6. Asthma

Effects of inhaled fluticasone on angiogenesis and vascular endothelial growth factor in asthma

BACKGROUND

Subepithelial hypervascularity and angiogenesis in the airways are part of structural remodelling of the airway wall in asthma, but the effects of inhaled corticosteroids (ICS) on these have not been explored. Increased vascularity in asthma may contribute to a number of functional abnormalities. A study was undertaken to explore angiogenic modulation by ICS and its likely regulation via vascular endothelial growth factor (VEGF), its receptors and the angiopoietins.

METHODS

A placebo-controlled intervention study with ICS in asthma was performed, examining vascularity, VEGF, its receptors (VEGFR1 and VEGFR2), and angiopoietin-1 (Ang1) to assess which of these factors were changed in the asthmatic airways after ICS treatment. Airway wall biopsy specimens, lavage fluid and cells were obtained from 35 patients with mild asthma randomised to receive ICS or placebo for 3 months, after which bronchoscopic examination and sample collection were repeated. Immunohistochemistry and image analysis were used to obtain quantitative measures of vessels, angiogenic sprouts, VEGF, VEGFR1, VEGFR2 and Ang1 staining in airway biopsy specimens. ELISA was used to assess VEGF concentrations in the lavage fluid.

RESULTS

Vessel, VEGF and sprout staining were decreased after 3 months of ICS treatment. VEGF levels remained unchanged. VEGF receptors and Ang1 staining were not reduced after treatment.

CONCLUSIONS

The findings of this study support an effect of ICS in downregulating angiogenic remodelling in the airways in asthma, associated with decreasing VEGF activity within the airway wall. The environment of the airways after treatment with ICS, with changes in the balance between VEGF, its receptors, Ang1 and sprouts, appears to be less angiogenic than in untreated asthma.

"Stress knocks hard on your immune system": asthma and the discourse on stress

Stress has been described by anthropologists and other scholars as a problematic concept, a discourse, a modern metaphor, a collective representation, and a cultural resource. The vast array of academic work in the arena of stress research belies the historical reality of stress as an object of inquiry; rather, stress is presented as new, the story of its emergence intermingled with processes of industrialization, individualism, and perceptions of modern life. This article traces the uses to which the concept of stress is put in the illness narratives of persons with asthma. It argues that multiple invocations of stress not only make visible the workings of personal responsibility and individualism regarding chronic illness management in the contemporary United States but also gesture toward the social relations of sickness that lie beyond individual control.

Does the combination of inhaled steroids with long acting beta2 agonists decrease the risk for osteoporosis? A 1-year prospective follow-up study

Combination of inhaled corticosteroids (ICS) with long acting beta2 agonists has been used increasingly in the treatment of moderate-severe asthma, however there is indefinitive data about their effect on bone loss. The aim of this study was to compare the effects of treatment with single ICS and combination of ICS with long acting beta2 agonists (combination therapy) on BMD and biomarkers of bone metabolism in adult patients with asthma over 1 year period. Forty-three patients with asthma were enrolled. Patients were separated into two groups according to their use of asthma drugs: single ICS or combination therapy (ICS plus long-acting inhaled beta2-agonist). Change in bone mineral density (BMD) and biochemical markers of bone metabolism were measured at baseline and at the end of 1 year. Mean ages and basal BMD of patients did not differ between the two groups (P > 0.05). The decrease in BMD was higher in the single ICS group than the combination therapy group, however there was no significant difference between them (P > 0.05). One year change (%) in BMD and biochemical markers of bone metabolism were not different between two groups (P > 0.05). In conclusion, use of ICS-in the range of doses used- does not seem to have an effect on the change of BMD. However, our data indicate a nonsignificant trend towards reducing bone loss with the use of combination therapy. Future studies are needed to provide definitive evidence for this trend to allow us suggesting combination therapy for minimizing bone loss.

Primary prevention of asthma: age and sex influence sensitivity to allergen-induced airway inflammation and contribute to asthma heterogeneity in Guinea pigs

BACKGROUND

Limiting allergen exposure in the sensitization phase has been proposed as a means of primary prevention of asthma, but its effectiveness is debated.

HYPOTHESIS

Primary prevention of asthma is more effective in limiting asthma symptoms in young guinea pigs compared with adults, whether males or females.

METHODS

The following experimental groups were used: young/young, sensitized and challenged before sexual maturity; young/adult, sensitized young and challenged after sexual maturity; adult/adult, sensitized and challenged after sexual maturity. Males and females were sensitized intraperitoneally with varying doses of ovalbumin (OVA) and challenged intratracheally with a constant OVA dose. Cellular infiltration into lung and lavage fluid as well as airway hyperresponsiveness to intravenous methacholine was determined 24 h later.

RESULTS

In unsensitized animals, density of resident inflammatory cells as well as baseline pulmonary function differed with age and sex. Maximum OVA-induced eosinophilia in females occurred at a lower sensitizing dose of OVA than in males, and the slopes of the dose-response relationship differed significantly between sexes. Young females had more pronounced increases in eosinophils compared with some adult treatment groups. The concentrations of OVA-specific antibodies were not directly related to differences in cellular infiltration. Airway hyperresponsiveness to methacholine challenge was observed in all treatment groups.

CONCLUSION

Young animals require major reductions in allergen exposure compared with adults to effectively limit airway inflammation in primary prevention. Heterogeneity of asthma symptoms seen with age and sex suggests that primary prevention by limiting allergen exposure or treatment with anti-inflammatory or bronchodilator drugs may be more effective strategies for specific age and gender populations.

Association of depressive symptoms and disease activity in children with asthma: methodological and clinical implications

OBJECTIVE

This study was designed to assess the prevalence of depressive symptoms in children with asthma and the association between depression and asthma activity.

METHOD

Children ages 7 to 17 (n = 129) were recruited from a hospital emergency department after presenting for asthma symptoms. The majority of subjects were from disadvantaged, inner city families. Subjects' asthma disease activity was assessed using the revised National Heart, Lung, and Blood Institute guidelines, and subjects' emotional status was assessed by a combination of self-, parent-, and clinician-reported measures. Parental emotional status was assessed by self-report.

