CD48 on blood leukocytes and in serum of asthma patients varies with severity

BACKGROUND

CD48 is a membrane receptor (mCD48) on eosinophils and mast cells and exists in a soluble form (sCD48). CD48 has a pivotal role in murine asthma and in the proinflammatory interactions of mast cells with eosinophils via its ligand CD244. Thus, CD48 might be important in human asthma.

METHODS

Therefore, two separate cohorts (IL and UK) comprising mild, moderate, and severe asthma and healthy volunteers were evaluated for blood leukocyte mCD48 expression and sCD48 in serum. Asthmatic bronchial biopsies were immunostained for CD48. sCD48 effect on CD244-dependent eosinophil activation was evaluated.

RESULTS

Eosinophil mCD48 expression was significantly elevated in moderate while downregulated in severe asthma. mCD48 expression on B, T, and NK cells and monocytes in severe asthma was significantly increased. sCD48 levels were significantly higher in mild while reduced in severe asthma. sCD48 optimal cutoff values for differentiating asthma from health were identified as >1482 pg/ml (IL) and >1619 pg/ml (UK). In asthmatic bronchial biopsies, mCD48 was expressed predominantly by eosinophils. sCD48 inhibited anti-CD244-induced eosinophil activation.

CONCLUSIONS

mCD48 and sCD48 are differentially expressed in the peripheral blood of asthma patients of varying severity. sCD48 inhibits CD244-mediated eosinophil activation. These findings suggest that CD48 may play an important role in human asthma.

From "blockbusters" to "biosimilars": an opportunity for patients, medical specialists and health care providers

Advances in basic research and research and development plans of pharmaceutical companies are radically changing the kind of available drugs and therapeutic targets. We are switching from predominantly chemical molecules, aimed at treating large populations of patients (blockbuster drugs), to a new generation of products, mostly biotech, aimed at modifying a specific pathogenetic mechanism. In other word we are moving fast to targeted therapy, which represents the first step toward personalized therapy, where the right drug at the right dose is administered to the right person, at the right time. Like the patent expiration of chemical products has corresponded to the development of generic drugs, the expiration of new biotech products will witness the appearance of biosimilars. The latter are biologic products that are highly similar but not identical to the reference medical products in terms of quality, safety and efficacy. This implies specific research, clinical monitoring, physicians updating of knowledge for a safe and appropriate use of these products. We are the beginning of a devolution in patient's care and physicians' practice.

Effects of omalizumab on markers of inflammation in patients with allergic asthma

Asthma is a chronic inflammatory disease of the airways in which immunoglobulin E (IgE) plays a key role by activating a variety of inflammatory cells through interactions with FcepsilonRI and FcepsilonRII receptors. The role of IgE in allergic inflammation provided the rationale for developing omalizumab, a humanized monoclonal anti-IgE antibody, for patients with moderate-to-severe or severe allergic asthma. The reductions in circulating levels of IgE resulting from omalizumab treatment leads to reductions in FcepsilonRI expression on mast cells, basophils and dendritic cells. This combined effect results in attenuation of several markers of inflammation, including peripheral and bronchial tissue eosinophilia and levels of granulocyte macrophage colony stimulating factor, interleukin (IL)-2, IL-4, IL-5 and IL-13. By blocking IgE binding to its receptors and diminishing dendritic cell FcepsilonRI receptor expression, omalizumab may also reduce allergen presentation to T cells and the production of Th2 cytokines. The anti-inflammatory effects of omalizumab may, therefore, explain the reductions in asthma exacerbations and symptoms seen in clinical trials in patients with moderate-to-severe or severe, persistent, inadequately controlled allergic asthma.

The Brussels Declaration: the need for change in asthma management

Asthma is a highly prevalent condition across Europe and numerous guidelines have been developed to optimise management. However, asthma can be neither cured nor prevented, treatment choices are limited and many patients have poorly controlled or uncontrolled asthma. The Brussels Declaration on Asthma, sponsored by The Asthma, Allergy and Inflammation Research Charity, was developed to call attention to the shortfalls in asthma management and to urge European policy makers to recognise that asthma is a public health problem that should be a political priority. The Declaration urges recognition and action on the following points: the systemic inflammatory component of asthma should be better understood and considered in assessments of treatment efficacy; current research must be communicated and responded to quickly; the European Medicines Agency guidance note on asthma should be updated; "real world" studies should be funded and results used to inform guidelines; variations in care across Europe should be addressed; people with asthma should participate in their own care; the impact of environmental factors should be understood; and targets should be set for improvement. The present paper reviews the evidence supporting the need for change in asthma management and summarises the ten key points contained in the Brussels Declaration.

Predicting and evaluating response to omalizumab in patients with severe allergic asthma

BACKGROUND

Omalizumab is a monoclonal antibody indicated for treatment of severe persistent allergic asthma inadequately controlled despite optimal controller therapy. We investigated whether patient selection could be targeted further.

METHODS

Data from seven randomized controlled omalizumab trials were analyzed to investigate whether pre-treatment patient baseline clinical characteristics could be identified that were predictive of a superior response to omalizumab. We also studied whether patients who respond to omalizumab following a course of treatment could be reliably identified. Univariate/multivariate analyses of INNOVATE data were performed to identify predictive baseline measures and further investigated in efficacy analyses of pooled data from seven studies. The best method of identifying responders to omalizumab following treatment was determined by assessing the ability of various clinical response criteria to identify responders and discriminate patient exacerbation and other outcomes.

