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

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

A systematic evaluation of mechanisms in chronic cough.

We tested the hypothesis that hyperresponsiveness of the upper airway (UAHR) is present in patients with chronic cough of diverse etiology. We determined the frequency of bronchial hyperresponsiveness (BHR), hyperresponsiveness of the upper airway, sputum eosinophilia, pulmonary aspiration, and psychological symptoms in adults with chronic cough. Consecutive adults (n = 30) presenting to a tertiary referral clinic with chronic cough were compared with a group of 20 asymptomatic adults. Measurements included histamine provocation testing with measurement of flow volume curves to determine inspiratory and expiratory airflow obstruction; hypertonic saline induced sputum for analysis of eosinophils, mast cells and lipid-laden macrophages; and a validated psychological symptom questionnaire. Symptomatic rhinitis and gastroesophageal reflux were common causes of chronic cough. BHR occurred in seven patients (23%) and in no control subjects (p < 0.05). UAHR occurred in 40% of patients with cough and in four (20%) control subjects (p > 0.05). Eosinophils were present in the sputum of more patients with cough than control subjects (50% versus 19%; p < 0.05). High degrees of eosinophilia were present in six patients with cough, including three without BHR. No subject had significant lipid-laden macrophages. There was greater somatization in patients with chronic cough; ten subjects scored in the clinically significant range (p < 0.05). Abnormalities in one or more of these tests were 7.67-fold (95% CI 1.83-34.52) more likely to occur in cough patients than control subjects. We conclude that chronic cough is a nonspecific symptom that is associated with several apparently unrelated mechanisms. These include UAHR, somatization, BHR, and eosinophilic bronchitis. UAHR cannot be implicated as a single unifying mechanism. These findings emphasize the need to systematically evaluate several different causes of cough in patients who present with chronic cough.

Comparison of oral bambuterol and terbutaline in elderly patients with chronic reversible airflow obstruction.

Bambuterol, a carbamate prodrug of terbutaline, is the first once-daily oral beta 2-agonist. The effect/side effect ratio of bambuterol oral solution was compared with terbutaline mixture in elderly patients with chronic reversible obstructive airways disease. The study was of a double-blind, crossover, randomized design and consisted of a 4-7-day run-in period followed by four consecutive treatment periods each of 2 weeks. The treatments were bambuterol solution 20 mg nocte (B20), 10 mg nocte (B10), terbutaline mixture 3 mg t.i.d., (T), and placebo solution (P). Patients measured daily peak expiratory flow rate (PEFR), asthma symptoms, use of inhaled beta 2-agonist, and tremor. Of 84 patients, 66 completed all periods. Mean age was 67 years (60-90), basal FEV1 1.49 L, and reversibility of FEV1 30%. Ninety-four percent of the patients used inhaled/oral steroids in constant dosage. All treatments were significantly more effective than placebo. B20 resulted in higher morning PEFR than T (306 +/- 2.9 L/min vs. 297 +/- 2.9 L/min), while B10 gave equivalent results to T. No differences were seen in the use of inhaled beta 2-agonist. Less shortness of breath was experienced during the night with B20 and during the day with B10 compared with placebo. Both B20 and T produced more tremor than B10 and P. In elderly patients with chronic reversible airways obstruction once-daily bambuterol (10-20 mg) has a better effect/side effect ratio than 3 mg terbutaline thrice daily.

Using quality-control analysis of peak expiratory flow recordings to guide therapy for asthma.

OBJECTIVE: To compare the action points in published asthma management plans with those derived from quality-control analysis of peak expiratory flow recordings. DESIGN: Longitudinal observational study. SETTING: An ambulatory asthma education and management program in a tertiary care hospital. PATIENTS: 35 adults with asthma and exacerbation of asthma. MEASUREMENTS: Peak expiratory flow diaries and symptom recordings. RESULTS: Asthma action points from published asthma management guidelines had poor operating characteristics. The success rate was 35% when the action point was a peak expiratory flow rate less than 60% of the patient's best peak flow. The success rate improved to 88% when the action point was a peak expiratory flow rate less than 80% of the patient's best peak flow. Published action points had a high failure rate. Peak flow decreased to below the published action points during a stable period of asthma in 7% to 51% of patients studied. Action points defined using quality-control analysis did significantly better. A peak flow value less than 3 standard deviations below the patient's mean peak flow detected 84% of exacerbations and had a low failure rate (19%). Other quality-control tests had sensitivities of 91% and 71%. Quality-control action points could detect exacerbations up to 4.5 days earlier than conventional methods. CONCLUSIONS: Individualized action points can be derived for patients with asthma by applying quality-control analysis to peak flow recordings. These action points are more sensitive in detecting exacerbations of asthma and have fewer false-positive results. Action plans developed in this manner should be more useful for the early detection of deteriorating asthma.