RESULTS

Depressive symptoms within the clinical range were reported in 26% of subjects and 43% of mothers, although symptom severity varied across scales. Self-reported depressive symptoms were more strongly correlated with asthma activity (r = 0.25) than clinician-reported (r = 0.14) or parent-reported symptoms (r = 0.12/0.18). Depressive symptoms in parents were correlated with child's depression scores but not with their asthma activity.

CONCLUSIONS

Depressive symptoms were common and associated with asthma activity in this inner city population of asthmatic children. Self-reported depressive symptoms were more strongly associated with child's asthma activity than either parental depression or parental/clinician ratings of the child's depression.

Clinical evaluation of the Chinese herbal medicine formula STA-1 in the treatment of allergic asthma

Although some formulae of traditional Chinese medicines (TCM) have been used for antiasthma treatment, few of them have had sufficient discussion on their efficacy, safety and mechanisms. In this study, the availability of the TCM formula STA-1 for the treatment of allergic asthma was investigated by conducting a double-blind, placebo-controlled and randomized trial. One hundred and twenty patients between the ages of 5 to 20 years with mild-to-moderate asthma were included. These patients were treated with either STA-1 or placebo in a dose of 80 g/kg/day and were administered twice daily for 6 months. The main outcome measures were a daily diary record of symptoms, supplementary bronchodilator and glucocorticoid treatment, changes of pulmonary function (forced expiratory volume in 1 s), changes of total and Dermatophagoides pteronyssinus (DP)-specific IgE and side effects. The results showed a statistically significant reduction of symptom scores, systemic steroid dose, total IgE and specific IgE in the STA-1 group. Furthermore, STA-1 also improved the pulmonary lung function FEV(1) compared with the placebo group and only minimal side effects were shown. These results suggested that STA-1 is available for the treatment of mild-to-moderate chronic asthma.

Induction of asthma and the environment: what we know and need to know

The prevalence of asthma has increased dramatically over the last 25 years in the United States and in other nations as a result of ill-defined changes in living conditions in modern society. On 18 and 19 October 2004 the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences sponsored the workshop "Environmental Influences on the Induction and Incidence of Asthma" to review current scientific evidence with respect to factors that may contribute to the induction of asthma. Participants addressed two broad questions: a) What does the science suggest that regulatory and public health agencies could do now to reduce the incidence of asthma? and b) What research is needed to improve our understanding of the factors that contribute to the induction of asthma and our ability to manage this problem? In this article (one of four articles resulting from the workshop), we briefly characterize asthma and its public health and economic impacts, and intervention strategies that have been successfully used to prevent induction of asthma in the workplace. We conclude with the findings of seven working groups that focus on ambient air, indoor pollutants (biologics), occupational exposures, early life stages, older adults, intrinsic susceptibility, and lifestyle. These groups found strong scientific support for public health efforts to limit in utero and postnatal exposure to cigarette smoke. However, with respect to other potential types of interventions, participants noted many scientific questions, which are summarized in this article. Research to address these questions could have a significant public health and economic impact that would be well worth the investment.

Recreational and occupational field exposure to freshwater cyanobacteria--a review of anecdotal and case reports, epidemiological studies and the challenges for epidemiologic assessment

Cyanobacteria are common inhabitants of freshwater lakes and reservoirs throughout the world. Under favourable conditions, certain cyanobacteria can dominate the phytoplankton within a waterbody and form nuisance blooms. Case reports and anecdotal references dating from 1949 describe a range of illnesses associated with recreational exposure to cyanobacteria: hay fever-like symptoms, pruritic skin rashes and gastro-intestinal symptoms are most frequently reported. Some papers give convincing descriptions of allergic reactions while others describe more serious acute illnesses, with symptoms such as severe headache, pneumonia, fever, myalgia, vertigo and blistering in the mouth. A coroner in the United States found that a teenage boy died as a result of accidentally ingesting a neurotoxic cyanotoxin from a golf course pond. This death is the first recorded human fatality attributed to recreational exposure to cyanobacteria, although uncertainties surround the forensic identification of the suspected cyanotoxin in this case. We systematically reviewed the literature on recreational exposure to freshwater cyanobacteria. Epidemiological data are limited, with six studies conducted since 1990. Statistically significant increases in symptoms were reported in individuals exposed to cyanobacteria compared to unexposed counterparts in two Australian cohort studies, though minor morbidity appeared to be the main finding. The four other small studies (three from the UK, one Australian) did not report any significant association. However, the potential for serious injury or death remains, as freshwater cyanobacteria under bloom conditions are capable of producing potent toxins that cause specific and severe dysfunction to hepatic or central nervous systems. The exposure route for these toxins is oral, from ingestion of recreational water, and possibly by inhalation.A range of freshwater microbial agents may cause acute conditions that present with features that resemble illnesses attributed to contact with cyanobacteria and, conversely, acute illness resulting from exposure to cyanobacteria or cyanotoxins in recreational waters could be misdiagnosed. Accurately assessing exposure to cyanobacteria in recreational waters is difficult and unreliable at present, as specific biomarkers are unavailable. However, diagnosis of cyanobacteria-related illness should be considered for individuals presenting with acute illness following freshwater contact if a description is given of a waterbody visibly affected by planktonic mass development.

Differential regulation of neurotrophin expression in human bronchial smooth muscle cells

Background

Human bronchial smooth muscle cells (HBSMC) may regulate airway inflammation by secreting cytokines, chemokines and growth factors. The neurotrophins, including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), have been shown to be elevated during airway inflammation and evoke airway hyperresponsiveness. We studied if HBSMC may be a source of NGF, BDNF and NT-3, and if so, how inflammatory cytokines may influence their production.

Methods

Basal and cytokine (IL-1β, IFN-γ, IL-4)-stimulated neurotrophin expression in HBSMC cultured in vitro was quantified. The mRNA expression was quantified by real-time RT-PCR and the protein secretion into the cell culture medium by ELISA.

