Sputum cell counts to manage prednisone-dependent asthma: effects on FEV1 and eosinophilic exacerbations.

BACKGROUND: Prednisone dependence in asthma is usually described based on clinical and spirometric characteristics. It is generally believed that these patients have frequent exacerbations and lose lung function rapidly because of uncontrolled airway eosinophilia. OBJECTIVES: The objectives of this study are to report the effect on asthma exacerbations and the change in lung function over time in prednisone-dependent asthma when severe asthma is managed using a protocol that aims to maintain normal sputum cell counts. METHODS: A retrospective survey of patients prospectively assessed in a university tertiary care asthma clinic. RESULTS: 52 patients (30 males, mean age 51 years, 64% non-atopic) were followed for a median period of 5.4 years (min-max: 0.2-35.2). Monitoring with the aim of keeping sputum eosinophils below 3% resulted in higher doses of corticosteroids (median daily dose of prednisone was 10 mg and for inhaled corticosteroids was 1500 µg of fluticasone equivalent) than at baseline and this was associated with predictable adverse effects. Despite the disease severity, 10 patients (19%) did not require LABA for symptom control. Most importantly, over the period of follow-up, there were only 0.3 eosinophilic exacerbations/patient/year. Overall, there was an increase in FEV1 over the period of follow-up (mean +84.6 ml/year) rather than an expected decline. CONCLUSIONS: Monitoring of eosinophils in sputum enables to maintain symptom control and preserve FEV1 in patients with severe prednisone-dependent asthma.

The use of cellular and molecular biomarkers to manage COPD exacerbations.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) exacerbations are a common cause of respiratory morbidity and mortality, and have various etiologies. Multiple cellular and molecular biomarkers have been associated with exacerbations. Quantitative sputum cell counts are able to identify the presence and type of bronchitis, which is an important contributor to exacerbations. Their utility to monitor bronchitis and to help treat exacerbations has been evaluated, yet they are not used in routine clinical practice. Areas covered: This review will provide a brief summary of biomarkers utilized in COPD, with a focus on the application of cellular markers for the management of exacerbations. A case study will demonstrate the application of these methods. With quantitative sputum cell counts, the presence of eosinophilic bronchitis predicts corticosteroid-responsiveness, while neutrophilic bronchitis identifies infection and suggests the need for antibiotics. Gastroesophageal reflux-related aspiration and heart failure can also be identified by examining sputum. Expert commentary: Quantitative sputum cytometry is an essential tool in the management of exacerbations of COPD, particularly those prone to frequent exacerbations. Treatment based on sputum cell counts is superior to current guideline-based recommendations to prevent future exacerbations and hospitalizations in observational and single-centre controlled trials. Large multicentre clinical trials are necessary to confirm this.

Dose-dependent anti-inflammatory effect of inhaled mometasone furoate/formoterol in subjects with asthma.

OBJECTIVE: A well-controlled study in patients with allergic asthma was warranted to assess dose-dependency between fractional concentration of exhaled nitric oxide (FeNO) and sputum eosinophils to a combination of an inhaled corticosteroid plus a long-acting ß2-agonist. We sought to characterize the dose-dependency of mometasone furoate/formoterol (MF/F) using FeNO and sputum eosinophil percentage as surrogates of airway inflammation in subjects with allergic asthma. METHODS: Following a 2-week, open-label run-in, 93 subjects (≥12 y) using only short-acting beta agonist reliever medication as needed, were randomized to twice daily (BID) placebo; MF/F 100/10 µg, 200/10 µg, or 400/10 µg (via pressurized metered-dose inhaler [MDI]); MF-MDI 200 µg; or MF 200 µg via dry powder inhaler (DPI) during a 2-week, double-blind treatment period. RESULTS: All active treatments demonstrated significant percentage reductions from baseline in FeNO compared with placebo at all time points (P ≤ 0.034). At endpoint, mean MF/F treatment group FeNO reductions ranged from -35.3% to -61.4%. Sputum eosinophil percentage reductions from baseline were significant compared with placebo for the MF/F 200/10 µg, MF/F 400/10 µg, and MF-DPI 200 µg groups at endpoint (P ≤ 0.023). Escalating MF/F doses significantly reduced both FeNO (P ≤ 0.001) and sputum eosinophil (P ≤ 0.022) levels in a dose-dependent manner at all time points. All treatments were well tolerated; no serious adverse events were observed. CONCLUSION: All 3 MF/F doses demonstrated pronounced, clinically meaningful, dose-dependent reductions in FeNO, with reduced sputum eosinophil levels for MF/F 200/10 µg and MF/F 400/10 µg. These findings suggest both inflammatory markers may be useful in assessing corticosteroid responsiveness in asthma patients, and perhaps identifying the same asthma subphenotype. Clinical Trials.gov: NCT00635882.

