Granulocyte markers in induced sputum in patients with respiratory disorders and healthy persons obtained by two sputum-processing methods

Utility of eosinophil peroxidase as a biomarker of eosinophilic inflammation in asthma

BACKGROUND

The relative utility of eosinophil peroxidase (EPX) and blood and sputum eosinophil counts as disease biomarkers in asthma is uncertain.

OBJECTIVE

We sought to determine the utility of EPX as a biomarker of systemic and airway eosinophilic inflammation in asthma.

METHODS

EPX protein was measured by immunoassay in serum and sputum in 110 healthy controls to establish a normal reference range and in repeated samples of serum and sputum collected during 3 years of observation in 480 participants in the Severe Asthma Research Program 3.

RESULTS

Over 3 years, EPX levels in patients with asthma were higher than normal in 27% to 31% of serum samples and 36% to 53% of sputum samples. Eosinophils and EPX correlated better in blood than in sputum (rs values of 0.74 and 0.43, respectively), and high sputum EPX levels occurred in 27% of participants with blood eosinophil counts less than 150 cells/μL and 42% of participants with blood eosinophil counts between 150 and 299 cells/μL. Patients with persistently high sputum EPX values for 3 years were characterized by severe airflow obstruction, frequent exacerbations, and high mucus plug scores. In 59 patients with asthma who started mepolizumab during observation, serum EPX levels normalized in 96% but sputum EPX normalized in only 49%. Lung function remained abnormal even when sputum EPX normalized.

CONCLUSIONS

Serum EPX is a valid protein biomarker of systemic eosinophilic inflammation in asthma, and sputum EPX levels are a more sensitive biomarker of airway eosinophilic inflammation than sputum eosinophil counts. Eosinophil measures in blood frequently miss airway eosinophilic inflammation, and mepolizumab frequently fails to normalize airway eosinophilic inflammation even though it invariably normalizes systemic eosinophilic inflammation.

Eosinophil cationic protein (ECP) correlates with eosinophil cell counts in the induced sputum of elite swimmers

Introduction

Swimming practice has been associated with eosinophilic inflammation, however, the underlying mechanisms are not fully understood. The eosinophil cationic protein (ECP) in induced sputum may be used as a potential biomarker to assess airway eosinophilic inflammation among elite swimmers. The objective of this study is to characterize ECP levels in sputum supernatant in elite swimmers and evaluate ECP as an eosinophilic inflammatory marker.

Material and methods

Elite swimmers annually screened in our department (n = 27) were invited to participate in this cross-sectional study. Swimmers who agreed to participate (n = 24, 46% girls) performed lung function and skin-prick tests. Induced sputum was also collected and analyzed for differential cell counts and ECP measurements in sputum supernatant (ImmunoCAPTM 100, ECP, Thermo Fisher Scientific, Uppsala, Sweden).

Results

The median ECP level was 15.60 μg/L (6.02-38.75 μg/L) and higher levels were found among boys (27.90 (11.20-46.30) μg/L vs 6.65 (2.82-22.80) μg/L, P = .02). In addition, ECP levels in the sputum supernatant were positively correlated with eosinophil cell counts in the induced sputum (r = 0.583, P = .08).

Conclusions

ECP levels correlated positively with eosinophil counts in the induced sputum in elite swimmers. The measurement of ECP in sputum supernatant may be a useful marker to assess and manage eosinophilic inflammatory changes in the airways of elite swimmers.

Concurrence of elevated FeNO and airway hyperresponsiveness in nonasthmatic adolescents

OBJECTIVES

The aim of this study was to investigate airway responsiveness and eosinophil and neutrophil inflammatory markers in clinically confirmed nonasthmatic adolescents with elevated fractional exhaled nitric oxide (FeNO), a marker of type-2 inflammation in the airways.

METHODOLOGY

A total of 959 subjects from a general population, aged 12 to 15 years, answered a standardised questionnaire and underwent FeNO measurements at a screening visit at school. Adolescents without asthma, who had elevated FeNO (FeNO₁₀₀  > 15 ppb) (n = 19), and control subjects, with low FeNO (FeNO₁₀₀  < 5 ppb) and without reported symptoms of asthma or allergy (n = 28), participated in a follow-up study where FeNO₅₀ , airway responsiveness to methacholine (PD₂₀ ), blood eosinophil counts, and serum neutrophil lipocalin (HNL) and myeloperoxidase (MPO) levels were measured. Questionnaire follow-ups were performed 4 and 16 years later.

RESULTS

Airway responsiveness (PD₂₀ : 6.94 [1.87, 11.39] vs 11.42 [6.33, 59.4] µmol; P < .05) and blood eosinophil counts (0.31 [0.20, 0.44] vs 0.13 [0.1, 0.22] 10⁹ /L; P < .001) (geometric mean [95% CI]) were higher among cases than controls. A significant correlation between blood eosinophils and FeNO was found (rho = 0.41; P = .005). In contrast, serum HNL and MPO were lower in cases than controls (P < .05 both), and there was a negative correlation between HNL and FeNO (r = -0.31; P = .04). At both follow-ups, a higher proportion of subjects reported allergic symptoms compared with baseline (P = .02, P = .01).

CONCLUSIONS

Elevated FeNO in nonasthmatic adolescents was associated with airway hyperresponsiveness, elevated blood eosinophil counts, and lower systemic activation of neutrophils.

Lung Sound Analysis Provides A Useful Index For Both Airway Narrowing And Airway Inflammation In Patients With Bronchial Asthma

Background

The expiration-to-inspiration sound power ratio in a midfrequency range (E/I MF), a parameter of lung sound analysis (LSA), has been reported to be useful as an index of airway inflammation in patients with bronchial asthma. However, the E/I MF reflects airway narrowing caused by airway inflammation, and there is thus concern that it may not be an index of airway eosinophilic inflammation itself.

Methods

A total of 131 patients with bronchial asthma were classified into four groups according to the presence or absence of airway narrowing and airway inflammation to examine whether the E/I MF could serve as an index of airway inflammation.

Results

The E/I MF was significantly higher in patients with a normal forced expiratory volume in one second (FEV₁) and high fractional exhaled nitric oxide (FeNO), those with a low FEV₁ and normal FeNO, and those with a low FEV₁ and high FeNO than in those with a normal FEV₁ and normal FeNO (p < 0.05–0.01). In particular, the E/I MF was high even in the patients who had no airway narrowing but had airway inflammation (p < 0.01). The results of multivariate analysis of factors involved in FeNO in patients with a normal FEV₁ revealed that the E/I MF was an independent factor (p = 0.0281).

