Bronchial thermoplasty increases airway volume measured by functional respiratory imaging

BACKGROUND

The purpose of this study was to use CT scanning with computational fluid dynamics to evaluate the mechanisms by which Bronchial Thermoplasty (BT) improves asthmatic symptoms.

METHODS

The study was conducted in a university teaching hospital, experienced in performing BT. Imaging studies were performed before, and after, BT of the left lung, and prior to treatment of the right lung, which therefore acted as a control. On each occasion, two high-resolution CT scans were performed, one at full inspiration (TLC) and the other at Functional Residual Capacity (FRC). The study protocol was offered to 10 patients, all of whom met the definition of severe asthma, despite high dose inhaled corticosteroids and dual long acting bronchodilators.

RESULTS

Significant increases in airway luminal volume were observed on the treated side, compared with control, at both full inspiration (by 27%) and at FRC (by 17%). The ratio of distal airway volume to lung volume significantly increased on the treated side. The change in airway volume with inspiration from FRC increased by 48% on the treated side compared to 5% in the control lung, suggesting treatment increased airway distensibility. No effect was observed on airway wall thickness, nor air trapping. There was a trend towards correlation between the improvement in airway volume at TLC and improvement in symptoms.

CONCLUSION

This study demonstrates that BT increases the luminal airway volume on the treated side compared to the control lung. We suggest that this is an important link between the airway smooth muscle atrophy demonstrated pathologically, and the improvement in symptoms observed clinically.

Effectiveness and response predictors of omalizumab in a severe allergic asthma population with a high prevalence of comorbidities: the Australian Xolair Registry

BACKGROUND

Severe asthma is a high impact disease. Omalizumab targets the allergic inflammatory pathway; however, effectiveness data in a population with significant comorbidities are limited.

AIMS

To describe severe allergic asthma, omalizumab treatment outcomes and predictors of response among the Australian Xolair Registry participants.

METHODS

A web-based post-marketing surveillance registry was established to characterise the use, effectiveness and adverse effects of omalizumab (Xolair) for severe allergic asthma.

RESULTS

Participants (n = 192) (mean age 51 years, 118 female) with severe allergic asthma from 21 clinics in Australia were assessed, and 180 received omalizumab therapy. They had poor asthma control (Asthma Control Questionnaire, ACQ-5, mean score 3.56) and significant quality of life impairment (Asthma-related Quality of Life Questionnaire score 3.57), and 52% were using daily oral corticosteroid (OCS). Overall, 95% had one or more comorbidities (rhinitis 48%, obesity 45%, cardiovascular disease 23%). The omalizumab responder rate, assessed by an improvement of at least 0.5 in ACQ-5, was high at 83%. OCS use was significantly reduced. The response in participants with comorbid obesity and cardiovascular disease was similar to those without these conditions. Baseline ACQ-5 ≥ 2.0 (P = 0.002) and older age (P = 0.05) predicted the magnitude of change in ACQ-5 in response to omalizumab. Drug-related adverse events included anaphylactoid reactions (n = 4), headache (n = 2) and chest pains (n = 1).

CONCLUSION

Australian patients with severe allergic asthma report a high disease burden and have extensive comorbidity. Symptomatic response to omalizumab was high despite significant comorbid disease. Omalizumab is an effective targeted therapy for severe allergic asthma with comorbidity in a real-life setting.

Breast milk polyunsaturated fatty acids: associations with adolescent allergic disease and lung function

BACKGROUND

It has been hypothesized that n-3 PUFA in breast milk may assist immune and lung development. There are very limited data on possible long-term effects on allergic disease and lung function. The aim was to investigate associations of n-3 and n-6 PUFA levels in colostrum and breast milk with allergic disease and lung function at ages 12 and 18 years.

METHODS

Polyunsaturated fatty acids were measured in 194 colostrum samples and in 118 three-month expressed breast milk samples from mothers of children enrolled in the Melbourne Atopy Cohort (MACS) Study, a high-risk birth cohort study. Associations with allergic diseases, skin prick tests and lung function assessed at 12 and 18 years were estimated using multivariable regression.

RESULTS

Higher levels of n-3 but not n-6 PUFAs in colostrum were associated with a trend towards increased odds of allergic diseases, with strong associations observed for allergic rhinitis at 12 (OR = 5.69[95% CI: 1.83,17.60] per weight%) and 18 years (4.43[1.46,13.39]) and eczema at 18 years (9.89[1.44, 68.49]). Higher levels of colostrum n-3 PUFAs were associated with reduced sensitization (3.37[1.18, 9.6]), mean FEV₁ (-166 ml [-332, -1]) and FEV₁ /FVC ratio (-4.6%, [-8.1, -1.1]) at 12 years.

CONCLUSION

Higher levels of colostrum n-3 PUFAs were associated with increased risks of allergic rhinitis and eczema up to 18 years, and sensitization and reduced lung function at 12 years. As residual confounding may have caused these associations, they should be replicated, but these results could indicate that strategies that increase maternal n-3 PUFA intake may not aid in allergic disease prevention.

Allergy tests do not predict food triggers in adult patients with eosinophilic oesophagitis. A comprehensive prospective study using five modalities

BACKGROUND

The use of allergy tests to guide dietary treatment for eosinophilic oesophagitis (EoE) is controversial and data are limited. Aeroallergen sensitisation patterns and food triggers have been defined in Northern Hemisphere cohorts only.

AIMS

To determine if allergy tests that are routinely available can predict food triggers in adult patients with EoE. To define the food triggers and aeroallergen sensitisation patterns in a novel Southern Hemisphere (Australian) cohort of patients.

METHODS

Consecutive patients with EoE who elected to undergo dietary therapy were prospectively assessed, demographic details and atopic characteristics recorded, and allergy tests, comprising skin-prick and skin-patch tests, serum allergen-specific IgE, basophil activation test and serum food-specific IgG, were performed. Patients underwent a six-food elimination diet with a structured algorithm that included endoscopic and histological examination of the oesophagus a minimum of 2 weeks after each challenge. Response was defined as <15 eosinophils per HPF. Foods defined as triggers were considered as gold standard and were compared with those identified by allergy testing.

RESULTS

No allergy test could accurately predict actual food triggers. Concordance among skin-prick and serum allergen-specific IgE was high for aeroallergens only. Among seasonal aeroallergens, rye-grass sensitisation was predominant. Food triggers were commonly wheat, milk and egg, alone or in combination.