Local and systemic immunological parameters associated with remission of asthma symptoms in children.

The immunological and clinical parameters that are associated with asthma remission are poorly understood. The cytokine and local mediator changes associated with the resolution of asthma symptoms were examined in three groups of subjects 12-18 years of age (n = 15 in each group): (a) continuing asthma group (CA) who had persistent symptoms since early childhood, (b) an age, sex and atopic status-matched group who had persistent symptoms in early childhood but in whom these had resolved (RA), and (c) a non-atopic, non-asthmatic control group. Clinical parameters, sputum cell counts, peripheral blood mononuclear cell (PBMC) cytokine production and activation marker expression were determined. All of the CA had methacholine airway hyperresponsiveness compared with only half of the RA subjects. The CA showed elevated numbers of eosinophils and increased ECP and IL-5 in sputum, which were not observed in the RA. PBMC cytokine studies revealed increased production of the type 1 cytokines IL-12, IFN-γ and TNF-α in the CA group compared with the RA group, under a range of activation conditions, however, the production of IL-4 and IL-5 were unchanged. These findings suggest that decreased type 1 cytokine expression as well as decreased eosinophilic inflammation is associated with the resolution of asthma symptoms.

Persistent sputum cellularity and neutrophils may predict bronchiectasis.

BACKGROUND: Quantitative cell counts in sputum provide an accurate assessment of the type and severity of bronchitis. OBJECTIVE: To examine whether sputum cell counts could identify bronchiectasis in patients with recurrent bronchitis. METHODS: A retrospective survey of a clinical database (January 2004 to January 2005) of quantitative cell counts from sputum selected from expectorate in patients with obstructive airways diseases was used to identify predictors of bronchiectasis using ROC curves. This was prospectively evaluated (February 2005 to April 2008) using high-resolution computed tomography scans of thorax that were independently scored by a radiologist who was blinded to the clinical details. RESULTS: The retrospective survey identified 41 patients with bronchiectasis among 490 patients with airway diseases. Total cell count of 60 × 106/g or greater of the selected sputum with predominant neutrophils on two occasions had a sensitivity of 86.7%, a specificity of 87.5%, and positive and negative predictive values of 93% and 78%, respectively, to identify bronchiectasis. In the prospective study, 10 of 14 (71%) patients who met these criteria were identified to have bronchiectasis. Both total cell count and the percentage of neutrophils correlated with radiographic bronchiectasis severity. CONCLUSIONS: Persistent or recurrent intense sputum cellularity with neutrophilia is suggestive of bronchiectasis.

Lipid and smoker's inclusions in sputum macrophages in patients with airway diseases.

We studied the effect of tobacco smoking on macrophage lipid index and macrophage smokers inclusions in induced sputum in 256 patients (143 non-smokers, 81 ex-smokers and 32 current smokers). Lipid index was, using the Oil red O stain, the sum of the lipid staining droplet score (range 0-4) in 100 macrophages. Smokers inclusions were assessed using Wright's stain and graded as "none", "few", "moderate" or "many". Lipid index was significantly higher in current smokers (112.5, SD 58.5 units) than ex-smokers (29.2, SD 42.8 units) or non-smokers (13.4, SD 121.7). Smokers inclusions were present in all current smokers but only in 2 non-smokers. The mean smoking history of current smokers with few macrophage inclusions was 15.0 (SD 11.2), moderate 21.6 (SD 15.7), and many 30.0 (SD 21.9) pack years. There was a significant difference between the length of time ex-smokers had quit smoking if they had no or few smokers inclusions (mean 17.6 (SD 11.2) years) compared to those with moderate or many smokers inclusions (mean 2.8 (SD 5.8) years) (p = 0.01). Lipid index was significantly correlated with smokers inclusions (r = 0.72, p < 0.01). We conclude that smoker's inclusions within sputum macrophages is a reliable indicator of cigarette smoking and that the sputum lipid index cannot be used as an assessment of oropharyngeal reflux in cigarette smokers.

