Eosinophils In Induced Sputum Research Articles

Reduced eosinophil apoptosis in induced sputum correlates with asthma severity.

This study was carried out to investigate the relationship between induced sputum eosinophil apoptosis and clinical severity score, airway obstruction and symptom scores in patients with chronic stable asthma. Altogether, 41 chronic stable asthmatic subjects of varying severity defined by Aas score and 17 control subjects underwent spirometry, symptom questionnaire and successful sputum induction. Sputum was processed and cytospins prepared for light microscopy to determine normal and apoptotic eosinophils. Mild asthmatic subjects had a significantly lower percentage sputum eosinophils and a significantly higher eosinophil apoptotic ratio (AR) than moderate or chronic severe asthmatics. Severe asthmatic subjects had a significantly greater age, duration of asthma and sputum eosinophil count x mL(-1) than mild asthmatic subjects. Asthmatic subjects' symptom scores, severity scores and age inversely correlated with AR and the percentage of sputum eosinophils. Baseline forced expiratory volume in one second inversely correlated with percentage sputum eosinophils and positively correlated with AR. The study demonstrates a relationship between reduced sputum eosinophil apoptosis and increased clinical severity of chronic stable asthma, providing additional evidence that eosinophil apoptosis may be important in the resolution of eosinophilic airway inflammation in asthma.

Migration to a western country increases asthma symptoms but not eosinophilic airway inflammation.

The prevalence of asthma symptoms varies markedly throughout the world. However, the asthma mechanisms involved are not defined. Studying the effects of migration can help identify the reasons for this geographic variation. The aims of this study were to examine the prevalence of asthma symptoms, airway hyperresponsiveness (AHR), and induced sputum eosinophils in adolescents who migrate to Australia. The study was conducted in Sydney, Australia, where adolescent students completed a video symptom questionnaire, hypertonic saline challenge, sputum induction, and allergy skin testing. The 211 students had widely different cultural backgrounds, including Asian, South Pacific, Middle Eastern, European, and African countries. Among adolescents who were migrants to Australia, the prevalence of asthma symptoms was higher than that reported using a similar methodology in their country of origin. Asthma symptom prevalence was related to residence time in Australia. The prevalence of wheeze was 17.2% in recent arrivals, 20.5% in adolescents living in Australia for >2 years, and 36.3% in those living all their lifetime in Australia (P = 0.013). For every year of residence in Australia, there was an 11% increase in prevalence of current wheeze (odds ratio, 1.11; P = 0.02). This effect was not related to atopy, AHR, or eosinophilic airway inflammation. Sputum neutrophils were elevated in recent arrivals. In conclusion, adolescents who migrate to Australia report increased asthma symptoms, compared to their country of origin, and asthma symptoms are further increased for every additional year of residence in Australia. The development of wheeze after migration to Australia was independent of eosinophilic inflammation and consistent with noneosinophilic asthma mechanisms.

Clinical usefulness of inflammatory markers in asthma.

Asthma is a significant and increasing health problem. Airway inflammation and hyperresponsiveness are key pathophysiological mechanisms underlying asthma. Currently, effective treatments target these two processes and can lead to clinically important improvements in disease control. At present, decisions to initiate or modify therapy are based on symptoms and measures of airway caliber, with no direct assessment of airway inflammation or hyperresponsiveness. It is now possible to measure airway inflammation using noninvasive markers such as exhaled gases, induced sputum and serum measurements. Exhaled nitric oxide (eNO) and induced sputum eosinophils show the greatest promise as clinically useful markers of airway inflammation in asthma. Induced sputum can now be applied to the diagnosis of airway diseases, based on its ability to detect eosinophilic bronchitis in cough, and to differentiate between eosinophilic and non-eosinophilic asthma. The place of induced sputum and eNO in the ongoing monitoring of patients with asthma are now being investigated in controlled trials.