CONCLUSIONS

None of the currently-available allergy tests predicts food triggers for EoE. Exclusion-rechallenge methodology with oesophageal histological assessment remains the only effective investigation. The same food triggers were identified in this southern hemisphere cohort as previously described.

Seasonal recurrence of food bolus obstruction in eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a newly recognised condition that is apparently increasing in prevalence, and the aetiology is poorly understood. The role of aeroallergens in EoE is controversial, given the success of dietary therapy. Massive aeroallergen exposure leading to food bolus obstruction events (FBOE) has been described, and the diagnosis of EoE by esophageal biopsy noted to be more common in the pollen season according to previous case series.

AIM

To determine if a seasonal variation and a geographical variation occurred in EoE presenting as FBOE in adults, and to track the prevalence of FBOE and EoE over time.

METHOD

A retrospective case-control study analysis was performed from January 2002 to January 2012 to identify all FBOE in adults presenting to five tertiary hospitals in Melbourne, Australia. Endoscopy, histopathological reports, case notes and blood tests were examined, and postcodes recorded. Records of pollen counts were obtained. Cases were defined according to esophageal biopsy and grouped based on month of diagnosis. All other causes of FBOE served as controls.

RESULTS

One thousand, one hundred and thirty-two FBOE were identified. Biopsies were only performed in 278 of these cases, and 85 patients were found to have EoE after biopsy. Patients with EoE were younger (mean age 38 years, range 18-72) compared with those with alternative diagnosis (mean age 64.4 range 22-92), more likely to be male (M : F = 4:1 compared with 1.68:1 ) and had a higher eosinophil count in venous blood. Overall no seasonality was demonstrated in FBOE secondary to any diagnosis, although the six cases of recurrent FBOE secondary to EoE mainly occurred in the grass pollen season in subsequent years. FBOE cases were evenly distributed throughout metropolitan Melbourne irrespective of population density. EoE as a percentage of FBOE increased over time.

CONCLUSION

Seasonal aeroallergens may be important for a subgroup of patients with EoE presenting as recurrent FBOE. Esophageal biopsies are performed in a minority of patients, representing a significant departure from ideal management and contributing to recurrent unnecessary FBOE. EoE is an increasingly important cause of FBOE.

Real-life effectiveness of omalizumab in severe allergic asthma above the recommended dosing range criteria

BACKGROUND

Omalizumab (Xolair) dosing in severe allergic asthma is based on serum IgE and bodyweight. In Australia, patients eligible for omalizumab but exceeding recommended ranges for IgE (30-1500 IU/mL) and bodyweight (30-150 kg) may still receive a ceiling dose of 750 mg/4 weeks. About 62% of patients receiving government-subsidized omalizumab are enrolled in the Australian Xolair Registry (AXR).

OBJECTIVES

To determine whether AXR participants above the recommended dosing ranges benefit from omalizumab and to compare their response to within-range participants.

METHODS

Data were stratified according to dose range status (above-range or within-range). Further sub-analyses were conducted according to the reason for being above the dosing range (IgE only vs. IgE and weight).

RESULTS

Data for 179 participants were analysed. About 55 (31%) were above recommended dosing criteria; other characteristics were similar to within-range participants. Above-range participants had higher baseline IgE [812 (IQR 632, 1747) IU/mL vs. 209 (IQR 134, 306) IU/mL] and received higher doses of omalizumab [750 (IQR 650, 750) mg] compared to within-range participants [450 (IQR, 300, 600) mg]. At 6 months, improvements in Juniper 5-item Asthma Control Questionnaire (ACQ-5, 3.61 down to 2.01 for above-range, 3.47 down to 1.93 for within-range, P < 0.0001 for both) and Asthma Quality of Life Questionnaire (AQLQ mean score (3.22 up to 4.41 for above-range, 3.71 up to 4.88 for within-range, P < 0.0001) were observed in both groups. Forced expiratory volume in one second (FEV₁ ) improved among above-range participants. There was no difference in response between above-range and within-range participants. Above-range participants due to either IgE alone or IgE and weight had similar improvements in ACQ-5, AQLQ and FEV₁ .

CONCLUSIONS AND CLINICAL RELEVANCE

Patients with severe allergic asthma above recommended dosing criteria for omalizumab have significantly improved symptom control, quality of life and lung function to a similar degree to within-range participants, achieved without dose escalation above 750 mg.

A prospective open clinical trial of a proton pump inhibitor, elimination diet and/or budesonide for eosinophilic oesophagitis

BACKGROUND

Elimination diets and high-dose proton pump inhibitors (PPI) are advocated as first-line treatments in patients with eosinophilic oesophagitis (EoE).

AIM

To record the treatment outcome for patients with EoE prospectively managed according to a clinical algorithm.

METHODS

Patients with oesophageal eosinophilia commenced esomeprazole 40 mg twice daily for 8 weeks. Those in histological remission were re-classified as PPI-responsive oesophageal eosinophilia. Nonresponders were offered the 6-food elimination diet with a PPI, or topical budesonide monotherapy (1 mg orally twice daily as an aqueous gel). Once disease control was achieved remission was reassessed at 3 months (all modalities) and an additional 6 months (diet group).

RESULTS

Of 107 patients who completed 8 weeks of PPI, 25 (23%) were PPI-responsive. 56 of 81 (69%) of patients with EoE chose the elimination diet with PPI. 29 (52%) had complete remission, 23 completed dietary reintroduction and food triggers were identified in 20 (36%). 25 chose budesonide with 23/25 (92%) responding. Remission was sustained in >85% of patients at 3 months with all treatment modalities. At 9 months, only 10/18 (55%) of patients who responded to the elimination diet with PPI remained complaint and sustained remission.

CONCLUSIONS

Many patients previously diagnosed with EoE will respond to PPI. Initial response >50% is possible with the elimination diet plus PPI, but many will fail to undergo food reintroduction, or will cease the diet and relapse, resulting in only one in four patient sustaining remission at 9 months. Budesonide is very effective short term, but longer term study is needed.