Results

We observed a constitutive NGF, BDNF and NT-3 expression. IL-1β stimulated a transient increase of NGF, while the increase of BDNF had a later onset and was more sustained. COX-inhibitors (indomethacin and NS-398) markedly decreased IL-1β-stimulated secretion of BDNF, but not IL-1β-stimulated NGF secretion. IFN-γ increased NGF expression, down-regulated BDNF expression and synergistically enhanced IL-1β-stimulated NGF expression. In contrast, IL-4 had no effect on basal NGF and BDNF expression, but decreased IL-1β-stimulated NGF expression. NT-3 was not altered by the tested cytokines.

Conclusion

Taken together, our data indicate that, in addition to the contractile capacity, HBSMC can express NGF, BDNF and NT-3. The expression of these neurotrophins may be differently regulated by inflammatory cytokines, suggesting a dynamic interplay that might have a potential role in airway inflammation.

Cutaneous, but not airway, latex exposure induces allergic lung inflammation and airway hyperreactivity in mice

As respiratory symptoms are common in addition to skin reactions in natural rubber latex allergy, we investigated the significance of different allergen exposure routes in the development of lung inflammation and airway hyperreactivity (AHR). Both intracutaneous (IC) and intraperitoneal (IP) exposure followed by airway challenge with latex proteins induced an influx of mononuclear cells and eosinophils to the lungs. AHR and lung mucus production increased significantly after IC and IP but not after intranasal (IN) exposure. Infiltration of inflammatory cells was associated with the induction of T-helper type 2 (Th2) cytokines and several CC chemokines. Only a marginal induction of these mediators was found after IN exposure. On the contrary, increased levels of transforming growth factor-beta1 and forkhead box 3 mRNA, markers of regulatory activities, were found in the lungs after IN but not after IC exposure. Finally, IC and IP, but not IN, latex exposure induced a striking increase in specific immunoglobulin E (IgE) levels. Cutaneous latex exposure in the absence of adjuvant followed by airway challenge induces a local Th2-dominated lung inflammation and a systemic IgE response. Cutaneous exposure to proteins eluting from latex products may therefore profoundly contribute to the development of asthma in latex allergy.

Antimicrobial therapy in childhood asthma and wheezing

There is an increasing number of viral and bacterial pathogens suspected of contributing to asthma pathogenesis in childhood, making it more difficult for the practitioner to make specific therapy decisions. This review discusses the role of viruses, e.g. respiratory syncytial virus, human metapneumovirus, influenza viruses and rhinoviruses, as well as the role of the atypical bacteria Chlamydophila pneumoniae and Mycoplasma pneumoniae, as contributors to childhood asthma. Diagnosis, prevention, and therapy are discussed, including a summary of drugs, i.e. macrolide antibacterials, antivirals, and vaccine regimens already available, or at least in clinical trials. For the practitioner dealing with patients every day, drug regimens are assigned to the individual pathogens and an algorithm for the management of atypical infections in patients with asthma or recurrent wheezing is presented.

Exhaled nitric oxide and bronchial wall thickening in asthmatics during and after acute exacerbation: evidence of bronchial wall remodeling

To assess whether bronchial wall thickening during asthma exacerbations is due to active inflammation in severe asthmatics, we measured bronchial wall thickness and exhaled nitric oxide (FeNO) following treatment. Nine asthmatics were compared with seven controls with high-resolution computed tomography, spirometry, and FeNO measurements. The asthmatic bronchial wall area percent and FeNO was greater than controls. Following treatment, the FEV1 markedly improved, FeNO decreased modestly, and bronchial wall area percent did not change significantly. Bronchial wall thickening persisted after treatment of acute asthma exacerbation despite improvement in spirometry and decline in FeNO, possibly due to chronic airway remodeling.

Association of asthma-related symptoms with snoring and apnea and effect on health-related quality of life

OBJECTIVES

This study aimed to investigate the association of asthma-related symptoms with snoring and apnea, and to assess their effects on health-related quality of life (HRQL).

DESIGN

Population-based cross-sectional study.

SUBJECTS AND METHODS

A total of 10,224 parents and grandparents of students from 14 randomly selected primary schools in city center were asked to answer questionnaires sent by their children. All subjects were questioned for asthma-related symptoms, sleep-related disorders (snoring and apnea), and for HRQL using the Respiratory Questionnaire, Sleep and Health Questionnaire, and Short Form-12 (SF-12) Health Survey, respectively.

RESULTS

The overall response rate to questionnaires was 97.7%, and all analysis was performed on 7,469 subjects (3,920 women and 3,549 men) who provided sufficient responses to questions. There were 2,713 subjects who reported asthma-related symptoms. The snoring and the observed apnea were more prevalent in subjects with asthma-related symptoms (54.0% vs 41.4%; odds ratio [OR], 1.7; 95% confidence interval [CI], 1.5 to 1.8; p < 0.001) than those without asthma-related symptoms (16.7% vs 7.0%; OR, 2.7; 95% CI, 2.3 to 3.1; p < 0.001), respectively. Asthma-related symptoms were found to be associated with snoring (OR, 1.5; 95% CI, 1.3 to 1.6; p < 0.001) and observed apnea (OR, 2.2; 95% CI, 1.8 to 2.5; p < 0.001) after adjusting for gender, age, body mass index, income, education, and smoking. Also, HRQL was found to be adversely affected by asthma-related symptoms, snoring, and observed apnea (beta = - 0.26, p < 0.001; beta = - 0.07, p < 0.001; and beta = - 0.08, p < 0.001, respectively, for SF-12 overall score) after adjusting for other confounding factors.

CONCLUSION

Present data suggest that there is a link between the sleep-related breathing disorders and asthma-related symptoms. Moreover, the presence of snoring and observed apnea in individuals with asthma-related symptoms causes further impairment in HRQL. The effects on HRQL of coexistence of these three disorders should be supported by clinical studies.

