High levels of Epstein-Barr virus in COPD.

Latent viral infection has been implicated in the pathophysiology of chronic obstructive pulmonary disease (COPD). Epstein-Barr virus (EBV) is known to be important in pulmonary fibrosis. The current authors hypothesised that EBV is associated with the pathogenesis of COPD. Sputum samples were collected from patients both during exacerbations of COPD and when stable. A control group of smokers who did not have airways obstruction also had their sputum examined. The presence of EBV DNA was established and quantified using a real-time nucleic acid amplification assay. A total of 136 patients with COPD were recruited during an acute exacerbation and a total of 68 when stable. EBV was detected in 65 (48%) exacerbation cases and 31 (46%) stable patients. In the comparison group of 16 nonobstructed smokers, EBV was demonstrated in only one (6%) case. Risk of COPD in patients with EBV and who are smokers confers an odds ratio of 12.6. Epstein-Barr virus DNA is more frequently identified in the respiratory tract of chronic obstructive pulmonary disease patients in comparison with unaffected smokers. It is present both during exacerbation and when stable, suggesting that infection is persistent. Smokers who do not develop chronic obstructive pulmonary disease rarely have Epstein-Barr virus in their sputum. This finding may be of importance in the pathogenesis of chronic obstructive pulmonary disease.

Childhood respiratory infections and hospital admissions for COPD.

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) exacerbations are associated with viral infections. We wished to determine if respiratory viral infection of children in the community was associated with hospital admissions of patients with exacerbations of COPD. METHODS: We collected data over a 45-month period from the Northern Ireland Regional Virus Laboratory and from a general hospital in the same locality. We studied the relationship between upper respiratory infections in children and COPD admissions. We also examined the role of school holidays. RESULTS: Correlations were seen between the frequency of all viral infections in children and the number of adult COPD hospitalizations (P<0.005). Subgroup analysis showed distinct relationships with epidemics of; influenza A (P<0.001), influenza B (P<0.05), adenovirus (P=0.05), respiratory syncytial virus (P<0.005) and hospital admissions of patients with COPD. There were significantly fewer COPD admissions in the week after the start of a school holiday period (P<0.05). CONCLUSIONS: When children are hospitalized with viral respiratory infection there is an associated rise in adult COPD admissions. This suggests exacerbations of COPD are associated with epidemics of respiratory viruses. When children are on school holidays there is a reduction in COPD admissions in the community. This provides further support for respiratory viruses in the pathogenesis of COPD exacerbations.

Neutrophil transmigration across human airway epithelial monolayers: mechanisms and dependence on electrical resistance.

To examine neutrophil transepithelial migration in the basolateral-to-luminal direction, bronchial epithelial cells (16HBE) were grown at an air-medium interface on the lower face of permeable supports, and resistance across each membrane was recorded before measuring neutrophil transmigration over 2 h. Subconfluent monolayers (resistance < 250 Omega) permitted high spontaneous migration of neutrophils (7.4+/-1%), which was further enhanced (29.7+/-3%) in response to interleukin (IL)-8 (100 ng/ml). Confluent monolayers (250 to 700 Omega) showed low spontaneous migration (2+/- 0.5%) but responded markedly to IL-8 (12.4+/-1.3%). Left in culture, 16HBE resistances continued to increase and were associated with minimal spontaneous migration (< 0.5%) or responses to IL-8. Using cells in the 250 to 700 Omega range, neutrophil migration to IL-8 was dose-dependent and was enhanced when epithelial cells were incubated with a combination of tumor necrosis factor-alpha and interferon-gamma. Neutrophil migration was stimulus-specific and was reduced by preincubation of epithelial cells with a F(ab')(2) anti-intercellular adhesion molecule (ICAM)-1, or by preincubation of neutrophils with anti-CD18, anti-CD11a, anti-CD11b, or anti-CD11c, but not by anti-CD11d, indicating a role for beta(2)-integrin-ICAM-1 interaction in the migration process.

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.

Evaluation of single-dose inhaled corticosteroid activity with an allergen challenge model.