An alteration in the host-parasite relationship in subjects with chronic bronchitis prone to recurrent episodes of acute bronchitis.

Acute episodes of bronchitis have been shown to be unequally distributed within a population of subjects with chronic bronchitis. Two groups were identified based on incidence of acute bronchitis--subjects who were 'infection-prone' (2-5 infections per year) and those who were 'non-infection-prone' (0-1 infections per year). Minor differences in clinical parameters existed, except for smoking experience. The non-infection-prone group included more current smokers, and the total smoking experience (in 'pack years') was significantly greater in this group. Between-year analysis demonstrated a stability of classification, established after a minimum of two years' prospective observation. Parameters of the host-parasite relationship were assessed in both groups. A significantly greater polybacterial colonization of the oropharynx was observed for chronic bronchitics, both infection-prone (P < 0.0001) and non-infection-prone (P < 0.001), compared with control subjects. Infection-prone chronic bronchitics had significantly greater total bacteria cultured from the oropharynx compared to the non-infection-prone group (P < 0.05); adherence of indigenous microflora to buccal epithelial cells, in particular Gram-positive cocci (P < 0.01) and in vitro adherence of non-serotypable Haemophilus influenzae to buccal cells (P < 0.05) compared with the control and non-infection-prone groups. These studies suggest that an important variation in subjects with chronic bronchitis is the binding capacity of epithelial cells for bacteria, which when increased enhances susceptibility to colonization and clinical infection.

Acute myopathy in status asthmaticus.

An acute myopathy complicating life-threatening asthma has been reported with increasing frequency. We present a further 3 patients with this complication. Each patient had nerve conduction studies, electromyography and muscle biopsy performed. The records of a cohort of 12 patients, ventilated in an intensive care unit over a 16 month period, were reviewed. Eleven out of the 12 patients developed an elevated creatine kinase level (median 1311 U/L, range 185-9973 U/L) and 4 developed symptomatic weakness. The myopathy of status asthmaticus is not a homogeneous clinicopathological entity. Although myopathy is the predominant feature, there is a neuropathic component in some patients. Full recovery is usual. The combination of corticosteroids and neuromuscular blocking agents has been proposed as the possible cause of the complication.

Biotypes of Haemophilus parainfluenzae from the respiratory secretions in chronic bronchitis.

A total of 2401 isolates of Haemophilus parainfluenzae was isolated from respiratory secretions of 36 healthy adults and 128 patients with chronic bronchitis over a period of 1 year. The isolates were allocated to eight biotypes, by their production of indole, urease and ornithine decarboxylase. Biotypes I and II constituted most of the isolates of H. parainfluenzae from the oropharynx of controls (75%) and chronic bronchitics (c. 90%). Among the patients, there was no difference in the isolation rate between oropharyngeal swabs and sputum specimens. Biotypes III, IV, VI, VII and VIII were isolated less frequently, as was a new taxon defined here as biotype V which does not produce indole, urease or ornithine decarboxylase. Biotype III was isolated significantly less frequently from cases of chronic bronchitis than from controls, whereas biotype II was isolated somewhat more frequently from the patients, especially during acute episodes.

Evaluation of a selective medium for the isolation and differentiation of Haemophilus influenzae and Haemophilus parainfluenzae from the respiratory tract of chronic bronchitics.

Respiratory tract specimens from chronic bronchitic patients were cultured for Haemophilus species on conventional chocolate agar and a modified sucrose medium in order to determine the accuracy of the new medium in differentiating Haemophilus influenzae from Haemophilus parainfluenzae strains. Haemophilus influenzae biotypes II and III and Haemophilus parainfluenzae biotypes I and II were found to be the predominant strains isolated from the respiratory tract. The modified sucrose medium was found to be a rapid and reliable means of differentiating Haemophilus influenzae from Haemophilus parainfluenzae by sucrose fermentation, on initial isolation.

Urinary uric acid:creatinine ratio, serum erythropoietin, and blood 2,3-diphosphoglycerate in patients with obstructive sleep apnea.

