Inter-relationships between airway inflammation, reticular basement membrane thickening and bronchial hyper-reactivity to methacholine in asthma; a systematic bronchoalveolar lavage and airway biopsy analysis

BACKGROUND

Asthma is accepted as a disease characterized by airway inflammation, with evidence that airway structural changes, or 'remodelling' occurs. There are few studies relating airway physiology, inflammation and remodelling, however. We have carried out a study of inter-relationships between airway inflammation, airway remodelling, reticular basement membrane (RBM) thickening, and bronchial hyper-reactivity (BHR), before and after high-dose inhaled corticosteroid (fluticasone propionate 750 microg b.d.), in a group of relatively mild but symptomatic, steroid naïve asthma patients.

METHODS

Double-blind, randomized, placebo-controlled, parallel group study of inhaled corticosteroid (ICS) in 35 asthmatics, with bronchoalveolar lavage (BAL) and airway endobronchial biopsy (EBB) for inflammatory cell profiles and EBB for airway remodelling carried out at baseline, 3 and 12 months.

RESULTS

At baseline RBM thickening was related to BAL mast cells and EBB eosinophil counts. In turn baseline log EBB EG2 eosinophil count, log%BAL epithelial cells and log RBM thickness explained 55% of the variability in BHR.

CONCLUSION

We provide new information that airway inflammation, remodelling, and BHR in asthma are inter-related and improved by ICS therapy. Our data potentially support the need for early and long-term intervention with ICS even in relatively mild asthmatics, and the need to further assess the potential merit of longitudinal BHR testing in management of some patients, as this may reflect both airway inflammation and remodelling.

Anti-IgE for chronic asthma in adults and children

BACKGROUND

Omalizumab is a recombinant humanised monoclonal antibody directed against immunoglobulin E (anti-IgE) to inhibit the immune system's response to allergen exposure. Omalizumab is directed against the binding site of IgE for its high affinity Fc receptor. It prevents free serum IgE from attaching to mast cells and other effector cells and prevents IgE mediated inflammatory changes.

OBJECTIVES

To determine the efficacy of anti-IgE compared with placebo in patients with allergic asthma

SEARCH STRATEGY

We searched the Cochrane Airways Group Asthma trials register for potentially relevant studies (February 2006).

SELECTION CRITERIA

Randomised controlled trials examining anti-IgE administered in any manner for any duration. Trials with co-interventions were included as long as they were the same in each arm.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed study quality and extracted and entered data. Three modes of administration were identified from the published literature (inhaled, intravenous and subcutaneous injection). Subgroup analysis was performed by asthma severity. Data were extracted from published and unpublished sources.

MAIN RESULTS

Fourteen trials (15 group comparisons) were included in the review, contributing a total of 3143 mild to severe allergic asthmatic participants with high levels of IgE. Treatment with intravenous and subcutaneous Omalizumab significantly reduced free IgE compared with placebo. Omalizumab led to a significant reduction in inhaled steroid (ICS) consumption compared with placebo (-119 mcg/day (95% CI -154 to -83, three trials)). There were significant increases in the number of participants who were able to reduce ICS by over 50% (odds ratio (OR) 2.50, 95% confidence interval (CI) 2.02 to 3.10 (four trials)); or completely withdraw their daily ICS intake (OR 2.50 (95%CI 2.00 to 3.13; four trials)). Participants treated with Omalizumab were less likely to suffer an asthma exacerbation with treatment as an adjunct to ICS (OR 0.52, 95%CI 0.41 to 0.65, five trials), or as an ICS tapering agent (OR 0.47, 95% CI 0.37 to 0.60, four trials).

AUTHORS' CONCLUSIONS

Omalizumab was significantly more effective than placebo at increasing the numbers of patients who were able to reduce or withdraw their inhaled steroids, but the clinical value of the reduction in steroid consumption has be considered in the light of the high cost of Omalizumab. The impressive placebo effects observed in control groups bring into question the true effect of Omalizumab. Omalizumab was effective in reducing asthma exacerbations as an adjunctive therapy to inhaled steroids, and during steroid tapering phases of clinical trials. Omalizumab was generally well tolerated, although there were more injection site reactions with Omalizumab. Patient and physician assessments of the drug were positive. Further assessment in paediatric populations is necessary, as is direct double-dummy comparison with ICS.

The dynamics and associations of airway neutrophilia post lung transplantation

Bronchoalveolar lavage (BAL) neutrophilia has been repeatedly observed in lung transplant recipients with established bronchiolitis obliterans syndrome (BOS). Little is known of the fluctuations in BAL and airway neutrophilic inflammation post-transplant. This prospective longitudinal study aimed to evaluate the dynamic changes of lung allograft neutrophils with time, immunosuppression, infection and BOS. A total of 28, initially healthy, BOS 0, lung transplant recipients underwent 134 bronchoscopic assessments, including BAL and endobronchial biopsies (EBB) (with immunohistochemistry) over 3-year follow up. Subsequently, 21 developed BOS 0p and 16 ultimately BOS. Compared to controls, there was early and persistent BAL neutrophilia (p < 0.05), contrasting with an initially normal EBB that shows a progressive increased airway wall neutrophil infiltrate. BAL neutrophilia (but not airway wall neutrophilia) was most striking when there was concomitant bronchopulmonary infection, particularly in the patients with BOS. Univariate and multivariate analyses suggested that BAL neutrophilia was linked to markers of infection while EBB neutrophilia was linked with coexistent inflammation with macrophages and lymphocytes.