Conclusion

The E/I MF is a useful index of airway inflammation in the treatment of asthma, regardless of the presence or absence of airway narrowing.

Phenotype classification using the combination of lung sound analysis and fractional exhaled nitric oxide for evaluating asthma treatment

BACKGROUND

We report the utility of combining lung sound analysis and fractional exhaled nitric oxide (FeNO) for phenotype classification of airway inflammation in patients with bronchial asthma. We investigated the usefulness of the combination of the expiration-to-inspiration sound power ratio in the mid-frequency range (E/I MF) of 200-400 Hz and FeNO for comprehensively classifying disease type and evaluating asthma treatment.

METHODS

A total of 233 patients with bronchial asthma were included. The cutoff values of FeNO and E/I MF were set to 38 ppb and 0.36, respectively, according to a previous study. The patients were divided into 4 subgroups based on the FeNO and E/I MF cutoff values. Respiratory function, the percentages of sputum eosinophils and neutrophils, and patient background characteristics were compared among groups.

RESULTS

Respiratory function was well controlled in the FeNO low/E/I MF low group (good control). Sputum neutrophil was higher and FEV₁,%pred was lower in the FeNO low/E/I MF high group (poor control). History of childhood asthma and atopic asthma were associated with the FeNO high/E/I MF low group (insufficient control). The FeNO high/E/I MF high group corresponded to a longer disease duration, increased blood or sputum eosinophils, and lower FEV₁/FVC (poor control).

CONCLUSIONS

The combination of FeNO and E/I MF assessed by lung sound analysis allows the condition of airway narrowing and the degree of airway inflammation to be assessed in patients with asthma and is useful for evaluating bronchial asthma treatments.

Airway inflammation phenotype prediction in asthma patients using lung sound analysis with fractional exhaled nitric oxide

BACKGROUND

We previously reported the results of lung sound analysis in patients with bronchial asthma and demonstrated that the exhalation-to-inhalation sound pressure ratio in the low frequency range between 100 and 200 Hz (E/I LF) was correlated with the presence of airway inflammation and airway obstruction. We classified asthma patients by airway inflammation phenotype using the induced sputum eosinophil and neutrophil ratio and determined whether this phenotype could be predicted using E/I LF and fractional exhaled nitric oxide values.

METHODS

Steroid-naive bronchial asthma patients were classified into four phenotypes, including "Low inflammation" (35 patients), "Eosinophilic type" (58 patients), "Neutrophilic type" (15 patients), and "Mixed type" (15 patients) based on the results of induced sputum examinations. The E/I LF data and FeNO levels were then evaluated for the four phenotype groups; the prediction powers of these two indices were then analyzed for each phenotype.

RESULTS

The median E/I LF value was highest in the "Mixed type" and lowest in the "Low inflammation" group. FeNO differentiated between the "Low inflammation" and "Eosinophilic type" groups, "Low inflammation" and "Neutrophilic type" groups, and "Neutrophilic type" and "Mixed type" (p < 0.0001, p = 0.007, and p = 0.04, respectively). E/I LF differentiated between the "Low inflammation" and "Eosinophilic type" groups (p = 0.006). E/I LF could distinguish the "Mixed type" group from the "Low inflammation" and "Eosinophilic type" groups (p = 0.002).

CONCLUSIONS

A combination of the E/I LF value and FeNO may be useful for the classification of the airway inflammation phenotype in patients with bronchial asthma.

Lung sound analysis can be an index of the control of bronchial asthma

BACKGROUND

We assessed whether lung sound analysis (LSA) is a valid measure of airway obstruction and inflammation in patients with bronchial asthma during treatment with inhaled corticosteroids (ICSs).

METHODS

63 good adherence patients with bronchial asthma and 18 poor adherence patients were examined by LSA, spirometry, fractional exhaled nitric oxide (FeNO), and induced sputum. The expiration-to-inspiration lung sound power ratio at low frequencies between 100 and 200 Hz (E/I LF) obtained by LSA was compared between healthy volunteers and bronchial asthma patients. Next, post-ICS treatment changes were compared in bronchial asthma patients between the good adherence patients and the poor adherence patients.

RESULTS

E/I LF was significantly higher in bronchial asthma patients (0.62 ± 0.21) than in healthy volunteers (0.44 ± 0.12, p < 0.001). The good adherence patients demonstrated a significant reduction in E/I LF from pre-treatment to post-treatment (0.55 ± 0.21 to 0.46 ± 0.16, p = 0.002), whereas the poor adherence patients did not show a significant change. The decrease of E/I LF correlated with the improvement of FEV₁/FVC ratio during the ICS treatment (r = -0.26, p = 0.04). The subjects with higher pre-treatment E/I LF values had significantly lower FEV₁/FVC and V_50,%pred (p < 0.001), and significantly higher FeNO and sputum eosinophil percentages (p = 0.008 and p < 0.001, respectively).

CONCLUSIONS

The E/I LF measurement obtained by LSA is useful as an indicator of changes in airway obstruction and inflammation and can be used for monitoring the therapeutic course of bronchial asthma patients.

Trigger of bronchial hyperresponsiveness development may not always need eosinophilic airway inflammation in very early stage of asthma

Background:

Cough variant asthma (CVA), a suggested precursor of standard bronchial asthma (SBA), is characterized by positive bronchial hyperresponsiveness (BHR) and a chronic cough response to bronchodilator that persists for >8 weeks.

Objective:

Airway inflammation, BHR, and airway obstructive damage were analyzed to assess whether CVA represents early or mild-stage SBA.

Methods:

Patients with newly diagnosed CVA (n = 72) and SBA (n = 84) naive to oral or inhaled corticosteroids and without exacerbated asthma were subjected to spirometry, impulse oscillometry, BHR tests, sputum induction, and fractional exhaled nitric oxide measurements.