RESULTS

Baseline total immunoglobulin E (IgE) was the only predictor of efficacy in INNOVATE. However, pooled analysis showed treatment benefits irrespective of IgE levels. In omalizumab-treated patients, physician's overall assessment following a course of treatment identified 61% as responders and best discriminated treatment outcomes.

CONCLUSION

Baseline characteristics do not reliably predict benefit with omalizumab. Physician's overall assessment after 16 weeks of treatment is the most meaningful measure of response to therapy.

Asthma control or severity: that is the question

In the first National Heart Lung and Blood Institute and Global Initiative for Asthma (GINA) guidelines, the level of symptoms and airflow limitation and its variability allowed asthma to be subdivided by severity into four subcategories (intermittent, mild persistent, moderate persistent, and severe persistent). It is important to recognize, however, that asthma severity involves both the severity of the underlying disease and its responsiveness to treatment. Thus, the first update of the GINA guidelines defined asthma severity depending on the clinical features already proposed as well as the current treatment of the patient. In addition, severity is not a fixed feature of asthma, but may change over months or years, whereas the classification by severity suggests a static feature. Moreover, using severity as an outcome measure has limited value in predicting what treatment will be required and what the response to that treatment might be. Because of these considerations, the classification of asthma severity is no longer recommended as the basis for treatment decisions, a periodic assessment of asthma control being more relevant and useful.

Environmental risk factors and allergic bronchial asthma

The prevalence of allergic respiratory diseases such as bronchial asthma has increased in recent years, especially in industrialized countries. A change in the genetic predisposition is an unlikely cause of the increase in allergic diseases because genetic changes in a population require several generations. Consequently, this increase may be explained by changes in environmental factors, including indoor and outdoor air pollution. Over the past two decades, there has been increasing interest in studies of air pollution and its effects on human health. Although the role played by outdoor pollutants in allergic sensitization of the airways has yet to be clarified, a body of evidence suggests that urbanization, with its high levels of vehicle emissions, and a westernized lifestyle are linked to the rising frequency of respiratory allergic diseases observed in most industrialized countries, and there is considerable evidence that asthmatic persons are at increased risk of developing asthma exacerbations with exposure to ozone, nitrogen dioxide, sulphur dioxide and inhalable particulate matter. However, it is not easy to evaluate the impact of air pollution on the timing of asthma exacerbations and on the prevalence of asthma in general. As concentrations of airborne allergens and air pollutants are frequently increased contemporaneously, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of allergic respiratory allergy and bronchial asthma. Pollinosis is frequently used to study the interrelationship between air pollution and respiratory allergy. Climatic factors (temperature, wind speed, humidity, thunderstorms, etc) can affect both components (biological and chemical) of this interaction. By attaching to the surface of pollen grains and of plant-derived particles of paucimicronic size, pollutants could modify not only the morphology of these antigen-carrying agents but also their allergenic potential. In addition, by inducing airway inflammation, which increases airway permeability, pollutants overcome the mucosal barrier and could be able to "prime" allergen-induced responses. There are also observations that a thunderstorm occurring during pollen season can induce severe asthma attacks in pollinosis patients. After rupture by thunderstorm, pollen grains may release part of their cytoplasmic content, including inhalable, allergen-carrying paucimicronic particles.

The effect of treatment with omalizumab, an anti-IgE antibody, on asthma exacerbations and emergency medical visits in patients with severe persistent asthma

BACKGROUND

Patients with severe persistent asthma who are inadequately controlled despite treatment according to current asthma management guidelines have a significant unmet medical need. Such patients are at high risk of serious exacerbations and asthma-related mortality.

METHODS

Here, we pooled data from seven studies to determine the effect of omalizumab, an anti-immunoglobulin E (IgE) monoclonal antibody, on asthma exacerbations in patients with severe persistent asthma. Omalizumab was added to current asthma therapy and compared with placebo (in five double-blind studies) or with current asthma therapy alone (in two open-label studies). The studies included 4308 patients (2511 treated with omalizumab), 93% of whom had severe persistent asthma according to the Global Initiative for Asthma (GINA) 2002 classification. Using the Poisson regression model, results were calculated as the ratio of treatment effect (omalizumab : control) on the standardized exacerbation rate per year.

RESULTS

Omalizumab significantly reduced the rate of asthma exacerbations by 38% (P < 0.0001 vs control) and the rate of total emergency visits by 47% (P < 0.0001 vs control). Analysis of demographic subgroups showed that the efficacy of omalizumab on asthma exacerbations was unaffected by patient age, gender, baseline serum IgE (split by median) or by 2- or 4-weekly dosing schedule, although benefit in absolute terms appeared to be greatest in patients with more severe asthma, defined by a lower value of percentage predicted forced expiratory volume in 1 s (FEV(1)) at baseline.

CONCLUSIONS

These results suggest that omalizumab may fulfil an important need in patients with severe persistent asthma, many of whom are not adequately controlled on current therapy.

Identification of novel expressed sequences, up-regulated in the leucocytes of chronic fatigue syndrome patients

BACKGROUND

Chronic fatigue syndrome (CFS) is an increasing medical phenomenon of unknown aetiology leading to high levels of chronic morbidity. Of the many hypotheses that purport to explain this disease, immune system activation, as a central feature, has remained prominent but unsubstantiated. Supporting this, a number of important cytokines have previously been shown to be over-expressed in disease subjects. The diagnosis of CFS is highly problematic since no biological markers specific to this disease have been identified. The discovery of genes relating to this condition is an important goal in seeking to correctly categorize and understand this complex syndrome.

OBJECTIVE

The aim of this study was to screen for changes in gene expression in the lymphocytes of CFS patients.