Reslizumab for poorly controlled, eosinophilic asthma: a randomized, placebo-controlled study.

RATIONALE: Eosinophilic asthma is a phenotype of asthma characterized by the persistence of eosinophils in the airways. IL-5 is involved in the activation and survival of eosinophils. OBJECTIVES: To evaluate the effect of the antibody to IL-5, reslizumab, in patients with eosinophilic asthma that is poorly controlled with high-dose inhaled corticosteroid. METHODS: Patients were randomly assigned to receive infusions of reslizumab at 3.0 mg/kg (n = 53) or placebo (n = 53) at baseline and at Weeks 4, 8, and 12, with stratification by baseline Asthma Control Questionnaire (ACQ) score less than or equal to 2 or greater than 2. The primary efficacy measure was the difference between the reslizumab and placebo groups in the change in ACQ score from baseline to end of therapy (Week 15 or early withdrawal). MEASUREMENTS AND MAIN RESULTS: Mean changes from baseline to end of therapy in ACQ score were -0.7 in the reslizumab group and -0.3 in the placebo group (P = 0.054) and in FEV(1) were 0.18 and -0.08 L, respectively (P = 0.002). In those patients with nasal polyps, the changes in ACQ score were -1.0 and -0.1, respectively (P = 0.012). Median percentage reductions from baseline in sputum eosinophils were 95.4 and 38.7%, respectively (P = 0.007). Eight percent of patients in the reslizumab group and 19% of patients in the placebo group had an asthma exacerbation (P = 0.083). The most common adverse events with reslizumab were nasopharyngitis, fatigue, and pharyngolaryngeal pain. CONCLUSIONS: Patients receiving reslizumab showed significantly greater reductions in sputum eosinophils, improvements in airway function, and a trend toward greater asthma control than those receiving placebo. Reslizumab was generally well tolerated.

Heterogeneity of bronchitis in airway diseases in tertiary care clinical practice.

BACKGROUND: Sputum cell counts have identified inflammatory subtypes of bronchitis in relatively small numbers of subjects with asthma, chronic obstructive pulmonary disease (COPD) and chronic cough in research studies. The prevalence of different subtypes of bronchitis in routine clinical practice, however, has not been reported. OBJECTIVE: To examine the heterogeneity of bronchitis and its relationship to the severity of airflow obstruction. METHODS: A retrospective cross-sectional survey based on a computerized database of spontaneous or induced sputum cell counts examined in a large university tertiary respiratory outpatient clinic. RESULTS: The database contained 4232 consecutive sputum records from 2443 patients with chronic cough (39%), asthma (37%), asthma with COPD (9%), COPD (13%) and bronchiectasis (3%). Total and differential cell counts were obtained from 86% of successful sputum samples. Induced sputum provided more viable samples than spontaneous expectorate. Approximately one-third of patients with asthma and one-fifth of patients with COPD experience eosinophilic bronchitis. Asthmatic patients with moderate to severe airflow obstruction had a greater number of sputum eosinophils. There was a significantly higher number of total cell counts and percentage of neutrophils in the sputum of COPD patients with moderate and severe airflow obstruction than in those with mild airflow obstruction. CONCLUSION: There is heterogeneity in the cellularity of sputum in various airway diseases. Patients with clinically stable airway diseases may have high sputum cell counts. During exacerbations, more patients may experience neutrophilic bronchitis. Severity of airflow obstruction is associated with eosinophilic bronchitis in patients with asthma, and neutrophilic bronchitis in patients with nonasthmatic COPD.

Association between proximity to major roads and sputum cell counts.