Asthma exacerbations and sputum eosinophil counts: a randomised controlled trial

Treatment decisions in asthma are based on assessments of symptoms and simple measures of lung function, which do not relate closely to underlying eosinophilic airway inflammation. We aimed to assess whether a management strategy that minimises eosinophilic inflammation reduces asthma exacerbations compared with a standard management strategy. We recruited 74 patients with moderate to severe asthma from hospital clinics and randomly allocated them to management either by standard British Thoracic Society asthma guidelines (BTS management group) or by normalisation of the induced sputum eosinophil count and reduction of symptoms (sputum management group). We assessed patients nine times over 12 months. The results were used to manage those in the sputum management group, but were not disclosed in the BTS group. The primary outcomes were the number of severe exacerbations and control of eosinophilic inflammation, measured by induced sputum eosinophil count. Analyses were by intention to treat. The sputum eosinophil count was 63% (95% CI 24-100) lower over 12 months in the sputum management group than in the BTS management group (p=0.002). Patients in the sputum management group had significantly fewer severe asthma exacerbations than did patients in the BTS management group (35 vs 109; p=0.01) and significantly fewer patients were admitted to hospital with asthma (one vs six, p=0.047). The average daily dose of inhaled or oral corticosteroids did not differ between the two groups. A treatment strategy directed at normalisation of the induced sputum eosinophil count reduces asthma exacerbations and admissions without the need for additional anti-inflammatory treatment.

Differential Cell Counts in Sputum in Respiratory Epidemiology: A Pilot Study

The aim of this pilot study was to determine whether measuring sputum differential cell counts, particularly eosinophils, could be a useful method of validating self-reported symptoms suggesting asthma in epidemiologic studies. In this cross-sectional study, we selected four groups of adult subjects by reported symptoms and diagnoses from among those previously randomly identified in a population study. Subjects were selected with no respiratory symptoms ever (normal group), or reporting a diagnosis of asthma (asthma group), or reporting recurrent wheezing not diagnosed as asthma (wheeze group), or reporting exposure to industrial irritants, but not asthma or wheezing (exposed group). Current respiratory symptoms, airway responsiveness to methacholine challenge, and sputum cell counts were determined. The study was completed by 107 subjects aged 20 to 44 years. There were no significant differences in FEV(1) percent predicted, total cell count, and sputum eosinophil count among the four groups. Subjects with reported asthma had greater airway responsiveness as reflected in a lower bronchial reactivity (BR) index. There was a weak correlation between BR index and sputum eosinophils. In a community setting, induced sputum eosinophil cell counts in subjects reporting asthma or wheezing were most often within the normal range and not sufficiently often abnormal to be useful in validating a diagnosis of asthma in epidemiologic studies.

Induced sputum eosinophils and neutrophils and bronchiectasis severity in allergic bronchopulmonary aspergillosis.

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction to the fungus Aspergillus fumigatus that may progress to bronchiectasis. The aim of the present study was to characterize airway inflammation in patients with clinically stable ABPA and asthma, and to correlate this with bronchiectasis severity. Subjects with ABPA and central bronchiectasis (ABPA-CB; n=16) and ABPA with serological evidence alone (ABPA-S; n=10) were studied. Comparison groups were A. fumigatus-sensitized asthma (n=19), non-A. fumigatus-sensitized asthma (n=15) and healthy controls (n=8). Hypertonic saline challenge, sputum induction and high-resolution computed tomography (HRCT) of the chest were performed. Sputum eosinophil numbers were markedly elevated in ABPA-CB (median 8.4%) compared to ABPA-S (2.4%), A. fumigatus-sensitized asthma (1.8%), asthma (1.8%) and controls (0.3%) (p<0.01); sputum eosinophil cationic protein levels were higher in ABPA-CB (median 13,706 ng.mL(-1)), compared to ABPA-S (1,633.5 ng.mL(-1)), A. fumigatus-sensitized asthma (1,550.7 ng.mL(-1)), asthma (309.2 ng.mL(-1)), and controls (110 ng.mL(-1)) (p<0.001). ABPA-CB also showed increased sputum neutrophil number (median 60.3%) compared to the other groups (controls 29.3%) (p=0.01). The severity of bronchiectasis on HRCT correlated with sputum neutrophil (r=0.6) and eosinophil number (r=0.5) but not serum immunoglobulin-E levels. In conclusion, clinically stable allergic bronchopulmonary aspergillosis with bronchiectasis is characterized by an intense heterogenous inflammatory infiltrate consisting of eosinophils and neutrophils, which correlates closely with the severity of bronchiectasis on high-resolution computed tomography. Sputum analysis may be useful in monitoring the course of allergic bronchopulmonary aspergillosis.