Risk factors for eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic antigen driven disease, whereby food and/or aeroallergens result in inflammation and luminal narrowing, and the clinical symptoms of dysphagia and food bolus obstruction events (FBOE). Established risk factors are male gender, Caucasian race and atopy. Increased risk amongst family members, and a single nucleotide polymorphism (SNP) in a gene coding thymic stromal lymphopoietin (TSLP) on the pseudoautosomal region of the X and Y chromosomes supports a genetic predisposition. Environmental factors including the timing and nature of food and aeroallergen exposure to the developing immune system may be important, whilst esophageal barrier function integrity and the influence of microbiota are worthy of future research.

Flow and Particle Deposition Patterns in a Realistic Human Double Bifurcation Airway Model

Velocity profiles, local deposition efficiencies (DE), and deposition patterns of aerosol particles in the first three generations (i.e., double bifurcations) of an airway model have been simulated numerically, in which the airway model was constructed from computed tomography (CT) scan data of real human tracheobronchial airways. Three steady inhalation conditions, 15, 30, and 60 L/min, were simulated and a range of micrometer particle sizes (1-20 mum diameter) were injected into the model. Results were then compared with experimental and other numerical results which had employed either similar model geometry or test conditions. The effects of inhalation conditions on velocity profiles and particle deposition were studied. The data indicated that the local deposition efficiencies in the first bifurcation increased with a rise in the Stokes number (St) within St range from 0.0004 to 0.7. Within the same St range, DE in the second bifurcations (both left and right) was dropped dramatically after St increased to 0.17. Also, the second bifurcation in the right side (B2.1, closer to first bifurcation than left side, B2.2) was found to show a much higher (almost double) DE than the left side. This may be due to the fact that the left main bronchus is longer and has greater angulation than the right main bronchus. Generally, the present simulation using a computational fluid dynamic (CFD) technique obtained concurrent results with subtle differences compared to other works. However, due to omission of larynx in the model, which is known to significantly modify airflow and hence particle deposition, the present model may only serve as the "stepping stone" to simulating and analyzing dose-response or inhalation risk assessment visually for clinical researchers.

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.

Enhancing validity: what counts as an asthma attack?

BACKGROUND

Major epidemiological studies in asthma use the question: "How many attacks of asthma have you had in the last 12 months?" We set out to study what constitutes an asthma attack from the perspective of people with asthma. We also examined concordance between qualitative responses and standard quantitative measures of this question.

METHODS

Individuals aged 18 to 70 years who sought care for asthma at Emergency Departments in an Australian central city, a suburban and a regional hospital were recruited. Sixty two (43 women and 19 men) participants were interviewed in depth. All interviews were taped, transcribed and thematically analyzed. Demographic data and responses to respiratory health data were also collected.

FINDINGS

Widely varying responses to the question, "How many attacks of asthma have you had in the last 12 months?" were found in the quantitative data set. Comparison of quantitative and qualitative data sets showed good agreement between these two responses (intraclass correlation 0.66). People defined asthma attacks as "major" and "minor," as determined by the degree of personal control they were able to exercise. A strongly unifying description of a severe attack was that it was "out of control." Patient's recognized that upper respiratory tract infections commonly triggered major attacks.

INTERPRETATION

A commonly asked question about the number of asthma attacks in the past year needs refinement in order to enhance validity. Asthma action plans should use the words "out of control" when defining a severe attack of asthma.

Choosing to attend an asthma doctor: a qualitative study in adults attending emergency departments

BACKGROUND

Asthma treatment guidelines currently recommend a 'therapeutic partnership' to achieve best care. It is frequently assumed that individuals presenting to emergency departments with asthma do not have a good doctor-patient relationship. We asked what is the nature of patients' relationships with their doctors in those presenting to hospital emergency departments for asthma care.

METHODS

A qualitative study of all consenting individuals aged 18-70 years who presented to a hospital emergency department over 2 months was carried out. Sixty-two participants (19 male) engaged in in-depth interviews which were taped, transcribed and underwent thematic analysis. Questionnaire data were also collected and asthma severity determined.

RESULTS

Nearly all patients (61/62) had a doctor whom they saw for their asthma. Patients made thoughtful choices on where they sought care according to their needs. Our findings identified that perceptions of doctors' competence, listening to patients and time constraints were important influences on doctor-patient relationships. Participants had strong expectations that their personal disease experience would be acknowledged by their doctors.

CONCLUSION

This group of patients had doctors who cared for their asthma. The acceptability of medical care was determined as much by patient choice as by the quality of the doctor-patient relationship.

Asthma management: how effective is it in the community?

BACKGROUND

The National Asthma Campaign (NAC) was launched in Australia in 1989 with the major objective of improving asthma management through the implementation of a six-step asthma management plan.

AIM

The objective of the present study was to analyse the management of asthma in a cohort of adults with self-reported asthma 10 years after the commencement of the NAC.

METHODS

The subjects were participants in the laboratory phase of a cross-sectional epidemiological study conducted in Melbourne in 1999-2000. Participants completed the detailed European Community Respiratory Health Survey, which included specific questions about their asthma management. Participants were included in this analysis if they had a positive response to the question 'Have you ever had asthma?'. This resulted in a total of 435 subjects.

RESULTS

Of the subjects with self-reported asthma, over half of the participants reported that a doctor had ever measured their breathing (52.9%). However, only 10.1% of participants reported that they owned a peakflow meter (PFM) and only 13.3% reported that they had ever been given a written action plan. In comparison with data reported from 1993, doctor measurement of lung function has decreased significantly (P < 0.000 1), as has PFM ownership (P < 0.0001) and, importantly, possession of a written action plan (P = 0.0004).

CONCLUSIONS

Asthma management among adults still falls well short of NAC guidelines. The decline in some key features over recent years suggests that new management and dissemination strategies are required.

Mouldy houses influence symptoms of asthma among atopic individuals

BACKGROUND

The influence of current levels of indoor fungi on asthma is a controversial issue that needs to be resolved in order to advise patients appropriately.

OBJECTIVE

To assess the seasonal variation in indoor fungal levels and the impact of these levels on asthma among mould-sensitized individuals.

METHODS

Thirty-five young adults with current asthma and sensitization to fungi were visited four times over 1 year. At each home visit a questionnaire was administered and samples of dust and air were collected. Participants also recorded information on symptoms, peak expiratory flows (PEF) and medication use. Dust samples were analysed for house dust mite allergen (Der p 1) and total fungal biomass (ergosterol). Total and genus-specific fungal propagules were identified in air samples. Seasonal variation in allergen levels and significant independent effects of fungal levels on peak flow variability (PFV) were identified by repeated measures analysis of variance.

