Determining asthma treatment by monitoring sputum cell counts: effect on exacerbations.

One important goal of asthma treatment is to reduce exacerbations. The current authors investigated if the use of sputum cell counts to guide treatment would achieve this goal. A total of 117 adults with asthma were entered into a multicentre, randomised, parallel group-effectiveness study for two treatment strategies over a 2-yr period. In one strategy (the clinical strategy: CS) treatment was based on symptoms and spirometry. In the other (the sputum strategy: SS) sputum cell counts were used to guide corticosteroid therapy to keep eosinophils250 microg, and was due to fewer eosinophilic exacerbations. The cumulative dose of corticosteroid during the trial was similar in both groups. Monitoring sputum cell counts was found to benefit patients with moderate-to-severe asthma by reducing the number of eosinophilic exacerbations and by reducing the severity of both eosinophilic and noneosinophilic exacerbations without increasing the total corticosteroid dose. It had no influence on the frequency of noneosinophilic exacerbations, which were the most common exacerbations.

Sputum induction: effect of nebulizer output and inhalation time on cell counts and fluid-phase measures.

BACKGROUND: A knowledge of the factors that can affect induced sputum results is essential in order to standardize the procedure. OBJECTIVE: We investigated the influence of nebulizer output on sputum cell counts and fluid phase measurements at increasing times of sputum induction. METHODS: Eighteen adults with stable asthma inhaled an aerosol of 3% hypertonic saline to induce sputum after 7, 14 and 21 min on 2 days separated by 48 h. On one day, in random order, the ultrasonic nebulizer used had a relatively low output of 0.87 mL/min (particle size 5.58 microm mass median aerodynamic diameter, MMAD) and, on the other, a higher output of 1.90 mL/min (particle size 4.14 microm MMAD). The sputum was selected from each expectorate and examined blind to the induction procedures. RESULTS: With both nebulizers, the 14- and 21-min samples were lower in weight, neutrophils, eosinophils, eosinophil cationic protein (ECP) and interleukin (IL)-8 and higher in macrophages. The higher output nebulizer induced sputum with higher cell viability and lower ECP and IL-8. CONCLUSION: The results identify that the volume of hypertonic saline inhaled in sputum induction influences the fluid-phase measurements. The duration of induction does alter the cell counts and suggests that the later expectorated sputum samples originate from more peripheral airways. The results draw attention to the need to standardize the volume and time of nebulization to accurately interpret and compare results.

Clinical judgement of airway inflammation versus sputum cell counts in patients with asthma.

The inflammatory component of asthma is usually assessed indirectly by symptoms and spirometry, these may be inaccurate. It can now be assessed directly and reliably by the examination of sputum cell counts. There is no information on how clinical assessment of the presence and type of airway inflammation compares with actual measurements. In this single-centre observational study, sputum was collected from 76 consecutive adults with asthma attending a tertiary chest clinic after their physicians had recorded the expected cell counts in sputum. The authors examined the extent of agreement between clinical judgement of sputum cell counts and actual counts in asthmatic patients (Cohen's Kappa) and the possible predictors of agreement (multiple logistic regression). Sixty-seven of the 76 sputum samples were suitable for analysis. Agreement between expected and actual cell counts occurred in 30/67 patients. The overall agreement for the different cell types was poor (estimated K=0.14, 95% confidence interval (CI)=0.02, 0.26). The experience of the physician in using sputum cell counts in clinical practice, steroid requirement at the time of assessment, and control of asthma as assessed by the physician or by the patient could not predict the chances of agreement or disagreement. Unaware of the sputum results, the physicians often changed treatment in a way that seemed inappropriate for the cell counts present. There is poor agreement between clinical judgement of the presence and type of airway inflammation in asthmatic patients and sputum cell counts. The impact of sputum examination on the outcomes of anti-inflammatory treatment now needs investigation.

Success and safety of sputum induction in the clinical setting.