Results:

In the patients with CVA, spirometry demonstrated higher forced expiratory volume in 1 second (FEV₁) to forced vital capacity ratio, FEV₁ percent predicted, flow volume at 50% of vital capacity % predicted, and flow volume at 25% of vital capacity % predicted values, and impulse oscillometry demonstrated lower R₅–Z₂₀, AX, and Fres, and higher X₅ values. In addition, the fractional exhaled nitric oxide and sputum eosinophil numbers were lower and the PC₂₀ was higher than in patients with moderate SBA. However, these factors were similar in the patients with CVA and in the patients with intermittent mild SBA. A significantly smaller proportion of the patients with CVA had increased sputum eosinophils than the patients with intermittent mild SBA (p < 0.0001). However, interestingly, among the patients with CVA, no significant differences in the PC₂₀ values were found between the patients with and those without increased sputum eosinophils.

Conclusions:

All measures of central and peripheral airway obstruction, eosinophilic inflammation, and airway hyperresponsiveness in patients with CVA were milder than in patients with moderate SBA but were similar to those of patients with intermittent mild SBA. In CVA, the BHR was not affected by airway eosinophilic inflammation, which indicated that the very early development of BHR may not always need airway eosinophilic inflammation.

Lung Sound Analysis and Airway Inflammation in Bronchial Asthma

BACKGROUND

Our previous study on lung sound analysis (LSA) revealed that the expiration-to-inspiration sound power ratio in a low-frequency range (E/I LF) was increased in patients with bronchial asthma, even when they have no wheezes.

OBJECTIVE

We also monitored the expiration-to-inspiration sound power ratio in a mid-frequency range (E/I MF) and the mid- to low-frequency sound power ratio for inspiration and expiration (ie, I MF/LF and E MF/LF, respectively) using a new software program to examine which parameter is most suitable as an index of airway inflammation in patients with asthma.

METHODS

A study was conducted in 31 patients with mild-to-moderate bronchial asthma to examine potential correlations of LSA parameters (E/I LF, E/I MF, I MF/LF, and E MF/LF) with spirogram parameters, airway hyperresponsiveness (PC20), fractional exhaled nitric oxide (NO), and sputum eosinophils.

RESULTS

E/I LF was significantly correlated with airway narrowing (forced expiratory volume in 1 second [FEV1.0]/forced vital capacity [FVC]%: r = -0.50, maximal expiratory flow at 50% [V50],%pred: r = -0.50) and peripheral airway inflammation (alveolar NO: r = 0.36, eosinophils in peripheral sputum: r = 0.41). E/I MF was significantly correlated with airway narrowing (FEV1.0/FVC%: r = -0.46, V50,%pred: r = -0.49), airway inflammation (bronchial NO: r = 0.43, alveolar NO: r = 0.47, eosinophils in peripheral sputum: r = 0.50), and airway hyperresponsiveness (logPC20: r = -0.49). E MF/LF was significantly correlated with airway inflammation (NO: r = 0.36, eosinophils in sputum: r = 0.40) and airway hyperresponsiveness (logPC20: r = -0.40). I MF/LF was not significantly correlated with any parameters.

CONCLUSIONS

Among the 4 LSA parameters investigated, E/I MF demonstrated the highest correlation with airway inflammation, and also with bronchial hyperresponsiveness.

Level of serum neutrophil gelatinase-associated lipocalin in childhood asthma

BACKGROUND

The role of neutrophil gelatinase-associated lipocalin (NGAL) in childhood asthma remains unknown. This study aimed to measure the serum levels of NGAL in children with asthma and to investigate the correlation between NGAL and transforming growth factor beta 1 (TGF-β1), a good indicator of airway remodeling in children with asthma.

METHODS

This prospective, cross-sectional study was conducted on 75 children. Serum NGAL and TGF-β1 concentrations were measured by the ELISA method. Complete blood count, high sensitive C reactive protein (hsCRP), eosinophil cationic protein (ECP), and total serum IgE were investigated in the study population. Atopy in the asthma group was investigated using a skin prick test and specific IgE measurements.

RESULTS

Forty-three asthmatic children and 32 healthy children were enrolled in the study. Total eosinophil numbers, white blood cell count, total serum IgE levels and ECP levels were significantly higher in the asthma group than in the control group (p<0.05). Similarly, serum TGF-β1 levels were significantly higher in children with asthma (p=0.012). The difference in NGAL levels between the groups was insignificant (p=0.268). NGAL levels did not show a significant correlation with total IgE, ECP, eosinophil numbers and TGF-β1 levels (p>0.05).

CONCLUSION

As a conclusion, while elevated TGF-β1 levels in children with asthma might be regarded as an indicator of airway remodeling, we did not find a similar prediction strength for NGAL. Further studies are required to better identify the role of NGAL in childhood asthma and to determine its potential use as a clinical marker.

Bronchial inflammation in seasonal allergic rhinitis with or without asthma in relation to natural exposure to pollen allergens

BACKGROUND

Nasal inflammation in allergic rhinitis enhances bronchial Th2 driven inflammation and development of asthma. We assessed bronchial inflammation induced by natural allergen exposure during pollen season in patients with pollinosis with or without asthma to show the intensity of inflammation in asthma and rhinitis and possible persistence of inflammation in periods without allergen exposure.

METHODS

Sputum was induced in 52 patients with seasonal allergic rhinitis without asthma, 38 patients with seasonal allergic rhinitis and seasonal asthma and 23 healthy volunteers. Sampling was performed 6-8 weeks before the expected beginning of symptoms, during symptomatic period and 6-8 weeks after the end of symptoms. Sputum ECP was measured by means of chemi-luminiscent immunometric assay and sputum cell counts were assessed by classical staining and immunocytochemistry.

RESULTS

Sputum eosinophils were on the whole higher in both asthma and rhinitis compared to controls (p<0.001, p=0.003). The rise of eosinophils during pollen season compared with values out of pollen season was significant in asthma (classical staining) (p=0.014) and slightly apparent in rhinitis (immunocytochemistry) (p=0.073). The seasonal rise of sputum ECP was observed only in rhinitis (p=0.006).

CONCLUSIONS

Inflammation of the lower airway in patients with allergic rhinitis with and without asthma has been confirmed by means of both sputum eosinophil count and sputum ECP level. Persistent inflammation of lower airway in periods without allergen exposure was proven in seasonal asthma. This may have implications for the therapy of seasonal allergic rhinitis with and without asthma in terms of promoting long-term anti-inflammatory treatment.