BACKGROUND: Air pollution caused by motor vehicle emissions has been associated with exacerbations of obstructive airway diseases; however, the nature of the resulting bronchitis has not been quantified. OBJECTIVE: To examine whether proximity to major roads or highways is associated with an increase in sputum neutrophils or eosinophils, and to evaluate the effect of proximity to roads on spirometry and exacerbations in patients with asthma. METHODS: A retrospective study of 485 sputum cell counts from patients attending a tertiary chest clinic in Hamilton, Ontario, identified eosinophilic or neutrophilic bronchitis. Patients' residences were geocoded to the street network of Hamilton using geographic information system software. Associations among bronchitis, lung function, and proximity to major roads and highways were examined using multinomial logistic and multivariate linear regression analyses adjusted for patient age, smoking status and corticosteroid medications. RESULTS: Patients living within 1000 m of highways showed an increased risk of bronchitis (OR 3.8 [95% CI 1.0 to 13.7]; P<0.05), particularly neutrophilic bronchitis (OR 4.7 [95% CI 1.2 to 18.7]; P<0.05) as well as an increased risk of an asthma diagnosis (OR 1.9 [95% CI 1.0 to 3.4]; P<0.05). Patients living within 300 m of a major road were at increased risk for an asthma exacerbation (OR 1.9 [95% CI 1.5 to 15.5]; P<0.01) and lower lung function, particularly in women (P=0.036). CONCLUSION: In patients with airway diseases, living close to a highway or major road was associated with neutrophilic bronchitis, an increased risk of asthma diagnosis, asthma exacerbations and lower lung function.

Reproducibility, validity, and responsiveness of cell counts in blown nasal secretions.

Cell counts in nasal secretions are not used in routine clinical practice to decide on anti-inflammatory or antimicrobial therapy. This study investigated the reproducibility, reliability (validity), and responsiveness of cell counts in blown nasal secretions with a view to implementing this in routine clinical practice. Nasal secretions were obtained from 19 subjects with allergic rhinitis on 3 days in random order (each separated by 1-2 days) by spontaneously blowing their noses (on 2 days) and by a nasal lavage by the modified Grunberg method on the 3rd day. Total and differential cell counts were performed after dispersing the solutions with dithiothreitol as described previously. At the end of the study, subjects had 1 week of open label treatment with nasal corticosteroids if they had nasal eosinophilia or an antibiotic if they had nasal neutrophilia. If the cell counts were normal, they were not treated. The proportion of eosinophil (%) was highly reproducible (intraclass correlation coefficient [ICC], 0.93), and the total cell count (×106/g) and the proportion of neutrophil (%) were modestly reproducible in blown nasal secretions (ICC, 0.46 and 0.55, respectively). The total cell count was consistently and significantly higher in the blown nasal secretions. The proportion of eosinophils (R(s) = 0.4; p < 0.05) and neutrophils (R(s) = 0.6; p < 0.05) showed modest correlation in the two types of samples. The responsiveness index for eosinophil count was 4.0 and for neutrophil count was 1.5. Total and differential cell counts can be reliably and reproducibly obtained from spontaneously blown nasal secretions. The cell counts are responsive to treatment and can help identify allergic and infective rhinosinusitis and guide therapy and are easy to implement in routine clinical practice.

Measuring bronchitis in airway diseases: clinical implementation and application: Airway hyperresponsiveness in asthma: its measurement and clinical significance.

Airway inflammation is fundamental to the cause and persistence of asthma and other airway conditions. It contributes to symptoms, variable airflow limitation, airway hyperresponsiveness, and the structural changes (remodeling) associated with asthma. However, the presence and type of airway inflammation can be difficult to detect clinically, delaying the introduction of appropriate treatment. Cellular inflammation in the airway can be accurately and reliably assessed by examining spontaneous or, when not available, induced sputum. Induced sputum cell counts are relatively noninvasive, safe, and reliable. They can accurately discriminate eosinophilic airway inflammation from noneosinophilic airway inflammation and, thus, help to guide therapy. Eosinophilic airway inflammation is steroid responsive, whereas noneosinophilic (usually neutrophilic) inflammation generally is not. Monitoring of airway inflammation using sputum cell counts helps to identify the impending loss of asthma control and, thus, the need to adjust antiinflammatory medications in patients with a variety of airway diseases, such as asthma, smoker's COPD, and chronic cough. Other noninvasive, indirect measurements of airway inflammation, such as exhaled nitric oxide, do not help to identify the cellular nature of airway inflammation associated with exacerbations of airway diseases, particularly in patients who are already on corticosteroids. Thus, although they can be a predictor of steroid responsiveness, these measures do not help to reduce asthma exacerbations when used in clinical practice. The clinical usefulness of measurements in exhaled breath condensate has not yet been established.