Airway mast cells and eosinophils correlate with clinical severity and airway hyperresponsiveness in corticosteroid-treated asthma

Background: The relationship between airway inflammation and asthma severity in corticosteroid-treated asthma is unclear. Objectives: Our purpose was to characterize the inflammatory cell profile of the airway lumen and epithelium in corticosteroid-treated asthma and to relate these findings to clinical and physiologic markers of asthma severity. Methods: Adults (n = 20) with asthma received standardized high-dose inhaled corticosteroid therapy with beclomethasone 2000 μg per day for 8 weeks. Airway responsiveness to methacholine and hypertonic (4.5%) saline solution was then assessed, followed by sputum induction and, 1 week later, bronchoscopy with bronchoalveolar lavage and bronchial brush biopsy to assess inflammatory cells. Results: Clinical asthma severity was associated with airway hyperresponsiveness. Metachromatic cells were the main granulocyte present in bronchial brush biopsy specimens and correlated with airway responsiveness to saline solution (r = –0.75), methacholine (r = –0.74), peak flow variability (r = 0.59), and clinical asthma severity (r = 0.57). Eosinophils were the main granulocyte present in sputum and correlated with airway responsiveness to saline solution (r = –0.63) but not with other clinical markers of asthma severity. Bronchoalveolar lavage cell counts were not related to clinical asthma severity. Conclusions: In asthmatic patients treated with cortico-steroids, the dominant inflammatory effector cell in the epithelium is the metachromatic cell, and in sputum it is the eosinophil. These cells correlate with the degree of airway hyperresponsiveness. Clinical asthma severity correlates with airway responsiveness and epithelial metachromatic cells. Induced sputum eosinophils and airway responsiveness to hypertonic saline solution may be useful markers of airway inflammation for clinical practice. (J Allergy Clin Immunol 2000;105:752-9.)

Induced sputum eosinophils in the assessment of asthma and chronic cough.

To evaluate induced sputum eosinophils in asthma and chronic cough. This was an analytical, cross-sectional study set in an ambulatory respiratory clinic. Subjects (n=75) referred for evaluation of symptomatic asthma or episodic respiratory symptoms had a clinical assessment, spirometry, hypertonic saline challenge and induced sputum. Two diagnostic groups were identified. The first group comprised subjects with symptomatic asthma and variable airway obstruction (VAO) (n=32). The second group included subjects with episodic respiratory symptoms and no VAO (n=43). The prevalence of eosinophilic bronchitis (eosinophils >2.75%) was greatest in asthma (n=14, 44%), compared to the episodic respiratory symptoms group (n=9, 21%, P = 0.02). Clinical variables did not predict increased eosinophils (P > 0.05). Sputum eosinophils were highest in asthmatics not using inhaled corticosteroids (6.5% vs 0.5%, P = 0.02). Sputum neutrophils were higher in subjects using inhaled corticosteroid (53% vs 25%, P = 0.04). Airway inflammation with eosinophilia was common among patients presenting to a respiratory clinic, especially those with asthma who were not using inhaled corticosteroids. Induced sputum also identified eosinophilic bronchitis in those without asthma. It was not possible to detect the presence or absence of airway eosinophilia by routine clinical assessment. The results in this study imply that the assessment of induced sputum eosinophils may be a useful guide to therapy, especially in the assessment of persistent symptoms in asthmatics on corticosteroids, and in the assessment of non-asthmatic subjects with symptoms.

