Induced sputum cellularity. Reference values and distribution in normal volunteers

Sputum eosinophilia is a determinant of FEV1 decline in occupational asthma: results of an observational study

OBJECTIVE

To evaluate the potential determinants of forced expiratory volume in 1 s (FEV1) decline in workers with occupational asthma (OA) still exposed to the causative agent. We hypothesised that sputum eosinophilia might be a predictor of poor asthma outcome after diagnosis.

SETTING, DESIGN AND PARTICIPANTS

In a specialistic clinical centre of the University Hospital of Pisa, we studied 39 participants (28 M, 11 F) diagnosed as having OA, routinely followed up between 1990 and 2009. They were a subgroup of 94 participants diagnosed as affected by OA in that period: 9 had been removed from work at the diagnosis, 21 were excluded for having ceased occupational exposure after few months from diagnosis, and 25 were lost at the follow-up or had no acceptable sputum measurements at the diagnosis. Estimates of the decline in FEV1 were obtained by means of simple regression analysis during the period of occupational exposure after diagnosis. Logistic regression was used to analyse the effects of factors (baseline FEV1 and sputum inflammatory cells, duration and type of exposure) that may potentially influence FEV1 decline.

RESULTS

At follow-up (5.7+3.7 years), most participants were still symptomatic despite inhaled corticosteroids (ICS) treatment and had their occupational exposure reduced. Participants with higher sputum eosinophils (>3%) at baseline had a significantly greater decline of FEV1 (-52.5 vs -18.6 mL/year, p=0.012). Logistic regression showed that persistent exposure and sputum eosinophilia were significantly associated with a greater decline in FEV1 (OR 11.5, 95% CI 1.8 to 71.4, p=0.009 and OR 6.7, 95% CI 1.1 to 41.7, p= 0.042, respectively).

CONCLUSIONS

Sputum eosinophilia at diagnosis, together with the persistence of occupational exposure during follow-up, may contribute to a greater decline in FEV1 in patients with OA still at work. Further long-term studies are required as to whether intensive ICS treatment may be beneficial for patients with OA and increase ad eosinophilic inflammation.

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.

Longitudinal measurement of airway inflammation over one year in children and adults with intermittent asthma

BACKGROUND

Asthma is an inflammatory disease of the airways, but in clinical practice inflammation is rarely monitored. The aim of this study was to assess the level of airway inflammation in steroid naïve adult and pediatric patients with intermittent asthma over one year.

METHODS

54 children and 50 adults with intermittent asthma (GINA step 1) were included. On up to 6 visits lung function, airway hyperresponsiveness to methacholine (PC20FEV1), sputum eosinophils and exhaled nitric oxide (FeNO) were assessed.

RESULTS

36 pediatric and 34 adult patients were able to produce at least three adequate sputum samples over the study period and were included into the analysis.In 8 children (22%) the percentage of sputum eosinophils was always below 2.5%. A higher level of eosinophils (>2.5%) was found on at least one visit in 16 (44%) and always >2.5% in 12 children (33%). In the adult group the respective numbers were 14 patients (41%) with always low (<2.5%), 17 (50%) with at least once over 2.5% and three patients (9%) were always above the threshold of 2.5% sputum eosinophils.

CONCLUSION

These results demonstrate that a substantial number of children and adults with intermittent asthma under ß-agonist treatment only, have variable or persistently high levels of eosinophilic airway inflammation. Long-term studies are needed to observe the progression of asthma severity in such patient populations.

Characteristics of eosinophilic and non-eosinophilic asthma during treatment with inhaled corticosteroids

OBJECTIVE

Eosinophilic inflammation in the respiratory tract is a hallmark of bronchial asthma. In naïve cases, the inflammatory profile is associated with disease severity and reactivity to inhaled corticosteroids (ICS). Sustained airway eosinophilia has been reported during ICS treatment. However, the immunological characteristics of these cases are not known and it is unclear if this situation contributes to asthma control. This study was performed to determine the answer of these questions.

METHODS

To compare phenotypes of eosinophilic and non-eosinophilic asthma (EA and NEA, respectively) under ICS treatment, clinical data were obtained from asthmatic subjects (n = 22) and healthy controls (n = 10), and the leukocyte compositions of induced sputum and peripheral blood were determined. T lymphocyte profiles in systemic blood were assessed by flow cytometry.

RESULTS

A higher frequency of emergency room visits was observed in the NEA group, which had a higher neutrophil count relative to the total inflammatory cell population in induced sputum than the EA group (59.5 versus 36.6%; p < 0.01). The fraction of helper T (Th)17 lymphocytes as well as the ratio of Th17 to regulatory T cells (Treg) in the peripheral blood was higher in the NEA than in the EA group (0.24 versus 0.13; p < 0.05).

CONCLUSIONS

Th17 were more prevalent than Treg cells in the peripheral blood of NEA patients under ICS treatment, corresponding to neutrophil-dominant airway inflammation and a severe asthmatic phenotype. Thus, an imbalance in Th17/Treg may be associated with the pathogenesis of NEA in patients undergoing ICS treatment.

Developing and emerging clinical asthma phenotypes

For more than a century, clinicians have attempted to subdivide asthma into different phenotypes based on triggers that cause asthma attacks, the course of the disease, or the prognosis. The first phenotypes that were described included allergic asthma, intrinsic or nonallergic asthma, infectious asthma, and aspirin-exacerbated asthma. These phenotypes are being reviewed elsewhere in this issue of the journal. The present article focuses on developing and emerging clinical asthma phenotypes. First, asthma phenotypes that are associated with environmental exposures (occupational agents, cigarette smoke, air pollution, cold dry air); second, asthma phenotypes that are associated with specific symptoms or clinical characteristics (cough, obesity, adult onset of disease); and third, asthma phenotypes that are based on biomarkers. This latter approach is the most promising because it attempts to identify asthma phenotypes with different underlying mechanisms so that therapies can be better targeted toward disease-specific features and disease outcomes can be improved.

Reference ranges for induced sputum eosinophil counts in Korean adult population

Background

Induced sputum analyses are widely utilized to evaluate airway inflammation in asthmatics. However, the values have not been examined in Korean adults.

