in epithelial injury as measured by a significant increase in the number of airway epithelial cells in induced sputum. There was no change in airway inflammation by induced sputum inflammatory cell counts or cytokine levels. Epithelial shedding was associated with an increase in barrier function, as measured by both a decrease in DTPA clearance and decreased albumin in induced sputum. This likely reflects the normal repair response.ConclusionInhaled corticosteroids cause injury to normal airway epithelium. These effects warrant further evaluation in asthma, where the dysregulated repair response may contribute to airway remodeling.

Cough frequency in health and disease

To the Editor: Chronic cough is a difficult clinical problem, partly because there is an absence of well-validated means to assess cough [1, 2]. We have previously reported that the semi-automated computerised Leicester Cough Monitor detects cough accurately over 6 h and that cough frequency is increased in patients with chronic cough compared to controls [3, 4]. There remains uncertainty on the performance of the system over 24 h and across the range of expected cough frequency in larger populations. We set out to address these questions in healthy adult volunteers and adult volunteers with respiratory disease. 44 healthy volunteers were recruited from those responding to a poster advertisement. All reported no current respiratory symptoms, were nonsmokers with a <5 pack-yr past smoking history and had normal spirometric values, methacholine airway responsiveness and induced sputum inflammatory cell counts. 78 patients with respiratory disease were recruited from respiratory clinics. The diagnostic criteria for the conditions have been described previously [5]. Six current smokers and four males taking angiotensin converting enzyme inhibitors (ACEi) were also recruited. The study was approved by the Leicestershire, Northampton and Rutland Research Ethics Committee. All volunteers underwent spirometry and those with normal spirometry had a methacholine inhalation test using the tidal breathing method. The Leicester Cough Monitor (iRiver iFP-799 mp3 device; iRiver Europe GmbH, Eschborn, Germany and Sennheiser MKE 2–5 field microphone; Sennheiser electronic GmbH & Co. KG, Wedemark, Germany) was attached and recordings obtained and analysed as …

Menopausal asthma: a new biological phenotype?

Female hormones play an important role in women's lung health, especially in asthma pathophysiology. Although a growing interest has recently been aroused in asthma related to short-term reproductive states, menopausal asthma has been little studied in the past. The aim of the present study was to explore airway inflammation in menopausal asthmatic women in a noninvasive manner. Forty consecutive women with menopausal asthma, 35 consecutive women with premenopausal asthma and 30 age-matched healthy controls were enrolled in the study. Urinary LTE-4, induced sputum inflammatory cells, and exhaled LTE-4, IL-6, pH, and NO levels were measured in all the subjects enrolled. Women with menopausal asthma showed decreased estradiol concentrations, high sputum neutrophils, and exhaled IL-6. Women with premenopausal asthma presented instead an essentially eosinophilic inflammatory pattern. Higher urine and breath condensate LTE-4 concentrations were found in premenopausal and menopausal asthma compared to controls. Our results substantiate the existence of a new biological phenotype of menopausal asthma that is mainly characterized by neutrophilic airways inflammation and shares several characteristics of the severe asthma phenotype.

Inflammatory biomarkers in airways of patients with severe asthma compared with non‐severe asthma

About 5-10% of patients with asthma suffer from poorly-controlled disease despite corticosteroid (CS) therapy. We determined whether there were any differences in inflammatory biomarkers between severe and non-severe asthma patients. Nineteen severe and 20 non-severe asthma patients were recruited and underwent collection of induced sputum, bronchoalveolar lavage (BAL) fluid and bronchial biopsies. Biopsy results showed no differences in eosinophils (major basic protein positive), neutrophils, macrophages, T cells and mast cells in the bronchial submucosa. However, subbasement membrane (SBM) thickness and smooth muscle area were increased in the biopsies. No significant differences were observed in the induced sputum inflammatory cells. In BAL fluid, there was a significant increase in neutrophils but a significant decrease in macrophages. Eosinophil counts were non-significantly increased threefold in both sputum and BAL in severe asthma. Levels of IL-8 and IL-13 in sputum supernatants were similar in both groups of asthma patients. There was a significant inverse correlation between post-bronchodilator forced expiratory volume in 1 s and provocative concentration of methacholine causing a 20% fall in FEV(1) with SBM thickness. Differences in inflammatory cells were observed mainly in terms of increased neutrophils and reduction in macrophage numbers in BAL fluid with a trend towards increased eosinophils in severe asthma compared with non-severe asthma. However, the most notable features are the increase in features of airway wall remodelling of SBM thickness and smooth muscle area.