Oxidative stress and free radicals in COPD--implications and relevance for treatment

Oxidative stress occurs when free radicals and other reactive species overwhelm the availability of antioxidants. Reactive oxygen species (ROS), reactive nitrogen species, and their counterpart antioxidant agents are essential for physiological signaling and host defense, as well as for the evolution and persistence of inflammation. When their normal steady state is disturbed, imbalances between oxidants and antioxidants may provoke pathological reactions causing a range of nonrespiratory and respiratory diseases, particularly chronic obstructive pulmonary disease (COPD). In the respiratory system, ROS may be either exogenous from more or less inhalative gaseous or particulate agents such as air pollutants, cigarette smoke, ambient high-altitude hypoxia, and some occupational dusts, or endogenously generated in the context of defense mechanisms against such infectious pathogens as bacteria, viruses, or fungi. ROS may also damage body tissues depending on the amount and duration of exposure and may further act as triggers for enzymatically generated ROS released from respiratory, immune, and inflammatory cells. This paper focuses on the general relevance of free radicals for the development and progression of both COPD and pulmonary emphysema as well as novel perspectives on therapeutic options. Unfortunately, current treatment options do not suffice to prevent chronic airway inflammation and are not yet able to substantially alter the course of COPD. Effective therapeutic antioxidant measures are urgently needed to control and mitigate local as well as systemic oxygen bursts in COPD and other respiratory diseases. In addition to current therapeutic prospects and aspects of genomic medicine, trending research topics in COPD are presented.

Prediction of airway inflammation in patients with asymptomatic asthma by using lung sound analysis

BACKGROUND

The intensity and frequency of sounds in a lung sound analysis (LSA) may be related to airway constriction; however, whether any factors of an LSA can predict airway eosinophilic inflammation in patients with asthma is unknown.

OBJECTIVE

To determine whether an LSA can predict airway eosinophilic inflammation in patients with asymptomatic asthma.

METHODS

The expiratory-inspiratory ratios of sound power in the low-frequency range (E-I LF) from 36 patients with asymptomatic asthma were compared with those of 14 healthy controls. The relations of E-I LF with airway eosinophilic inflammation were analyzed. The E-I LF cutoff value for predicting airway eosinophilic inflammation also was analyzed.

RESULTS

The mean ± SD E-I LF was higher in the patients with asthma and with increased sputum eosinophils than in those patients without increased sputum eosinophils (0.45 ± 0.24 vs 0.20 ± 0.12; P < .001) or in the healthy controls (0.25 ± 0.10; P = .003). A multiple regression analysis showed that the sputum eosinophil ratio and exhaled nitric oxide were independently correlated with E-I LF, P = .0003 and P = .032, respectively. For the prediction of increased sputum eosinophils and increased fractional exhaled nitric oxide levels, the E-I LF thresholds of 0.29 and 0.30 showed sensitivities of 0.80 and 0.74 and specificities of 0.83 and 0.77, respectively.

CONCLUSIONS

We showed that LSAs can safely predict airway inflammation of patients with asymptomatic asthma.

Sputum myeloperoxidase in chronic obstructive pulmonary disease

Background

Airway inflammation, especially neutrophilic airway inflammation, is a cardinal pathophysiologic feature in chronic obstructive pulmonary disease (COPD) patients. The ideal biomarkers characterizing the inflammation might have important potential clinical applications in disease assessment and therapeutic intervention. Sputum myeloperoxidase (MPO) is recognized as a marker of neutrophil activity. The purpose of this meta-analysis is to determine whether sputum MPO levels could reflect disease status or be regulated by regular medications for COPD.

Methods

Studies were identified by searching PubMed, Embase, the Cochrane Database, CINAHL and http://www.controlled-trials.com for relevant reports published before September 2012. Observational studies comparing sputum MPO in COPD patients and healthy subjects or asthmatics, or within the COPD group, and studies comparing sputum MPO before and after treatment were all included. Data were independently extracted by two investigators and analyzed using STATA 10.0 software.

Results

A total of 24 studies were included in the meta-analysis. Sputum MPO levels were increased in stable COPD patients when compared with normal controls, and this increase was especially pronounced during exacerbations as compared with MPO levels during the stable state. Theophylline treatment was able to reduce MPO levels in COPD patients, while glucocorticoid treatment failed to achieve the same result.

Conclusion

Sputum MPO might be a promising biomarker for guiding COPD management; however, further investigations are needed to confirm this.

A halotyrosine antibody that detects increased protein modifications in asthma patients

Airway inflammation has a pathophysiological role in asthma. Eosinophils, which are commonly increased in asthmatic airways, express eosinophil peroxidase and thereby produce hypobromite and bromotyrosine. Bromotyrosine is believed to be a specific marker for eosinophil activity, but developing an antibody against monobromotyrosine, the predominant brominated tyrosine residue found in vivo has proven difficult. We evaluated whether a 3-bromobenozoic acid hapten antigen produced antibodies that recognized halogenated tyrosine residues. Studies with small-molecule inhibitors or brominated or chlorinated protein suggested that a mouse monoclonal antibody (BTK-94C) selectively bound free and protein mono- and dibromotyrosine and, to a lesser degree, chlorotyrosine, and thus was designated a general halotyrosine antibody. We evaluated if this antibody had potential for characterizing human asthma using an enzyme-linked immunosorbent assay (ELISA) microarray platform to examine the halogenation of 23 proteins in three independent sets of sputum samples (52 samples total). In 15 healthy control or asthmatic subjects, ICAM, PDGF and RANTES had greater proportional amounts of halogenation in asthmatic subjects and the halogenation signal was associated with the severity of exercise-induced airway hyperresponsiveness. In 17 severe asthma patients treated with placebo or mepolizumab to suppress eosinophils, drug-related decreases in halogenation were observed with p values ranging from 0.006 to 0.11 for these 3 proteins. Analysis of 20 subjects that either had neutrophilic asthma or were healthy controls demonstrated a broad increase in halotyrosine (possibly chlorotyrosine) in neutrophilic asthmatics. Overall, these results suggest that an ELISA utilizing BTK-94C could prove useful for assessing airway inflammation in asthma patients.