Objective

The purpose of this study is to determine reference ranges for induced sputum eosinophils and their influencing factors in Korean adults.

Methods

A total of 208 healthy nonasthmatic adults were recruited. Sputum induction and processing followed the international standard protocols.

Results

Adequate sputum samples were successfully collected from 81 subjects (38.9%). The upper 90 percentile for sputum eosinophil was calculated as 3.5%. The median value of eosinophil count percentage was significantly higher in subjects with atopy than those without atopy (median, 1.6%; range, 0-11.0% vs. median, 0%; range 0-3.6%, p=0.030). However, no significant correlations were found with age, gender, body mass index, smoking status, blood eosinophil, or fractional exhaled nitric oxide levels.

Conclusion

Current study was the first attempt to determine the reference ranges of induced sputum eosinophils in Korean adults. The cutoff value for sputum eosinophilia was 3.5%, and was significantly associated with atopy.

Relationship between airway neutrophilia and ageing in asthmatics and non-asthmatics

BACKGROUND AND OBJECTIVE

Increased sputum neutrophilia has been observed in asthma, but also during normal ageing in asthmatics and non-asthmatics. It remains unclear what constitutes 'normal' neutrophil levels in different age groups.

METHODS

We assessed the relationship between age and airway neutrophils of 194 asthmatics and 243 non-asthmatics (age range: 6-80 years). Regression analyses were used to assess this relationship adjusted for confounders including asthma status, atopy, gender, smoking and current use of inhaled corticosteroids (ICS). Age-corrected reference values for different age groups were determined using the 95th percentile of non-asthmatic participants.

RESULTS

Age was positively associated with sputum neutrophils in both asthmatic and non-asthmatic adults (0.46% neutrophil increase/year (95% confidence interval (CI) 0.18, 0.73) and 0.44%/year (0.25, 0.64, respectively), but no association was found in the <20-year age category. Individuals with high sputum neutrophil counts (>95th percentile of non-asthmatic counts for any given age group) were significantly more likely to be asthmatic (odds ratio = 2.5; 95% CI: 1.3, 5.0), with the greatest effect observed in the older age group. Other factors that independently associated with increased sputum neutrophil levels included atopy in non-asthmatic adults, male gender and current use of ICS in asthmatic adults. Age-specific reference values for neutrophil percentage were under 20 years-76%, 20-40 years-62%, 40-60 years-63% and over 60 years-67%.

CONCLUSIONS

Airway neutrophilia is related to age in adults, with a neutrophilic asthma phenotype present in older adults. The use of appropriate age-specific reference values is recommended for future studies aimed at elucidating the role of neutrophils in asthma.

Regulation of airway nucleotides in chronic lung diseases

The physiological relevance of the purinergic signaling network for airway defenses is emerging through cumulating reports of abnormal ATP and adenosine (ADO) levels in the airway secretions of patients with asthma, chronic pulmonary obstructive diseases, cystic fibrosis and idiopathic pulmonary fibrosis. The consequences for airway defenses range from abnormal clearance responses to the destruction of lung tissue by excessive inflammation. This chapter reviews the challenges of assessing airway purines in human subjects, and identifies the general trend in aberrant airway composition. Most diseases are associated with an accumulation of ATP and/or ADO in bronchoalveolar lavage, sputum or exhaled breadth condensate. Intriguing is the case of cystic fibrosis patients, which do not accumulate airway ADO, but its precursor, AMP. This observation launched the investigation of ectonucleotidases as target proteins for the correction of airway purine levels in chronic respiratory diseases. This chapter exposes the extensive rearrangement of the enzymatic network taking place in diseased airways, and identifies signaling pathways likely involved in the aberrant regulation of the airway purines.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Exhaled matrix metalloproteinase-9 (MMP-9) in different biological phenotypes of asthma

BACKGROUND AND OBJECTIVES

Airway remodeling is a main feature of asthma. Different biological phenotypes of severe asthma have been recently recognized by the ENFUMOSA study group and among these one is characterized by neutrophilic airway inflammation. Concentrations of MMP-9 in airways have been suggested as a marker to monitor airway remodeling in asthma.

OBJECTIVE

The aim of the present study was to explore airway remodeling in different biological phenotypes of asthma by measuring MMP-9 in EBC and correlating these with other variables.

METHODS

Sixty consecutive subjects with asthma and 20 healthy controls were enrolled in the study. Exhaled MMP-9, pH and NO levels and inflammatory cells in sputum were measured in all subjects enrolled.

RESULTS

We observed an increase of exhaled MMP-9 in asthmatic subjects compared to controls. Higher exhaled MMP-9 concentrations were described in severe asthmatics compared to mild to moderate especially in those with neutrophilic airway inflammation. We further found a correlation between exhaled MMP-9 and percentage of neutrophils in sputum, FEV1, exhaled NO and pH.

CONCLUSION

Our results seem to substantiate the feasibility of measuring exhaled MMP-9 in the breath of asthmatic patients. MMP-9 may be considered a proxy of the amount of the ongoing airway remodeling in asthma. MMP-9 has been shown to be differentially released in different phenotypes of asthma. The measure of exhaled MMP-9 could help to monitor the ongoing airway remodeling, recognize severe stages of asthma, and possibly help determine the appropriate choice of therapy.

Establishing a normal range for induced sputum cell counts in Western Canada

BACKGROUND

Induced sputum cell counts are a noninvasive, reliable method for evaluating the presence, type and degree of airway inflammation. Whether current reference values for induced sputum cell counts are applicable in other induced-sputum laboratories, particularly those in Western Canada or at elevated altitude, is not clear.

OBJECTIVES

To describe the normal range of induced sputum cell counts in healthy adults in Western Canada.

METHODS

A total of 105 healthy nonsmoking adults with normal bronchial responsiveness and no history of lung disease proceeded with sputum induction. Sputum samples were fixed in formalin.