It has previously been reported that sputum induction is successful and safe in the clinical research setting. The authors examined the success and safety of sputum induction in routine clinical practice in patients with asthma or chronic airflow limitation of varying severity. Records of 304 patients with asthma and 25 with smoking related chronic airflow limitation were examined retrospectively. All had sputum induced as part of their routine clinical evaluation. When the baseline post salbutamol forced expiratory volume in one second (FEV1) was > or =70% predicted, the inductions consisted of inhalation of an aerosol of 3%, 4% and 5% saline, each given for 7 min. If the FEV1 was <70%, or there were other reasons for concern, the inductions were initiated with normal saline for shorter periods. Inhalations were discontinued when sputum was obtained or when there was a fall in FEV1 > or =20%. Success was identified by obtaining nonsquamous total and differential cell counts containing macrophages, and safety by the fall in FEV1. The overall success was 93%. The procedure was safe even amongst patients with an FEV1 of <60% and <1 L. Of 77 patients with an FEV1 between 40-59%, 8% fell by > or =20% and of 35 patients with an FEV1 <40%, 6% fell by 20%. Carefully standardized sputum induction can be successful and safe in patients with asthma or chronic airflow limitation in clinical practice, even when moderate or severe airflow limitation is present.

Anti-inflammatory effects of salmeterol compared with beclomethasone in eosinophilic mild exacerbations of asthma: a randomized, placebo controlled trial.

BACKGROUND: Salmeterol is a potent long acting beta-agonist that is effective in relieving the symptoms and airflow limitation of asthma. OBJECTIVE: To determine whether the effect of salmeterol on clinical parameters in a mild eosinophilic exacerbation of asthma was similar to that of beclomethasone dipropionate (BDP) and, thus, is due to an anti-inflammatory property. PATIENTS AND METHODS: Thirty-four asthmatics with a persistent increase in symptoms for at least two weeks and an increase of sputum eosinophils of 4% or more were randomized in a double-blind fashion to one of three groups that received daily treatment with 100 mg salmeterol, 1 mg BDP or placebo in divided doses using identical pressurized inhalers. Patients were treated with study medications for three weeks, followed by one week of open label BDP (500 mg bid). Patients were seen at weekly intervals, and sputum and blood were obtained on each visit. The primary outcome measure was a change in sputum eosinophils, and secondary outcomes were changes in blood eosinophils, eosinophilic cationic protein (ECP) and clinical parameters. Three patients (one in each group) could not produce any sputum after randomization and were excluded from the analysis. RESULTS: Twelve patients received salmeterol, 10 received BDP and nine received placebo. Salmeterol treatment had no effect on sputum eosinophils geometric mean, (from 35.5 [24.9] to 26.9% [25.8]), blood eosinophils (from 7.6 [4.8] to 7.2% [3.9]) or ECP (from 33.1 [18.1] to 27.8 [16.3] mg/L) but improved morning peak expiratory flow (PEF) and diurnal variation of PEF, and decreased the use of rescue medication more than placebo (P<0.05 for all comparisons). In contrast, BDP improved both inflammatory indexes (sputum eosinophils from 22.5 [17.9] to 5.7% [6.8], blood eosinophils from 9.0 [5.5] to 2.1% 1.0, and serum ECP from 36.5 [22.0] to 16.1 [10.1] mg/L) as well as clinical parameters. CONCLUSIONS: These results show that salmeterol improves the symptoms and airway function of patients with asthma, but has no effect on eosinophilic airway infiltration. These findings support current asthma guidelines, which recommend the initial use of inhaled steroid to maximize clinical improvement. While salmeterol also produces clinical improvement, it does not suppress sputum eosinophilia. The analysis of induced or spontaneous sputum for inflammatory indexes may be a valuable clinical test to guide the use of inhaled steroid and/or a long acting beta-agonist.

Asthma and natural colds. Inflammatory indices in induced sputum: a feasibility study.