RESULTS

Significant seasonal variations were observed in viable airborne fungi, ergosterol levels in the floor dust and PFV. PFV correlated significantly with symptom scores and the dose of reliever medication. PFV was also significantly associated with smoking and visible mould. The association between visible mould and PFV was independent of season, smoking and the dose of reliever medication. However, there was no association between total fungi, specific fungi or ergosterol and PFV. Der p 1 levels had no significant influence on asthma, even in HDM-sensitized individuals.

CONCLUSIONS

Mouldy homes adversely influence asthma in asthmatics sensitized to fungi.

Wheeze not current asthma affects quality of life in young adults with asthma

BACKGROUND

A study was undertaken to investigate quality of life in asthma, defined by differing criteria, to see which may be most appropriate in epidemiological studies.

METHODS

The 426 adults were participants in the follow up phase of the European Community Respiratory Health Survey (ECRHS) in Melbourne. As part of the laboratory visit, participants completed the SF-36 quality of life questionnaire, a detailed respiratory questionnaire, and underwent lung function testing.

RESULTS

Both the physical component summary and the mental component summary scores were significantly worse in those with wheeze in the previous 12 months than in those without wheeze. Only the mental component summary score was significantly worse in those with current asthma than in those without. In contrast, in those with current asthma or bronchial hyperreactivity only, neither of the summary scales was significantly different between cases and controls.

CONCLUSIONS

Quality of life is severely impaired in individuals with wheeze in the previous 12 months while individuals with current asthma or bronchial hyperreactivity alone did not appear to have significantly reduced quality of life.

Current indoor allergen levels of fungi and cats, but not house dust mites, influence allergy and asthma in adults with high dust mite exposure

We assessed the influence of current indoor levels of fungi, house dust mite allergen (Der p 1), and cat allergen (Fel d 1) on sensitization and asthma in adults. A total of 485 adults answered a questionnaire and had skin prick tests and lung function tests. Dust and air samples were collected from their bedrooms. The dust was analyzed for Der p 1, Fel d 1, and fungal biomass (ergosterol). Fungal propagules were measured in air samples. Current asthma was defined as having wheezed during the past 12 mo plus bronchial hyperreactivity (BHR) to methacholine. High exposure to total airborne fungi was associated with increased BHR, but perhaps paradoxically with a lower risk of being sensitized to fungi. Ergosterol levels in floor dust were a risk factor both for being sensitized to fungi and having wheezed within the last year. High Fel d 1 levels in floor dust were found to increase the risk of being sensitized to cats and in beds to increase the risk of current asthma. Although Der p 1 levels in homes were high, people exposed to high Der p 1 levels in floor dust were less likely to be sensitized to house dust mites or to have wheezed within the past year. Current indoor levels of fungi and Fel d 1, but not Der p 1, influenced sensitization and asthma in adults with high dust mite exposure.

Effect of a long-acting beta2-agonist over three months on airway wall vascular remodeling in asthma

There are few data regarding the potential effects of antiasthma treatment on indices of airway remodeling, such as the increased subepithelial airway vascularity in patients with asthma. We studied 45 symptomatic subjects with asthma who were receiving treatment with low dose inhaled corticosteroids (ICS) (range 200-500 microg twice a day) and 28 normal subjects without asthma as a control population. Subjects underwent bronchoscopy with airway biopsy and subjects with asthma were then randomized to receive supplementary inhaled salmeterol 50 microg twice a day, fluticasone propionate 100 microg twice a day, or placebo for 3 mo in addition to their baseline ICS. Biopsy of the airway was then repeated. The biopsies were analyzed for vascular structures in the subepithelial lamina propria. Sufficient biopsy material was available for analysis of vascularity in 34 of the subjects with asthma and 28 of the normal subjects. We confirmed that airways of subjects with asthma had a significant increase in the number of vessels/mm2 of lamina propria compared with airways of normal subjects (524 +/- 137 vessels/mm2, n = 34 versus 425 +/- 130 vessels/mm2, n = 28; p = 0.004). There was a decrease in the density of vessels of lamina propria after treatment only in the salmeterol group compared with baseline (before, 535 +/- 153 vessels/mm2 versus after, 400 +/- 142 vessels/mm2; n = 12; p = 0.04). There was no significant change within the fluticasone (n = 11) or placebo (n = 11) treatment groups, but also no significant differences between the groups. Notably, no treatment was associated with increased airway wall vascularity. The demonstrated fall in vessel number within the salmeterol-treated group may suggest an advantageous effect of long-acting beta2-agonists on this manifestation of airway remodeling over the 3-mo time scale of this study, which is complementary to the action of ICS on airway vascularity.

Leukotriene antagonists. Do they offer new hope for asthmatics?

BACKGROUND

Leukotrienes are potent chemical mediators important in allergic inflammation. Leukotriene receptor antagonists are a new class of oral asthma drugs which target and block the action of these mediators.

OBJECTIVE

To review the action of leukotrienes and the clinical effects of leukotriene receptor antagonists in asthma.

DISCUSSION

Leukotrienes mediate bronchospasm, airway oedema, mucus hypersecretion and increased airway reactivity. Leukotriene receptor antagonist drugs have a mild short and long term bronchodilator effect, with evidence of an anti inflammatory effect. The clinical benefits include improved symptoms, reduced rescue bronchodilator requirements, and reduced inhaled steroid requirements. Their oral formulation may provide improved adherence compared to inhaled medication. Clinical studies suggest they may be less efficacious than inhaled steroids or long acting beta 2 agonists in improving lung function and symptom control, but there was a heterogeneity in response to all classes of asthma drugs. Hence, currently, the only way to judge effectiveness is a therapeutic trial for 4-6 weeks. Although they are unlikely to replace currently available asthma medication, they are likely to be useful adjuncts to treatment.