The role of lipocalins in airway disease

The pathogenesis of allergic airway inflammation and disease is complex and still not fully understood. Many cells, factors and mediators are involved in the different aspects of induction, maintenance and persistence of airway inflammation. The heterogeneity and redundancy of this system is one of the main reasons why novel therapeutic targets focusing on the pathogenesis of asthma only hesitantly reach the market and clinical application. Thus, it seems mandatory that we proceed in our efforts to better understand this micro cosmos to succeed in the development of safe and effective drugs for the treatment of more severe and refractory forms of asthma and chronic obstructive pulmonary disease. One of the more recently discovered mediators in the context of airway inflammation are the lipocalins (Lcns). They are a family of proteins that share functional and structural similarities and are involved in the transport of small hydrophobic molecules such as steroids and lipids into the cell. Lcns are found in many different cell types from plants and bacteria through invertebrate cells to cells of vertebrate origin. The purpose of this review is to summarize the role of Lcns in airway diseases, focusing on allergic and infectious inflammation. In particular, we will summarize the present knowledge about Lipocalin 1 and Lipocalin 2, where exciting new discoveries in the recent years have highlighted their role in pulmonary disease and infection. This new class of proteins is another putative candidate for the development of novel drugs against airway inflammation.

The fractional exhaled nitric oxide and serum high sensitivity C-reactive protein levels in cough variant asthma and typical bronchial asthma

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is known to be a good marker of airway eosinophilic inflammation in bronchial asthma. Recently, serum high sensitivity C-reactive protein (hs-CRP) has been shown to be also useful to detect the airway inflammation.

METHODS

Newly diagnosed 90 cough variant asthma and 92 bronchial asthma patients were enrolled. FeNO, serum hs-CRP, pulmonary function tests, bronchial hyperresponsiveness, IgE and sputum eosinophils ratio were compared. Ninety healthy control subjects were set for FeNO and serum hs-CRP normal range reference. We have compared the clinical utilities of FeNO and serum hs-CRP to differentiate bronchial asthma and cough variant asthma.

RESULTS

FeNO was significantly higher in bronchial asthma (92.6 ± 85.5ppb) than in cough variant asthma (35.6 ± 43.3; p < 0.001) and both were significantly higher than normal range (18.0 ± 6.4, p < 0.001, respectively), and in differentiating between the two groups showed a sensitivity of 0.69 and a specificity of 0.73 at the cutoff value of 28 ppb. Serum hs-CRP did not differ significantly between bronchial asthma (723 ± 1162ng/ml) and cough variant asthma (558 ± 758) even if both were significantly higher than normal range (345 ± 401, p < 0.01 and p < 0.05 respectively).

CONCLUSIONS

FeNO is more useful than serum hs-CRP in differentiating patients with bronchial asthma from those with cough variant asthma, and healthy persons.

Salt chamber treatment is ineffective in treating eosinophilic inflammation in asthma

BACKGROUND

We have shown that salt chamber treatment reduces airway hyper-responsiveness as an add-on therapy in adult asthmatics on inhaled corticosteroids.

METHODS

We assessed whether this effect is due to the suppression of eosinophilic airway inflammation. Thirty-nine adult asthmatics on inhaled corticosteroids were randomized to receive active salt chamber treatment with low-salt treatment 6.6 mg/m(3) (n = 14), high-salt treatment 10.8 mg/m(3) (n = 15) or placebo 0.3 mg/m(3) (n = 10) 10 times in a 2 weeks' period in a double-blind manner.

RESULTS

The level of induced sputum eosinophilic cationic protein μg/l, was 3070 before and 4651 after the low-salt treatment period, on average. In the high-salt treatment group, it was 12 192 μg/l vs 11 803 and in the placebo group 3942 vs 4144, respectively. Salt chamber treatment had no effect on sputum eosinophil or neutrophil cell numbers.

CONCLUSIONS

The reduction in hyper-responsiveness observed in the previous study is probably not due to the effect on eosinophilic inflammation.

Inflammatory phenotypes in adult asthma: clinical applications

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Thirteen-year follow-up of early intervention with an inhaled corticosteroid in patients with asthma

BACKGROUND

In a 3-year study, adult patients who recently developed asthma (symptoms for less than 1 year) were treated for 2 years with the inhaled corticosteroid (ICS) budesonide (early therapy) or terbutaline. During the third year of the study, terbutaline-treated patients received budesonide (delayed therapy). Differences in lung function and bronchial responsiveness to histamine were observed between the 2 groups.

OBJECTIVE

We compared the effects of early versus delayed budesonide therapy after a 10-year follow-up period (13 years after the study began) and current real-life data.

METHODS

Of the original 103 patients, 90 were re-examined 13 years after study initiation. After the third year of the study, all patients had their medications, including the dose of ICS, individually adjusted.

RESULTS

After the follow-up period, lung function was within the normal range for the entire group (all patients); bronchial responsiveness significantly improved compared with baseline data. No statistically significant differences in clinical or functional variables were found between patients given early or delayed budesonide therapy. However, the delayed therapy group had a higher neutrophil count and higher concentrations of eosinophilic cationic protein and myeloperoxidase in induced sputum. This group had also used more asthma medication and hospital days.

CONCLUSIONS

Patients with relatively mild asthma who received ICS within 12 months of their first asthma symptoms or after a 2-year delay achieved equally good functional control of asthma after 10 years of individualized therapy. However, the delayed therapy group exhibited slightly less optimal disease control and more signs of airway inflammation.

Airway biomarkers of the oxidant burden in asthma and chronic obstructive pulmonary disease: current and future perspectives

The pathogenesis of asthma and chronic obstructive pulmonary disease (COPD) has been claimed to be attributable to increased systemic and local oxidative stress. Detection of the oxidant burden and evaluation of their progression and phenotypes by oxidant biomarkers have proved challenging and difficult. A large number of asthmatics are cigarette smokers and smoke itself contains oxidants complicating further the use of oxidant biomarkers. One of the most widely used oxidant markers in asthma is exhaled nitric oxide (NO), which plays an important role in the pathogenesis of asthma and disease monitoring. Another oxidant marker that has been widely investigated in COPD is 8-isoprostane, but it is probably not capable of differentiating asthma from COPD, or even sensitive in the early assessment of these diseases. None of the current biomarkers have been shown to be better than exhaled NO in asthma. There is a need to identify new biomarkers for obstructive airway diseases, especially their differential diagnosis. A comprehensive evaluation of oxidant markers and their combinations will be presented in this review. In brief, it seems that additional analyses utilizing powerful tools such as genomics, metabolomics, lipidomics, and proteomics will be required to improve the specificity and sensitivity of the next generation of biomarkers.