Exhaled nitric oxide in paediatric asthma

Assessment of airway function is difficult in young children with asthma, and in addition, only reflects the status of the disease at the time of the measurement. Thus, there is increasing interest in monitoring airway inflammation in asthma, which may provide a longer term assessment of disease activity. Most methods of assessing asthmatic inflammation are invasive, and are not feasible in the paediatric population. This review discusses exhaled nitric oxide as a marker of asthmatic inflammation, and compares it with other recognized markers. Exhaled nitric oxide has the potential to become a noninvasive method of assessing asthma control in the paediatric population.

Sudden death due to asphyxia by esophageal polyp: two case reports and review of asphyxial deaths

Asphyxia, not an uncommon cause of sudden death, may result from numerous etiologies. Foreign-body aspiration and strangulation are 2 extrinsic causes. Airway obstruction may also be caused by laryngeal edema, asthma, infection, or anaphylaxis. Chronic causes of asphyxia include musculoskeletal diseases (eg, muscular dystrophy, amyotrophic lateral sclerosis), neurologic disorders (eg, myasthenia gravis, multiple sclerosis), respiratory disease (eg, emphysema, chronic bronchitis), or tumors. The manner of death in cases of asphyxiation may be natural, accidental, homicide, or suicide. For the death investigator, determining the cause and manner of death can often be quite challenging. We report here 2 cases of an esophageal fibrovascular polyp causing sudden asphyxial death, review of the literature, and discussion of other differential diagnoses in the case of asphyxial death.

Bronchodilator activity of Phymatodes scolopendria (Burm.) Ching and its bioactive constituent

Phymatodes scolopendria (Burm.) Ching (Polypodiaceae) is widely used in the Eastern coast of Madagascar to treat respiratory disorders. Bioassay-guided fractionation using guinea pig trachea pre-contracted with histamine to monitor the activity led to the isolation of 1,2-benzopyrone (coumarin) as the main active constituent. Effectively, it induced a concentration-dependent relaxation of the histamine with a median effective concentration (EC(50)) of 35.03 microg/ml, or carbachol (EC(50) = 33.41 microg/ml) pre-contracted guinea pig trachea, and also provoked 100% relaxation at 72.10 microg/ml. It was less active either on KCl pre-contracted trachea (EC(50) = 130.78 microg/ml) or endothelium denuded trachea (153.4 +/- 22 microg/ml). It inhibited, in a non-competitive manner, the histamine and the external calcium spasm effect on the isolated trachea but it did not significantly modify the broncho-constrictive activity of KCl. When combined with theophylline, coumarin produced a significant additive relaxing effect on pre-contracted trachea. Furthermore, its bronchodilator effect was not blocked by propranolol. In vivo, pre-treated guinea pig with coumarin showed significant resistance to histamine inhalation, with an adequate dose protecting 50% of the tested animals (AD(50)) of 75 mg/kg. These results indicate that the bronchodilator effect of coumarin is partly due to the endothelium-dependent tracheal relaxation, and may be mediated through a non-specific tracheal relaxation.

CD38 expression is insensitive to steroid action in cells treated with tumor necrosis factor-alpha and interferon-gamma by a mechanism involving the up-regulation of the glucocorticoid receptor beta isoform

Evidence shows that the CD38 molecule, recently involved in the two main features of asthma, bronchial hyper-responsiveness and airway inflammation, could represent a new potential therapeutic target for asthma. In this study, we investigated whether glucocorticoid (GC), the most effective treatment for lung diseases, can affect CD38 expression in human airway smooth muscle (ASM) cells treated with different pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNFalpha) and interferons (IFNs). We found that CD38 expression induced by TNFalpha alone was completely abrogated by fluticasone (100 nM), dexamethasone (1 microM), or budesonide (100 nM). In contrast, the synergistic induction of CD38 by the combination of TNFalpha with IFNgamma or IFNbeta, but not with IL-1beta or IL-13, was completely insensitive to the GC inhibitory effects. We also found that TNFalpha and IFNgamma impaired GC responsiveness by inhibiting steroid induced both 1) GRalpha-DNA binding activity and 2) GC-responsive element-(GRE)-dependent gene transcription. Although levels of the GC receptor (GR) alpha isoform remained unchanged, expression of GRbeta, the dominant-negative GR isoform, was synergistically increased by TNFalpha and IFNgamma with a GRalpha/GRbeta ratio of 1 to 3. More importantly, fluticasone failed to induce GRE-dependent gene transcription and to suppress TNFalpha-induced CD38 expression in ASM cells transfected with constitutively active GRbeta. We conclude that, upon pro-inflammatory cytokine stimulation, CD38 expression becomes insensitive to GC action by a mechanism involving the up-regulation of GRbeta isoform, thus providing a novel in vitro cellular model to dissect GC resistance in primary cells.

The beta-agonist isoproterenol attenuates EGF-stimulated wound closure in human airway epithelial cells

Asthma is a disease characterized by reversible airway obstruction. An additional hallmark of chronic asthma is altered wound healing that leads to airway remodeling. Although beta-agonists are effective in treating the bronchospasm associated with asthma, their effects on airway wound healing, which are related to airway remodeling, are unknown. It has been demonstrated that beta-agonists can alter the signaling of epidermal growth factor (EGF) receptors, which are important in timely wound healing. Therefore, we hypothesized that the beta-agonist isoproterenol would affect wound healing. Using an in vitro scrape wound assay, we demonstrated that isoproterenol attenuates EGF-stimulated wound healing in 16HBE airway epithelial cell cultures. Through experiments with forskolin and cells overexpressing beta2-adrenergic receptor-yellow fluorescent protein, we show that attenuation is due to the accumulation of cAMP and the involvement of at least one additional pathway. Furthermore, attenuation is not due to a direct effect on the EGF receptor or to an alteration of the ERK/MAPK signaling cascade. Based on these results, we propose that isoproterenol may exert its effects through other MAPK signaling pathways (JNK and/or p38) or through parallel mechanisms. These results also demonstrate a problem of potential therapeutic relevance in which a commonly prescribed medication may alter wound healing and contribute to the remodeling of asthmatic airways.