Bronchoalveolar lavage fluid urea as a measure of pulmonary permeability in healthy smokers

The effects of cigarette smoking on blood to airway pulmonary permeability to the low-molecular-weight solute urea were investigated, in an attempt to evaluate its use as a dilution marker for bronchoalveolar lavage (BAL) studies. Five healthy normal smokers who smoked a cigarette 10 min prior to undergoing a 3 x 60 mL bronchoalveolar lavage (BAL), and five nonsmokers who also underwent BAL but without cigarette smoke exposure were studied. Five minutes before bronchoscopy, 4 MBq 3H-water and 1 MBq 14C-urea were injected intravenously and biochemical urea assays and an indirect radiotracer method were used to evaluate permeability. It was shown that the smoking group had less urea in their BAL supernatants compared to nonsmokers the results using the radiotracer method being significant (p<0.005). Using both methods, it was shown that levels of urea increased in sequentially aspirated aliquots in both groups. The median directly assayed levels of urea in the smokers rose as follows: aliquot 1 0.05 micromol x mL(-1), (range 0.03-0.14), aliquot 2 0.10 micromol x mL(-1) (0.07-0.17), aliquot 3 0.12 micromol x mL(-1) (0.06-0.23) (p<0.05). This led to significantly increased calculated levels of epithelial lining fluid in the sequential aliquots (p<0.05). In addition, there were large but variable amounts of labelled water detected in both subject groups indicating a complex interaction between the BAL procedure and the circulation. Changing urea measurements during the bronchoalveolar lavage procedure confound the use of the urea (epithelial lining fluid) method for normalizing dilution factors. The use of epithelial lining fluid determinations in smokers ignores the additional and probably complex permeability changes. The present data suggest that acute exposure to cigarette smoke in smokers may decrease blood to airway permeability.

An antiinflammatory effect of salmeterol, a long-acting beta(2) agonist, assessed in airway biopsies and bronchoalveolar lavage in asthma

The addition of long-acting beta(2) agonists to inhaled corticosteroid (ICS) therapy in symptomatic patients with asthma improves clinical status more than increasing the dose of ICS. It has been suggested that these benefits could be at the cost of an increase in airway inflammation, but few histopathological studies have been performed in the relevant group. In a double-blind, parallel-group, placebo-controlled study, we randomly assigned 50 symptomatic patients with asthma who were receiving ICS (range, 100 -500 microgram/d) to 12 wk of supplementary treatment with salmeterol (50 microgram twice daily) or fluticasone (100 microgram twice daily) or placebo. Bronchial biopsies and BAL were obtained from 45 patients before and after treatment and analyzed. After treatment with salmeterol there was no deterioration of airway inflammation as assessed by mast cells, lymphocytes, or macrophages in BAL or biopsies, but rather a significant fall in EG1-positive eosinophils in the lamina propria (from a median 18.3 to 7.6 cells/mm, p = 0.01), which was not seen after treatment with fluticasone. The only cellular effect of added fluticasone was a decrease in BAL lymphocyte activation. There was a concurrent improvement in clinical status, more marked with salmeterol than with increased ICS. Thus, adding salmeterol to ICS is not associated with increased "allergic" airway inflammation, but conversely with a complementary antieosinophil effect.

Prevalence and residential determinants of fungi within homes in Melbourne, Australia

BACKGROUND

Recent epidemiological studies suggest that the adverse respiratory health effects caused by the inhalation of fungal propagules are substantial. Knowledge of the prevalence and environmental determinants of indoor fungal levels is essential in designing effective avoidance measures.

AIM

To investigate the prevalence of fungi and the influence of residential characteristics on levels of fungi within homes in Melbourne, Australia.

METHODS

Floor dust and air samples were collected from bedrooms in 485 houses over 1 year. The dust was analysed for ergosterol, a marker of cumulative fungal biomass exposure. Total and genera-specific fungal propagules were identified in air samples. Details of the relevant residential characteristics were documented using a questionnaire. Independent predictors (P < 0.05) of ergosterol and total fungal propagules were identified by multiple linear regression.

RESULTS

Fifty-five percent of the houses had viable fungal propagules exceeding 500 CFU/m3. Cladosporium and Penicillium were identified as the most prevalent and abundant fungal genera in indoor air. The median ergosterol level in bedroom floor was 3.8 microg/g of dust. Multivariate analysis showed that total fungal propagules in indoor air were lower in bedrooms with a ceiling fan, without visible mould, and those that were more frequently vacuumed, had a solid fuel fire, had windows closed at the time of the sampling or lacked pets. The presence of more than one cat had the greatest effect on total fungal propagules. Ergosterol levels were significantly lower in homes without old fitted carpets, visible mould or pets and those with frequent airing and regular use of an extractor fan in the kitchen. Old wall-to-wall carpets had the greatest effect on ergosterol.

CONCLUSIONS

High indoor fungal exposures were associated with infrequent ventilation or vacuuming, presence of pets, visible mould and old carpets.

A reliable and valid home visit report for studies of asthma in young adults

Validated instruments are not available to assess the residential characteristics. The aim of this study was to assess the reliability and validity of an interviewer-administered home visit report. The validity of 48 items in the Home Visit Report was examined against: observations made by a researcher, measurements of relative humidity, cat allergen, and ergosterol, a biomaker of fungal exposure and a biochemical test. Test-retest reliability of 10 fixed residential characteristics was assessed comparing the responses obtained in the main study with the pilot study, Kappa, ANOVA and Wilcoxon Rank Sum tests were applied to assess the agreement and P < 0.05 was considered as statistically significant. Among 44 items examined for the validity against observations, there was a perfect or almost perfect agreement in 21 (kappa = 0.9-1) and substantial agreement (kappa = 0.6-0.8) in 19. Higher cat allergen levels were observed with cat ownership and cat being allowed indoors. Observed condensation was associated with relative humidity and observed mould was associated with ergosterol levels. The agreement on the type of carpet and the test was substantial (kappa = 0.6). Among 10 items examined for reliability, there was a perfect or almost perfect agreement in 9 (kappa = 0.9-1) and substantial agreement (kappa = 0.7) in one. In conclusion, the Home Visit Report validated in this study provides reliable and valid data.