IN CONCLUSION

(i) BAL neutrophilia is predominantly associated with infection; (ii) Airway wall neutrophilia (as monitored by EBB) increases with time post-transplant and is not associated with infection; (iii) By itself, BOS is not the major contributor to BAL and EBB neutrophilia.

Changes in indoor allergen and fungal levels predict changes in asthma activity among young adults

BACKGROUND

Exposures to allergens are thought to be important risk factors for asthma. We conducted a longitudinal study of indoor allergen and fungal levels in Melbourne homes between 1996 and 1998 to examine the effect of changes in allergen exposure upon asthma and associated outcomes.

METHODS

Participants were visited at home in 1996 (n=485) and 1998 (n=360), when dust and air samples were collected from their bedrooms and assayed for Der p 1, Fel d 1, ergosterol and fungal propagules. Subjects then attended the lung function laboratory to complete a questionnaire, spirometry, methacholine challenge and skin prick testing. The associations between the change in allergen levels and change in clinical outcomes were examined using multiple logistic and linear regression.

RESULTS

Participants whose Cladosporium fungal exposure doubled had 52% greater odds of having had an attack of asthma in the last 12 months. A doubling of fungal exposure was also associated with 53% greater odds of developing atopy. A doubling of Fel d 1 floor levels was associated with 73% increased odds of doctor-diagnosed asthma. A doubling of Der p 1 levels in bed dust was associated with a 64% greater odds of persistent bronchial hyper-reactivity.

CONCLUSIONS

These findings provide evidence that changes in indoor levels of fungi and house dust mites can affect the risk of development and persistence of asthma and atopy in adults. Further studies are required to establish any benefit of sustained reductions in indoor allergen exposures, and to determine whether these effects are truly 'allergic' or because of immune stimulation in the airway through other less specific mechanisms.

Encasement of bedding does not improve asthma in atopic adult asthmatics

AIM

We evaluated the impact of impermeable bed covers on asthma in asthmatics with clinically relevant house dust mite (HDM) sensitization.

METHODS

The study included 32 HDM-sensitized asthmatics in whom HDM allergy was considered as a significant factor in their asthma. They were randomized into either an intervention group whose bedding was encased with impermeable covers, or a control group who received cotton covers. Before and 3 and 6 months after encasement, dust samples were collected from the bedding and assayed for Der p 1. Clinical outcomes included quality of life, lung function, bronchial reactivity to methacholine, symptoms, medications and peak flow rates.

RESULTS

Baseline Der p 1 levels in both the active and the placebo groups were comparable and high (19.2 vs 18.9 microg/g of dust). There was a significant reduction in Der p 1 levels in the active group after 6 months, but not in the placebo group (7.3 vs 21.9 microg/g of dust). Quality of life improved significantly in both the intervention and control groups, but there was no significant difference in the improvements between the groups. There was no significant change in lung function, symptoms, and requirements for medications.

CONCLUSIONS

Encasement of bedding significantly reduced the Der p 1 levels. However, this was not sufficient to produce worthwhile clinical improvement in those in whom dust mite avoidance might well have been recommended as part of their clinical management.

Time to death, airway wall inflammation and remodelling in fatal asthma

Fatal asthma is characterised pathologically by airway wall remodelling, eosinophil and neutrophil infiltration, accumulation of mucus in the airway lumen and smooth muscle shortening. The durations of fatal attacks of asthma show a clear bimodal distribution. Airway smooth muscle contraction and the accumulation of luminal mucus may contribute to death from asthma and relate to time to death. The current authors have examined these two components in uninflated lung tissue in cases of fatal asthma from the second Victorian asthma mortality study. Based on time from onset of symptoms to death, cases fell into two distinct groups: short course <3 (1.5+/-0.6 mean+/-sd) h; and long course >8 (12.3+/-5.9) h. Short course cases had more muscle shortening, higher levels of salbutamol and higher ratios of neutrophils to eosinophils than long course cases, who tended to have more mucus in the lumen. In conclusion, this study confirms the dichotomy of both time to death and the eosinophil/neutrophil ratio in cases of fatal asthma. It suggests that in short course cases acute airway narrowing is due, predominantly, to bronchoconstriction despite higher blood levels of salbutamol. Mucus accumulation may be more important in long course cases.

Action plans for chronic obstructive pulmonary disease

BACKGROUND

The effectiveness of action plans as treatment for chronic obstructive pulmonary disease (COPD) is not known.