Isoquercitrin from Argemone platyceras inhibits carbachol and leukotriene D4-induced contraction in guinea-pig airways

Argemone platyceras is used in Mexico as a remedy for cough, bronchitis and pneumonia. The present study was performed to investigate the pharmacological anti-asthmatic properties of Argemone platyceras on airways and to identify its active principles. Methanol extracts of leaves and flowers, subsequent organic and aqueous extraction phases, and silica gel chromatography fractions were assayed on the carbachol-induced response, and/or on ovalbumin antigenic challenge, and on leukotriene D(4)-induced response of tracheae from sensitized and non-sensitized guinea-pigs. Methanol extracts, ethyl-acetate phase, and its fractions 6 and 7 inhibited the carbachol-induced contractile response. Isoquercitrin and rutin were the main compounds found in fractions 6 and 7 respectively. Isoquercitrin (fraction 6) abolished the response to ovalbumin, and decreased the contractile response to leukotriene D(4). Because of its effect on carbachol-induced contractile response, on the late-phase response to ovalbumin, and on leukotriene D(4)-induced contractile response, isoquercitrin might be highly useful in treatment of asthma.

Clues to asthma pathogenesis from microarray expression studies

Asthma is a chronic inflammatory disease characterized by airway hyperresponsiveness (AHR), tissue remodeling, and airflow obstruction. The pathogenesis of asthma is only partly understood, and there is an urgent need for improved therapeutic strategies for this disease. Microarray technology has considerable promise as a tool for discovery of novel asthma therapeutic targets, although the field is still in its infancy. A number of studies have described expression profiles derived from human asthmatic lung tissue, mouse airway tissue, or from key cell types associated with asthma, but to date relatively few studies have exploited these findings to discover new pathways involved in the pathogenesis of asthma. Among the genes to have been identified by array studies and validated by further studies are monokine induced by interferon (IFN)-gamma, fatty acid binding proteins (FABP), and complement factor 5 (C5). Here we provide examples of microarray approaches to the discovery of new molecules associated with asthma. We anticipate that these types of analyses will provide considerable insight into asthma pathogenesis and will provide a wealth of new molecules for downstream analyses such as gene deficient mouse studies, or monoclonal antibody production.

[Written asthma action plans: a useful tool for self-management]

Written action plans for asthma have been recommended for many years. However, despite the fact that their effectiveness has been demonstrated, they are not used enough. The plans that we propose are serviceable and the method that we suggest makes them easy to use in the treatment of asthmatic children. These plans are made for patients who do not use a peak-flow meter (plans based on symptoms) and those who control this tool (plans based on peak expiratory flow).

Induction and inhibition of the Th2 phenotype spread: implications for childhood asthma

The interactions between genetic and environmental factors play a major role in the development of childhood asthma. We hypothesized that a pre-existing Th2/asthmatic response can promote Th2 responses to newly encountered Ags (i.e., phenotype spread). To test this hypothesis, we developed a mouse model in which the requirements for the induction and inhibition of phenotype spread to a clinically relevant neo-allergen (i.e., ragweed) were investigated. Our results indicate that 1) phenotype spread to the neo-allergen can be induced only within the first 8 h after a bronchial challenge with the first Ag (OVA); 2) Th2 differentiation of naive CD4(+) T cells occurs in bronchial lymph nodes; 3) trafficking of naive CD4(+) T cells to local lymph nodes and IL-4 produced by OVA-activated Th2 cells play essential roles in the differentiation of naive CD4(+) T cells to Th2 cells; and 4) suppression of the production of chemokines involved in the homing of naive CD4(+) T and Th2 cells to bronchial lymph nodes by a TLR9 agonist inhibited phenotype spread and abrogated the consequent development of experimental asthma. These findings provide a mechanistic insight into Th2 phenotype spread and offer an animal model for testing relevant immunomodulatory interventions.

Improving asthma control in patients suboptimally controlled on inhaled steroids and long-acting beta2-agonists: addition of montelukast in an open-label pilot study

BACKGROUND

Airway inflammation and symptoms often persist in asthma patients despite treatment with inhaled corticosteroids (ICS) and long-acting beta2-agonists (LABA). It is hypothesized that the leukotriene receptor antagonist montelukast, treating a pathway of inflammation distinct from that of ICS, might confer additional benefit.

OBJECTIVE

To evaluate the efficacy of montelukast in improving asthma control in patients symptomatic on a fixed-association (FA) medium dose of ICS and LABA.

METHODS

A 2-month, open-label, real-life observational study was undertaken by 131 Belgian pulmonologists. Patients (> or = 15 years old) suffering from persistent asthma (pre-bronchodilator FEV1 > or = 60% of predicted value) and insufficiently controlled on a FA therapy of fluticasone/salmeterol or budesonide/formoterol were given montelukast 10 mg daily as add-on therapy. Asthma control was assessed by the standardized Juniper asthma control questionnaire (ACQ) at baseline and after a 2-month treatment with montelukast. Global evaluation of therapy was made both by the patients and physicians.

RESULTS

A total of 313 patients were eligible for analysis. Forty-nine per cent received inhaled fluticasone/salmeterol and the rest budesonide/formoterol. Mean ACQ score decreased significantly on montelukast (13.9 +/- 5.1 at baseline versus 7.4 +/- 4.7 on montelukast, p < 0.001), with a significant improvement in all individual symptom scores (p < 0.001) and in pre-bronchodilator FEV1 score (from 2.2 +/- 1.5 to 1.6 +/- 1.4; p < 0.001). Parallel to these results, 78.6% of the patients reported a global improvement of their asthma. The same proportion of improvement was observed in the global evaluation made by the physicians (kappa = 0.66).

CONCLUSION

This pilot study suggests that addition of montelukast in patients symptomatic on a FA of ICS and LABA may result in significant improvements in asthma control. A randomised, placebo-controlled clinical trial seems warranted.

A comparative study of bronchodilator reversibility with albuterol, between asthma symptomatic and asymptomatic children according to ISAAC questionnaire in Mexico City

BACKGROUND

Asthma is an important childhood disease. Recent surveys of the International Study of Asthma and Allergies in Childhood (ISAAC) suggest that the prevalence of asthma is increasing but these surveys do not include any pulmonary tests to confirm the possible diagnosis of asthma.