RESULTS

Sixty-nine subjects were included in the final analyses. The mean ± SD and median (interquartile range) of the cell counts, respectively, were: total cell count 2.453 ± 2.108, 2.000 (2.512); neutrophils 1.212 ± 1.491, 0.721 (1.016); eosinophils 0.034 ± 0.069, 0.005 (0.043); macrophages 1.050 ± 1.213, 0.696 (1.005); lymphocytes 0.057 ± 0.161, 0.001 (0.049); and bronchial epithelial cells 0.041 ± 0.126, 0.000 (0.027). The respective differential cell percentages were: neutrophils 50.3 ± 23.5, 51.9 (32); eosinophils 1.4 ± 2.3, 0.3 (2); macrophages 43 ± 22.8, 39.3 (32); lymphocytes 2.6 ± 5.2, 0.4 (2.5); and bronchial epithelial cells 2.2 ± 4.8, 0.0 (2.9). Bland-Altman analysis and intraclass correlation coefficients revealed excellent interobserver agreement for measurement of sputum cell types.

DISCUSSION

The range of induced sputum cell counts performed in a laboratory in Western Canada in healthy nonsmoking adult subjects was described; cellular distributions were similar to previous studies. This was also the first description of normal values for formalin-fixed induced sputum samples.

CONCLUSIONS

These results confirm that current reference values for induced sputum are generalizable across different laboratories, including those in Western Canada and those at elevated altitude, and are also generalizable to formalin-fixed samples, allowing use in the broader Canadian asthma population.

Chronic cough: an update

Cough persisting beyond 8 weeks (ie, chronic cough) is one of the most common reasons for an outpatient visit. A protracted cough can negatively affect one's quality of life by causing anxiety, physical discomfort, social isolation, and personal embarrassment. Herein, the anatomy and physiology of the cough reflex are reviewed. Upper airway cough syndrome, asthma, eosinophilic bronchitis, and gastroesophageal reflux disease account for most chronic cough after excluding smoking, angiotensin-converting enzyme inhibitor use, and chronic bronchitis. Many patients have more than one reason for chronic cough. Treating the underlying cause(s) resolves cough in most instances. There are some coughs that seem refractory despite an extensive work-up. The possibility of a hypersensitive cough reflex response has been proposed to explain these cases. Several clinical algorithms to evaluate chronic cough are presented.

Can we predict sputum eosinophilia from clinical assessment in patients referred to an adult asthma clinic?

BACKGROUND

There is overwhelming evidence that asthma guidelines aimed at reducing airway inflammation are superior to those based on clinical symptoms alone. This involves targeting eosinophilic inflammation with inhaled corticosteroids.

AIM

Because induced sputum is not readily available, our study set out to investigate whether the collective or singular use of routine asthma investigations can predict sputum eosinophilia.

METHODS

Eighty patients underwent skin prick testing, blood tests (IgE, full blood count), spirometry, exhaled fraction nitric oxide (FeNO), PD15 to hypertonic saline, and induced sputum testing at first assessment. A predictive model for sputum eosinophilia (defined as ≥3% eosinophils) was sought using routinely available tests.

RESULTS

Fifty-four subjects underwent both induced sputum and FeNO testing. Seventeen (30%) revealed eosinophilic inflammation, nine (16%) neutrophilic, four (7%) mixed granulocytic and 26 (46%) paucigranulocytic. Positive predictors for sputum eosinophilia included low forced expiratory volume in 1 s (FEV(1))% predicted, raised serum eosinophil, positive smoking history, Polynesian ethnicity and negative asthma family history. There was a non-statistically significant trend for FeNO predicting sputum eosinophilia. The best combination of predictors was low FEV(1)% predicted, raised serum eosinophil, positive smoking history and negative family history of asthma.

CONCLUSION

This study demonstrates that the serum eosinophil count and FEV(1) combined with aspects of a clinical history may provide a simple and practical alternative to assessment of airway (sputum) eosinophilia in the clinical setting. A full blood count can be performed at a substantially lesser cost and with greater accessibility than induced sputum. We feel the time has come for the clinical utility of the serum eosinophil count to be revisited.

Aging and airway inflammation

BACKGROUND

Since little is known of airways inflammation in the elderly, we have carried out a study to explore the presence of some inflammatory markers in the airways of healthy subjects of different ages using a non-invasive method which is particularly suitable for aged people.

OBJECTIVE

The aim of this work was to investigate whether parameters, including (1) pH, IL-8 and TNF-α in exhaled breath condensate (EBC), (2) exhaled nitric oxide levels (NO), and (3) inflammatory cell profile in induced sputum, are age-related.

MATERIALS AND METHODS

Thirty healthy adults (10 subjects below the age of 30 [A], 10 subjects between 30 and 60 years [B], and 10 subjects over 60 years of age [C]), were enrolled in the study. IL-8 and TNF-α levels were measured in breath condensate. Exhaled pH was measured after deaeration/decarbonation by means of a pH-meter. A rapid-response chemiluminescence NO analyzer was used to quantify NO. Induced sputum was collected, homogenized with dithiothreitol, and cytospins for differential cell were produced.

RESULTS

The levels of IL-8 and TNF-α in EBC, the levels of exhaled NO, and the percentage of neutrophils in induced sputum were significantly elevated in C and B compared with A; the EBC pH level was significantly reduced in C and B compared with A. The EBC levels of IL-8, TNF-α, pH, the level of exhaled NO, and the percentage of neutrophils correlated significantly with age.

CONCLUSION

This study has shown the presence of age-related airways inflammation in healthy subjects.

Phenotyping airways disease: an A to E approach

The airway diseases asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous conditions with overlapping pathophysiological and clinical features. It has previously been proposed that this heterogeneity may be characterized in terms of five relatively independent domains labelled from A to E, namely airway hyperresponsiveness (AHR), bronchitis, cough reflex hypersensitivity, damage to the airways and surrounding lung parenchyma, and extrapulmonary factors. Airway hyperresponsiveness occurs in both asthma and COPD, accounting for variable day to day symptoms, although the mechanisms most likely differ between the two conditions. Bronchitis, or airway inflammation, may be predominantly eosinophilic or neutrophilic, with different treatments required for each. Cough reflex hypersensitivity is thought to underlie the chronic dry cough out of proportion to other symptoms that can occur in association with airways disease. Structural changes associated with airway disease (damage) include bronchial wall thickening, airway smooth muscle hypertrophy, bronchiectasis and emphysema. Finally, a variety of extrapulmonary factors may impact upon airway disease, including rhinosinusitis, gastroesophageal reflux disease, obesity and dysfunctional breathing. This article discusses the A to E concept in detail and describes how this framework may be used to assess and treat patients with airway diseases in the clinic.