We examined the feasibility of using induced sputum to evaluate the airway inflammatory response to natural acute respiratory virus infections. We recruited eight asthmatics and nine healthy subjects on Day 4 of a cold. Viral infection was confirmed in six of the asthmatics (influenza A or B) and six of the healthy subjects (influenza A, rhinovirus, adenovirus, respiratory syncytial virus, and coronavirus). In the subjects with confirmed virus infection, five of the asthmatics had an objective exacerbation of asthma during the cold. Their sputum on Day 4 showed a high median total cell count of 19.7 x 10(6) cells/ml with a modest neutrophilia (58. 5%) and high levels of interleukin-8 (IL-8) (16,000 pg/ml), eosinophilic cationic protein (ECP) (1,880 microgram/L) and very high levels of fibrinogen (250 mg/L). In contrast, the proportion (1.3%) and absolute number of eosinophils was low. IL-2 levels were within the normal range, whereas IL-5 and interferon gamma were under the limit of detection of the assays. In the healthy subjects with a confirmed virus infection the sputum findings were qualitatively similar but significantly less prominent. Sputum IL-8 on Day 4 was strongly correlated with neutrophils (rs = 0.8, p < 0.001). This correlation was also significant when each group was analyzed separately. On Day 21 there was a fall in the absolute number of neutrophils and in ECP and fibrinogen levels in both groups. Similar results were found in the two asthmatic and three healthy subjects with a cold of comparable severity but in whom viral infection was not confirmed. We conclude that induced sputum examination can be used to study the effects of natural colds and influenza on the airways of the lungs. The results also suggest that natural colds, on Day 4, cause neutrophilic lower airway inflammation that is greater in asthmatics than in healthy subjects. The greater inflammatory response in asthmatics may be due to the changes associated with trivial eosinophilia or to the different viruses involved.

Potential masking effects of salmeterol on airway inflammation in asthma.

We hypothesized that regular use of long-acting beta-agonists could delay recognition of ("mask") increasing airway inflammation. We studied steroid-sparing and "masking" effects of salmeterol versus placebo in 13 asthmatic individuals requiring >= 1,500 microgram inhaled corticosteroid daily. Corticosteroid doses were reduced weekly until criteria were met for an exacerbation or the corticosteroid was fully withdrawn. Subjects were restabilized on their original dose of inhaled corticosteroid for 4 wk before crossover to the alternative treatment. Subjects maintained symptom and peak expiratory flow (PEF) diaries, and underwent weekly spirometric, methacholine challenge, sputum eosinophil, and serum eosinophil cationic protein (ECP) measurements. Mean corticosteroid dose was reduced by 87% during salmeterol treatment, versus 69% with placebo (p = 0.04). Sputum eosinophils increased before exacerbation despite stable symptoms, FEV1, and PEF. In the week before clinical exacerbation, sputum eosinophil counts were higher in the salmeterol-treatment arm (19.9 +/- 29.8% [mean +/- SD], versus placebo 9.3 +/- 17.6%; p = 0.006). Five subjects showed > 10% sputum eosinophilia before exacerbation during salmeterol treatment, as compared with two receiving placebo. In this model, salmeterol controlled symptoms and lung function until inflammation became significantly more advanced. We conclude that the bronchodilating and symptom-relieving effects of salmeterol can mask increasing inflammation and delay awareness of worsening asthma.

Induced sputum, bronchoalveolar lavage and blood from mild asthmatics: inflammatory cells, lymphocyte subsets and soluble markers compared.

Airway inflammation in asthma can be measured directly by invasive bronchoalveolar lavage (BAL), directly and relatively noninvasively by induced sputum and indirectly from peripheral blood. We compared cellular and fluid phase indices of inflammation in induced sputum, BAL and blood from 11 adults with mild stable asthma. On one day, induced sputum selected from saliva was collected and on the next, blood and BAL. Median results of sputum compared with BAL showed a higher number of nonsquamous cells (53 versus 0.8 x 10(6) cells x mL(-1), p=0.003), more neutrophils (34.3 versus 1.0%, p<0.001), CD4+ and CD19+ T-cells (76.5 versus 54.7%, p=0.01 and 5.2 versus 1.1%, p=0.03, respectively), fewer macrophages (603 versus 95.0%, p=0.002) and markedly higher levels of eosinophil cationic protein (ECP) (264 versus 2.0 microg x L(-1), p<0.001), tryptase (17.6 versus 2.2 UI x L(-1), p<0.001) and fibrinogen (1,400 versus 150 microg x L(-1), p=0.001). Sputum and BAL neutrophils and CD4+ T-cells were strongly correlated. Sputum and BAL differed from blood by having higher proportions of T-cells (94.9 and 98.9% versus 87.7%, p=0.002) and lower proportions of CD19+ T-lymphocytes (p=0.04 and 0.006). Sputum also differed from blood by having higher proportions of CD4+ T-cells (76.5 versus 51.4%, p=0.001), lower proportions of CD8+ cells (24.0 versus 403%, p=0.04) and a higher CD4+/CD8+ ratio (3.3 versus 1.4, p=0.01). We conclude that in mild asthmatics, sputum, bronchoalveolar lavage and blood measure different compartments of inflammation. Induced selected sputum has the advantage over bronchoalveolar lavage of higher density of cell recovery and stronger signal for fluid-phase markers.