OBJECTIVE

To compare bronchodilator reversibility with the albuterol test in symptomatic and asymptomatic 6-7-year-old children with asthma participating in the ISAAC survey and living in Mexico City.

PATIENTS AND METHODS

We performed an observational, descriptive, comparative, cross sectional study in children participating in phase 3b of the ISAAC study. According to the ISAAC questionnaire children were classified as asthma symptomatic or asymptomatic. Both groups had bronchodilator reversibility with the albuterol test, using the guidelines of the American Thoracic Society to confirm or rule out the diagnosis of asthma.

RESULTS

The asymptomatic group had a baseline FEV1 of 1.70 +/- 0.34 l/sec (mean +/- SD) and an endpoint FEV1 of 1.76 +/- 0.42 l/sec; in the symptomatic group the respective values were 1.51 +/- 0.41 l/sec and 1.57 +/- 0.44 l/sec (p < 0.05). A positive reversibility test was found in 13/136 (9.6 %) children in the asymptomatic group and in 22/112 (19.6 %) children in the symptomatic group (p < 0.05).

CONCLUSION

Because of its low sensitivity, bronchodilator reversibility cannot be considered a diagnostic tool to confirm diagnosis of asthma.

Transient receptor potential and other ion channels as pharmaceutical targets in airway smooth muscle cells

Regardless of the triggering stimulus in asthma, contraction of the airway smooth muscle (ASM) is considered to be an important pathway leading to the manifestation of asthmatic symptoms. Therefore, the various ion channels that modulate ASM contraction and relaxation are particularly attractive targets for therapy. Although voltage-operated Ca2+ channels (VOCC) are the most extensively characterised Ca(2+)-permeable channels in ASM cells and are obvious pharmacological targets, blockers of VOCC have not been successful in alleviating ASM contraction in asthma. Similarly, although the Cl- and K+ channels also modulate ASM contraction and relaxation by regulating plasma membrane potential, pharmacological interventions directed against these channels have failed to abrogate ASM contraction in asthma. A large body of evidence suggests that store-operated Ca2+ channels (SOCC) and Ca(2+)-permeable second messenger-activated non-selective cation channels (NSCC) predominantly mediate ASM contraction. However, development of pharmacological interventions involving these channels has been hampered by the paucity of information regarding their molecular identity. Members of the mammalian transient receptor potential (TRP) protein family, which form voltage-independent channels with variable Ca2+ selectivity that are activated by store depletion and/or by intracellular messengers, are potential molecular candidates for SOCC and NSCC in ASM cells. While the function of TRP channels in ASM cells remains to be elucidated and there are, at present, essentially no good TRP channel antagonists, this group of proteins is a potentially valuable pharmaceutical target for the treatment of asthma.

Viruses in asthma exacerbations

PURPOSE OF REVIEW

Respiratory viruses are well recognized as major triggers of acute exacerbations of asthma in children and adults, resulting in frequent outpatients visits and hospitalizations. Clinical and epidemiologic evidence supports this association. The application of molecular diagnostic methods has improved understanding of viral epidemiology and the pathophysiological mechanisms involved in viral induced acute asthma. This article reviews publications since October 2002 for an update of the role of viruses in exacerbations of asthma.

RECENT FINDINGS

Respiratory viruses are present in most patients hospitalized for life-threatening asthma and acute non life-threatening asthma. Rhinovirus is the most common, but coinfection with other viruses may be important. Patients with asthma are not more susceptible to upper respiratory tract rhinovirus infections than healthy people but suffer from more severe consequences of the lower respiratory tract infection. Recent epidemiologic studies suggest that viruses provoke asthma attacks by additive or synergistic interactions with allergen exposure or with air pollution. An impaired antiviral immunity to rhinovirus may lead to impaired viral clearance and hence prolonged symptoms. Respiratory viral infections cause asthmatic exacerbations by triggering recruitment of Th2-type cells into the lungs. There is no specific antiviral strategy for prevention of respiratory-triggered asthma exacerbations, although clinical trials of potential antiviral agents are ongoing. Indirect prevention strategies focus on the reduction of overall airway inflammation to reduce the severity of the host response to respiratory viral infections.

SUMMARY

Respiratory viral infections are a major cause of morbidity and mortality in asthma. There is a lack of specific antiviral strategies in the prevention or reduction of viral-triggered asthma exacerbations. Recent advances in understanding of the epidemiology and immunopathogenesis of respiratory viral infection in asthma provide opportunities or identification of specific targets for antiviral agents and strategies for management and prevention.

Dietary intake of fatty acids, antioxidants and selected food groups and asthma in adults

OBJECTIVE

Within a prospective study, we explored the associations between dietary intake of fatty acids, antioxidants and relevant food sources of these nutrients on the clinical manifestation of asthma in adulthood.

METHOD

A total of 105 newly physician-diagnosed cases of asthma from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort were identified during follow-up and matched with 420 controls. Baseline dietary intake was obtained by means of validated food frequency questionnaires. The association of dietary intake variables and asthma risk was explored by unconditional logistic regression models.

RESULTS

A high intake of oleic acid (C18:1 n-9) was positively associated with asthma (P-value for trend 0.035), while no significant associations were found for the other dietary fatty acids. Most prominently, a high margarine intake increased the risk of onset of asthma in adulthood (adjusted odds ratio (OR) 3rd tertile: 1.73 (95% confidence interval (95% CI): 1.05-2.87), P for trend=0.050), the effect being stronger in men (2nd tertile: OR=1.66, 3rd tertile: OR=2.51) than in women (2nd tertile: OR=0.91; 3rd tertile: OR=1.47). The dietary intake of antioxidants and their main food sources had no effect on asthma risk.

CONCLUSIONS

In summary, the present results provide evidence that even in adulthood a high margarine intake increases the risk of clinical onset of asthma. Whether oleic acid may serve as a proxy for margarine-derived trans-fatty acids (C18:1 t9) remains to be clarified.