Effectiveness of treatment with high-frequency chest wall oscillation in patients with bronchiectasis

Background

High-frequency airway clearance (HFCWC) assist devices generate either positive or negative trans-respiratory pressure excursions to produce high-frequency, small-volume oscillations in the airways.

HFCWC can lead to changes in volume of 15–57 ml and in flow up to 1.6 L/s, which generate minimal coughing to mobilize secretions. The typical treatment lasts 20–30 minutes, and consists of short periods of compression at different frequencies, separated by coughing.

The aim of this study was to find the more efficacious treatment in patients with bronchiectasis: traditional techniques of chest physiotherapy (CPT) versus high frequency oscillation of the chest wall in patients with bronchiectasis.

Methods

37 patients were enrolled. Seven of them were excluded. Computer randomization divided the patients into three groups:

– 10 patients treated with HFCWO by using the Vest® Airway Clearance System;

– 10 patients treated with traditional techniques of air way clearance (PEP bottle, PEP mask, ELTGOL, vibratory positive expiratory pressure);

– 10 patients received medical therapy only (control group).

To be eligible for enrollment, participants had to be between 18 and 85 years old and have a diagnosis of bronchiectasis, confirmed on high resolution computed tomography. Exclusion criteria: lack of informed consent, signs of exacerbation, cystic fibrosis. Before the treatment, each patient had blood tests, sputum volume and cell count, pulmonary function tests and on the quality of life inventories (MMRC, CAT, BCSS). The results were processed through the covariance analysis, performed with the R-Project statistical program. It has been considered a positive result p <005.

Results

Both treatments (traditional CPT and HFCWO) showed a significant improvement in some biochemical and functional respiratory tests as well as in the quality of life compared to the control group. The use of HFCWO compared to CPT also produced a significant improvement in blood inflammation parameter C-RP (p ≤0.019), parameters of lung functionality associated with bronchial obstruction (FVC, FEV1) (p ≤0.006 and p ≤0.001), and in the dyspnea. Improvement in quality of life scales was noted. (BCSS, CAT) (both p ≤0.001). No significant changes of total cell counts in sputum samples were observed in the two groups. In the HFCWO group a significant reduction of neutrophils percentage (p≤0.002) and a significant increase of macrophages percentage (p ≤0.012).

Conclusions

The HFCWO technique provides an improvement both in pulmonary function and quality of life related parameters in patients with chronic hypersecretive disease. Since those patients need daily airway clearance, this treatment should be included among the principal options in chest physiotherapy. The study was registered as ChiCTR-TRC-12002134 at http://www.chictr.org.

[Interest for evaluation of bronchial inflammation in asthma]

Asthma is a heterogeneous chronic inflammatory disease. The respiratory functional tests are sometimes insufficient to confirm the diagnosis. Other tools are developed to estimate the bronchial inflammation such as tests of bronchial provocation, measure of exhaled nitric oxide, induced sputum and exhaled breath condensate. This review presents these non-invasive methods, approaches their interests on the identification of the disease and the treatment.

The impact of diurnal variation on induced sputum cell counts in healthy adults

BACKGROUND

Induced sputum cell counts are a non-invasive, reliable method for evaluating the presence, type, and degree of inflammation in the airways of the lungs. Current reference values for induced sputum cell counts in healthy adults do not account for the effects of circadian rhythm, including diurnal variation. The objective of this study was to describe the diurnal variation in induced sputum cell counts, compared between early morning and late afternoon, in healthy adult individuals.

METHODS

100 healthy adult subjects with no history of lung disease and normal bronchial reactivity proceeded with induced sputum testing at 7 am and 4 pm on different days. The order of testing was randomized. The cytotechnologist preparing and performing the cell counts was blinded to the sample collection time and subject characteristics.

RESULTS

65 subjects were included in the final analyses. There was no significant change in the total and differential sputum cell counts between the 7 am and 4 pm collections. There was good inter-observer agreement with respect to differential sputum cell count interpretation.

CONCLUSIONS

This is the largest study to assess the variation in induced sputum cell counts in healthy adult subjects at different times of the day. We found no significant change in total and differential sputum cell counts between the 7 am and 4 pm collection time points. This is in contrast to studies in asthmatics that demonstrated a circadian variation in sputum cell counts and other markers of inflammation, suggesting that fluctuations in airway inflammatory cells during the day are a disease-specific effect.

Distribution of sputum cellular phenotype in a large asthma cohort: predicting factors for eosinophilic vs neutrophilic inflammation

Background

Phenotyping asthma according to airway inflammation allows identification of responders to targeted therapy. Induced sputum is technically demanding. We aimed to identify predictors of sputum inflammatory phenotypes according to easily available clinical characteristics.

Methods

This retrospective study was conducted in 508 asthmatics with successful sputum induction recruited from the University Asthma Clinic of Liege. Receiver-operating characteristic (ROC) curve and multiple logistic regression analysis were used to assess the relationship between sputum eosinophil or neutrophil count and a set of covariates. Equations predicting sputum eosinophils and neutrophils were then validated in an independent group of asthmatics.

Results

Eosinophilic (≥3%) and neutrophilic (≥76%) airway inflammation were observed in 46% and 18% of patients respectively. Predictors of sputum eosinophilia ≥3% were high blood eosinophils, FE_NO and IgE level and low FEV₁/FVC. The derived equation was validated with a Cohen’s kappa coefficient of 0.59 (p < 0.0001). ROC curves showed a cut-off value of 220/mm³ (AUC = 0.79, p < 0.0001) or 3% (AUC = 0.81, p < 0.0001) for blood eosinophils to identify sputum eosinophilia ≥3%. Independent predictors of sputum neutrophilia were advanced age and high FRC but not blood neutrophil count.