OBJECTIVES

To assess the efficacy of action plans in the management of COPD.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register, CENTRAL, MEDLINE, CINAHL and the National Research Register of Ongoing Trials. We also searched reference lists of identified studies. The search was completed in August 2004.

SELECTION CRITERIA

Randomised controlled trials of action plans in COPD. Studies with a primary diagnosis of asthma excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Investigators were contacted for additional information when necessary. Study results were combined in meta-analyses using the Cochrane Collaboration software RevMan.

MAIN RESULTS

There was evidence of a positive effect of action plans on self-management knowledge. The mean difference (MD) for recognition of a severe exacerbation was 2.50; 95% confidence interval 1.04 to 3.96, for self-action in severe exacerbations MD 1.50; 95% confidence interval 0.62 to 2.38 and the use of antibiotics MD 6.00; 95% confidence interval 2.68 to 9.32. There was also evidence of a positive effect on the initiation of antibiotics (odds ratio (OR) 10.16; 95% confidence interval 2.02 to 51.09) and/or oral steroids (OR 6.58; 95% confidence interval 1.29 to 33.62). However, there was no evidence of significant effects on healthcare utilisation, health-related quality of life, lung function, functional capacity, symptom scores, mortality, anxiety, or depression. No trials used as outcomes: number of exacerbations, length of exacerbations, or days lost from work.

AUTHORS' CONCLUSIONS

This review shows there is evidence that action plans aid people with COPD in recognising and reacting appropriately to an exacerbation of their symptoms via the self-initiation of antibiotics or steroids. Further research needs to be completed with more comprehensive outcomes measures in order to ascertain whether this results in significantly decreased morbidity and/or mortality.

Biological dust exposure in the workplace is a risk factor for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. Although the main risk factor is smoking, 15-19% of COPD even in smokers has been attributed to occupational exposures. The aim of this study was to investigate the association between occupational exposure and risk of COPD.

METHODS

Participants were part of a cross sectional study of risk factors for COPD. A total of 1232 completed a detailed respiratory questionnaire, spirometric testing and measurement of gas transfer. Job histories were coded according to the International Standard Classification of Occupations. These codes were then used to establish occupational exposures using the ALOHA job exposure matrix.

RESULTS

The prevalence of emphysema was 2.4%, chronic obstructive bronchitis 1.8%, and COPD 3.4%. Subjects ever exposed to biological dusts had an increased risk of chronic obstructive bronchitis (OR 3.19; 95% CI 1.27 to 7.97), emphysema (OR 3.18; 95% CI 1.41 to 7.13), and COPD (OR 2.70, 95% CI 1.39 to 5.23). These risks were higher in women than in men. For biological dust, the risk of emphysema and COPD was also significantly increased in both the duration of exposure categories, again in women but not in men. No significant increased risks for COPD were found for mineral dust (OR 1.13; 95% CI 0.57 to 2.27) or gases/fumes (OR 1.63; 95% CI 0.83 to 3.22).

CONCLUSION

In this general population sample of adults, occupational exposures to biological dusts were associated with an increased risk of COPD which was higher in women. Preventive strategies should be aimed at reducing exposure to these agents in the workplace.

Oral corticosteroids for stable chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a common chronic lung disorder, usually related to cigarette smoking, representing a major and increasing cause of morbidity and mortality. It is defined "as a disease state characterized by airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases". The use of corticosteroids for their anti-inflammatory effects has been suggested.

OBJECTIVES

To assess the effects of oral corticosteroids on the health status of patients with stable COPD.

SEARCH STRATEGY

Searches of the Cochrane Airways Group Specialised Register and MEDLINE were carried out in December 2003 and 2004. Review articles and bibliographies were searched.

SELECTION CRITERIA

Randomised controlled prospective studies in adults with stable COPD ( post-bronchodilator FEV1 <80% of predicted, FEV1/FVC <70%) and a history of smoking, excluding known asthmatics, in which oral steroid use was compared with placebo and use of co-interventions was matched in both groups.

DATA COLLECTION AND ANALYSIS

Data was extracted independently by two reviewers. All trials were combined using Review Manager (version 4.2.7).

MAIN RESULTS

From 459 titles 24 studies met the inclusion criteria. Treatment lasted three weeks or less in 19 studies, high dose oral steroid was used in 21 studies and subjects had moderate or severe COPD in 15 studies. There was a significant difference in FEV1 after two weeks treatment, WMD 53.30 ml; 95% confidence interval 22.21 to 84.39 favouring oral steroid use compared to placebo when 14 studies with available data (n=396) were combined, with no significant heterogeneity. There was a significant increase in odds for individual patient FEV1 response greater than 20% from baseline with high dose oral steroid treatment compared to placebo, OR 2.71; 95% CI 1.84 to 4.01 (9 studies) . It would be necessary to treat 7 patients (95% CI 5 to 12) with oral corticosteroids to achieve one extra case of increasing FEV1 by more than 20%, with a placebo group risk of 0.13. All differences in health-related quality of life were less than the minimum clinically important difference. There were small statistically significant advantages for functional capacity and respiratory symptom of wheeze with oral steroid treatment but no significant difference in risk of withdrawal from study due to an exacerbation or rate of serious exacerbations over 2 years with low dose oral steroid treatment. There was an increased risk of adverse effects, including increased blood glucose, adrenal suppression and reduced serum osteocalcin.