Airway responsiveness to indirect challenges in COPD.

Patients with chronic obstructive pulmonary disease (COPD) demonstrate airway hyperresponsiveness to a number of indirect stimuli. Hyperresponsiveness to cold air hyperventilation, exercise, and drugs like propranalol and methoxamine seem to be able to distinguish patients with COPD from those with asthma, whereas hyperresponsiveness to stimuli like adenosine 5-monophosphate (AMP) and hypertonic saline seem unable to do so. The relationship of airway responsiveness to indirect stimuli and airway inflammation has received little study. The clinical relevance of hyperresponsiveness to an indirect challenge, including the impact on the natural history, relation to types of bronchitis, baseline airway calibre, and response to treatment need to be studied.

Clinical equivalence testing of inhaled bronchodilators.

There are no standardized methods to demonstrate in-vivo bioequivalence of inhaled bronchodilators. The most practical method of showing therapeutic equivalence in vivo is by estimating their relative potencies (RP) in clinical efficacy studies. The RP of bronchodilators may be estimated by comparing either their bronchodilator or bronchoprotective properties. Bronchodilator studies are easier to perform and may better model the physiologic effect of many agents, including inhaled beta-agonists. However, it may be difficult to demonstrate steep dose-response for these outcomes, except in cumulative study designs. Bioequivalence trials may be especially challenging when involving pressurized metered-dose inhalers, as a single actuation - the lowest feasible dose to include in the evaluation, may already produce bronchodilation that is at or near the plateau of the dose-response curve. Protection against bronchoconstriction induced by a direct inhaled stimulus like methacholine or histamine affords a reliable and practical method of comparing inhaled bronchodilators and estimating their RP. Inhalational bronchoprovocation testing allows for easier repeatability and quantitation of the stimulus necessary to produce a predetermined degree of bronchoconstriction, and the degree of protection afforded by the bronchoprotection agent. RP studies using adequate methodology are necessary to compare long-acting bronchodilators and both short- and long-acting bronchodilators in patients who are also on inhaled corticosteroids.

Mepolizumab for prednisone-dependent asthma with sputum eosinophilia.

BACKGROUND: Eosinophilic inflammation, which may be a consequence of interleukin-5 action, is a characteristic feature of some forms of asthma. However, in three previous clinical trials involving patients with asthma, blockade of this cytokine did not result in a significant improvement in outcomes. We studied the prednisone-sparing effect of mepolizumab, a monoclonal antibody against interleukin-5, in a rare subgroup of patients who have sputum eosinophilia and airway symptoms despite continued treatment with prednisone. Secondary objectives were to examine its effect on the number of eosinophils in sputum and blood, symptoms, and airflow limitation. METHODS: In this randomized, double-blind, parallel-group trial involving patients with persistent sputum eosinophilia and symptoms despite prednisone treatment, we assigned 9 patients to receive mepolizumab (administered in five monthly infusions of 750 mg each) and 11 patients to receive placebo. RESULTS: There were 12 asthma exacerbations in 10 patients who received placebo, 9 of whom had sputum eosinophilia at the time of exacerbation. In comparison, only one patient who received mepolizumab had an asthma exacerbation, and this episode was not associated with sputum eosinophilia (P=0.002). Patients who received mepolizumab were able to reduce their prednisone dose by a mean (+/-SD) of 83.8+/-33.4% of their maximum possible dose, as compared with 47.7+/-40.5% in the placebo group (P=0.04). The use of mepolizumab was associated with a significant decrease in the number of sputum and blood eosinophils. Improvements in eosinophil numbers, asthma control, and forced expiratory volume in 1 second were maintained for 8 weeks after the last infusion. There were no serious adverse events. CONCLUSIONS: Mepolizumab reduced the number of blood and sputum eosinophils and allowed prednisone sparing in patients who had asthma with sputum eosinophilia despite prednisone treatment. (ClinicalTrials.gov number, NCT00292877.)

Cost-effectiveness of various diagnostic approaches for occupational asthma.