METHODS

'Differential Display' is a method for comparing mRNA populations for the induction or suppression of genes. In this technique, mRNA populations from control and test subjects can be 'displayed' by gel electrophoresis and screened for differing banding patterns. These differences are indicative of altered gene expression between samples, and the genes that correspond to these bands can be cloned and identified. Differential display has been used to compare expression levels between four control subjects and seven CFS patients.

RESULTS

Twelve short expressed sequence tags have been identified that were over-expressed in lymphocytes from CFS patients. Two of these correspond to cathepsin C and MAIL1 - genes known to be upregulated in activated lymphocytes. The expression level of seven of the differentially displayed sequences have been verified by quantifying relative level of these transcripts using TAQman quantitative PCR.

CONCLUSION

Taken as a whole, the identification of novel gene tags up-regulated in CFS patients adds weight to the idea that CFS is a disease characterized by subtle changes in the immune system.

The effects of regular inhaled formoterol and budesonide on preformed Th-2 cytokines in mild asthmatics

In a recent placebo-controlled study in mild atopic asthmatics, we observed a significant decrease in eosinophils in the bronchial submucosa, after 2 months oftreatment with inhaled formoterol and budesonide. Biopsy material from each treatment group; formoterol (24 microg bid), budesonide (400 microg b. i. d.) and placebo has been further assessed to investigatethe role of Th-2 cytokines by immunohistochemistry using Mabs to eosinophils as an index of inflammation, IL-4 and IL-5. Treatment with formoterol significantly reduced the number of eosinophils (EG2+) in the submucosa and epithelium, but this was not paralleled by changes in cytokine immunoreactivity In contrast, treatment with budesonide significantly reduced both the number of eosinophils (EG2+) and immunoreactivity for IL-4 and IL-5 in the submucosa. Thus, while budesonide has effects on cytokines involved in eosinophil recruitmentthis explanation does not apply tothe eosinopaenia observed with the long-acting beta2 adrenoreceptor agonist formoterol.

Inhibition of mast cell tryptase by inhaled APC 366 attenuates allergen-induced late-phase airway obstruction in asthma

BACKGROUND

APC 366, a selective inhibitor of mast cell tryptase, has been shown to inhibit antigen-induced early asthmatic response (EAR), late asthmatic response (LAR), and bronchial hyperresponsiveness (BHR) in a sheep model of allergic asthma.

OBJECTIVE

The purpose of this study was to investigate the effects of APC 366 on antigen-induced EAR, LAR, and BHR in mild atopic asthmatics not on any anti-inflammatory therapy.

METHODS

Sixteen mild atopic asthmatics, each with a demonstrable antigen-induced EAR, LAR, and BHR to histamine, were recruited into this randomized, double-blinded, crossover study. APC 366 (5 mg)/placebo was administered by aerosol inhalation 3 times per day on treatment days 1 through 4. Allergen challenge was carried out on day 4. Histamine challenge was performed the following morning, 1 hour after final dosing.

RESULTS

Subjects were shown to have a significantly smaller overall mean area under the curve for the LAR (P =.012) and mean maximum fall in FEV(1) for the LAR (P =.007) after pretreatment with APC 366 in comparison with placebo. No significant effects on BHR were demonstrable. Although the EAR was reduced by 18% after treatment with APC 366 in comparison with placebo, this was not statistically significant.

CONCLUSION

Short-term repeated administration of APC 366 significantly reduced the magnitude of antigen-induced LAR in atopic asthmatics, which supports the role of mast cell tryptase in the pathophysiology of the LAR.

Efficacy of omalizumab, an anti-immunoglobulin E antibody, in patients with allergic asthma at high risk of serious asthma-related morbidity and mortality

AIM

Add-on therapy with omalizumab, an anti-immunoglobulin E antibody, is effective in improving disease control in patients with allergic asthma of varying severity. The aim of the present study was to determine the efficacy of omalizumab in a subgroup of patients at high risk of serious asthma-related morbidity and mortality.

METHODS

A meta-analysis was performed of three randomised, double-blind, placebo-controlled studies (studies 1, 2 and 3) that enrolled 1412 patients with moderate or severe allergic asthma, all requiring daily treatment with inhaled corticosteroids (ICS). Omalizumab was administered subcutaneously every 2 or 4 weeks at a total 4-weekly dose of at least 0.016 mg/kg/IgE [IU/ml]. Each study consisted of a 16-week steroid-stable phase and a 12-16-week steroid-reduction phase, followed by a 24-week extension phase (studies 1 and 2 only). The primary outcome measure was the annualised rate of significant asthma exacerbation episodes (sAEEs) during the steroid-stable phase for the pooled subgroup of 254 high-risk patients (omalizumab, n = 135; placebo, n = 119). sAEEs were those requiring a doubling of baseline ICS dose (studies 1 and 2 only) or use of systemic steroids (all three studies).

RESULTS

Overall, the number of patients with at least one sAEE during the steroid-stable phase was reduced from 35% (42/119) with placebo to 18% (24/135) with omalizumab. Mean sAEE rates were 1.56 and 0.69 per patient-year, respectively, a reduction of 56% with omalizumab (p = 0.007). Similar reductions in exacerbations in favour of omalizumab were observed for the whole study period and for all AEEs. In those with a history of hospitalisation in the last year, 6/49 (12%) on placebo vs. 2/44 (4.5%) on omalizumab were re-hospitalised during the study period. Patients treated with omalizumab also showed significantly greater improvements from baseline in PEFR (p = 0.026), overall AQoL (p = 0.042) and mean nocturnal (p = 0.007) and mean total (p = 0.011) asthma symptom scores compared with placebo.