AUTHORS' CONCLUSIONS

There is no evidence to support the long-term use of oral steroids at doses less than 10-15 mg prednisolone though some evidence that higher doses (>/= 30 mg prednisolone) improve lung function over a short period. Potentially harmful adverse effects e.g.. diabetes, hypertension, osteoporosis would prevent recommending long-term use at these high doses in most patients.

Long-acting beta2-agonists in asthma: an overview of Cochrane systematic reviews

According to major asthma management guidelines, long-acting beta2-agonists (LABAs) should be used only when asthma remains symptomatic in patients already receiving regular inhaled corticosteroids (ICSs). A large Cochrane systematic review provides evidence that LABAs are safe and beneficial in control of asthma; sub-group analyses indicating that this is true when ICSs are used and in their absence. Two other Cochrane systematic reviews have found that LABAs are more effective than regular short-acting beta2-agonists, and are as effective as theophylline with fewer side-effects. These reviews support guidelines in the use of LABA as additional therapy when asthma is inadequately controlled by ICS at moderate dose. However, guidelines may be too conservative, and more studies in stable mild asthma comparing their use and safety with placebo and ICS are required.

Prostacyclin for pulmonary hypertension in adults

BACKGROUND

Primary pulmonary hypertension (PPH) is progressive, resulting in right ventricular failure. Pulmonary hypertension can be idiopathic or associated with other conditions. Prostacyclin is a potent vasodilator and inhibitor of platelet aggregation, and can be given orally, subcutaneously, intravenously or inhaled via a nebuliser.

OBJECTIVES

To determine the efficacy of prostacyclin or one of its analogues in idiopathic primary pulmonary hypertension.

SEARCH STRATEGY

Electronic searches were carried out with pre-specified terms. Searches were current as of July 2004.

SELECTION CRITERIA

Two reviewers selected randomised controlled trials (RCTs) involving adults with pulmonary hypertension for inclusion.

DATA COLLECTION AND ANALYSIS

Study quality was assessed and data extracted independently by two reviewers. Outcomes were analysed as continuous and dichotomous outcomes. We sub-grouped data where possible by aetiology of PH (PPH, PH secondary to connective tissue disorder or mixed populations).

MAIN RESULTS

Nine RCTs of mixed duration (3 days-52 weeks), recruiting 1175 participants were included (NYHA functional classes II-IV). Intravenous prostacyclin versus usual care (four studies): There were significant improvements in exercise capacity of around 90 metres, cardiopulmonary haemodynamics and NYHA functional class over 3 days-12 weeks. Effects were consistent in primary and secondary pulmonary hypertension. Oral prostacyclin versus placebo (two studies): Short-term data (3-6 months) indicated that there was a significant improvement in exercise capacity, but data from one study of 52 weeks reported no significant difference at 12 months. No significant differences were observed for any other outcome. Subcutaneous treprostinil versus placebo (two studies, 8-12 weeks):One large study reported a significant median improvement in exercise capacity of around 16 metres. Cardiopulmonary haemodynamics and symptom scores favoured treprostinil. Infusion site pain and withdrawals due to adverse events were more frequent with treprostinil. Inhaled prostacyclin versus placebo (one study, 12 weeks):There was a significant increase in exercise capacity of approximately 36 metres. Treatment led to better symptom scores and functional class status than with placebo. Subgroup analyses reported by individual studies showed a better exercise capacity in participants with PPH, than those participants with PH secondary to other diseases. Side effects and adverse events were common in the studies.

AUTHORS' CONCLUSIONS

There is evidence that intravenous prostacyclin in addition to conventional therapy at tolerable doses optimised by titration, can confer some short-term benefits (up to 12 weeks of treatment) in exercise capacity, NYHA functional class and cardiopulmonary haemodynamics. There is also some evidence that patients with more severe disease based upon NYHA functional class showed a greater response to treatment.

Asthma and vaccination history in a young adult cohort

BACKGROUND

It has been suggested that childhood vaccinations may be associated with the onset of asthma. We investigated the association between asthma, atopy and vaccination history in a cohort of young adults living in Melbourne, Australia.

METHODS

Subjects were aged between 22 and 44 years and were surveyed by an interviewer-administered questionnaire. Questions were asked about vaccinations to measles, mumps and rubella (MMR), triple antigen (DTP), hepatitis B and Sabin polio vaccine (OPV). Atopy was assessed by skin prick testing to common aeroallergens.

RESULTS

There was no significant association observed for subjects diagnosed with asthma who had received measles or MMR vaccinations compared with those who did not receive measles or MMR vaccinations (RR 1.33, 95% CI 0.98-1.80). Non-significant associations were also observed for OPV and hepatitis B vaccinations (RR 3.27, 95% CI 0.50-21.3 and RR 1.08, 95% CI 0.83-1.41, respectively). However, subjects reporting full immunisation were found to be at higher risk to asthma (RR 1.52, 95% CI 1.09-2.11) but not atopy.