Modulatory effects of alveolar macrophages on CD4+ T-cell IL-5 responses correlate with IL-1beta, IL-6, and IL-12 production

Increasing evidence suggests that the pattern of T-cell cytokine production can be modulated by antigen presenting cell (APC)-derived factors during the cell interactions. Recently, it has been shown that alveolar macrophages (AMs) from atopic asthmatics (AA) but not atopic nonasthmatics (AN) enhance interleukin (IL)-5 production by CD4+ T-cells. The present study compared AM production of IL-1beta, IL-6, and IL-12, as well as their associated functional capacity to influence IL-5 production by allergen-specific CD4+ T-cells in 10 AA, 10 AN, and nine nonatopic control subjects (C). AMs from AA showed a relatively high production of IL-1beta and IL-6 (p<0.05) and a relatively low secretion of IL-12 compared to C, whereas AMs from AN and C behaved similarly. This study confirmed previous findings that co-culture with AMs augments IL-5 production from allergen-stimulated CD4+ T-cells only in AA and not in nonasthmatics even if they are atopic. On the other hand, stimulation with allergen alone did not enhance IL-5 production by CD4+ T-cells in either AA nor AN. AM-induced changes in CD4+ T-cell IL-5 production upon allergen stimulation significantly correlated with their ability to produce IL-1beta (r=0.59, p<0.01), IL-6 (r=0.56, p<0.01), and inversely with IL-12 (r=-64, p=0.002) in all atopic subjects, and even more closely with the ratio of IL-12/IL-1beta (r=-0.75, p<0.001) and IL-12/IL-6 production (r=-0.81, p<0.001) in these subjects. These findings suggest that the role of alveolar macrophages from atopic asthmatics in enhancing interleukin-5 production by allergen-specific CD4+ T-cells is due, at least partly, to their aberrant production of interleukin-1beta, interleukin-6, and particularly of interleukin-12.

Vascularity in asthmatic airways: relation to inhaled steroid dose

BACKGROUND

There is an increase in vascularity in the asthmatic airway. Although inhaled corticosteroids (ICS) are an effective anti-inflammatory treatment in asthma, there are few data on any effects on structural changes.

METHODS

Endobronchial biopsy specimens from seven asthmatic subjects not receiving ICS and 15 receiving 200-1500 microg/day beclomethasone dipropionate (BDP) were immunohistochemically stained with an anti-collagen type IV antibody to outline the endothelial basement membrane of the vessels. These were compared with biopsy tissue from 11 non-asthmatic controls (four atopic and seven non-atopic).

RESULTS

There was a significant increase in the density of vessels (number of vessels/mm2 of lamina propria) in the asthmatic subjects not on ICS compared with non-asthmatic controls (mean 485 (interquartile range (IQR) 390-597) versus 329 (IQR 248-376) vessels/mm2, p<0.05; 95% CI for the difference 48 to 286). There was no significant difference between asthmatic subjects on ICS and those not on ICS or control subjects in the number of vessels/mm2 (mean 421 (IQR 281-534)). However, patients who received >/=800 microg/day BDP tended to have a reduced number of vessels/mm2 compared with patients not on ICS and those receiving </=500 microg/day BDP (mean 366 (IQR 153-608) versus 494 (IQR 391-583), p = 0.08; 95% CI for the difference -31 to 288). Similarly, there was an increase in the percentage of lamina propria occupied by vessels in asthmatic patients not on ICS compared with controls (mean 15.6% (IQR 13.1-18.0) versus 10.1% (IQR 8.4-13.3), p<0.01; 95% CI for the difference 2.4 to 9.3) but a significant decrease in the percentage of lamina propria occupied by vessels was detected in asthmatic patients on ICS (mean 11.4% (IQR 9.1-14.9), p<0.01; 95% CI for the difference 0.7 to 7.7) compared with those not on ICS. The density of vessels correlated significantly with both airway hyperresponsiveness and percentage change in forced expiratory volume in one second (FEV1) after bronchodilator (r = -0. 38 for PD20 methacholine and r = 0.49 for change in percentage FEV1 after bronchodilator versus number of vessels/mm2, p<0.05).

CONCLUSION

These findings suggest that ICS, especially at higher doses, may reduce airway wall vascularity in asthmatic subjects but further longitudinal intervention studies are required to confirm this suggestion.

Residential characteristics influence Der p 1 levels in homes in Melbourne, Australia

BACKGROUND

Exposure to house dust mite (HDM) allergens is an important risk factor for childhood asthma. Knowledge of environmental determinants of HDM allergen levels is essential before designing rational avoidance measures.

AIM

To investigate the effect of domestic characteristics on HDM allergen (Der p 1) levels in Melbourne homes.

METHODS

Dust was collected from bed and floor of the bedrooms in 485 houses over a period of one year. Dust was analysed for Der p 1 levels using an enzyme-linked immunosorbent assay. Temperature and relative humidity were measured at the visit. Details of residential characteristics were collected using a questionnaire. Statistically significant predictors of Der p 1 levels (P < 0.05) were identified using multiple linear regression.

RESULTS

High levels of Der p 1 were observed in the floors (geometric mean 17.2 microg/g fine dust) as well as in the beds (geometric mean 20.3 microg/g fine dust). Der p 1 levels in the floor dust were significantly lower in winter and spring. They were higher in houses built before 1980 and those with central heating, weather board walls, damp bedrooms or fitted old wool carpets. Der p 1 levels in bed dust were significantly higher in houses built before 1980, with wooden floors built on stumps, with high relative humidity, with visible mould in the room, in beds with an old mattress or in beds without a quilt.

CONCLUSIONS

We would encourage construction of homes without carpets, wooden floors on stumps or weather board walls.

A cost-analysis of two approaches to infection control in a lung function laboratory

BACKGROUND

The Thoracic Society of Australia and New Zealand (TSANZ) guidelines for infection control in respiratory laboratories are based on a 'Universal Precautions' approach to patient care. This requires that one-way breathing valves, flow sensors, and other items, be cleaned and disinfected between patient use. However, this is impractical in a busy laboratory. The recent introduction of disposable barrier filters may provide a practical solution to this problem, although most consider this approach to be an expensive option.

AIM

To compare the cost of implementing the TSANZ infection control guidelines with the cost of using disposable barrier filters.

METHODS

Costs were based on the standard tests and equipment currently used in the lung function laboratory at The Alfred Hospital. We have assumed that a barrier filter offers the same degree of protection against cross-infection between patients as the TSANZ infection control guidelines. Time and motion studies were performed on the dismantling, cleaning, disinfecting, reassembling and re-calibrating of equipment. Conservative estimates were made as to the frequency of replacing pneumotachographs and rubber mouthpieces based on previous equipment turnover. Labour costs for a scientist to reprocess the equipment was based on $20.86/hour. The cost of employing a casual cleaner at an hourly rate of $14.07 to assist in reprocessing equipment was also investigated. The new high efficiency HyperFilter disposable barrier filter, costing $2.95 was used in this cost-analysis.