A noninvasive, inexpensive method of excluding significant sleep-associated hypoxemia would be desirable for patients being investigated and treated for obstructive sleep apnea (OSA). Sixty-eight such patients provided specimens before and after sleep studies for estimation of urinary uric acid:creatinine ratio (UA:Cr), serum erythropoietin (EPO), and blood 2,3-diphosphoglycerate (2,3-DPG). Mean (SD) morning 2,3-DPG was higher in 26 patients with overnight hypoxemia than in 42 normoxemic patients (2.54 [0.46] versus 2.24 [0.44] mmol/L; p = 0.01). Neither overnight change nor absolute values of serum EPO or urinary UA:Cr were significantly different between hypoxemic and normoxemic groups. There was a diurnal variation in serum EPO in normoxemic patients (P.M. EPO = 14.8 [7.1] mU/ml; A.M. EPO = 10.7 [7.1] mU/ml; p less than 0.05) but not in hypoxemic patients. Eighteen hypoxemic patients were restudied after using nasal continuous positive airway pressure (nCPAP) for at least 4 wk. Seven normoxemic patients not using nCPAP were restudied after a similar time. There were no significant differences between pretreatment and posttreatment nights in absolute values or percentage overnight change of blood 2,3-DPG or serum EPO in either group. In the hypoxemic (nCPAP) group, overnight change in urinary UA:Cr was lower on the second night (p = 0.04); there was no significant change in the control group. We conclude that although urinary UA:Cr, serum EPO, and 2,3-DPG may be physiologically related to hypoxemia, none of these measures can be used to predict accurately the presence of moderate nocturnal hypoxemia in patients with OSA or in monitoring the effect of their therapy.

Bacterial colonisation of the respiratory tract in chronic bronchitis.

One hundred and nine subjects with chronic bronchitis were studied prior to winter and without clinical infection, to determine baseline patterns of bacterial colonisation. Qualitative analysis of cultures of oropharyngeal swabs showed little difference from age matched normal controls (17) except for growth of small numbers of Gram negative coliforms in the chronic bronchitic group. Quantitation of bacteria colonising the oropharynx showed small numbers (mean of 10(5) cfu/ml), with no particular bacteria dominating. Haemophilus influenzae was present in 7.3% of throat swabs from chronic bronchitic patients, but the organism was always less than 10% of the total count. Quantitation of bacteria in sputum showed significantly higher numbers (mean 10(7) cfu/ml). H. influenzae was detected in 25.7% of available specimens, and when present constituted greater than 90% of the total count. Biotyping of H. influenzae isolates demonstrated a separate colonisation of the upper and lower respiratory tracts.

Supplemental oxygen and quality of sleep in patients with chronic obstructive lung disease.

The hypothesis that supplemental oxygen could improve the quality of sleep was tested in 23 consecutive patients (14 male, nine female; age 42-74 years) with chronic obstructive lung disease (mean (SD) FEV1 0.81 (0.32) litre, FEV1/FVC 37% (12%). Patients breathed compressed air or supplemental oxygen via nasal cannulas on consecutive nights in a randomised, double blind, crossover trial. Quality of sleep was assessed by questionnaire and by electroencephalographic sleep staging. The study had a power of 80% to detect, at the 0.05 level, a 20% improvement in total sleep time. Seventeen patients slept for two nights in the laboratory. Oxygenation during sleep was improved by oxygen administration, but there was no improvement in quality of sleep. There was an acclimatisation effect with better sleep on the second night. Six patients spent an additional acclimatisation night in the laboratory as well as the two study nights. There was no difference in sleep quality between the second and third nights or between the compressed air and the oxygen nights in these patients. Subgroups of patients with an arterial carbon dioxide tension of over 43 mm Hg (5.7 kPa) (n = 12) and arterial oxygen saturation of less than 90% (n = 11) while awake did not show any improvement in quality of sleep on the oxygen night. It is concluded that supplemental oxygen improves nocturnal oxygenation but does not immediately improve the quality of sleep in the laboratory in patients with chronic obstructive lung disease.

Biotyping respiratory Haemophilus species with the microbact system.

The biochemical characteristics of 114 respiratory Haemophilus isolates were examined by the Minitek and Microbact systems. The Microbact system was easy to use and read, although some of the less important reactions (glucose and xylose) were difficult to interpret on occasions. On the basis of the 3 crucial reactions--indole production, ornithine decarboxylase and urease activity--discrepancies between the two systems were minor. Given careful standardization of techniques the Microbact system is a suitable alternative to established techniques for the biotyping of H. influenzae and H. parainfluenzae.

Prediction of oxygenation during sleep in patients with chronic obstructive lung disease.

The accuracy of a prediction equation for assessing the lowest arterial oxygen saturation (SaO2) during sleep was determined in 24 consecutive patients with chronic obstructive lung disease referred for assessment for home oxygen therapy. Subjects had a mean (SD) FEV1 of 0.81 (0.31) litre and an FEV1/FVC of 37% (12%). There was reasonable agreement between predicted and measured values (mean difference [predicted-measured] = -2.5%) but the prediction was not precise as the 95% confidence interval for the difference was +8% to -13%. The duration of arterial oxygen desaturation, defined as the percentage of total sleep time spent below a given SaO2, was not predicted accurately. It is concluded that nocturnal arterial oxygen desaturation in individual patients with chronic obstructive lung disease cannot be predicted from "awake" measurements with sufficient accuracy to be clinically useful.