Interleukin-8 secretion and neutrophil recruitment accompanies induced sputum eosinophil activation in children with acute asthma.

Although airway inflammation is recognized as a key feature of asthma, the characteristics of airway inflammation in children with acute severe asthma are not well defined. The aim of this study was to describe the characteristics of airway inflammation in children with an acute exacerbation of asthma using sputum cell counts and fluid-phase measurements and to examine the changes in these parameters upon resolution of the exacerbation. Children (n = 38) presenting to the Emergency Department with acute asthma underwent successful sputum induction using ultrasonically nebulized normal saline (n = 22), or expectorated sputum spontaneously (n = 16). Sputum induction was repeated at least 2 wk later when the children had recovered (n = 28). Sputum portions were selected, dispersed and total and differential cell counts performed. Neutrophil elastase and EG2-positive eosinophils were assessed and fluid-phase eosinophil cationic protein (ECP), myeloperoxidase (MPO), interleukin-8 (IL-8), and IL-5 were measured. During the acute exacerbation the median (range) total cell count was 8.4 x 10(6)/ml (0.5 to 190.3), and fell significantly at resolution to 1.3 x 10(6)/ml (p < 0.01). The inflammatory cell infiltrate was mixed and included eosinophils (0.8 x 10(6)/ml), neutrophils (3.3 x 10(6)/ml), and mast cells. EG2(+) cells were high and correlated with the degree of airflow obstruction (r = -0.5, p = 0.02). They decreased significantly at resolution as did supernatant ECP (1,078 versus 272 ng/ml), suggesting that eosinophils were activated during the exacerbation. MPO was 220 ng/ ml at exacerbation and fell significantly to 1 ng/ml at resolution. Levels of IL-8 and IL-5 were elevated during the acute exacerbation and IL-8 concentrations decreased at resolution. In conclusion, airway inflammation can be studied in children with acute asthma by sputum induction. Airway inflammation is present during an acute exacerbation of asthma, and is characterized by infiltration and activation of both eosinophils and neutrophils. The heterogeneity of airway inflammation in acute asthma may influence response to corticosteroid therapy.

The Effect of glucocorticoid on the change of nitric oxide and cytokine levels in induced sputum from patients with bronchial asthma

Background It has been well known that bronchial asthma is a chronic airway inflammatory disorder. Recently, sputum specimen induced with hypertonic saline was introduced as a simple and useful noninvasive medium to investigate airway inflammation and symptom severity in patients with asthma. We examined the eosinophil, cationic protein (ECP), interleukin(IL)-3, IL-5, granulocyte-macrophage colony-stimulating factor (GM-CSF), and nitric oxide (NO) derivatives in induced sputum from patients with bronchial asthma in order to determine the role of NO and various inflammatory cytokines as a useful markers of airway inflammation of changes in pulmonary function tests and symptoms. Methods A total 30 patients with bronchial asthma received oral prednisolone 30 mg daily for 2 weeks. Forced expiratory volume in one second (FEV), total blood eosinophil count, and induced sputum eosinophil count, ECP, IL-3, IL-5, GM-CSF, and NO derivatives were determined before and after the administration of prednisolone. Results Of the 30 patients, 13 (43.3%) were male and 17 (56.7%) were female. The mean age of patients was 41.8 years (range 19-64 years). Two patients could not produce sputum at the second study and 3 could not be followed up after their first visit. Two weeks after the prednisolone administration, there was a significant increase in FEV1 (% of predicted value) from 78.1±20.6% to 90.3±18.3% (P<0.001). The eosinophil percentages in induced sputum were significantly decreased after treatment with prednisolone, with values of 56.1±27.2% versus 29.6±21.3% (P<0.001), and ECP were 134.5±68.1 µm/L versus 41.5±42.4 µm/L (P<0.001) respectively. After the prednisolone treatments, the eotaxin concentration also showed a decreasing tendency from 26.7±12.8 pg/ml to 21.7±8.7 pg/ml. There was a decreasing tendency but no significant differences in total blood eosinophil count(425.7±265.9 vs 287.7±294.7) and in the concentration of NO derivatives (70.4±44.6 µmol%/L vs 91.548.3 µmol/L) after the predinisolone treatments. IL-3, IL-5, GM-CSF were undetectable in the sputum of most subjects either before the prednisolone treatments of after the treatments. Before the prednisolone treatments, a significant inverse correlation was observed between FEV1 and sputum ECP (r=-0.364, P<0.05) and there was a significant correlation between sputum eosinophils and eotaxin (r=0.369, P<0.05). Conclusion The eotaxin and ECP concentration in induced sputum may be used as markers of airway inflammation after treatments in bronchial asthma. In addition, the measurement of sputum eosinophil percentages is believed to be a simple method displaying the degree of airway inflammation and airway obstruction before and after the predinisolone treatment in bronchial asthma. However, unlike exhaled NO, the examination of NO derivatives with Griess reaction in induced sputum is considered an ineffective marker of changing airway inflammation and obstructing symptoms.