RESULTS

The cost of reprocessing equipment required for spirometry alone was $17.58 per test if a scientist reprocesses the equipment, and $15.56 per test if a casual cleaner is employed to assist the scientist in performing these duties. In contrast, using a disposable filter would cost only $2.95 per test. Using a filter was considerably less expensive than following the TSANZ guidelines for all tests and equipment used in this cost-analysis.

CONCLUSIONS

The TSANZ infection control guidelines are expensive and impractical to implement. However, disposable barrier filters provide a practical and inexpensive method of infection control.

Differential regulation of allergen-specific T(H2)- but not T(H1)-type responses by alveolar macrophages in atopic asthma

BACKGROUND AND OBJECTIVE

Previous studies have suggested that quantitative differences in TH2-type cytokine responses in the airways are of particular importance in the pathogenesis of asthma. In this study we investigated whether alveolar macrophages (AMs) and peripheral blood monocytes (PMNs) are able to significantly influence the profiles of allergen-induced TH1 (IFN-gamma) and TH2 (IL-4 and IL-5) cytokine production by CD4+ T cells in atopic asthmatic subjects versus atopic nonasthmatic subjects and nonatopic normal subjects.

METHODS

Peripheral blood CD4+ T cells were cultured alone or cocultured with either PMNs or AMs with allergen stimulation in the 3 groups.

RESULTS

Although allergen stimulation did not change TH1 or TH2 cytokine responses in cultures of CD4+ T cells alone, the addition of PMNs to the cultures induced a significant increase in production of IL-4, IL-5, and IFN-gamma (P < .01 or P < .001) in atopic asthmatic subjects and atopic nonasthmatic subjects. However, PMNs induced a significant increase for IFN-gamma (P < .05) only in normal subjects. AMs from atopic asthmatic subjects significantly enhanced production of all 3 cytokines (P < .01 or P < .001), whereas the AMs from atopic nonasthmatic subjects significantly increased only production of IL-4 (P < .01) and IFN-gamma (P < .05) but not IL-5. Furthermore, IL-4 (P = .066) and IL-5 (P < .01) production in allergen-stimulated AM-CD4+ cell cocultures was higher in atopic asthmatic subjects but significantly lower in atopic nonasthmatic subjects (P < .05) as compared with the PMN-cocultures. For IFN-gamma, no difference was found between the AM and PMN cocultures in either atopic group. Allergen-stimulated IL-5 production in coculture with both AMs and PMNs inversely correlated with both baseline FEV1 percent predicted and PD20 methacholine in atopic asthmatic subjects (P < .05, P < .01, or P < .001).

CONCLUSION

These data suggest that AMs from atopic asthmatic subjects but not atopic nonasthmatic subjects, play a significant role in airway pathogenic immunity through enhancing TH2-type cytokine production.

The effects of monosodium glutamate in adults with asthma who perceive themselves to be monosodium glutamate-intolerant

BACKGROUND

Many previous clinical studies of food-induced asthma suffer from inadequate baseline or control data. A statistically valid, randomized, double-blind, placebo-controlled, monosodium glutamate (MSG)-challenge protocol was developed for identifying early and late asthmatic reactions in an individual.

OBJECTIVE

We sought to determine whether MSG would induce bronchoconstriction in a group of adults with asthma who perceived that they were MSG sensitive.

METHODS

Twelve subjects (seven women, mean age 35.3 years) with clinically documented asthma and a perception of MSG-induced asthma were recruited. FEV1 and peak expiratory flow data were obtained for 3 whole control days, as well as time-matched data for 3 separate challenge days (1 gm MSG, 5 gm MSG, and 5 gm lactose [placebo]). Opaque capsule challenges were given as a single dose in the morning after an overnight fast. Subjects complied with an elimination diet throughout the study. Nonspecific bronchial hyperresponsiveness was measured at baseline, after the control days, and at the conclusion of the challenges. Venous blood samples were taken at baseline and on each challenge day to determine soluble inflammatory marker (eosinophil cationic protein and tryptase) activity.

RESULTS

No immediate or definite late asthmatic reactions occurred. One subject's FEV1 declined more than 15% on MSG challenge, but 95% confidence limits for the control-day spirometry showed that this decline was within her daily variation, hence the challenge was deemed to be negative. No significant changes in bronchial hyperresponsiveness or soluble inflammatory markers were found.

CONCLUSIONS

MSG-induced asthma was not demonstrated in this study. This study highlighted the importance of adequate baseline and control data and indicated that such a rigorous protocol for individual assessment is feasible.

Do dairy products induce bronchoconstriction in adults with asthma?

BACKGROUND

Dairy products have often been implicated as a cause of exacerbation of asthma, but there is little scientific evidence to support this hypothesis.

OBJECTIVE

We sought to determine whether dairy products induce bronchoconstriction in a group of adults with asthma.

METHODS

Twenty subjects with asthma (13 women and 7 men) were recruited from respondents who had previously completed a food and asthma questionnaire. Ten subjects perceived that their asthma became worse with ingestion of dairy products (positive perceivers), whereas ten were negative perceivers. None of the subjects had positive skin prick test results with cow's milk. The study was a randomized, cross-over, double-blind, placebo-controlled trial. Subjects complied with a dairy-free diet throughout the study. The active challenge was a single-dose drink equivalent to 300 ml of cow's milk. A positive reaction was defined as a 15% reduction in both FEV1 and peak expiratory flow (PEF) on the active challenge day compared with results obtained at the same time on the placebo day.

RESULTS

For both FEV1 and PEF there were no statistically significantly differences in group means between active challenge and placebo challenge, between sequence of administration, or between perceptions. Nine subjects showed FEV1 or PEF changes that were greater than 15% of baseline values: four patients showed changes after both active and placebo treatment; two after treatment with placebo only; and three after active treatment alone. Of the latter group, two subjects showed changes only in PEF, and when one of these subjects underwent a further detailed study, no asthmatic reaction could be demonstrated.

CONCLUSION

It is unlikely that dairy products have a specific bronchoconstrictor effect in most patients with asthma, regardless of their perception.