BACKGROUND: Diagnosis of occupational asthma (OA) by specific inhalation challenge (SIC) can be costly and is not always available. The use of sputum testing to avoid this in some patients may be a more cost-effective alternative. OBJECTIVES: To compare the cost-effectiveness of SIC with serial measurements of sputum cell counts (sputum testing) and peak expiratory flow (PEF) monitoring. METHODS: Clinical data and testing costs for OA in 49 patients were collected during a previously published trial, modelled and compared using TreeAge Pro. Clinical outcome was the percentage of accurately diagnosed patients, using SIC as the gold standard. The PEF approach used the most accurate assessment of five experts who were blinded to SIC results. Differences in the proportion of eosinophils during periods on and off work were used for the sputum testing approach and in PEF/sputum for the combined approach. Unit costs were estimated from charges in Canadian hospitals. Data were analyzed by one-way and two-way analyses, and by probabilistic sensitivity analysis using a Monte Carlo simulation technique. RESULTS: The PEF approach had an estimated accuracy of 52% and cost $365 per patient tested. Compared with PEF monitoring, sputum testing was more accurate and cost an estimated $255 for each additional OA patient correctly diagnosed. SIC costs per additional correct diagnosis were $11,032 compared with sputum testing and $6,458 compared with PEF monitoring. The combined PEF/sputum testing approach was not cost-effective in the base case analysis, but cannot be excluded according to probabilistic sensitivity analyses. CONCLUSIONS: Although SIC remains the reference test to diagnose OA, when this test is not available, sputum testing is a cost-effective alternative to PEF for diagnosis of OA.

Sputum neutrophilia can mask eosinophilic bronchitis during exacerbations.

BACKGROUND: Exacerbations of airway disease are eosinophilic, neutrophilic, both or neither. The primary objective of the present study was to identify whether the treatment of a neutrophilic bronchitis can unmask an associated eosinophilia. METHODS: A retrospective survey of 2160 consecutive sputum cell counts from 1343 patients with airway disease was conducted to identify patients with an isolated neutrophilic bronchitis, which was defined as a sputum total cell count of greater than or equal to 12 x 10(6) cells/g of sputum and a proportion of neutrophils of 80% or greater. The characteristics of the patients who subsequently demonstrated sputum eosinophilia (3% or greater) within eight weeks of resolving the neutrophilia were compared with the patients who subsequently did not have sputum eosinophilia. RESULTS: Two hundred thirty-seven patients had 273 neutrophilic exacerbations. The sputum was re-examined within eight weeks in 65 patients (27.4%), of whom 38 (58.5%) had resolution of the neutrophilic bronchitis after treatment with an antibiotic. Of these 38 patients, 13 (34%) showed eosinophilia. CONCLUSIONS: A neutrophilic exacerbation of airway disease was observed to mask sputum eosinophilia in one-third of patients who had sputum cell counts available before and after antibiotic therapy. Hence, the absence of sputum eosinophilia during an infective exacerbation should not be used as an indication to reduce the dose of corticosteroids. To optimize therapy, repeat sputum cell count measurements are recommended after antibiotic treatment before changing corticosteroid treatment.

Changing pattern of sputum cell counts during successive exacerbations of airway disease.

BACKGROUND: Exacerbations of airway disease are eosinophilic, neutrophilic, both or neither, and this determines the treatment needed. We examined changes in the cellular nature of airway inflammation between consecutive exacerbations and their predictors in individual patients. METHODS: In a retrospective survey of 1786 consecutive sputum cell counts from 1139 patients with airway disease, we identified 79 patients with two or more exacerbations at an interval of >or=6 weeks. The patients were divided into those who demonstrated a change in the type of airway inflammation and those who did not. RESULTS: There were 186 exacerbations of airway disease over 22 months. The cellular nature of inflammation was eosinophilic in 43%, neutrophilic in 40%, combined eosinophilic and neutrophilic in 5% and unclassified in 12%. A change in the type of airway inflammation was seen in 38 patients (48%). Patients, whose previous exacerbation was eosinophilic or neutrophilic were twice or nearly three times more likely, respectively, to have a subsequent exacerbation of the same type. There was no significant difference in the time to the second exacerbation or the inflammatory type of the second exacerbation in relation to the first exacerbation, irrespective of the cellular nature of the first exacerbation. CONCLUSIONS: Quantitative sputum cell counts during successive exacerbations identify that they are commonly of different type, reflecting different causes and the need for different treatment. Their use, when available, helps to optimize therapy.