Conclusion

Eosinophilic and paucigranulocytic asthma are the dominant inflammatory phenotypes. Blood eosinophils provide a practical alternative to predict sputum eosinophilia but sputum neutrophil count is poorly related to blood neutrophils.

[Clinical application of induced and spontaneous sputum in asthma and chronic obstructive pulmonary disease]

In recent years induced sputum analysis has become a non-invasive method for the assessment of airway inflammation in obstructive airway diseases. Sputum induction is safe and well tolerated by the patients. The method has been standardized, and this has markedly improved the quality and reproducibility of sputum samples. Identification of sputum eosinophilia has the greatest clinical relevance as it predicts a favorable response to corticosteroids. Treatment strategy aiming normalisation of sputum eosinophil cell count may reduce the rate of exacerbations in asthma. Profiling inflammatory mediators in sputum supernatant provides new insights into the pathogenesis of asthma and chronic obstructive pulmonary disease. Cell type analysis in spontaneous sputum may also provide much information about inflammatory processes in the airways. Based on the results of clinical studies sputum analysis should be more often used in clinical settings in the future.

Elevated complement factor H levels in asthmatic sputa

BACKGROUND

The alternative pathway of the complement system is known to play a role in the generation of asthmatic airway inflammation, but its regulatory complement protein, factor H has not been investigated in this disease.

PURPOSE

Our aim was to determine the local bronchial complement factor H (CFH) levels in asthma, and to investigate its relationship with complement activation, systemic CFH concentrations and clinical characteristics of patients.

METHODS

Induced sputum and plasma were collected from 21 healthy and 26 asthmatic subjects, and complement factor H and SC5b-9 concentrations were assessed by ELISA. Total protein concentrations were determined by biuret-reaction based microassay system from induced sputa.

RESULTS

CFH was detectable in 81 % of healthy and 100 % of asthmatic subjects, while SC5b-9 exceeded the detection limit in 62 % of healthy subjects and 85 % of asthmatic patients. Sputum CFH concentrations and CFH/protein ratios were increased in samples from asthmatic patients, and correlated with loss of lung function, asthma control, severity and medication intensity, but not with plasma CFH concentrations. Sputum CFH/protein ratios were in positive correlation also with sputum eosinophilic cell counts in asthma. SC5b-9 concentrations were not higher in the asthmatic sputa, although they correlated with sputum CFH concentrations.

CONCLUSIONS

CFH level is elevated on asthmatic airway surface, and may be associated with uncontrolled inflammation in asthma.

Asthma phenotypes: the evolution from clinical to molecular approaches

Although asthma has been considered as a single disease for years, recent studies have increasingly focused on its heterogeneity. The characterization of this heterogeneity has promoted the concept that asthma consists of multiple phenotypes or consistent groupings of characteristics. Asthma phenotypes were initially focused on combinations of clinical characteristics, but they are now evolving to link biology to phenotype, often through a statistically based process. Ongoing studies of large-scale, molecularly and genetically focused and extensively clinically characterized cohorts of asthma should enhance our ability to molecularly understand these phenotypes and lead to more targeted and personalized approaches to asthma therapy.

Asthma outcomes: biomarkers

BACKGROUND

Measurement of biomarkers has been incorporated within clinical research studies of asthma to characterize the population and associate the disease with environmental and therapeutic effects.

OBJECTIVE

National Institutes of Health institutes and federal agencies convened an expert group to propose which biomarkers should be assessed as standardized asthma outcomes in future clinical research studies.

METHODS

We conducted a comprehensive search of the literature to identify studies that developed and/or tested asthma biomarkers. We identified biomarkers relevant to the underlying disease process progression and response to treatment. We classified the biomarkers as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.

RESULTS

Ten measures were identified; only 1, multiallergen screening to define atopy, is recommended as a core asthma outcome. Complete blood counts to measure total eosinophils, fractional exhaled nitric oxide (Feno), sputum eosinophils, urinary leukotrienes, and total and allergen-specific IgE are recommended as supplemental measures. Measurement of sputum polymorphonuclear leukocytes and other analytes, cortisol measures, airway imaging, breath markers, and system-wide studies (eg, genomics, proteomics) are considered as emerging outcome measures.

CONCLUSION

The working group participants propose the use of multiallergen screening in all asthma clinical trials to characterize study populations with respect to atopic status. Blood, sputum, and urine specimens should be stored in biobanks, and standard procedures should be developed to harmonize sample collection for clinical trial biorepositories.

Asthma diagnosis and airway bronchodilator response in HIV-infected patients

BACKGROUND

Despite the high prevalence of respiratory symptoms and obstructive lung disease in HIV-infected subjects, the prevalence of bronchodilator reversibility (BDR) and asthma has not been systematically studied during the era of combination antiretroviral therapy (ART).

OBJECTIVE

We sought to determine the prevalence of asthma diagnosis and related pulmonary function abnormalities in an HIV-infected cohort and to identify potential mechanisms.

METHODS

We performed a cross-sectional analysis of 223 HIV-infected subjects with data on respiratory symptoms and diagnoses, pulmonary function, sputum cell counts, and asthma-related cytokines and chemokines in serum/sputum.

RESULTS

Doctor-diagnosed asthma was present in 46 (20.6%), and BDR (≥200 mL and ≥12% increase in FEV(1) or forced vital capacity) was present in 20 (9.0%) participants. Pulmonary symptoms and function were worse in those with doctor-diagnosed asthma. Doctor-diagnosed asthma was independently associated with female sex (P = .04), body mass index of greater than 29.6 kg/m(2) (vs <29.6 kg/m(2), P = .03), history of bacterial or Pneumocystis pneumonia (P = .01), and not currently taking ART (P = .04) and in univariate analysis with parental history of asthma (n = 180, P = .004). High sputum eosinophil percentages (>2.3% based on the highest decile) were more likely in those with doctor-diagnosed asthma (P = .02) or BDR (P = .02). Doctor-diagnosed asthma tended to be more common with high sputum IL-4 (P = .02) and RANTES (P = .02) levels, whereas BDR was associated with high plasma macrophage inflammatory protein 1α (P = .002) and sputum macrophage inflammatory protein 1β (P = .001) levels.