Spontaneous and induced sputum to measure indices of airway inflammation in asthma.

Inhalation of hypertonic saline to induce sputum may alter cells and fluid-phase markers in sputum. We have compared indices of inflammation in sputum produced spontaneously with sputum induced by an aerosol of hypertonic saline. Twenty-three asthmatics produced spontaneous followed by induced sputum on the same day. The sputum specimen was separated from saliva within 2 h, dispersed with dithiothreitol (DTT) and processed to obtain cytospins and supernatant. The statistical power to detect a 20% difference in sputum parameters was > 90%. Results are expressed as median and interquartile range [IQR]. Induced sputum had a higher proportion of viable cells (77.0 [19.0] versus 47.0 [38.0]%, p < 0.001), less squamous cell contamination (1.0 [1.2] versus 1.8 [34.0]%, p < 0.001) and better quality cytospins (score of 8.0 [4.0] versus 4.0 [2.0], p < 0.001). It also had lower fluid-phase levels of eosinophil cationic protein (ECP) (1,358 [1,102] versus 1,574 [2,479] microg/L) and fibrinogen (1,560.0 [3,130.0] versus 4,350.0 [5,970.0] ng/ml) but only the latter was significantly different (p = 0.02). Induced sputum was similar to spontaneous sputum in weight (200.0 [219.0] versus 270.0 [227.0] mg), total cell count (3.3 [4.1] versus 3.5 [4.5] x 10(6)/ml), proportion of nonsquamous cells, and levels of tryptase. The agreement between induced and spontaneous measurements was good, but fluid-phase levels were affected by the low viability of some spontaneous samples. We conclude that for the indices measured in asthmatic subjects, induced sputum separated from saliva is similar to lower respiratory secretions expectorated spontaneously and has the advantage of better cell viability.

Exacerbations of asthma without sputum eosinophilia.

BACKGROUND: Sputum analysis provides a non-invasive method of examining the airway secretions of subjects with asthma in order to better understand the inflammatory process. Increased proportions of eosinophils are generally seen in the sputum of subjects with asthma, especially when there is an exacerbation. An unexpected observation in the sputum of subjects with mild exacerbations of asthma is reported. METHODS: Thirty four consecutive subjects with symptoms consistent with a mild exacerbation of asthma were recruited for a treatment study. Inclusion criteria required persistent symptoms of chest tightness, dyspnoea, or wheezing for two weeks (without spontaneous improvement or alteration in dose of inhaled corticosteroid) and a forced expiratory volume in one second (FEV1) that was reversible to more than 75% predicted or known best to ensure the exacerbation was mild. Sputum (spontaneous or induced with hypertonic saline) from all subjects was examined for differential cell counts. Eosinophilic sputum was defined as > or = 4% eosinophils on two occasions or > 10% eosinophils once. Clinical characteristics, sputum differential counts, and measurements of airways obstruction were compared between the subjects with and without sputum eosinophilia. RESULTS: Almost half of the subjects (16 of 34) considered to have mildly uncontrolled asthma had no sputum eosinophilia. In comparison with the subjects who had sputum eosinophilia the non-eosinophilic group had less airways obstruction (FEV1% predicted 88% v 70%) and less severe airways hyperresponsiveness (PC20 methacholine 0.45 mg/ml v 0.13 mg/ml). There was no difference between the groups in the type or prevalence of symptoms, history of recent infections, smoking, relevant allergen exposure, or use of inhaled corticosteroid. CONCLUSIONS: Symptoms of mildly uncontrolled asthma are not always associated with eosinophilic airways inflammation as measured by sputum analysis. The causes and treatment of the non-eosinophilic condition require further investigation.