Induction of allergic inflammation by interleukin-18 in experimental animal models

Interleukin-18 (IL-18) has been regarded as a proinflammatory cytokine because of its potent interferon-gamma-inducing activity. However, mutant mice that release excess amounts of IL-18 spontaneously develop pruritic chronic dermatitis-like atopic dermatitis (AD), suggesting the importance of IL-18 for the development of AD. Intriguingly, depletion of il-18 but not stat6, an essential transcriptional factor for IL-4 signaling, rescues the mice from AD, indicating IL-18-dependent, T-helper 2 (Th2) cell-independent AD. This type of AD is classified as innate-type allergy in contrast to Th2 cell-dependent ordinary allergy. Consistent with the previous studies, mice transferred with antigen-specific Th1 cells exhibit no airway hyperresponsiveness and respiratory eosinophilic inflammation after challenge with antigen alone. However, they suffer from asthma upon challenge with antigen plus IL-18, with comparable levels of both the alterations as in those transferred with Th2 cells following challenge with antigen. The former type of asthma is categorized as Th1-associated allergy. Therefore, it is definitely necessary to evaluate whether individual allergic disorders involve either of these IL-18-mediated pathways or a Th2-mediated one.

Evaluating the prophylactic potential of the phtalimide derivative LASSBio 552 on allergen-evoked inflammation in rats

A previous study showed that the novel tetrazolephtalimide derivative LASSBio 552 (2-4-[3-(1H-1,2,3,4-tetraazol-5-yl)propoxy]phenethyl-1,3-isoindolinedione) prevents LTD(4)-evoked tracheal contraction. This led us to examine the putative anti-inflammatory effect of LASSBio 552 in comparison with the leukotriene CysLT(1) receptor antagonist zafirlukast using a model of allergic pleurisy in rats. Treatment with either LASSBio 552 (24-96 micromol/kg, i.p.) or zafirlukast (9-72 micromol/kg, i.p.), 1 h before challenge, inhibited eosinophil and mononuclear cell influx into the pleural cavity 24 h post-challenge, but failed to alter the increased levels of eotaxin, plasma leakage, mast cell degranulation and neutrophil infiltration noted 6 h post-challenge. CD4(+) T cell recruitment 24 h post-challenge was also sensitive to LASSBio 552. This treatment failed to alter cysteinyl leukotriene production at 6 h, but clearly inhibited the phenomenon 24 h and 48 h post-challenge. In in vitro settings LASSBio 552 inhibited allergen-evoked cysteinyl leukotriene generation from isolated mast cells, while histamine release remained unchanged. It also slightly inhibited cysteinyl leukotriene production by eosinophils and mononuclear cells triggered by Ca(+2) ionophore A23187. A leukotriene CysLT(1) receptor transfected cell-based assay revealed that LASSBio 552 did not prevent LTD(4)-evoked Ca(+2) influx, indicating that it was not a leukotriene CysLT(1) receptor antagonist. These findings indicate that LASSBio 552 is able to inhibit eosinophil influx triggered by allergen chalenge in a mechanism at least partially associated with suppression of CD4(+) T cell influx and cysteinyl leukotriene production.

A novel effect for annexin 1-derived peptide ac2-26: reduction of allergic inflammation in the rat

Previous investigations have provided evidence that the N-terminal peptide of annexin 1 (peptide Ac2-26) has the capacity of reproducing the anti-inflammatory actions of the full-length protein in many systems. In the current study, we report the effectiveness of the peptide Ac2-26 as an antiallergic tool in a model of rat pleurisy and provide indication for some of the mechanisms involved. In rats inflamed by injection of ovalbumin into the pleural cavity 14 days postsensitization, peptide Ac2-26 (50-200 microg/cavity) inhibited mast cell degranulation, plasma protein leakage, and the accumulation of both neutrophils and eosinophils. Treatment with either peptide Ac2-26 (200 microg/cavity) or dexamethasone (1 mg/kg i.p.) inhibited ovalbumin-induced eotaxin release in the pleural effluents. In vitro, peptide Ac2-26 inhibited ovalbumin-evoked histamine release from subcutaneous tissue fragments obtained from sensitized rats (33-66 microM) and interleukin-13-evoked eotaxin generation from cultured rat mesothelial cells (16-33 microM) but not eosinophil chemotaxis. This work demonstrates that the annexin 1 mimetic peptide Ac2-26 prevents allergen-evoked eosinophilic inflammatory response in rats. Combined analysis of the in vivo and in vitro experiments presented herein suggests that the blockade of secretion of pivotal mediators for the allergic response, such as histamine and eotaxin, could be responsible for the inhibitory actions displayed by peptide Ac2-26.

Correlation between inhalant allergen-specific IgE and pulmonary function in children with asthma

Sensitization to aeroallergens is associated with diminished lung function in adults. Little has been studied on the relationship between the inhalant allergen-specific IgE and pulmonary function in asthmatic children. This study was focused on four major inhalant allergens found in Korea, including Dermatophagoides pteronyssinus (Der p.), Dermatophagoides farinae (Der f.), and Alternaria- and German cockroach-specific IgEs, with evaluation of pulmonary function in relation to the amount of allergens. The parents or legal guardians of participants enrolled in this study gave informed consent. Fifty-five asthmatic patients and 48 nonasthmatic children were included. The amounts of specific IgE for the four specified inhalant allergens were determined by employing the CAP system FEIA. Forced expiratory volume in 1 sec (FEV(1))/forced vital capacity (FVC), FEV(1), and forced expiratory flow between 25% and 75% of FVC (FEF(25-75)) of subjects were evaluated through pulmonary function tests. In the asthmatic group, FEV(1), FEV(1)/FVC, and FEF(25-75) were significantly reduced (P < 0.05): reduction in FEV(1) (r = -0.44) and FEF(25-75) (r = -0.33) in association with the Der f.-specific allergen, and reduction in FEV(1) (r = -0.37) and FEF(25-75) (r = -0.34) in association with the Der p.-specific allergen, were observed. However, there was no significant correlation with German cockroach and Alternaria allergen. In the control group, no significant correlation was detectable between the allergen-specific IgE titers and the results of pulmonary function tests. In asthmatic patients, Der p.- and Der f.-specific IgEs, and not German cockroach and Alternaria, seem to play a considerable role in reduced pulmonary function among asthmatic children.