CONCLUSION

Asthma diagnosis and BDR are prevalent in an HIV-infected outpatient cohort, and associations with family history, obesity, allergic inflammation, prior infection, absence of ART, and increased HIV-stimulated cytokines suggest possible mechanisms of HIV-associated asthma.

Canadian Thoracic Society 2012 guideline update: diagnosis and management of asthma in preschoolers, children and adults

BACKGROUND

In 2010, the Canadian Thoracic Society (CTS) published a Consensus Summary for the diagnosis and management of asthma in children six years of age and older, and adults, including an updated Asthma Management Continuum. The CTS Asthma Clinical Assembly subsequently began a formal clinical practice guideline update process, focusing, in this first iteration, on topics of controversy and⁄or gaps in the previous guidelines.

METHODS

Four clinical questions were identified as a focus for the updated guideline: the role of noninvasive measurements of airway inflammation for the adjustment of anti-inflammatory therapy; the initiation of adjunct therapy to inhaled corticosteroids (ICS) for uncontrolled asthma; the role of a single inhaler of an ICS⁄long-acting beta(2)-agonist combination as a reliever, and as a reliever and a controller; and the escalation of controller medication for acute loss of asthma control as part of a self-management action plan. The expert panel followed an adaptation process to identify and appraise existing guidelines on the specified topics. In addition, literature searches were performed to identify relevant systematic reviews and randomized controlled trials. The panel formally assessed and graded the evidence, and made 34 recommendations.

RESULTS

The updated guideline recommendations outline a role for inclusion of assessment of sputum eosinophils, in addition to standard measures of asthma control, to guide adjustment of controller therapy in adults with moderate to severe asthma. Appraisal of the evidence regarding which adjunct controller therapy to add to ICS and at what ICS dose to begin adjunct therapy in children and adults with poor asthma control supported the 2010 CTS Consensus Summary recommendations. New recommendations for the adjustment of controller medication within written action plans are provided. Finally, priority areas for future research were identified.

CONCLUSIONS

The present clinical practice guideline is the first update of the CTS Asthma Guidelines following the Canadian Respiratory Guidelines Committee's new guideline development process. Tools and strategies to support guideline implementation will be developed and the CTS will continue to regularly provide updates reflecting new evidence.

A large subgroup of mild-to-moderate asthma is persistently noneosinophilic

RATIONALE

Airway eosinophilia is typical of asthma, and many controller treatments target eosinophilic disease. Asthma is clinically heterogeneous, however, and a subgroup of people with asthma do not have airway eosinophilia. The size of this subgroup is uncertain because prior studies have not examined repeated measures of sputum cytology to determine when people with asthma have intermittent versus persistent sputum eosinophila and when they are persistently noneosinophilic.

OBJECTIVES

To determine the prevalence and clinical characteristics of the noneosinophilic asthma phenotype.

METHODS

We analyzed sputum cytology data from 995 subjects with asthma enrolled in clinical trials in the Asthma Clinical Research Network where they had undergone sputum induction and measures of sputum cytology, often repeatedly, and assessment of responses to standardized asthma treatments.

MEASUREMENTS AND MAIN RESULTS

In cross-sectional analyses, sputum eosinophilia (≥2% eosinophils) was found in only 36% of subjects with asthma not taking an inhaled corticosteroid (ICS) and 17% of ICS-treated subjects with asthma; an absence of eosinophilia was noted frequently, even in subjects with asthma whose disease was suboptimally controlled. In repeated measures analyses of people with asthma not taking an ICS, 22% of subjects had sputum eosinophilia on every occasion (persistent eosinophilia); 31% had eosinophilia on at least one occasion (intermittent eosinophilia); and 47% had no eosinophilia on every occasion (persistently noneosinophilic). Two weeks of combined antiinflammatory therapy caused significant improvements in airflow obstruction in eosinophilic asthma, but not in persistently noneosinophilic asthma. In contrast, bronchodilator responses to albuterol were similar in eosinophilic and noneosinophilic asthma.

CONCLUSIONS

Approximately half of patients with mild-to-moderate asthma have persistently noneosinophilic disease, a disease phenotype that responds poorly to currently available antiinflammatory therapy.

Acute respiratory effects in firefighters

BACKGROUND

Associations between acute respiratory inflammatory responses, changes in bronchial hyperresponsiveness, serum pneumoprotein levels, and exposure to fire smoke were studied.

METHODS

The study comprised 51 firefighters. Blood samples were taken within 24 hr following exposure to fire smoke, and after a week and 3 months. Sputum was induced within 5 days post-exposure and subjects underwent spirometry and methacholine provocation one week post-exposure. Exposure was registered by a questionnaire.

RESULTS

No changes were observed following smoke exposure in bronchial hyperresponsiveness and serum pneumoprotein levels. Nevertheless, in a sizable proportion of the firefighters (44%) elevated sputum neutrophil levels (≥60%) were found. Serum IL-8 concentrations were higher 24 hr post-exposure compared to pre-exposure. Elevated neutrophil levels in sputum were associated with elevated serum IL-8 (β = 0.010, P = 0.004) and TNFα (β = 0.005, P = 0.034) levels within 24 hr post-exposure and IL-8 elevation lasted up to 3 months.

CONCLUSIONS

Acute exposure to fire smoke induces acute neutrophilic airway and long-lasting systemic inflammation in healthy firefighters in the absence of bronchial hyperresponsiveness.

Exhaled nitric oxide and exhaled breath condensate pH as predictors of sputum cell counts in optimally treated asthmatic smokers

BACKGROUND AND OBJECTIVE

Smoking is thought to modify the pattern of airway inflammation. Induced sputum provides useful information on cellular phenotype in inflammatory airways disorders; however, it is time-consuming and difficult to implement in everyday clinical practice. The aim of this study was to determine whether exhaled NO (FeNO) and exhaled breath condensate (EBC) pH differed in asthmatic smokers compared with asthmatic non-smokers and healthy subjects, and to evaluate the performance of FeNO and EBC pH for predicting the cellular phenotype of induced sputum.