Salmeterol plus fluticasone propionate versus fluticasone propionate plus montelukast: a randomised controlled trial investigating the effects on airway inflammation in asthma

BackgroundFew studies have compared treatment strategies in patients with asthma poorly controlled on low dose inhaled corticosteroids, and little is known about the effects of different treatments on airway inflammation. In this double-blind, placebo-controlled, parallel group study, we compared the effects of salmeterol plus fluticasone propionate (FP) (Seretide™; SFC) and FP plus montelukast (FP/M) on sputum inflammatory markers, airway responsiveness, lung function, and symptoms in adult asthmatics.MethodsSixty-six subjects were randomised to SFC or FP/M for 12 weeks. The primary outcome was changes in neutrophil, eosinophil, macrophage, lymphocyte, and epithelial cell levels in induced sputum. Additional outcomes included the change in other sputum markers of airway inflammation, airway responsiveness, symptom control, and lung function.ResultsBoth treatments had no significant effect on induced sputum inflammatory cells, although there was a trend for a reduction in sputum eosinophils. Both treatments significantly improved airway responsiveness, whereas SFC generally led to greater improvements in symptom control and lung function than FP/M. FP/M led to significantly greater reductions in sputum cysteinyl leukotrienes than SFC (treatment ratio 1.80; 95% CI 1.09, 2.94).ConclusionBoth treatments led to similar control of eosinophilic airway inflammation, although PEF and symptom control were better with SFC.Study numberSAM40030 (SOLTA)

Nasal and Airway Inflammatory Features of Subjects with Nasal Polyposis With or Without Asthma

RATIONALE: Nasal polyposis is found in about 5% of patients with bronchial asthma. In most nasal polyps, eosinophils constitute more than 60% of the cell population. Based on the united airways concept, we need to assess if upper airway eosinophilic inflammation plays a role in the development or increase in lower airway inflammation observed in asthma. AIM: To compare nasal lavage (NL) and induced sputum inflammatory cell differential between subjects with nasal polyps with or without asthma. METHODS: Twenty-nine subjects with nasal polyposis were included in the study: 14 with mild asthma, only taking β2 agonists on an as needed basis, and 15 without asthma. The study included one visit where spirometry and methacholine were performed and NL and IS with differential cell counts were obtained. RESULTS: FEV1 was similar between asthmatic (mean ± sem; 3.1 ± 0.4L) and non asthmatic subjects (3.5 ± 0.2L, p > 0.05). There were no differences in NL % eosinophils between both groups (asthmatics: 16.4 ± 8.5%, non asthmatics: 10.5 ± 4.2%, p > 0.05). Compared to normal values, sputum eosinophils were higher in asthmatic (4.2 ± 3.8%) and in non asthmatic (6.6 ± 3.2%) subjects. In the asthmatic group, a significant correlation was observed between sputum and NL % eosinophils (r = 0.63, p = 0.03) but not in the non asthmatic group. CONCLUSIONS: Lower airway inflammation is present in subjects with nasal polyposis without asthma. The potential for such inflammation to contribute to the development of asthma should be evaluated.

Sputum eosinophilia in idiopathic pulmonary fibrosis

Cough is a common symptom in idiopathic pulmonary fibrosis that is difficult to treat and has a major impact on quality of life. We tested the hypothesis that the cough and increased cough reflex sensitivity seen in patients with idiopathic pulmonary fibrosis may be due to airway inflammation in a prospective, cross-sectional study. We measured the induced sputum inflammatory cell profile and cell-free supernatant inflammatory mediator concentrations in 15 patients with idiopathic pulmonary fibrosis, 17 healthy controls and 15 patients with chronic obstructive pulmonary disease. Both the geometric mean sputum differential eosinophil cell count and median eosinophilic-cationic-protein concentration were significantly higher in patients with idiopathic pulmonary fibrosis than controls (2.1% vs 0.3%; p <0.001 and 1.1 mg/ml versus 0.2 mg/ml; p=0.03 respectively). There were no significant differences in sputum eosinophil counts and eosinophilic-cationic-protein concentrations between patients with idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease. Sputum leukotriene-B4 concentrations were significantly lower in patients with idiopathic pulmonary fibrosis (p=0.03) and chronic obstructive pulmonary disease (p=0.008) compared to controls. Idiopathic pulmonary fibrosis is characterised by the presence of active eosinophilic airway inflammation raising the possibility that airway inflammation may contribute to symptoms such as cough.

The Relationship of Induced-Sputum Inflammatory Cells to BAL and Biopsy

The Relationship of Induced-Sputum Inflammatory Cells to BAL and Biopsy

Eosinophils in induced sputum from asymptomatic smokers with normal lung function

Cigarette smoking is the dominant risk factor for chronic obstructive pulmonary disease (COPD). However, only 10–15% of smokers develop the disease and early changes within the airways are poorly defined. We aimed to compare cell profiles in induced sputum (IS) from asymptomatic smokers to that from healthy subjects, and to ascertain whether or not inflammatory cells in IS are related to lung function and smoking habit. We recruited 34 heavy, non-allergic asymptomatic smokers with normal lung function and 15 healthy volunteers, who performed lung function tests and IS by hypertonic saline (3%) solution. In smokers, significant correlation between pack-years and FEF25–75(rs=−0·43, P<0·02) was found. In IS, smokers had higher counts of macrophages (P<0·01) and eosinophils (P<0·02), when compared to those of healthy subjects. Additionally, eosinophils were found in IS of 14 out of 34 smokers, with eosinophils had a higher pack-years (31±25 vs. 13±10, P=0·02) and lower FEF25–75%value (78%±34 vs. 100%±23, P<0·04), when compared to smokers without eosinophils. Additionally, on the basis of regression equations by stepwise multiple regression analysis, eosinophils were predicted by pack-years (r2=0·41). Our results showed that asymptomatic smokers have evidence of inflammatory cells in IS samples. In addition, we found that the degree of eosinophilic inflammation is related to early changes of lung function and can be predicted by smoking habit.