CONCLUSIONS

In patients at high risk of serious asthma-related morbidity and mortality, treatment with omalizumab offers the potential to halve the rate of asthma exacerbations and improve disease control.

CAM research and development

The growth in complementary medicine and its integration into conventional medicine will certainly require the development of a well defined research strategy within the UK. This paper summarizes discussions that occurred under the umbrella of the Foundation for Integrated Medicine, involving both conventional and complementary medical practitioners. It is the first UK-based consensus document that defines a research strategy for complementary and alternative medicine and looks specifically at problems such as priority setting, research methodology, research capacity and support, potential funding streams and possible routes for the dissemination of CAM research. It concludes that for CAM to have an established future within UK healthcare, it must be subject to rigorous scrutiny. The methods employed should be appropriate to the task and should embrace a wide spectrum, both quantitative, qualitative and incorporating projects that involve good practice and audit.

Interleukin-5 production by human airway epithelial cells

Interleukin (IL)-5 is a pleiotropic cytokine that exhibits biologic activity on cells of diverse hemopoieitic lineages. IL-5 enhances mediator release from human basophils and plays a pivotal role in the chemoattraction, proliferation, differentiation, survival, and activation of eosinophils. Th2- and Tc2-like T cells, mast cells, basophils, and eosinophils are the known cellular sources of this cytokine. Using a sensitive and novel reverse transcription-polymerase chain reaction enzyme-linked immunosorbent assay system, we found that IL-5 messenger RNA (mRNA) was constitutively expressed in bronchial biopsies obtained from healthy individuals, and that the levels of IL-5 mRNA expression decreased 1. 5 h after exposure to 0.12 ppm ozone for 2 h. Because the oxidative effects of ozone are confined to the epithelial cell surface and it is known that ozone induces epithelial damage and shedding, we hypothesized that epithelial cells might be a source of IL-5 mRNA. We demonstrate here that both transformed human bronchial epithelial cell lines (A549 and 16HBE14o-) and primary human bronchial and nasal epithelial cells grown in culture constitutively express IL-5 mRNA, which is upregulated on stimulation with tumor necrosis factor (TNF)-alpha. Culture supernatants derived from A549 cells exposed to TNF-alpha and interferon-gamma demonstrated detectable levels of IL-5 protein, and immunostaining of bronchial biopsies obtained from healthy human airways revealed the presence of IL-5 protein localized to the bronchial epithelium. To our knowledge, this is the first report demonstrating IL-5 production by human airway epithelial cells. This observation provides further evidence for the role of airway epithelium in regulating airway immune responses, in particular enhancing chemotaxis, activation, and survival of eosinophils, which could play an important role in the pathogenesis of bronchial asthma.

The relationship between anthropometric measurements at birth: asthma and atopy in childhood

BACKGROUND

Recent studies have reported that a large head circumference at birth is associated with an increased risk of raised serum IgE in adult life, and asthma during childhood.

OBJECTIVE

To examine the relationship between head circumference and other anthropometric measurements at birth and asthma and indices of atopy in childhood.

METHODS

The presence of asthma and measures of atopic status (total serum IgE level and skin prick tests to common allergens) were assessed prospectively in offspring of families participating in a community-based genetic study in Southampton, UK. Measures of perinatal variables including birth weight, head circumference at birth, and gestational age were obtained from hospital records of 239 offspring aged 6-23 years.

RESULTS

Children with a head circumference of 37 cm or more at birth had a relative risk of an elevated serum total IgE (> 150 IU) of 3.2 (95% CI 1.0-10.4). There were no consistent relationships between head circumference at birth and either skin prick positivity or the development of clinical asthma. There was no significant association between other perinatal markers and measures of atopic status or clinical asthma.

CONCLUSION

The study has identified that a large head circumference at birth is associated with an increased risk of an elevated total serum IgE in childhood. The reasons for this association, and the lack of an association with asthma are unclear and will require further research.

B7 costimulation is required for IL-5 and IL-13 secretion by bronchial biopsy tissue of atopic asthmatic subjects in response to allergen stimulation

Asthma is a complex disorder characterized by airway hyperreactivity and inflammation. To analyze cellular interactions required for the secretion of cytokines by the bronchial mucosa, we have evaluated the ex vivo response of tissue explants to allergen. Endobronchial mucosal biopsy tissue from mild atopic asthmatic subjects and normal control subjects were maintained in culture for 24 h. To detect reactivity to allergen, the explants were stimulated with dust mite extract Dermatophagoides pteronyssinus (Der p). Our analysis revealed that without any overt stimulation, mRNA transcripts for interleukin (IL)-5 and IL-13 were expressed by asthmatic but not normal bronchial tissue. In contrast, the expression of interferon-gamma was observed in a higher proportion of cultured bronchial biopsies from the normal control subjects than in those from asthmatic subjects. Addition of Der p allergen did not change the cytokine profile of the explants from control volunteers but augmented the expression of IL-5 mRNA and induced secretion of the protein by the asthmatic bronchial tissue. In most cases, allergen also increased the production of IL-13 by bronchial tissue from asthmatic subjects. The allergen-induced secretion of IL-5 and IL-13 was inhibited by the fusion protein CTLA-4Ig, reflecting a requirement for CD80 (B7-1) and/or CD86 (B7-2) costimulation for the expression of the Th2 cytokines. This requirement for B7/CD28 costimulation is consistent with the hypothesis that IL-5 and IL-13 are produced by allergen-specific T cells resident in the asthmatic bronchial mucosa.