METHODS

Asthmatic smokers (n = 40) and non-smoking asthmatic patients (n = 43) were recruited for the study. Healthy smoking (n = 30) or non-smoking (n = 30) subjects served as controls. FeNO and EBC pH were measured and all subjects underwent sputum induction for assessment of cell counts.

RESULTS

EBC pH was significantly lower in asthmatic smokers compared with non-smokers (P < 0.01). FeNO levels were also significantly lower in asthmatic smokers compared with non-smokers (P < 0.001). EBC pH was inversely associated with sputum eosinophils in both asthmatic smokers and non-smokers (P < 0.001), whereas it was inversely associated with sputum neutrophils only in asthmatic smokers (P < 0.001). FeNO was positively associated with sputum eosinophils both in asthmatic smokers and non-smokers (P < 0.001) but was not associated with sputum neutrophils. In asthmatic smokers, FeNO was a better predictor of sputum eosinophilia, whereas EBC pH was a better predictor of sputum neutrophilia. A combination of FeNO ≤ 14 ppb together with EBC pH > 7.20 predicted the paucigranulocytic induced sputum phenotype.

CONCLUSIONS

EBC pH and FeNO levels were significantly lower in asthmatic smokers compared with non-smokers. Combined specific cut-off levels for FeNO and EBC pH may predict the paucigranulocytic phenotype in asthmatic smokers.

Neutrophilic airways inflammation in lung cancer: the role of exhaled LTB-4 and IL-8

BACKGROUND

Recent advances in lung cancer biology presuppose its inflammatory origin. In this regard, LTB-4 and IL-8 are recognized to play a crucial role in neutrophil recruitment into airways during lung cancer.Notwithstanding the intriguing hypothesis, the exact role of neutrophilic inflammation in tumour biology remains complex and not completely known.The aim of this study was to give our contribution in this field by investigating LTB-4 and IL-8 in the breath condensate of NSCLC patients and verifying their role in cancer development and progression.

METHOD

We enrolled 50 NSCLC patients and 35 controls. LTB-4 and IL-8 concentrations were measured in the breath condensate and the blood of all the subjects under study using EIA kits. Thirty NSCLC patients and ten controls underwent induced sputum collection and analysis.

RESULTS

LTB-4 and IL-8 resulted higher in breath condensate and the blood of NSCLC patients compared to controls. Significantly higher concentrations were found as the cancer stages progressed. A positive correlation was observed between exhaled IL-8 and LTB-4 and the percentage of neutrophils in the induced sputum.

CONCLUSION

The high concentrations of exhaled LTB-4 and IL-8 showed the presence of a neutrophilic inflammation in the airways of NSCLC patients and gave a further support to the inflammatory signalling in lung cancer. These exhaled proteins could represent a suitable non-invasive marker in the diagnosis and monitoring of lung cancer.

Composição celular do escarro induzido em adultos saudáveis

OBJETIVO: Estabelecer valores de referência para a celularidade de amostras de escarro induzido coletadas de indivíduos adultos saudáveis. MÉTODOS: O escarro induzido foi obtido de 88 adultos saudáveis que nunca fumaram (39 homens) com média de idade de 36 anos (variação: 18-68 anos) residentes há pelo menos dois anos em Florianópolis, uma cidade brasileira não industrial e de tamanho médio. As amostras foram processadas, e foi realizada a contagem total e diferencial das células. RESULTADOS: A média da contagem celular total foi de 4,8 ± 4,2 × 10(6) células/g. Houve predomínio de macrófagos (média de 77,5 ± 14,7%) e de neutrófilos (média de 23,4 ± 14,3%). Os eosinófilos estiveram virtualmente ausentes (média de 0,1 ± 0,3%). A proporção de linfócitos e de células broncoepiteliais foi pequena. Não houve efeito da idade ou de atopia sobre a contagem celular total ou diferencial. CONCLUSÕES: Nesta população de indivíduos saudáveis, macrófagos e neutrófilos foram as células predominantes no escarro induzido. Contudo, a proporção de neutrófilos foi inferior à previamente relatada, sugerindo que os valores de normalidade podem variar de acordo com o local onde ele é amostrado

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

BACKGROUND

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

RESULTS

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

CONCLUSIONS

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

Expiratory flows and airway inflammation in elderly asthmatic patients

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

Simplified detection of eosinophils in induced sputum

OBJECTIVE AND DESIGN

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

MATERIAL

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

RESULTS

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

CONCLUSION

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

Dyspnea perception in asthma: role of airways inflammation, age and emotional status

OBJECTIVES

Dyspnea perception in asthmatics differs between subjects. Poor perception is usually associated with increased risk of asthma attack/exacerbation. The advanced stage of the disease and the presence of eosinophilic airways inflammation have been recently recognized as being responsible for poor dyspnea perception. However, few studies are available on this topic.

DESIGN

The aim of this study was to analyse the influence of inflammatory pattern, age and affective status on dyspnea perception in asthmatic subjects.

SUBJECTS AND INTERVENTIONS

Seventy-one consecutive asthmatic patients were recruited and underwent induced sputum, exhaled NO measurement and breath condensate collection. Perception of dyspnea was evaluated as a BORG-VAS/FEV(1) slope before and after the broncho-reversibility test and correlated with the stage of asthma, inflammatory markers, age and depression scale.

RESULTS

Dyspnea perception decreases with the worsening of asthma, with the advance of age and of depression status. Furthermore, airways inflammation plays a key role in the decline of dyspnea perception as proved by the negative correlation observed between inflammatory cells in sputum, exhaled pH and NO and BORG-VAS/FEV(1) slope.

CONCLUSIONS

The results of our study suggested that airways inflammation, depression status, advance age and severity of asthma influence dyspnea perception and suggest a straight control to identify and better manage poor preceptor asthmatics.

Menopausal asthma: a new biological phenotype?