Effects of breathing supplemental oxygen before progressive exercise in patients with chronic obstructive lung disease.

A study was carried out to determine whether supplemental oxygen before exercise would improve maximum exercise performance and relieve exertional dyspnoea in 20 patients with chronic obstructive lung disease (mean FEV1 0.79 l; forced vital capacity 2.30 l). Patients performed two progressive treadmill exercise tests to a symptom limited maximum, with at least 30 minutes rest between tests. They received compressed air or supplemental oxygen from nasal prongs for 10 minutes before exercise in a double blind randomised trial with a crossover design. Heart rate and breathlessness score on a visual analogue scale were compared between tests at 75% of the maximum distance walked in the compressed air test. The mean arterial oxygen saturation (SaO2) after oxygen (93%) was significantly higher than after compressed air (91%). There was no significant change, however, in maximum distance walked or maximum heart rate, or in the breathlessness score or heart rate at 75% of maximum distance walked. The study had a power of 93% for detecting an increase of 50 metres in maximum distance walked. There was an order effect, with better performance on the second test; but the magnitude of the difference was small. It is concluded that administration of supplemental oxygen sufficient to raise SaO2 above 90% for 10 minutes before exercise is unlikely to improve maximum exercise performance or breathlessness on exertion in patients with chronic obstructive lung disease.

Domiciliary oxygen: rationalization of supply in the Hunter region from 1982-1986.

In October 1982, a clinic was planned at The Royal Newcastle Hospital to review the usage of domiciliary oxygen that was funded by the Provision of Aids for Disabled Persons scheme in the Hunter Region of New South Wales. Patient review included an assessment of the indications for domiciliary oxygen, education in the use of oxygen, the efficiency of delivery arrangements and the transfer from cylinders to concentrators as indicated. Between January and June 1983, 111 patients who were receiving oxygen at home were reviewed: 84 (76%) of these patients had chronic obstructive pulmonary disease; their two-year survival was 80% (95% confidence interval, 69%-87%) and five-year survival was 36% (95% confidence interval, 25%-46%). In 66 (59%) patients, review led to a reduction in the usage of domiciliary oxygen which was estimated to save $40,000 each year in the Hunter Region. In the year from 1985-1986 the decrease in the usage of oxygen at home represented an actual cost saving of $60,000 for the region ($470 per person) which translated into a saving of $95,000 ($740 per person) when inflation was taken into account. If our experience is projected nation-wide, the potential exists for a considerable cost saving by means of programmes to rationalize the use of domiciliary oxygen.

Quantitation of isotype specific Haemophilus influenzae antibody in serum and saliva of normal subjects and chronic bronchitics.

An immunoglobulin isotype specific radioimmunoassay procedure has been developed to assess the antibody response to Haemophilus influenzae somatic antigens in serum and mucosal secretions. This assay was reproducible (between assay CV% 13.9; within assay CV% 4.5 IgG, 3.9 IgA, 3.0 IgM) and specific for H1/H2 antigens. Different patterns of antibody were observed in healthy children (aged 5-10 years), adults and patients with chronic bronchitis. In serum, 20% of chronic bronchitics had antibody levels greater than those observed in healthy adults. In saliva, the proportion of chronic bronchitic patients with high levels (greater than 12% binding) of IgG specific antibody was significantly greater (P less than 0.05) than in healthy adults or children. The proportion of children and chronic bronchitics which had antibody levels of up to 4% binding was significantly greater (P less than 0.05) than that observed in healthy adults. A similar pattern was observed for IgM specific antibody. The occurrence of IgA specific antibody in the saliva in children and chronic bronchitics was consistently greater than that observed in adults for all levels of antibody (P less than 0.05). Chronic bronchitics with high levels of antibody had greater infection and mortality rates.

Oral immunisation with killed Haemophilus influenzae for protection against acute bronchitis in chronic obstructive lung disease.

Fifty patients with chronic obstructive lung disease were randomly allocated to three groups, to assess whether an oral vaccine containing non-typable Haemophilus influenzae protected against acute bronchitis. The double-blind prospective study over a three-month winter period included two placebo groups and one test group. Oral immunisation with H influenzae induced a tenfold reduction in the incidence of infection (p less than 0.001). During the subsequent winter, without further immunisation, protection by the vaccine was no longer statistically significant. There was no clear correlation between clinical protection and either carriage of H influenzae or the level of antibody to H influenzae antigen in saliva.