The effects of regular inhaled formoterol, budesonide, and placebo on mucosal inflammation and clinical indices in mild asthma

The present study was designed to observe the effects of 8 wk of treatment with formoterol (Foradil) 24 microgram, budesonide 400 microgram, and matched placebo inhaled twice a day on inflammatory indices in the bronchial mucosa of 64 patients with mild atopic asthma. Biopsies were obtained at the start and 1 wk before stopping a 9-wk period of treatment, and inflammatory cell numbers were assessed in the submucosa and epithelium by immunohistochemistry. Regular formoterol significantly reduced the number of submucosal mast cells, with a similar trend for eosinophils but not activated T cells. A subgroup analysis conducted in biopsies with >= 10 eosinophils per mm2 revealed a significant reduction in eosinophil numbers when compared with both pretreatment baseline (p < 0.01) and changes after placebo (p < 0.01). Parallel, but less pronounced, effects were observed on mast cell but not on CD25(+) T cell numbers. There was no effect of any of the three treatments on BAL levels of mast cell or eosinophil mediators. We conclude that regular treatment with inhaled formoterol reduces rather than increases inflammatory cells in the mucosa of asthmatic patients. It is possible that these cellular effects of formoterol may contribute to the therapeutic efficacy of this drug when used regularly in the treatment

Case-control study of salmeterol and near-fatal attacks of asthma

BACKGROUND

A case-control study was undertaken to investigate the hypothesis that the use of the long acting beta agonist salmeterol increases the risk of a near-fatal attack of asthma.

METHODS

The cases comprised admissions to the intensive care unit (ICU) for asthma in 14 major hospitals within the Wessex region in 1992. For each of the cases four age-matched controls were selected from asthma admissions to the same hospital during the same period. Information on prescribed drug therapy for the 48 cases and 185 controls was collected from the hospital admission records.

RESULTS

The patients admitted to the ICU had greater chronic asthma severity and had generally been prescribed more asthma drugs than the control admissions to hospital. The relative risk of a near-fatal attack of asthma in patients prescribed inhaled salmeterol was 2.32 (95% CI 1.05 to 5.16), p = 0.04. However, the salmeterol relative risk decreased to 1.42 (95% CI 0.49 to 4.10), p = 0.52 when the analysis was restricted to the more chronically severe patients (those in the subgroup of patients with a hospital admission for asthma in the previous 12 months). These findings suggest that the increased unadjusted relative risk with salmeterol is predominantly due to confounding by severity--that is, the increased relative risk is due to patients with more severe asthma (at greatest risk of a near-fatal asthma attack) being preferentially prescribed salmeterol. This interpretation is supported by the finding in this study that, within the control group (selected from the population of asthmatics requiring hospital admission), salmeterol was preferentially prescribed to the most severe patients (a threefold greater prescription of salmeterol to control patients if they had been admitted to hospital in the 12 months prior to the index admission). There was no increased risk of a near-fatal attack of asthma in patients prescribed a beta agonist by metered dose inhaler (OR 0.75 (95% CI 0.31 to 1.78), p = 0.51). In contrast, the relative risks for beta agonists delivered by nebulisation (OR 3.86 (95% CI 1.99 to 7.50), p < 0.001) and oral theophylline (OR 2.45 (95% CI 1.26 to 4.78), p < 0.01) were increased and did not markedly decrease when the analysis was restricted to the more severe asthmatic subjects.

CONCLUSIONS

Although these findings are not conclusive, particularly because of the small numbers involved in some subgroup analyses, they suggest that the use of salmeterol by patients with chronic severe asthma is not associated with a significantly increased risk of a near-fatal attack of asthma. If a near-fatal asthma attack is considered to be an intermediate step in a process by which a severe attack of asthma may become fatal, these results would suggest that salmeterol is unlikely to be associated with an increased risk of death, at least by this mechanism.

Cultured nasal polyps from nonatopic and atopic patients release RANTES spontaneously and after stimulation with phytohemagglutinin

BACKGROUND

Eosinophil infiltration of tissue is a hallmark of nasal polyposis in both nonatopic and atopic patients. These cells are thought to play a key role in the nasal polyp inflammatory process.

OBJECTIVE

The objective of this study was to investigate whether cultured nasal polyps derived from nonatopic and atopic patients release RANTES both spontaneously and after phytohemagglutinin (PHA) stimulation.

METHODS

Nasal polyps were obtained from 12 subjects (6 nonatopic and 6 atopic), cut into 2 to 3 mm large specimens, and cultured for 48 hours with or without PHA. RANTES was measured in the culture supernatant by ELISA (R&D Systems, U.K.).

RESULTS

Immunoreactive RANTES was found to be present in the culture supernatant of nasal polyps derived from both nonatopic and atopic patients with no difference between the two groups (median: 3.8 vs 2.9 pg/mg/ml). On incubation with PHA, nasal polyps from both nonatopic and atopic patients released sevenfold and 11-fold greater amounts of RANTES than unstimulated samples. As determined by immunohistochemistry, RANTES was localized to the vascular endothelium in nasal polyps from both groups of patients.

CONCLUSIONS

This study demonstrates that cultured nasal polyps derived from both nonatopic and atopic patients release RANTES spontaneously and after PHA stimulation. This observation and the finding that RANTES is present in nasal polyp endothelial cells suggest that this chemokine may be an important mediator of eosinophil and lymphocyte recruitment in both nonatopic and atopic nasal polyposis.