CONCLUSIONS

Our results show relatively weak support for the hypothesis that childhood vaccinations may lead to increased risk of asthma, but caution is advised due to possible recall bias.

Systemic corticosteroids for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

COPD is a common condition, mainly related to smoking. The burden of the disease is increasing and it is projected to rank fifth in 2020 for the world-wide burden of disease. Acute exacerbations of COPD, usually related to superimposed infection occur commonly and systemic corticosteroids are widely used in their management in combination with other treatments including antibiotics, oxygen supplementation and bronchodilators.

OBJECTIVES

To determine the efficacy of corticosteroids, administered either parenterally or orally, on the outcome in patients with acute exacerbations of COPD.

SEARCH STRATEGY

Searches were carried out using the Cochrane Airways Group COPD RCT register with additional studies sought in the bibliographies of randomised controlled trials and review articles. Authors of identified randomised controlled trials were contacted for other published and unpublished studies. The last search was carried out in August 2004.

SELECTION CRITERIA

Randomised controlled trials comparing corticosteroids, administered either parenterally or orally, with appropriate placebo. Other interventions e.g. bronchodilators and antibiotics were standardised. Clinical studies of acute asthma were excluded.

DATA COLLECTION AND ANALYSIS

Data was extracted independently by two reviewers. Outcome data was sent to authors for verification. All trials were combined using Review Manager (version 4.2.4) for analyses.

MAIN RESULTS

Ten studies were identified that fulfilled the inclusion criteria. There were significantly fewer treatment failures within thirty days in patients given corticosteroid treatment, odds ratio 0.48; 95% confidence interval 0.34 to 0.68 and Hazard Ratio 0.78; 95% confidence interval 0.63 to 0.97. It would have been necessary to treat 9 patients (95%CI 6 to 14) with systemic corticosteroids to avoid one treatment failure in this time period. There was no significant difference in mortality. The early FEV1, up to 72 hours, showed a significant treatment benefit, weighted mean difference 140 mls (95% confidence interval 80-200 mls), although this benefit was not found for later time points. There was a significant improvement in breathlessness and blood gases between 6 - 72 hours after treatment. There was an increased likelihood of an adverse drug reaction with corticosteroid treatment, odds ratio 2.29; 95% confidence interval 1.55 to 3.38. Overall one extra adverse effect occurred for every 6 people treated (95% CI 4 to 10). The risk of hyperglycaemia was significantly increased, odds ratio 5.48; 95% confidence interval 1.58 to 18.96.

AUTHORS' CONCLUSIONS

Treatment of an exacerbation of COPD with oral or parenteral corticosteroids significantly reduces treatment failure and the need for additional medical treatment . It increases the rate of improvement in lung function and dyspnoea over the first 72 hours, but at a significantly increased risk of an adverse drug reaction.

Airway iron and iron-regulatory cytokines in cystic fibrosis

Iron availability is critical to Pseudomonas aeruginosa. The current authors determined sputum iron, ferritin, microalbumin levels and total cell counts (TCC) in 19 adult patients with cystic fibrosis (CF) during an acute exacerbation and repeated analyses following a median of 12 days antibiotic treatment. The current authors also determined sputum interleukin (IL)-1beta and tumour necrosis factor (TNF)-alpha levels because of their putative role in intracellular iron homeostasis. Additional data were obtained from 17 stable CF patients, eight patients with stable chronic obstructive pulmonary disease (COPD) and six normal subjects. Overall, sputum iron, ferritin, microalbumin, IL-1beta and TNF-alpha concentrations and TCCs were significantly elevated in the CF patients compared to those with COPD and normal controls. Sputum ferritin levels were significantly elevated in acute versus stable CF patients and there was a trend for sputum TCC to be higher, but all other inflammatory indices were similar. In the CF patients, sputum iron was positively and strongly related to IL-1beta, TNF-alpha, ferritin and microalbumin levels, but negatively related to forced expiratory volume in one second % predicted. In those acute patients who clinically improved with antibiotics (n=14), there were significant decreases in sputum TCC, iron, ferritin and IL-1beta content, but not TNF-alpha or albumin levels. However, changes in sputum TNF-alpha in acute patients were still closely related to changes in iron, ferritin and albumin content, and changes in IL-1beta were related to changes in sputum ferritin content. Iron and iron-regulatory cytokines may play a role in cystic fibrosis lung disease and the increased iron content may even facilitate Pseudomonas aeruginosa infection.