Chronic bronchitis and chronic obstructive pulmonary disease. The Finnish Action Programme, interim report

The Finnish National Prevention and Treatment Programme for Chronic Bronchitis and COPD, launched in 1998, has, to date, been running for 6 years (2003). The goals of this action programme were to reduce the incidence of COPD and the number of moderate and severe cases of the disease, and to reduce both the number of days of hospitalisation and treatment costs. A prevalent implementation of over 250 information and training events started. Health centres and pharmacies appointed a person in charge of COPD patients. In order to improve the cooperation between primary and specialised care, two thirds of hospital districts created local COPD treatment chains. The early diagnosis of COPD by spirometric examination was activated during the programme. Number of health centres with available spirometric services increased to 95%. Before the start of the programme, approximately 5-9% of the adult population had COPD. During the whole programme, the proportion of male and female smokers decreased from 30% to 26% and from 20% to 19%, respectively. The total number of hospitalisation periods and days due to COPD decreased by 15% and 18%, respectively. Both the number of pensioners and daily sickness days due to COPD also decreased by 18%. Registered COPD induced deaths remained at their previous levels during the monitoring period, i.e. around 1000 deaths out of 5.2 millions annually. The measures recommended by the programme have been widely introduced but they need to be still more effective.

Respiratory symptoms, bronchial hyper-responsiveness, and eosinophilic airway inflammation in patients with moderate-to-severe atopic dermatitis

BACKGROUND

Patients with atopic dermatitis (AD) often have symptoms suggestive of asthma or rhinitis. The prevalence and signs of respiratory disease in AD patients have been studied to a limited extent.

OBJECTIVES

To assess the prevalence and clustering of respiratory symptoms, bronchial hyper-responsiveness (BHR), and eosinophilic airway inflammation in patients with moderate-to-severe AD.

METHODS

Eighty-six consecutive patients with moderate-to-severe AD and 49 randomly selected control subjects without AD were studied by questionnaire, flow volume spirometry, histamine challenge to detect BHR, induced sputum test to detect eosinophilic airway inflammation, and skin prick tests (SPTs) and total serum immunoglobulin (Ig)E measurements to detect atopy.

RESULTS

The patients with AD showed increased risk of physician-diagnosed asthma (36% vs. 2%, odds ratio (OR) 10.1, confidence interval (CI) 1.3-79.7, P=0.03), physician-diagnosed allergic rhinitis (AR) (45% vs. 6%, OR 4.5, CI 1.2-16.7, P=0.02), BHR (51% vs. 10%, OR 5.5, CI 1.5-20.1, P=0.01), and sputum eosinophilia (81% vs. 11%, OR 76.1, CI 9.3-623.5, P<0.0001) compared with the control subjects. In AD patients, elevated s-IgE and positive SPTs were associated with the occurrence of physician-diagnosed asthma and AR, BHR, and the presence of sputum eosinophilia.

CONCLUSIONS

BHR and eosinophilic airway inflammation are more common in patients with AD than in control subjects. The highest prevalences were seen in patients with AD who were SPT positive and had high IgE levels. Longitudinal studies are needed to assess the outcome of patients with signs of airway disease, in order to identify those who need early initiation of asthma treatment.

Total eosinophil cationic protein levels in induced sputum as a marker of changes in eosinophilic inflammation in a patient with allergic asthma

BACKGROUND

Counting eosinophils in induced sputum seems to be a better way to survey disease activity than indirect clinical assessments of airway inflammation, such as pulmonary function measurement. The conventional analysis of induced sputum, however, is time-consuming and requires skilled personnel, which have restricted its use.

OBJECTIVE

To determine whether measuring eosinophil cationic protein (ECP) levels in the entire sputum sample could replace the method of counting eosinophils and measuring ECP levels in the supernatant only to establish a clinically more applicable method of studying the intraindividual changes in eosinophilic activity in induced sputum.

METHODS

In 13 patients with mild, nonsymptomatic allergic asthma, sputum was induced before and 24 hours after allergen challenge. The entire sputum sample was diluted with 0.1% dithiothreitol, incubated, and divided into 2 parts. One part was processed according to the conventional method, and released ECP levels in the supernatant were measured. The second part was treated with a lysing reagent. Cell debris was separated, and total (intracellular and extracellular) ECP levels in the solution were measured.

RESULTS

We found good correlation between total ECP levels in the entire sputum sample and released ECP levels in the supernatant before (r = 0.97) and 24 hours after (r = 0.99) allergen challenge (P < .01 for both). We also found a good correlation between the changes in total and released ECP levels (r = 0.99; P < .01).

CONCLUSIONS

Total ECP concentration seems to reflect the eosinophilic inflammatory changes in asthma and might be a useful tool in clinical practice.

Bronchial Hyperresponsiveness, Airway Inflammation, and Airflow Limitation in Endurance Athletes

BACKGROUND

Whereas a high prevalence of bronchial abnormalities has been reported in endurance athletes, its underlying mechanisms and consequences during exercise are still unclear.

STUDY OBJECTIVES

The purpose of this study was to assess the following: (1) bronchial responsiveness to methacholine and to exercise; (2) airway inflammation; and (3) airflow limitation during intense exercise in endurance athletes with respiratory symptoms.

DESIGN

Cross-sectional observational study.

SETTING

Lung function and exercise laboratory at a university hospital.

PATIENTS AND MEASUREMENTS

Thirty-nine endurance athletes and 13 sedentary control subjects were explored for the following: (1) self-reported respiratory symptoms; (2) bronchial hyperresponsiveness (BHR) to methacholine and exercise; (3) airflow limitation during intense exercise; and (4) bronchial inflammation using induced sputum and nitric oxide (NO) exhalation.

RESULTS

Fifteen athletes (38%) showed BHR to methacholine and/or exercise in association with bronchial eosinophilia (mean [+/- SD] eosinophil count, 4.1 +/- 8.5% vs 0.3 +/- 0.9% vs 0%, respectively), higher NO concentrations (19 +/- 10 vs 14 +/- 4 vs 13 +/- 4 parts per billion, respectively), a higher prevalence of atopy, and more exercise-induced symptoms compared with non-hyperresponsive athletes and control subjects (p < 0.05). Furthermore, airflow limitation during intense exercise was observed in eight athletes, among whom five had BHR. Athletes with airflow limitation reported more symptoms and had FEV1, FEV1/FVC ratio, and forced expiratory flow at midexpiratory phase values of 14%, 9%, and 29%, respectively, lower compared with those of nonlimited athletes (p < 0.05).