Effects of ozone on epithelium and sensory nerves in the bronchial mucosa of healthy humans

Neuropeptides released from sensory nerves during inflammation have potent effects on bronchomotor tone, airway secretion, and inflammatory cells. We investigated the effects of ozone on sensory nerves by exposing 12 healthy, nonsmoking subjects to 0.2 ppm ozone and filtered air (FA) for 2 h on separate occasions, with intermittent exercise and rest. Spirometry was performed at baseline and 15 min after exposures, and bronchoscopy (bronchial biopsy and bronchoalveolar lavage [BAL]) was done 6 h after exposure. Frozen sections were immunostained for the anatomic neural marker protein gene peptide (PGP) 9.5 and the sensory neutropeptides substance P (SP) and calcitonin-gene-related peptide (CGRP). Nerves in the submucosa were quantified by image analysis. A trend toward an increase in the levels of polymorphonuclear leukocytes (PMNs) (air versus ozone, median [interquartile range]: 3.5 [2 to 5.3%] versus 9.8 [4.2 to 16.3%], p = 0.07) and ciliated epithelial cells (median [interquartile range]: 1.6 [1.3 to 3.4%] versus 5 [2.2 to 9.8%], p = 0.05) was observed in the BAL fluid (BALF). There was a significant decrease in SP immunoreactivity following ozone exposure (median [interquartile range]: 0.6 [0.05 to 1.2] versus 0.15 [0.08 to 0.18], p < 0.05). A significant inverse correlation was observed between SP immunoreactivity and: (1) percent PMNs and ciliated epithelial cells in the BALF; and (2) percent change in FEV1 following exposure to ozone. These findings indicate that short-term exposure to 0.2 ppm ozone causes epithelial shedding and stimulates subepithelial sensory nerves to release SP into the airways. The release of SP could contribute to bronchoconstriction and subsequent neutrophil infiltration into the airways.

Short-term ozone exposure upregulates P-selectin in normal human airways

Short-term exposure to ambient levels of ozone induces neutrophilic bronchitis. To investigate the early events contributing to inflammatory cell recruitment in the airways we exposed 12 healthy nonsmoking volunteers to 0.12 ppm ozone or filtered air for 2 h on two separate occasions. Spirometry and fiberoptic bronchoscopy were performed immediately and at 1.5 h after the two exposures, respectively. Total protein, albumin, and total and differential cell counts were performed on the bronchial wash and BAL fluid. Bronchial biopsies were embedded in glycol methacrylate and immunostained for inflammatory cells, including neutrophils, mast cells, total T-cells (CD3), T-cell subset CD8, and leukocyte endothelial adhesion molecules, including VCAM-1, ICAM-1, E-selectin, and P-selectin. No significant changes were observed in FEV1, FVC, or any inflammatory indices in the bronchial wash and BAL fluid. In addition, no significant differences were seen in inflammatory cell numbers or percentages of vessels expressing VCAM-1, E-selectin, or ICAM-1 in the biopsies. The percentage of vessels expressing P-selectin increased significantly after ozone exposure: p = 0.016; median (IQR), 28.76 (26.36-36.94) versus 47.06 (38.14-56.86)%. The upregulation of P-selectin could signify an early inflammatory response to ozone such as margination and rolling of the neutrophils on the vessel wall prior to transendothelial migration.

The effect of treatment with oral corticosteroids on asthma symptoms and airway inflammation

To improve understanding of the mechanisms of action of oral corticosteroids in asthma, we have conducted a double-blind, placebo-controlled study with prednisolone (20 mg for 2 wk followed by 10 mg for 4 wk) or placebo in 14 and 13 atopic corticosteroid-naive asthmatic subjects, respectively. Before and after treatment subjects underwent bronchoscopy with bronchoalveolar lavage (BAL) and bronchial biopsy. Treatment with prednisolone, but not placebo, significantly reduced asthma symptoms (from mean +/- SEM total weekly score of 34 +/- 6.2 to 15.7 +/- 3.2, p = 0.02) and albuterol usage (from mean +/- SEM number of puffs/wk of 29.7 +/- 6.2 to 18.2 +/- 3.7, p = 0.01) and significantly increased FEV1 (from 89.8 +/- 4.4% to 99.3 +/- 4.1% of predicted, p = 0.03). There were no significant changes in inflammatory or epithelial cell counts, levels of T-cell activation or albumin concentration in BAL. However, immunohistochemistry of bronchial biopsies showed that in the submucosa prednisolone significantly decreased numbers of mast cells by 62% (from median 45 to 17/mm2, p = 0.01), eosinophils by 81% (from median 30.1 to 5.7/mm2, p = 0.004), and CD4+ T-cells by 68% (from median 64.6 to 18.5/mm2, p = 0.02). In the epithelium only the reduction in the numbers of eosinophils was significant (from median 1.1 to 0/mm of epithelium, p = 0.02). There were no significant changes in any cell counts in the subjects receiving placebo, and comparison of the changes between the treatment groups identified a significant prednisolone-related reduction in submucosal eosinophil and mast cell counts (p = 0.003 and 0.03, respectively). The temporal association between the clinical and physiologic improvement, and the correlation between the magnitude of change in CD4+ T-cell counts in the submucosa and increase in PC20 methacholine (rs = 0.60, p = 0.049) suggests that the reduction in airways inflammatory cell numbers underlies the clinical efficacy of oral corticosteroids.