Decreased lung capillary blood volume post-exercise is compensated by increased membrane diffusing capacity

The diffusing capacity of the lung for carbon monoxide (DLCO) decreases to below the pre-exercise value in the hours following a bout of intense exercise. Two mechanisms have been proposed: (1) development of pulmonary oedema and (2) redistribution of central blood volume to peripheral muscles causing a reduction in pulmonary capillary blood volume ( V(c)). In the present study DLCO, V(c) and the membrane diffusing capacity ( D(m)) were measured in nine healthy females using a rebreathing method, in contrast to the single breath technique employed in previous studies. DLCO, V(c) and D(m) were measured before and at 1, 2, 3, 16 and 24 h following maximal treadmill exercise. Compared with pre-exercise values, DLCO was depressed by up to 8.9 (3.0)% ( P<0.05) for the first 3 h following exercise, but had returned to pre-exercise values by 16 h post-exercise. V(c) fell by 21.2 (4.1)% ( P<0.05) at 3 h post-exercise, but at the same time D(m) increased by 14.7 (9.1)%. It was concluded that: (1) the increase in D(m) made it unlikely that the fall in DLCO was due to interstitial oedema and injury to the blood gas barrier; (2) on the other hand, the reduction in DLCO following exercise was consistent with a redistribution of blood away from the lungs; and (3) the trend for D(m) and V(c) to reciprocate one another indicates a situation in which a fall in V(c) nevertheless promotes gas transfer at the respiratory membrane. It is suggested that this effect is brought about by the reorientation of red blood cells within the pulmonary capillaries following exercise.

Bronchodilator reversibility in Australian adults with chronic obstructive pulmonary disease

BACKGROUND AND AIMS

Bronchodilator reversibility (BDR) and inhaled corticosteroid (ICS) use were assessed for volunteers who responded to an advertisement requesting current or ex-smokers who were experiencing breathlessness to attend for lung function testing.

METHODS

One hundred and fifty-four volunteers responded. Forced expiratory volume (FEV1) was measured before and after 400 microg of salbutamol. Significant BDR was assessed according to guidelines of: (i) the American Thoracic Society (> or =12% plus 200 mL of baseline FEV1 or forced vital capacity), (ii) the British-Thoracic Society (BTS) (> or =15% plus 200 mL of baseline FEV1), (iii) the European Thoracic Society (> or =10% predicted FEV1), and (iv) the most commonly used criteria in Australia and New Zealand (> or =15% of baseline FEV1).

RESULTS

One hundred and twenty-three subjects (33 female; 40 current smokers; median pack years 48 (range 5-144)) were suitable for analysis (i.e. had no history of asthma, demonstrable airflow limitation and a forced expiratory ratio (FER) of <70%). Twenty (16%) patients had an FEV1 within the normal range but FER of <70%, 24 (20%) patients had mild disease (FEV1 60-80% predicted), 31 (24%) patients had moderate disease (FEV1 40-59% predicted), and 48 (39%) patients had severe disease (FEV1 <40% predicted), according to BTS criteria. Significant BDR was evident in: (i) 58 (47%) subjects by American criteria, (ii) 26 (21%) subjects by British criteria, (iii) 19 (15%) subjects by European criteria and (iv) 36 (29%) subjects by Australasian criteria. ICS use was reported by 71 (58%) subjects overall and was weakly, but significantly, related to poorer FEV1 (r = -0.2; P < 0.01), and greater BDR (r = 0.3; P < 0.005).

CONCLUSION

Chronic obstructive pulmonary disease in Australian volunteers with no history of asthma encompasses many individuals with significant BDR. Interestingly, most volunteers reported ICS use and this was related to poorer spirometry and greater BDR. However, until the underlying immuno-pathology has been determined they cannot be assumed to have "asthma" or even an "asthmatic element".

How well do doctors know their patients with severe asthma?

BACKGROUND

Rates of asthma mortality have fallen in Australia since the commencement of the National Asthma Campaign and promotion of the Australian asthma management plan. New strategies are now needed to further reduce mortality.

AIM

To examine agreement about key features between asthma patients and their general practitioners (GPs).

METHODS

We interviewed: (i) the next of kin of 56 asthma deaths, (ii) 91 asthma patients presenting to emergency departments with acute severe asthma and (iii) 147 of their GPs.

RESULTS

Agreement was substantial for usage of oral symptomatic medication, but poor for inhaled symptomatic and preventive medications. There was moderate agreement regarding hospital admissions within the last 12 months among the cases, but little about other markers of severity. There was moderate agreement where the presenting or fatal attack was triggered by an upper respiratory-tract infection or aspirin. The next of kin and GPs agreed about family problems, but not about other psychosocial issues. They also agreed about which cases had been given action plans or verbal instructions, but few other aspects of asthma management. There was also moderate agreement regarding the use of peak flow meters by the controls.

CONCLUSIONS

Doctors often have relatively poor insights into self-management practices, social background or trigger factors, even in high-risk patients. This should be considered when planning future campaigns to improve asthma management and further reduce mortality.