BACKGROUND: Inhaled corticosteroids are the most commonly used antiinflammatory agents for asthma. There is no simple way to compare objectively the relative potency of inhaled corticosteroids. The allergen-induced late asthmatic response (LAR) can be suppressed by a single dose of inhaled corticosteroid. OBJECTIVE: This study was undertaken to evaluate LAR as a model for the determination of the relative potency of single doses of inhaled corticosteroids. METHODS: We compared doses of 200 and 800 microg of a highly active inhaled corticosteroid (budesonide) with placebo and a marginally active investigational inhaled corticosteroid (D5159). Ten atopic patients with asthma completed a randomized, double-blind, double-dummy, multicenter, four-way, crossover trial. A standardized allergen challenge with the identical dose of allergen was performed 10 minutes after each of four blinded, single-dose treatments: 200 microg of budesonide, 800 microg of budesonide, 8 mg of D5159, and placebo, all administered from Turbuhaler. The LAR was recorded as the maximum percent fall in FEV1 between 4 and 7 hours, and the allergen-induced increase in methacholine airway responsiveness at 24 hours was recorded as the A log PC20 from the day before to the day after allergen challenge. RESULTS: There were no significant differences in the early asthmatic responses during the 4 days; the mean maximum percent in FEV1 fall ranged between 19.5% and 22%. D5159 produced a slight inhibition of the LAR with maximum percent fall in FEV1 recorded as 28.8% +/- 5.0% for D5159 versus 34.1% +/- 4.8% for placebo (p < 0.05). There was a greater reduction recorded after administration of the two doses of budesonide. The mean LAR was 15.1% +/- 3.8% for 200 microg of budesonide and 11.2% +/- 2.3% for 800 microg of budesonide (p < 0.01 compared with placebo and D5159). The two doses of budesonide were not statistically different. Airway responsiveness to methacholine increased by 1.07 doubling doses 24 hours after allergen challenge. This increased airway responsiveness was slightly, but not significantly, reduced by the three active treatments (0.6 to 0.91 doubling doses). CONCLUSION: The allergen-induced LAR model was able to differentiate a single dose of an active inhaled corticosteroid from placebo and a highly potent inhaled corticosteroid from a weak inhaled corticosteroid. The model did not differentiate between 2 fourfold doses of the highly active inhaled corticosteroid (at the doses used in this study), neither for the fall in FEV1 nor for the increase in airway hyperresponsiveness.

Effect of salmeterol compared with beclomethasone on allergen-induced asthmatic and inflammatory responses.

Salmeterol is a selective long-acting beta 2-agonist bronchodilator considered to have added anti-inflammatory effects, but this is controversial. We investigated the effects of a single dose of salmeterol, 100 micrograms, on the physiological and inflammatory responses to inhaled allergen and compared these with the effects of a single dose of beclomethasone, 500 micrograms, and of placebo. Eight atopic adults with mild stable asthma, treated only with inhaled short-acting beta 2-agonist when needed, attended the laboratory sequentially for screening tests, two single-blind control inhalation tests preceded 30 min by placebo or salmeterol and three allergen inhalation tests preceded by placebo, salmeterol or beclomethasone double-blind in random order. Airway responsiveness to methacholine (assessed as the provocative concentration of methacholine producing 20% fall in forced expiratory volume in one second (PC20)), induced sputum eosinophils, blood eosinophils and serum eosinophil cationic protein (ECP) were examined before and 7-48 h after treatment. The statistical power to detect twofold changes in blood and sputum parameters was > or = 90%. Salmeterol inhaled before allergen challenge completely prevented the early asthmatic response, late asthmatic response and fall in methacholine PC20 at 24 h, and produced additional bronchodilatation. These effects were similar to those obtained by the inhalation of a single dose of salmeterol before the control inhalation test, and significantly better than those observed after a single dose of beclomethasone inhaled before the allergen test. Beclomethasone had no effect on the early asthmatic response or on the fall in methacholine PC20 at 24 h but partially inhibited the late asthmatic response. Neither salmeterol nor beclomethasone had any significant effect on sputum or blood inflammatory changes 7-48 h after allergen inhalation. In conclusion, whilst salmeterol had no demonstrable anti-inflammatory action in sputum after allergen challenge in asthma, neither did a single dose of the positive anti-inflammatory control, beclomethasone. The latter result excludes a more positive judgement on the possible anti-inflammatory action of salmeterol. However, the results do indicate that potent functional effects of a single dose of salmeterol can mask the airway inflammatory cell influx caused by inhaled allergen.

Elevated B cells in sputum of asthmatics. Close correlation with eosinophils.

Sputum examination is a useful noninvasive method to study airway inflammation. We investigated the reproducibility and validity of the measurements of lymphocyte subsets in the sputum of 11 stable patients with asthma and 10 nonasthmatic smokers. Sputum was dispersed with 0.1% dithiothreitol. A differential cell count was made with Wright's stain. Aliquots were stained with antibodies to CD19 (B cells), CD3 (T cells), CD4 (helper), CD8 (suppressor), and the activation marker CD25 (IL2 receptor) on T-cell subsets and were assayed by flow cytometry. Sputum from patients with asthma compared with nonasthmatic subjects had more eosinophils (mean +/- SEM, 32.5 +/- 8.5 versus 1.3 +/- 0.5%, p < 0.01) and a higher proportion of lymphocytes that were B cells (16.2 +/- 3.2 versus 4.0 +/- 1.0%, p < 0.01), and these correlated closely with the eosinophils (r = 0.8, p < 0.01). Patients with asthma also had more activated T-helper cells (39.3 +/- 4.6 versus 9.0 +/- 9.0%, p = 0.05), but the comparison was limited to two smokers because of macrophage autofluorescence. The repeatability of measurements of helper T-cells (R = 0.94), suppressor T cells (R = 0.88), and activated helper T cells (R = 0.77) was good; repeatability of measurements of T and B cells could not be examined because these were reciprocals of each other. Asthmatic sputum has different lymphocyte profiles than sputum from nonasthmatic smoking control subjects. The results demonstrate a potential importance of antibody-producing lymphocytes in the airway and their relation to sputum eosinophilia in asthma.