The effect of intravenous administration of a chimeric anti-IgE antibody on serum IgE levels in atopic subjects: efficacy, safety, and pharmacokinetics

CGP 51901 is a non-anaphylactogenic mouse/human chimeric anti-human IgE antibody that binds to free IgE and surface IgE of IgE-expressing B cells but not to IgE bound to high affinity IgE receptors (Fc epsilonR1) on mast cells and basophils or low affinity IgE receptors (Fc epsilonR2) on other cells. A phase 1 double-blind, placebo-controlled, single dose study with doses of 3, 10, 30, and 100 mg of CGP 51901 was conducted in 33 pollen-sensitive subjects who had raised levels of serum IgE and received either intravenous CGP 51901 or placebo. The administration of CGP 51901 was well tolerated and resulted in a decrease of serum free IgE levels in a dose-dependent manner, with suppression after 100 mg of CGP 51901 reaching > 96%. Time of recovery to 50% of baseline IgE correlated with the dose of administered antibody and ranged from a mean of 1.3 d for the 3 mg to 39 d for the 100 mg dose. Total IgE, comprised of free and complexed IgE, increased as stored and newly synthesized IgE bound to CGP 51901. Complexed IgE was eliminated at a rate comparable with the terminal half-life of free CGP 51901 (11-13 d at all doses). Only one subject showed a weak antibody response against CGP 51901. We conclude that the use of anti-human IgE antibody is safe and effective in reducing serum IgE levels in atopic individuals and provides a potential therapeutic approach to the treatment of atopic diseases.

Phenotypic characterization of T cells infiltrating the conjunctiva in chronic allergic eye disease

BACKGROUND

Chronic allergic conjunctivitis comprises a spectrum of diseases including atopic keratoconjunctivitis, atopic blepharoconjunctivitis, vernal keratoconjunctivitis, and contact lens-associated giant pupillary conjunctivitis. Each condition is characterized by a complex immunopathology with a mixed cellular infiltrate. Treatment with conventional mast cell stabilizers is often unsatisfactory, and therapy depends heavily on topical corticosteroids.

OBJECTIVE

Recent evidence suggests that T lymphocytes play an important role in mediating the immunopathology seen in the chronic allergic response in the skin and the lungs.

METHODS

We have therefore investigated the prevalence of T cells and their subsets in the different chronic allergic eye conditions by means of immunohistochemistry.

RESULTS

We found significantly increased numbers of CD4+, CD45RO+, and HLA-DR+ T cells in the conjunctiva of patients with atopic and vernal keratoconjunctivitis and giant papillary conjunctivitis, with a corresponding upregulation of markers present on antigen presenting cells.

CONCLUSIONS

These findings suggest that like allergic conditions in the skin and lungs, CD4+ memory T cells are involved in the regulation of the immunopathology of chronic allergic eye responses. Further characterization of these T cells will provide the information necessary for future immunotherapeutic interventions.

Eosinophil recruitment following allergen challenge is associated with the release of the chemokine RANTES into asthmatic airways

Eosinophil infiltration of the airways in response to allergen exposure is a characteristic of bronchial asthma. However, the mechanisms by which these cells are recruited are poorly understood. We have investigated the presence of eosinophil chemotactic activity (ECA) in bronchoalveolar lavage fluid obtained from allergic asthmatics (n = 6) 4 h after endobronchial allergen challenge. ECA was purified by sequential heparin affinity chromatography and reverse-phase HPLC. A single peak of ECA was detected; SDS-PAGE and Western blot analysis showed that the peak contained a protein of 8 kDa and corresponded to the chemokine RANTES (regulated upon activation, normal T cell expressed and secreted). Consistent with this, the ECA was neutralized by an Ab to RANTES. Measurement of RANTES by ELISA in 10x concentrated bronchoalveolar lavage fluid showed increased levels of this chemokine at the allergen site (median, 187 pg/ml; range, 46-263 pg/ml) in comparison with a saline challenge control site (median, 32.5 pg/ml; range, 11-94 pg/ml), P < 0.005. Furthermore, there was a significant correlation between concentrations of immunoreactive RANTES and the number of eosinophils at the allergen challenge site (r = 0.8; p < 0.001), but not at the saline site (r = 0.2; p = 0.12). These results suggest that RANTES in involved in the recruitment of eosinophils into the asthmatic airways after allergen challenge.

Eosinophil recruitment following allergen challenge is associated with the release of the chemokine RANTES into asthmatic airways

Eosinophil infiltration of the airways in response to allergen exposure is a characteristic of bronchial asthma. However, the mechanisms by which these cells are recruited are poorly understood. We have investigated the presence of eosinophil chemotactic activity (ECA) in bronchoalveolar lavage fluid obtained from allergic asthmatics (n = 6) 4 h after endobronchial allergen challenge. ECA was purified by sequential heparin affinity chromatography and reverse-phase HPLC. A single peak of ECA was detected; SDS-PAGE and Western blot analysis showed that the peak contained a protein of 8 kDa and corresponded to the chemokine RANTES (regulated upon activation, normal T cell expressed and secreted). Consistent with this, the ECA was neutralized by an Ab to RANTES. Measurement of RANTES by ELISA in 10x concentrated bronchoalveolar lavage fluid showed increased levels of this chemokine at the allergen site (median, 187 pg/ml; range, 46-263 pg/ml) in comparison with a saline challenge control site (median, 32.5 pg/ml; range, 11-94 pg/ml), P &lt; 0.005. Furthermore, there was a significant correlation between concentrations of immunoreactive RANTES and the number of eosinophils at the allergen challenge site (r = 0.8; p &lt; 0.001), but not at the saline site (r = 0.2; p = 0.12). These results suggest that RANTES in involved in the recruitment of eosinophils into the asthmatic airways after allergen challenge.

Osteocalcin, growth, and inhaled corticosteroids: a prospective study

OBJECTIVES

To determine the relationship between biochemical markers of bone metabolism and statural growth, and their suitability as surrogate markers of inhaled corticosteroid induced growth suppression.