Effect of inhaled fluticasone propionate on BAL TGF-β1 and bFGF concentrations in clinically stable lung transplant recipients

BACKGROUND

Inhaled fluticasone propionate (FP) therapy decreases inflammation and sub-basement membrane thickness in asthmatic airways. Bronchiolitis obliterans syndrome (BOS) in lung transplant recipients (LTRs) involves progressive airway fibrosis and obliteration. Therefore, augmented immunosuppression may be of some benefit in treating BOS. In this study, we examined the effect of 3 months of treatment with high-dose inhaled FP on the concentrations of 2 fibrogenic factors, transforming growth factor (TGF)-beta(1) and beta fibrogenic growth factor (bFGF) in bronchoalveolar lavage (BAL) fluid from clinically stable LTRs.

METHODS

We conducted a randomized, double-blind, placebo-controlled, parallel group study with inhaled FP (750 microg, twice/day for 3 months) in 28 LTRs (15 FP and 13 placebo). We recruited 23 healthy controls. We performed spirometry, bronchoscopy, and bronchoalveolar lavage procedures before treatment and after 3 months of treatment. We used commercially available enzyme-linked immunosorbent assay kits to measure BAL fluid TGF-beta(1) and bFGF concentrations.

RESULTS

In LTRs before treatment, BAL TGF-beta(1) concentrations (but not bFGF concentrations), total cell counts, and neutrophil percentage increased compared with controls (p < 0.05). We found no significant differences between FP and placebo groups at baseline measurements. After treatment, BAL TGF-beta(1) concentrations significantly increased in the FP group (p = 0.03), but we found no difference between FP and placebo groups; BAL bFGF concentrations increased during treatment in both groups compared with controls (p < 0.05), but not significantly within either patient group (p > 0.05). We found a reverse correlation between forced expiratory volume in 1 second (FEV(1)) and BAL TGF-beta(1) concentration in the FP group (r = -0.53, p = 0.04), and between FEV(1) and BAL TGF-beta(1) concentration in the placebo group (r = -0.74, p = 0.004). Multivariable analysis indicated no significant independent effects of inhaled FP in either BAL TGF-beta(1) or bFGF concentrations.

CONCLUSIONS

Bronchoalveolar fluid TGF-beta(1) concentrations increased in LTRs after transplantation and may correlate with the decrease in lung function. Inhaled FP added to conventional immunosuppression had no effect on TGF-beta(1) or bFGF production in BAL fluid.

Fatty acid levels and risk of asthma in young adults

BACKGROUND

There is current interest in the possible protective effect of long chain (n-3) fatty acids from fish in chronic lung diseases such as asthma. The aim of this community based cross sectional study was to determine whether plasma long chain (n-3) fatty acids, as a measure of dietary intake, differed between 1601 young adults with and without asthma.

METHODS

Subjects of mean (SD) age 34.6 (7.1) years completed a detailed respiratory questionnaire, food frequency questionnaire, skin prick testing, and lung function tests including methacholine challenge test for bronchial hyperreactivity (BHR) and had venous blood taken for analysis of plasma fatty acids. Plasma fatty acid levels (%) were analysed using multiple logistic regression with alternative definitions of asthma and atopy as the outcomes.

RESULTS

Atopy was not associated with any plasma fatty acid. The n-3 polyunsaturated fatty acids and n-6:n-3 ratio were not consistently associated with asthma or atopy. The n-6 polyunsaturated fatty acid dihomo gamma-linolenic acid (DHGLA) was positively associated with current asthma (OR=1.30, 95% CI 1.06 to 1.60), asthma (OR=1.34, 95% CI 1.13 to 1.60), and doctor diagnosed asthma (OR=1.25, 95% CI 1.06 to 1.48).

CONCLUSION

Plasma n-3 fatty acids are not associated with a reduced risk of asthma or atopy among young adults. The association of DHGLA with asthma warrants further research to determine a cause-effect relationship.

Azathioprine as an oral corticosteroid sparing agent for asthma

BACKGROUND

For the majority of chronic asthmatics, symptoms are best controlled by using inhaled steroids. However, for a small group of asthmatics, symptoms can only be controlled by high doses of oral steroids. Continuous use of oral steroid is associated with severe side-effects, but it has been suggested that azathioprine, an immunosuppressive anti-metabolite, often used to reduce the immune response in chronic active hepatitis and severe rheumatoid arthritis, could be useful as an oral steroid sparing agent. There is a need to systematically evaluate the evidence regarding its use to reduce or eliminate oral corticosteroid usage.

OBJECTIVES

The objective of this review is to assess the efficacy of adding azathioprine in patients with stable asthma who are dependent on oral corticosteroids with the intention of eventually minimizing or eliminating the use of these steroids.

SEARCH STRATEGY

Searches of the Cochrane Airways Group asthma and wheeze trials register were undertaken with predefined search terms. Searches were current as of February 2003

SELECTION CRITERIA

Only studies with a randomised placebo-controlled design met the inclusion criteria for the review.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies for suitability for inclusion in the review. Data were extracted and entered into RevMan 4.2.2.

MAIN RESULTS

Two small trials recruiting 23 participants met the inclusion criteria for the review. Participants may have been suffering from comorbid lung disease. No data on oral steroid consumption were reported. No significant differences were observed in the studies for FEV(1), FVC, PaO(2) and symptoms. One study reported a statistically significant difference in SGaw, but the clinical importance of this is uncertain. Due to concerns over the small sample sizes and methodological shortcomings in terms of inadequate washout in one study, and methods used in outcome assessment for both studies, the findings of the studies are not generalisable to the issue of steroid tapering.