Attendance at an asthma educational intervention: characteristics of participants and non-participants

As part of an evaluation of the patient education component of the Australian Asthma Management plan, a randomized, controlled trial of asthma education was conducted in 1994/95 at the outpatient asthma and allergy clinic of The Alfred Hospital, a tertiary referral hospital in Melbourne, Australia. The objective of the study was to investigate which demographic and clinical characteristics were associated with attendance at asthma educational session. A total of 125 asthmatics aged over 16 years agreed to participate in the programme, and full compliance with the programme was 43.2%. Allocation to immediate, rather than delayed, education and age were the only significant predictors of attendance. Subjects randomized to the intervention were approximately three times more likely to attend than control subjects (OR = 3.3, 95% CI 1.5-7.3). Asthmatics over 60 years old were approximately six times more likely to attend (OR = 6.6, 95% CI 2.2-19.8) than the age group 16-30 years. The increasing trend in attendance across age categories was highly significant (P < 0.001). There was no relationship between attendance and gender, medication, atopy, smoking status or the physical accessibility of the hospital. Despite offering incentives and conducting the education sessions at subjects' preferred times, their compliance in attending sessions was poor. Over half of the asthmatics, who had expressed interest, failed to attend for their educational sessions. An alternative strategy is required to improve participation by young and employed asthmatics at hospital-based asthma education programmes.

Seasonal comparison of cytokine profiles in atopic asthmatics and atopic non-asthmatics

Previous studies have suggested that peripheral blood T cell cytokine release may reflect the situation in the bronchial mucosa in atopic asthmatics. We have therefore examined spontaneous, rye grass pollen-stimulated, and PHA-stimulated secretion of IL-2, IL-4, IL-5, and IFN-gamma in cultures of peripheral blood mononuclear cells (PBMC) from atopic asthmatic, atopic non-asthmatic and normal controls in and out of the rye grass pollen season. Compared to normal controls, both atopic groups showed higher IL-2 and IL-5 production (p < 0.01 and p < 0.05) and higher percentages of CD4 cells expressing CD25 and HLA-DR (p < 0.05) in response to rye grass pollen, elevated IL-4 production in response to PHA (p < 0.01), and a non-significant trend towards lower IFN-gamma production. However, the capacity of PBMC from atopic asthmatics to produce IL-5 was greater than that for atopic non-asthmatics (p < 0.05). Furthermore, seasonal changes in symptom score, FEV1 % predicted, and PD20 methacholine correlated with seasonal elevated production of IL-5 by PBMC in the asthmatic group (r = 0.862, -0.679, and -0.620; p < 0.01, 0.02, and 0.05, respectively). Our results suggest that elevated production of IL-2 and IL-4 and higher percentages of activated CD4 T cells are associated with atopy per se, but elevated production of IL-5 also relates to the clinical expression of atopic asthma.

Patients' perceptions of food-induced asthma

BACKGROUND

The influence of diet in asthma control remains unclear. However, there is likely to be a wide gap between patient perceptions and the probable actual role. Some 20-60% of people with asthma report food as a trigger factor while approximately 2.5% react to double-blind placebo-controlled challenges. The aim of this study was to determine: the frequency, type and sources of dietary advice being offered to patients, the prevalence of dietary modification, whether dietary changes were perceived to be of benefit and the type and sources of food/beverage reactions that people perceive they have experienced.

METHOD

A self-administered 'food and asthma' questionnaire was developed and mailed to 156 consecutive Alfred Hospital Asthma and Allergy Clinic patients registered on a computer database.

RESULTS

The completed questionnaire response rate was 86.5%. Dietary advice had been offered to 47% of respondents while 61% had tried to modify their diet. Dietary restriction was the most common dietary modification. Where dietary restriction had occurred 79% of respondents perceived that this had improved their asthma control. A doctor was the most common source of dietary advice. Seventy-three per cent reported that food induced asthma.

CONCLUSION

We confirmed that patients with asthma perceived diet to be important in their asthma control and that dietary modification is common despite its lack of objective basis. The influence of diet and asthma requires more research, evaluation and clinical attention.

Chronic airflow obstruction in long-term survivors of allogeneic bone marrow transplantation

Prospective pulmonary function tests (PFTs) of 49 long-term survivors of identical sibling bone marrow transplants (BMT) were analysed. Eight (16%) developed a persistent pulmonary syndrome characterised by a late onset, cough and dyspnoea, hyperinflation or patchy infiltrates on plain radiography and episodic bacterial infections. The predominant PFT pattern was obstructive (reduced forced expiratory ratio, FER) with a variable restrictive component (reduced vital capacity, VC). When compared with the other 41 patients (controls), mean FER (53% absolute) and VC (73% predicted) were significantly lower at 12 months (P = 0.005). Graft-versus-host disease (GVHD) was the only identifiable risk factor (odds ration 7.1). Five of 7 patients compared with 4 of 31 controls tested at 3 months had an abnormal FER or maximum mid-expiratory flow rate (MMFR), but not VC, prior to the onset of symptoms (P = 0.015). Patients with mild to moderate disease (FER 50-70%) had stable pulmonary function while severe cases progressed despite immunosuppressive agents. Earlier recognition of this syndrome by a reduced FER or MMFR may allow the initiation of therapy at a potentially reversible stage.

Chimeric CD7 monoclonal antibody therapy in rheumatoid arthritis

Murine monoclonal antibody (Mab) therapy in patients with rheumatoid arthritis (RA) produces an antimouse immunoglobulin response by the recipient. We studied a chimeric (human/mouse) CD7 Mab, in a dose ranging tolerability study in 10 patients with RA. Modest improvements in disease activity occurred with frequent acute adverse effects of malaise, fever and nausea. After treatment, peripheral blood T lymphocyte numbers fell by 50% and CD7 expression fell by 97% for less than 7 days. Our study demonstrates chimeric Mab function in vivo and illustrates the influence of antibody isotype and patient characteristics on adverse effects.

Urinary leukotriene E4 levels after allergen and exercise challenge in bronchial asthma

Urinary leukotriene E4 (LTE4) concentrations were measured in six asthmatic subjects after treadmill exercise, and in five asthmatic subjects after allergen challenge. Exercise and allergen challenge produced a 42 +/- 18% (mean +/- SD) and 22 +/- 8% fall in FEV1, respectively. The baseline concentration of urinary LTE4 in subjects challenged with exercise was 64 (27 to 150) pg/mg creatinine (geometric mean and 95% confidence interval), and in those challenged with allergen it was 36 (23 to 59) pg/mg creatinine. Urinary LTE4 concentrations did not change significantly in the 24 h after exercise. In contrast, there was a mean 4-fold increase in urinary LTE4 during the 3 h after allergen challenge.