Sputum eosinophil count to assess compliance with corticosteroid therapy in asthma

Sputum eosinophil count to assess compliance with corticosteroid therapy in asthma

Effect of inhaled steroids on airway hyperresponsiveness, sputum eosinophils, and exhaled nitric oxide levels in patients with asthma

BACKGROUNDAirway hyperresponsiveness, induced sputum eosinophils, and exhaled nitric oxide (NO) levels have all been proposed as non-invasive markers for monitoring airway inflammation in patients with asthma. The aim of this...

Levalbuterol hydrochloride

Racemic salbutamol (racemic albuterol) ameliorates symptoms of asthmaby activating b-adrenoceptors on nerve, smooth muscle and inflammatorycells within the airways. Racemic salbutamol comprises equal proportionsof 2 isomers: (S)-salbutamol and (R)-salbutamol, with the latter beingexclusively responsible for activation of b-adrenoceptors. Accordingly,within racemic salbutamol it is (R)-salbutamol that efficiently relievesobstruction of asthmatic airways and affords highly effective protectionfrom bronchoconstrictor stimuli, including allergens. During regular use ofracemic salbutamol, there is a progressive decline of protective efficacy anda corresponding intensification of airway responsiveness. This decline islargely absent during regular use of (R)-salbutamol. Consequently,bronchodilator responses to sub-maximal doses of (R)-salbutamol exceedresponses to the equivalent dose of (R)-salbutamol given as the racemate.For example, in asthmatics with baseline FEVs ≤ 60%, 1.25 mg of nebulised(R)-salbutamol achieved a maximal 52% change in FEV while 2.5 mg ofracemic salbutamol only achieved a 38% change in FEV. Since extrapulmonaryeffects (e.g., tremor, heart rate) of b agonists are related to dose andlimit the use of b agonist therapy, (R)-salbutamol at 0.63 mg providesuncompromised efficacy with marked reduction of side-effects. In additionto quantitative differences, the constituent isomers of salbutamol alsoexhibit qualitative differences. Thus, (R)-salbutamol inhibits activation ofhuman eosinophils in vitro whereas, under the same conditions andconcentrations, (S)-salbutamol augments activation of these cells. Thisproperty of (S)-salbutamol may explain why eosinophilia in inducedsputum from subjects with allergic asthma is increased by regular use ofracemic salbutamol. Similarly, the capacity of (R)-salbutamol to suppresshyperresponsiveness of the airways can be contrasted with the capacity of(S)-salbutamol to intensify hyperresponsiveness. This action of (S)-salbutamolwould explain why regular use of racemic salbutamol intensifies thebronchoconstrictor response to antigen in subjects with allergic asthma.Taken together, these findings imply that replacement of racemicsalbutamol by (R)-salbutamol will diminish, or even eliminate, theanomalous actions that have curtailed the efficacy of racemic salbutamol.Pharmacokinetically, (R)-salbutamol exhibits near absolute conformationalstability (i.e., no conversion to (S)-salbutamol). If in vitro anti-inflammatoryactions of (R)-salbutamol are also manifest in asthmatic airways, (R)-salbutamolcould provide a novel approach to asthma therapy which combinesbronchodilation and bronchoprotection with anti-inflammatory efficacy.