REVIEWER'S CONCLUSIONS

Currently there is a clear lack of evidence to support the use of azathioprine in the treatment of chronic asthma as a steroid sparing-agent. Large, long-term studies with pre-defined steroid reducing protocols are required before recommendations for clinical practice can be made.

Anti-IgE for chronic asthma in adults and children

BACKGROUND

Omalizumab is a recombinant humanised monoclonal antibody directed against immunoglobulin E (IgE) to inhibit the immune system's response to allergen exposure. Omalizumab is directed against the binding site of IgE for its high affinity Fc receptor. It prevents free serum IgE from attaching to mast cells and other effector cells and prevents IgE mediated inflammatory changes.

OBJECTIVES

To determine the efficacy of anti-IgE in patients with allergic asthma

SEARCH STRATEGY

We searched the Cochrane Airways Group Asthma trials register (February 2003) for potentially relevant studies.

SELECTION CRITERIA

Randomised controlled trials examining anti-IgE administered in any manner for any duration.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed study quality and extracted and entered data. Three modes of administration were identified from the published literature (inhaled, intravenous and subcutaneous injection). Subgroup analysis was performed by asthma severity. Data were extracted from published and unpublished sources.

MAIN RESULTS

Eight trials were included in the review, contributing a total of 2037 mild to severe allergic asthmatic participants with high levels of IgE. Treatment with intravenous and subcutaneous Omalizumab significantly reduced free IgE compared with placebo. Omalizumab led to a significant reduction in inhaled steroid consumption compared with placebo: -114 mcg/day (95% CI -150 to -78.13, two trials). There were significant increases in the number of participants who were able to reduce steroids by over 50%: odds ratio (OR) 2.50, 95% confidence interval (CI) 2.02 to 3.10 (four trials); or completely withdraw their daily steroid intake: OR 2.50, 95%CI 2.00 to 3.13 (four trials). Participants treated with Omalizumab were less likely to suffer an asthma exacerbation with treatment as an adjunct to steroids (OR 0.49, 95%CI 0.38 to 0.64, four trials), or as a steroid tapering agent (OR 0.47, 95% CI 0.37 to 0.60, four trials).

REVIEWERS' CONCLUSIONS

Omalizumab was significantly more effective than placebo at increasing the numbers of patients who were able to reduce or withdraw their inhaled steroids, but the mean difference in steroid consumption achieved with Omalizumab was of debatable clinical value. The impressive effects observed in control groups bring into question the true effect of Omalizumab. Omalizumab was effective in reducing asthma exacerbations as an adjunctive therapy to inhaled steroids. Omalizumab was well tolerated, although the safety profile requires longer term assessment. Patient and physician assessment of the drug was positive. Further assessment in paediatric and severe adult populations is necessary, as is double-dummy comparison with inhaled corticosteroids.

Possible anti-inflammatory effect of salmeterol against interleukin-8 and neutrophil activation in asthma in vivo

In-vitro data suggest that long-acting beta2-agonists may have a neutrophil-stabilising effect. A reduction in airway wall eosinophil number following introduction of salmeterol in persistent asthma has previously been described. There is currently interest in the "neutrophil system" in asthma, and thus the aim of the present study was to investigate the effect of salmeterol on interleukin (IL)-8, neutrophils and myeloperoxidase (MPO) in persistent asthma. In the same 12-week double-blind parallel-group placebo-controlled study as described previously, the effects on bronchoalveolar lavage fluid (BALF) IL-8, neutrophils and MPO of introducing salmeterol (50 microg b.i.d.) or giving additional inhaled corticosteroid (fluticasone 100 microg b.i.d.) in 45 subjects with persistent asthma already on low/moderate doses of inhaled corticosteroids were further investigated. At baseline, BALF IL-8 but not neutrophil or MPO levels were significantly raised in the asthmatic subjects compared to normal controls. MPO levels correlated strongly with IL-8 levels, and weakly with BALF neutrophil numbers in the asthmatics. Fluticasone treatment resulted in significantly elevated neutrophil numbers, but not MPO or IL-8 levels. In contrast, introducing salmeterol significantly reduced IL-8 and MPO levels, but did not affect BALF neutrophil numbers. Interestingly, salmeterol and fluticasone showed significantly contrasting effects on MPO and neutrophils, and there was a divergent effect on IL-8 levels that almost reached significance. Excessive interleukin-8 levels may be relevant to asthma pathogenesis, even in the setting of moderate-dose inhaled corticosteroid therapy. Reduction in interleukin-8 production and possibly stabilisation of airway neutrophil numbers may explain the greater clinical benefit of adding a long-acting beta2-agonist rather than merely increasing inhaled corticosteroid doses. Indeed, high-dose inhaled corticosteroid therapy alone may promote airway neutrophilia.