The effect of inhaled K+ channel openers on bronchoconstriction and airway microvascular leakage in anaesthetised guinea pigs.

Since orally administered K+ channel openers may have cardiovascular side effects, it is possible that inhaled administration would be preferred for the treatment of asthma. We have investigated whether inhaled levcromakalim and HOE 234 inhibit histamine-induced bronchoconstriction and airway plasma exudation in anaesthetised guinea pigs. We have also investigated whether inhaled HOE 234 inhibits the bronchoconstriction and plasma exudation induced by vagus nerve stimulation, which is due to the release of tachykinins from sensory nerves. Lung resistance was measured by airway resistance (RL) computed from airway and transpulmonary pressures and plasma exudation by measurement of Evans blue dye extravasation. Inhaled levcromakalim (25 mu g/ml) had a short duration of action, being effective against histamine-induced bronchoconstriction 2 min after pretreatment, but not at 10 min. Inhaled HOE 234 (25 mu g/ml) was similarly effective against histamine-induced bronchoconstriction but had a longer duration of action. Inhaled levcromakalim partially attenuated histamine-induced plasma extravasation in small airways, but not in the trachea or main bronchi, whereas inhaled HOE 234 had no effect. HOE 234 protected against non-adrenergic non-cholinergic nerve-induced bronchoconstriction, but had no effect on neurogenic- or substance P-induced plasma extravasation in the airway. Inhaled K+ channel openers protect against induced bronchoconstriction, but provide little or no protection against plasma exudation, possibly because of an increase in airway blood flow. In addition, inhaled HOE 234 had no effect on neurogenic leakage, suggesting that its vagal inhibitory effect on bronchoconstriction was on airway smooth muscle, rather than on release of neuropeptides from sensory nerves.

Effect of an oral potassium channel activator, BRL 38227, on airway function and responsiveness in asthmatic patients: comparison with oral salbutamol.

BACKGROUND: Potassium (K+) channel activators, such as cromakalim, open ATP sensitive K+ channels and relax airway smooth muscle in vitro and inhibit induced bronchoconstriction in vivo in animals. The prolonged half life of cromakalim gives it potential as an oral bronchodilator. The effect of orally administered BRL 38227 (the active enantiomer of cromakalim), at doses of 0.125, 0.25, and 0.5 mg, on airway function and airway responsiveness to histamine and methacholine has been investigated in asthmatic patients. METHODS: Seventeen patients with asthma were studied in three separate randomised double blind, placebo controlled studies. In the first study eight patients with moderately severe asthma were given 0.125, 0.25, and 0.5 mg of BRL 38227 or placebo, and responses to histamine were assessed before and five hours after treatment. In the second study responses to methacholine were measured before and five hours after 0.125 and 0.5 mg of BRL 38227 or placebo were given to nine patients with mild asthma. In the third study the effect of 0.5 mg of BRL 38227 or placebo was assessed in eight patients with mild asthma. Responses to histamine were measured before treatment and two and five hours after treatment. To provide a positive control study eight subjects who had taken part in studies 1 and 3 were also given oral salbutamol (8 mg) in a placebo controlled, double blind study. Responses to histamine were assessed before and two hours after treatment. RESULTS: BRL 38227 did not cause significant bronchodilatation or changes in airway responsiveness in any of the studies. Headache was reported in 19 of 25 of patients receiving (in some cases twice) 0.5 mg of BRL 38227. By contrast, oral salbutamol gave significant protection against histamine challenge (geometric mean 2.23 doubling dilutions). CONCLUSIONS: After a single oral dose of BRL 38227 no beneficial effect on airway function was detected, despite a high incidence of side effects, which indicates that the orally administered K+ channel activator BRL 38227 may not be useful in the management of asthma.

Inhibition of platelet-activating factor-induced bronchoconstriction by the leukotriene D4 receptor antagonist ICI 204,219.

We determined whether platelet-activating factor (PAF) caused bronchoconstriction through the release of leukotrienes (LT) by studying the effect of a potent LTD4 receptor antagonist, ICI 204,219, on PAF-induced bronchoconstriction in normal subjects. Eight males (age 20 to 36 yr) were given either 40 mg ICI 204,219 orally or matching placebo on 2 study days separated by 2 wk in a double-blind crossover study. Specific airway conductance (SGaw) was measured after inhalation of nebulized PAF (45 micrograms). ICI 204,219 caused a significant inhibition of PAF-induced bronchoconstriction as assessed by comparison of the maximum fail in SGaw or of the area under the curve of the time course of SGaw. ICI 204,219 did not inhibit PAF-induced neutropenia. PAF-induced bronchoconstriction is mediated largely by the release of sulfidopeptide leukotrienes in normal men.