DESIGN

Randomised, double blind, placebo controlled comparison of inhaled beclomethasone dipropionate 200 micrograms twice daily as dry powder for six months.

SETTING

Southampton.

OUTCOME MEASURES

Serum osteocalcin, urinary deoxypyridinoline, and statural growth.

SUBJECTS

7 to 9 year old children with recurrent wheeze.

RESULTS

There were no significant differences in serum osteocalcin between the beclomethasone dipropionate and placebo group measured at baseline or after three and six months' treatment, while deoxy-pyridinoline was significantly higher in the placebo treated children after three months. Growth was significantly decreased in the beclomethasone dipropionate group over the course of the study. Growth over the six months, both in those receiving beclomethasone dipropionate and those receiving placebo, was significantly correlated with serum osteocalcin measured at three months and six months.

CONCLUSION

Although serum osteocalcin shows excellent correlation with growth, it is a poor marker for decreased growth associated with use of inhaled corticosteroids.

Induction of nitric oxide synthase in asthma

Nitric oxide (NO) is a mediator of vasodilatation and bronchodilatation synthesised from L-arginine by the enzyme NO synthase, which is either constitutive or induced by lipopolysaccharides and/or cytokines. The presence and function of NO synthase in normal or diseased lung is not yet clear. Asthma is characterised by bronchial hyperresponsiveness, epithelial damage, inflammation, and increased cytokine production. To investigate the presence of NO synthase in asthma, we immunostained bronchial biopsies from non-steroid-treated people with asthma and non-asthmatic controls with specific polyvalent antisera to purified inducible NO synthase and to a selected peptide sequence of the same enzyme. Immunoreactivity was seen in the epithelium and some inflammatory cells in 22 of 23 biopsies from people with asthma, but in only 2 of 20 controls. To assess the relation of cytokines to NO synthase induction, bronchial epithelial cells in culture were stimulated with tumour necrosis factor (TNF alpha). Inducible enzyme immunoreactivity was found only in the treated cells. The existence of inducible NO synthase in human lungs suggests that increased production of NO, probably induced by cytokines, may be relevant to the pathology of asthma.

Investigative use of fibreoptic bronchoscopy for local airway challenge in asthma

Local airway challenge has advantages over inhalation bronchial challenge as the response of the airway can be restricted and directly observed. It has been safely performed in subjects with mild or moderate asthma, either by the direct instillation of challenge solution to the selected segmental airways via a bronchoscope, or delivered to an airway segment isolated with a double-balloon catheter. However, these techniques carry potential complications, such as generalized wheeze, and due care is required in selection of subjects. Most investigators have used the method for studying the airway events following allergen challenge. Others have studied the airway changes following challenge with non-allergen provocation agents, such as hypertonic saline, adenosine 5'-monophosphate and cold dry air. The method has helped to define changes in the inflammatory cells and mediators in relation to early and late airway responses to allergen. Similarly, study of airway events following local challenge with hypertonic solution has provided useful knowledge in understanding the mechanisms of exercise-induced asthma. With more experience and an improved margin of safety, it will be possible to study local changes in airway physiology following local airway challenge. Finally, the techniques also have potential use for studying the airway events following provocation with a wide range of agents of potential relevance to the pathogenesis of asthma.

Investigative use of fibreoptic bronchoscopy for local airway challenge in asthma

Local airway challenge has advantages over inhalation bronchial challenge as the response of the airway can be restricted and directly observed. It has been safely performed in subjects with mild or moderate asthma, either by the direct instillation of challenge solution to the selected segmental airways via a bronchoscope, or delivered to an airway segment isolated with a double-balloon catheter. However, these techniques carry potential complications, such as generalized wheeze, and due care is required in selection of subjects. Most investigators have used the method for studying the airway events following allergen challenge. Others have studied the airway changes following challenge with non-allergen provocation agents, such as hypertonic saline, adenosine 5'-monophosphate and cold dry air. The method has helped to define changes in the inflammatory cells and mediators in relation to early and late airway responses to allergen. Similarly, study of airway events following local challenge with hypertonic solution has provided useful knowledge in understanding the mechanisms of exercise-induced asthma. With more experience and an improved margin of safety, it will be possible to study local changes in airway physiology following local airway challenge. Finally, the techniques also have potential use for studying the airway events following provocation with a wide range of agents of potential relevance to the pathogenesis of asthma.

Mediator and cytokine mechanisms in asthma

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Respiratory symptoms in children at schools near a foundry

A survey was carried out in response to complaints of increased respiratory symptoms in children at schools near a foundry in Walsall, West Midlands. Air monitoring around the factory had shown concentrations of formaldehyde most of which were orders of magnitude below the current occupational exposure limit of 2.5 mg/m3, although concentrations up to 0.3 mg/m3 had been recorded over short periods. The study sample comprised children aged 6.8-7.8 years from 39 schools in the borough. Information about respiratory symptoms and potential risk factors for respiratory disease was elicited from parents by a self administered questionnaire. Data were obtained on 1334 children, a response rate of 81.8%. The prevalences of reported wheeze (11.1%), breathlessness (7.7%), and chest discomfort (8.6%) were similar to those in an earlier survey carried out in Southampton by the same method at the same time of year. Cough (prevalence = 18.4%) and chestiness at night (14.6%) were significantly less common than in Southampton. When sex, social class, housing tenure, passive smoking, and parental history of asthma were taken into account, the prevalences of symptoms at schools within one mile of the foundry were generally lower than in other parts of Walsall. These findings give no support to the hypothesis that foundry emissions cause respiratory disease in children, although an adverse effect in a few sensitive children cannot be ruled out.