Effects of thromboxane A 2 antagonist on airway hyperresponsiveness, exhaled nitric oxide, and induced sputum eosinophils in asthmatics

We examined effects of a thromboxane A 2 (TXA 2) antagonist seratrodast on airway hyperresponsiveness, exhaled nitric oxide (NO), and eosinophils in induced sputum in 14 asthmatics. Subjects were administered 80 mg of seratrodast once a day for 4 weeks. Respiratory conductance (Grs) was measured by the forced oscillation method and airway responsiveness was evaluated as the inhaled dose of methacholine, which induced 35% decrease in Grs. Subjects breathed into a Teflon bag, and NO concentration in the bag was measured by a chemiluminescence analyzer. Induced sputum comprised the entire expectorate produced during a 20 min inhalation of 3% saline, and was analyzed for total and differential cell counts. Airway hyperresponsiveness was significantly decreased by seratrodast. By contrast, no differences in either exhaled NO or percentage of eosinophils in sputum were observed before or after seratrodast. We conclude that seratrodast may attenuate airway hyperresponsiveness, presumably by antagonizing TXA 2 released from the inflamed airways.

Induced sputum eosinophil cationic protein (ECP) measurement in asthma and chronic obstructive airway disease (COAD)

Induced sputum is a useful way to monitor airway inflammation in asthma, but cell counts are time-consuming and labour intensive. The aim of this study was to evaluate a novel processing method using eosinophil cationic protein (ECP) as a biochemical marker of sputum eosinophil number and activation in subjects with asthma and other airway diseases. Sputum was dispersed with dithiothreitol and centrifuged to yield cell free supernatant and a cell pellet. The pellet was treated with a cellular lysis buffer to release cell-associated ECP. ECP was measured in sputum supernatant and in the lysed cell pellet and was compared with sputum eosinophil counts in 31 adults with asthma, chronic obstructive airway disease (COAD), bronchiectasis and healthy controls. The ratio of supernatant to pellet ECP was evaluated as an index of eosinophil degranulation. The effect of sputum processing reagents and storage time on ECP measurement was also evaluated. ECP measured in the cell pellet lysate correlated closely with sputum absolute eosinophil counts across a range of subject groups (r = 0.72, P = 0.004). Sputum eosinophil counts were less well correlated with supernatant ECP levels (r = 0.54, P < 0.05). Incubation with dithiothreitol or lysis buffer did not influence ECP measurement and sputum ECP levels were stable over a 6-9 month period. Sputum supernatant and pellet lysate ECP concentrations were increased in stable asthma, asthma exacerbations and COAD/bronchiectasis (P < 0.05). The ratio of supernatant to pellet ECP was used as an index of eosinophil degranulation and found to be elevated in asthma exacerbations, COAD and bronchiectasis, but not in stable asthma. The measurement of ECP in the sputum cell pellet provides a reliable and efficient estimate of sputum eosinophil counts which can potentially be used in clinical trials and epidemiological surveys. The ECP ratio may be a useful marker of eosinophil activation, and was increased in asthma exacerbation and COAD. The increased ECP in COAD reflects a non-selective accumulation of eosinophils in this condition.

Effect of regular inhaled salbutamol on airway responsiveness and airway inflammation in rhinitic non-asthmatic subjects.

BACKGROUND: Regular, inhaled beta 2 agonists may increase airway responsiveness in asthmatic subjects. The mechanism is not known but may be via an increase in airway inflammation. A study was...