CONCLUSION

BHR in endurance athletes was associated with the criteria of eosinophilic airway inflammation and atopy, whereas airflow limitation during exercise was primarily a consequence of decreased resting spirometric values. Both BHR and bronchial obstruction at rest with subsequent expiratory flow limitation during exercise may promote respiratory symptoms during exercise in athletes.

Determinants of increased exhaled nitric oxide in patients with suspected asthma

Exhaled nitric oxide (FENO) has been proposed as a marker of asthmatic inflammation, but it is unclear whether FENO in clinical use selects patients primarily according to their atopic or asthmatic status. The aim of this study was to investigate the determinants of increased FENO in patients with suspected asthma, by means of multinomial logistic regression analysis. The FENO of 132 patients referred because of symptoms suggestive of asthma were studied, and the explanatory factors tested included atopy according to prick skin tests, clinical asthma according to lung function tests, sputum eosinophilia and bronchial hyperresponsiveness (BHR). Slightly elevated FE(NO) levels were significantly explained only by sputum eosinophilia (OR: 3.7; 95% CI: 1.1-13.1; P=0.04), but for high levels of FE(NO) (> or =3 SD of predicted), clinical asthma (OR: 16.3; 95% CI: 5.4-49.7; P <0.0001) and sputum eosinophilia (OR: 12.0; 95% CI: 4.1-35.0; P >0.0001) were the characteristics with the highest prediction, followed by atopy and BHR. A significant interaction between asthma and atopy was observed relating to the effect on high FENO, but further analyses stratified by atopy showed significant associations between asthma and high FENO both in atopic and nonatopic patients. We conclude that in patients with symptoms suggesting asthma, slightly elevated and high levels of FENO are associated with sputum eosinophilia, whereas asthma is significantly associated only with high levels of FENO, irrespective of atopy. The results suggest that FENO is primarily a marker of airway eosinophilia, and that only high values of FENO may be useful to identify patients with atopic or nonatopic asthma.

Montelukast and fluticasone compared with salmeterol and fluticasone in protecting against asthma exacerbation in adults: one year, double blind, randomised, comparative trial

OBJECTIVES

To assess the effect of montelukast versus salmeterol added to inhaled fluticasone propionate on asthma exacerbation in patients whose symptoms are inadequately controlled with fluticasone alone. Design and setting A 52 week, two period, double blind, multicentre trial during which patients whose symptoms remained uncontrolled by inhaled corticosteroids were randomised to add montelukast or salmeterol.

PARTICIPANTS

Patients (15-72 years; n = 1490) had a clinical history of chronic asthma for > or = 1 year, a baseline forced expiratory volume in one second (FEV1) value 50-90% predicted, and a beta agonist improvement of > or = 12% in FEV1.

MAIN OUTCOME MEASURES

The primary end point was the percentage of patients with at least one asthma exacerbation.

RESULTS

20.1% of the patients in the group receiving montelukast and fluticasone had an asthma exacerbation compared with 19.1% in the group receiving salmeterol and fluticasone; the difference was 1% (95% confidence interval -3.1% to 5.0%). With a risk ratio (montelukast-fluticasone/salmeterol-fluticasone) of 1.05 (0.86 to 1.29), treatment with montelukast and fluticasone was shown to be non-inferior to treatment with salmeterol and fluticasone. Salmeterol and fluticasone significantly increased FEV1 before a beta agonist was used and morning peak expiratory flow compared with montelukast and fluticasone (P < or = 0.001), whereas FEV1 after a beta agonist was used and improvements in asthma specific quality of life and nocturnal awakenings were similar between the groups. Montelukast and fluticasone significantly (P = 0.011) reduced peripheral blood eosinophil counts compared with salmeterol and fluticasone. Both treatments were generally well tolerated.

CONCLUSION

The addition of montelukast in patients whose symptoms remain uncontrolled by inhaled fluticasone could provide equivalent clinical control to salmeterol.

Eosinophil granule proteins in the assessment of airway inflammation in pediatric bronchial asthma

Eosinophil granule proteins such as eosinophil cationic protein (ECP), eosinophil peroxidase (EPO) and eosinophil protein X (EPX) in serum and urine are indirect measures of eosinophil activity. The measures have been evaluated for prediction, diagnosis and monitoring of anti-inflammatory treatment modalities in children with asthma. Assessments in serum and urine are highly dependent on sampling procedures and must be performed under strictly controlled conditions using standardized sampling and laboratory procedures. The measures are influenced by circadian and seasonal variations. Measurement of the eosinophil granule proteins does not improve the predictive value of a family history of atopy. Due to insufficient sensitivity and specificity, the measures are not useful in the diagnosis of asthma in children, and the clinical use of eosinophil proteins in the individual child for assessment of asthma severity has not been sufficiently validated. Serum and urine eosinophil granule proteins, however, may be useful in extending our knowledge of suppressive effects on eosinophil activity of various doses, devices and administration regimens of inhaled glucocorticoids in children. Such evaluations may be performed in randomized, double-blind trials of well-defined age groups and they should include measures of compliance. One important aspect to look at would be the distinction between suppressive effects on eosinophil activity and clinically important anti-inflammatory effects. Considering the complexity of airway inflammation and the heterogeneity of childhood asthma, however, it may be too simplistic to look for a single measure of the inflammatory processes. In the future, perhaps, a combination of products of inflammatory cells may give more clinically relevant information with respect to prediction, diagnosis, monitoring and outcome of childhood asthma.