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Occupational exposure to bacterial single cell protein induces inflammation in lung and blood

Bacterial single cell protein (BSCP) is used as a protein enrichment in livestock and fish feed, and is extracted from dried bacterial mass. In the production of BSCP, workers are exposed to organic dust containing high levels of endotoxins that may induce acute airway inflammation. However, the long term effect on the airways of such exposure is not known, and we have examined inflammatory markers in induced sputum and blood among BSCP exposed workers. We included 21 non-smoking production workers (age 31-42 (range; mean 35)) without respiratory symptoms and 21 healthy non-exposed references (age 21-52 (range; mean 34)). Airborne endotoxin concentrations were measured, and induced sputum samples and blood samples were collected from the workers and non-exposed references. The airborne endotoxin concentration measured in inhaled air during the work shift was 430 EU/m(3) (50-2000) (median (range)). The percentage of neutrophils in induced sputum was 79% (66-93) (median (25th-75th percentiles)) and 31% (25-45) (p < 0.001) for operators and references, respectively. Protein analysis in induced sputum supernatant showed significantly elevated levels of interleukins IL-1beta and IL-12 (p < 0.05), while blood analysis showed significantly elevated levels of PDGF-BB (platelet-derived growth factor-BB) and RANTES (regulated upon activation normally T cell expressed and secreted) (p < 0.05). Workers exposed to BSCP had an airway inflammation characterized by a high level of neutrophils. However, only a few cytokines were elevated in lung and blood, which could imply low inflammatory activity suggestive of possible adaptation mechanisms due to daily exposure to BSCP, or that the inflammation reaction was a dose-related response occurring at higher levels.

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

Background

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

Methods

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

Results

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

Conclusions

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

Effects of oral prednisone on sputum eosinophils and cytokines in patients with severe refractory asthma

BACKGROUND

Severe asthma occurs in a heterogeneous group of patients in whom symptoms and airway inflammation persist despite maximal antiasthma treatment.

OBJECTIVE

To verify whether a short-term course of oral steroids would modify sputum inflammatory cytokine and sputum eosinophil concentrations and whether this effect is related to the presence of sputum eosinophilia.

METHODS

In 59 patients with severe refractory asthma, we measured pulmonary function and inflammatory markers in hypertonic saline-induced sputum before and after 2 weeks of treatment with 0.5 mg/kg of oral prednisone (n = 39) or placebo (n = 20) daily. Selected sputum portions were assayed for total and differential cell counts and supernatant interleukin (IL) 5 and IL-8 concentrations.

RESULTS

At baseline, no statistical differences were found among placebo- and prednisone-treated patients in terms of sputum inflammatory cell percentages and IL-5 and IL-8 concentrations. After treatment, forced expiratory volume in 1 second significantly increased and sputum eosinophil percentages and IL-5 and IL-8 concentrations significantly decreased in the prednisone group, whereas no changes were observed in the placebo group. The positive effect of prednisone treatment was observed only in patients with baseline sputum eosinophilia, whereas in noneosinophilic patients with severe asthma prednisone induced only a significant decrease of sputum IL-8.

CONCLUSIONS

Additional high-dose oral corticosteroids improve pulmonary function and reduce not only sputum eosinophil but also sputum proinflammatory cytokine concentrations in patients with severe refractory asthma.

CysLT1-R expression following allergen provocation in asthma and allergic rhinitis

Cysteinyl leukotrienes (CysLTs) contribute to allergic and inflammatory diseases through CysLT(1)-R. We aimed to assess CysLT(1)-R mRNA expression in induced sputum of rhinitics with or without asthma before and following allergen challenges. Both groups underwent nasal and "low dose" lung allergen challenges. Asthmatics also underwent "standard" lung challenge. Sputum was obtained before and at different time-points following the challenges for CysLT(1)-R, 5-lipoxygenase (5-LO), and eotaxin mRNA assessments. At baseline, there was no difference in mediator levels between groups. An increase in CysLT(1)-R mRNA (p=0.04) and a trend towards an increase in 5-LO and eotaxin (p=0.06 for both) at 24 h post-nasal challenge were observed. Following "low dose" lung allergen challenge, there was a trend towards an increase in CysLT(1)-R (p=0.07). In conclusion, CysLT(1)-R gene expression changes can be detected in sputum following allergen challenges. No difference was observed between groups, suggesting that changes in CysLT(1)-R expression occur whether or not the subject has concurrent asthma.

Noninvasive methods for assessment of airway inflammation in occupational settings

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Asthma: a disease of the whole bronchial tree]

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

Systemic and airway inflammation in sleep apnea and obesity: the role of ICAM-1 and IL-8

The recurrent hypoxic stress that characterizes obstructive sleep apnea (OSA) seems to play a role in the increased adherence of neutrophils to endothelial cells as well as in the resulting migration of the former to the inflamed area. Intercellular adhesion molecule 1 (ICAM-1) and interleukin (IL)-8 are markers widely used in OSA studies to investigate inflammation. The aim of this study was to measure ICAM-1 and IL-8 levels in the breath condensate and in the plasma and inflammatory cells in the induced sputum of 12 obese OSA (OO) patients, 10 nonobese OSA (NOO) patients, 10 obese non-OSA (ONO) subjects, and 8 healthy subjects (HS) using a specific enzyme immunoassay (EIA) kit. A significant increase in both plasma and exhaled IL-8 and ICAM concentrations and percentage neutrophils was observed in the induced sputum of obese OSA patients, non-obese OSA patients, and obese non-OSA subjects compared with healthy subjects. However, although these inflammatory markers were found to follow an upward trend in obese OSA patients no difference was observed in both either non-obese OSA patients and obese non-OSA subjects. Finally, a significant positive correlation was found to occur among IL-8, ICAM-1, and sputum neutrophils, as well as across the apnea-hypopnoea index (AHI), TST 90%, body mass index (BMI), and neck circumference. The data obtained confirm the occurrence of an ICAM- and IL-8-mediated neutrophilic airway inflammation in both OSA and obese patients. The degree of inflammation, which seems to worsen in cases of comorbidity (OSA and obesity), is likely to be responsible for the increased risk of developing cardiovascular events observed in these subjects, and therefore, it deserves to be elucidated even more.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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