Smoking and atopy as determinants of sputum eosinophilia and bronchial hyper-responsiveness in adults with normal lung function

Data concerning the determinants of sputum eosinophilia and bronchial hyper-responsiveness (BHR) in large cohorts of individuals with normal lung function are limited. Here, we assessed the occurrence of sputum eosinophilia and BHR and identified the risk factors for these variables in two populations living in North Karelia, Finland, and in Pitkäranta, the Republic of Karelia, Russia. These areas are geographically adjacent, but differ, however, fundamentally in major cultural, socioeconomical and lifestyle aspects. The study population comprised 790 Finns and 387 Russian, aged 25-54 years, who were randomly enrolled from the population registers. A methacholine challenge test to measure BHR was successfully performed in 581 (74%) Finns and 307 (79%) Russians with virtually normal lung function (FEV1 > 70% of predicted). Of these, induced sputum samples were obtained from 41% of the Finns and from 67% of the Russians. The proportion of current smokers was 27% among the former and 42% among the latter. Sputum eosinophilia was assessed using a semi-quantitative method, and total concentrations of sputum eosinophilic cationic protein (ECP) and myeloperoxidase (MPO) were measured using an immunoassay. Risk factors for BHR and sputum eosinophilia were identified with a regression analysis. The prevalence of sputum eosinophilia was 22% among the Finns and 19% among the Russians, and the respective figures for BHR were 14% and 13%. The median ECP concentration in sputum was significantly higher among the Russians as compared with the Finns (P<0.001), whereas for MPO, the difference did not achieve significance. Current smoking was significantly associated with both sputum eosinophilia and BHR in Russia (OR 3.1, 95% CI 1.2-7.6 for sputum eosinophilia, 2.8, 1.3-6.1 for BHR) and with BHR in Finland (2.1, 1.3-3.7). Atopy showed a tendency to be another risk factor for BHR in Finland (1.6, 0.98-2.6). In conclusion, sputum eosinophilia and BHR occurred commonly among the Finns and the Russians with normal lung function. Current smoking was significantly associated with BHR in both countries and additionally with sputum eosinophilia in Russia. Atopy was identified as a risk factor, albeit of borderline significance, for BHR in Finland only, suggesting that there may be differences in the aetiology and nature of BHR between the two countries.

Bronchial hyperresponsiveness and airway inflammation in adolescents with asymptomatic childhood asthma

BACKGROUND

About 70% of childhood asthmatics become free of asthma-related symptoms during adolescence. Little is known about bronchial hyperresponsiveness (BHR) and airway inflammation in young adults with "outgrown" childhood asthma.

METHODS

We studied 61 nonsmoking medical students (18 intermittent mild asthmatics, 23 students with outgrown childhood asthma but free of asthma-related symptoms for 10 years (asymptomatic asthmatics) and 20 healthy students). BHR and lung function were measured, and induced sputum samples analyzed for eosinophil count, eosinophilic cationic protein (ECP), granulocyte-macrophage colony stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha).

RESULTS

BHR was still present in most asymptomatic asthmatics, but it was milder compared with healthy students. Only three subjects with previous asthma had no BHR and no signs of airway inflammation. Percentages of eosinophil, and ECP, TNF-alpha and GM-CSF concentrations in induced sputum of mild asthmatics and asymptomatic asthma groups were higher than in the healthy group. In asymptomatic asthmatics group, the duration of asthma, sputum eosinophil percentage, and the level of TNF-alpha in sputum correlated significantly with BHR.

CONCLUSIONS

Only a few subjects with longstanding asymptomatic asthma could be considered as cured; most asymptomatic asthmatics continued to exhibit BHR and signs of airway inflammation. The outcome of childhood asthma and BHR was associated with the degree of airway inflammation and the duration of childhood asthma.

Safety, tolerability and acceptability of two dry powder inhalers in the administration of budesonide in steroid-treated asthmatic patients

The purpose of this randomized, double-blind parallel group study was to compare the safety, tolerability and acceptability of Easyhaler and Turbuhaler dry powder inhalers for the delivery of budesonide 800 microg day(-1) in adult asthmatic patients who had already been treated with inhaled corticosteroids for at least 6 months prior to the study Additionally the efficacy of the products was evaluated. The main objective was to evaluate the systemic safety of budesonide inhaled from Easyhaler (Giona Easyhaler, Orion Pharma, Finland) as determined by serum and urine cortisol measurements. The secondary objective was to compare the tolerability acceptability and efficacy of the two devices in the administration of budesonide. After a 2-week run-in period (baseline), patients were randomized on a 2:1 basis to receive budesonide from Easyhaler (n = 103) or from Turbuhaler (Pulmicort Turbuhaler, AstraZeneca, Sweden) (n = 58) 200 g dose(-1), two inhalations twice daily for 12 weeks. There was no statistically significant change in morning serum cortisol values from baseline to the end of treatment in either group. Urine free cortisol and urine cortisol/ creatinine ratio increased from baseline in both groups. There were no significant differences between the groups in terms of morning serum cortisol, urine cortisol, adverse events or efficacy variables, but Easyhaler was generally considered more acceptable to the patients. In conclusion, at 800 microg day(-1), Giona Easyhaler is as safe and efficacious as Pulmicort Turbuhaler in adult asthmatic patients previously treated with corticosteroids, but more acceptable to patients.

Measurement of airway inflammation in asthma

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

Eosinophilic airway inflammation as an underlying mechanism of undiagnosed prolonged cough in primary healthcare patients

Prolonged cough is a common problem in patients seen in general practice. Using a simple method of sputum induction and processing of sputum samples, we determined whether eosinophilic airway inflammation could be a cause of undiagnosed prolonged cough. Eighty-two patients who had had cough for more than 1 month were enrolled into the study, in six primary healthcare centres. Patients with known pulmonary disease, including asthma or chronic obstructive pulmonary disease (COPD), or who were known to have another cause of cough, or to have recently suffered from a respiratory infection, were excluded. Fifty-three healthy individuals served as controls. Sputum was induced by inhalation of 3% saline. Inflammatory cells in smears were studied semi-quantitatively. Concentrations of eosinophil cationic protein (ECP), eosinophil peroxidase (EPO), myeloperoxidase (MPO) and human neutrophilic lipocalin (HNL) were determined. Sputum induction proved safe and adequate samples were obtained from 91%. Sputum eosinophilia (eosinophils accounting for more than 5% of all cells in smears) was present in 14 patients with prolonged cough (19%) but in no healthy individual (P=0.001). Five of the 14 individuals (36%) who exhibited sputum eosinophilia appeared to have asthma, while nine of the 14 (64%) did not. Concentrations of ECP and EPO were higher in patients with prolonged cough than in healthy individuals (P=0.02 for ECP; 0.005 for EPO). We conclude that eosinophilic airway inflammation is a fairly common cause of prolonged cough, even in patients not suffering from asthma or COPD, or in whom no other cause of cough is known to be present. Induced sputum samples obtained in health centres can be studied in a central laboratory. Detection of eosinophilic airway inflammation could aid the decision regarding treatment.