Oxidative stress in the pathogenesis of asthma

Asthma affects 5% to 10% of the population of the United States. In asthmatics, oxidative stress occurs not only as a result of inflammation but also from environmental exposure to air pollution. The specific localization of antioxidants in the lung and the adaptive changes during asthma underscore the importance of oxidative stress, and therapeutic interventions that decrease exposure to environmental reactive oxygen species or augment endogenous antioxidant defenses might be beneficial as adjunctive therapies in asthmatic patients.

Induction of bone-marrow eosinophilia in mice submitted to surgery is dependent on stress-induced secretion of glucocorticoids

1 We examined bone-marrow in mice receiving subcutaneous implants of heat-coagulated egg white, which are known to present chronic eosinophilic inflammation at the implant site. Egg white implants (EWIs) induced marked bone-marrow eosinophilia, and increased bone-marrow cell responses to granulocyte-macrophage colony-stimulating factor and interleukin-5 in culture. These effects were observed as early as 24 h and lasted for, at least, 30 days in implant recipients. 2 We found, however, that increased eosinophil production was also observed in control mice which underwent surgery but received no EWI (sham-implanted mice), up to 15 days post-surgery. As this suggests an important contribution of nonspecific stress mechanisms to eosinopoiesis, we further evaluated the role of stress hormones produced by the adrenal glands in the bone-marrow eosinophilia of sham-implanted mice. 3 Bone-marrow eosinophilia in mice undergoing surgery was dissociated from increases in other haemopoietic lineages. Surgery by itself increased circulating corticosterone levels by 24 h, and the increase was prevented by inhibition of adrenal glucocorticoid production by metyrapone. The effect of surgery on bone-marrow eosinophilia was prevented by pretreatment with both the glucocorticoid receptor antagonist, mifepristone, and metyrapone, and by surgical adrenalectomy. 4 By contrast, cathecolamine receptor antagonists (propranolol, prazosin and yohimbine) were ineffective, indicating that cathecolamine release from the adrenal glands was not responsible for the effects on bone-marrow. 5 These results highlight a critical role for stress-induced glucocorticoid hormones in selectively upregulating bone-marrow eosinopoiesis in mice submitted to surgery.

Dynamic lung morphology of methacholine-induced heterogeneous bronchoconstriction

Hyperpolarized (HP) 3helium (3He) dynamic MRI was used to investigate airway response in rats following intravenous (i.v.) bolus administration of a contractile agent, methacholine (MCh). The method provides direct visualization of the ventilated regions within the lung. Heterogeneous bronchoconstriction following the i.v. MCh injection was evident using this technique. These 3He dynamic lung images revealed that the inspired fresh air was shunted to the less-constricted regions after the MCh challenge in a similar manner as described by Laplace's relationship for the stability between adjacent alveoli. The airways in the more-constricted regions became nearly closed, resulting in air trapping, while the airways in the less-constricted regions remained effectively open, leading to overinflation. These data suggest a lung model of airway constriction partitioned into ventilated and nonventilated regions. These nonventilated regions are heterogeneously distributed in the lung and this distribution cannot be deduced from spirometric measurement of the whole lung. We demonstrate that a combination of functional 3He images and anatomical 1H images provide an effective method to diagnose regional lung abnormalities in rats.

Glucocorticoid receptors in human airways

Inhaled and intranasal glucocorticoids are the most common and effective drugs for controlling symptoms and airway inflammation in respiratory diseases such as asthma, allergic rhinitis, and nasal polyposis. The last few years have seen a growing understanding of the mechanisms of glucocorticoid action and, in particular, the receptor that mediates glucocorticoid actions, the glucocorticoid receptor (GR). In this revision we present an update on the GR gene, the expression and regulation of its gene products, namely GRalpha and GRbeta, as well as their alterations in pathological states. GRalpha is responsible for the induction and repression of target genes, it is expressed in virtually all human cells and tissues, and its expression is known to be downregulated by glucocorticoids. GRbeta has been found to act as a dominant negative inhibitor of GRalpha-mediated transactivation in in vitro studies with transfected cells, but it does not appear to have a significant inhibitory effect on GRalpha-mediated transrepression. In addition, for most tissues the expression of GRbeta, at least at the mRNA level, is extremely low compared with that of GRalpha. Some pro-inflammatory cytokines appear to upregulate the expression of GRbeta, and increased GRbeta expression has been reported in diseases associated with glucocorticoid resistance or insensitivity, such as bronchial asthma, nasal polyposis, and ulcerative colitis. However, the possible role of GRbeta in modulating glucocorticoid sensitivity and/or resistance in vivo has been highly debated and it is not yet clear.

Insights into the pathogenesis of asthma utilizing murine models

Asthma is a common syndrome in children and adults. Despite the increasing prevalence and socioeconomic burden, the underlying pathophysiology remains poorly defined in a large percentage of asthmatics. Animal models and, in particular, murine models of allergic airway disease have helped to reveal some of the potential underlying mechanisms and have played an important role in identifying the importance of T cells and TH2 cytokines in development of allergen-induced inflammation and airway hyperresponsiveness. In addition, other cell types including mast cells and eosinophils have been implicated in the development of some aspects of the disease. To further understand this complex syndrome, the development of animal models which mimic elements of this chronic airway disease is essential.

Diesel exhaust particles suppress in vivo IFN-gamma production by inhibiting cytokine effects on NK and NKT cells

Diesel exhaust particles (DEP) have strong, selective Th2 adjuvant activity when inhaled with conventional Ags. We used a novel technique for measuring in vivo cytokine production to investigate possible mechanisms by which DEP might promote a Th2 response. Injection of DEP i.p. stimulated IL-6 secretion, but failed to increase IL-4, IL-10, or TNF-alpha secretion, and decreased basal levels of IFN-gamma. When injected with or before LPS, DEP had little effect on the LPS-induced TNF-alpha responses, but partially inhibited the LPS-induced IL-10 response and strongly inhibited the LPS-induced IFN-gamma response. DEP also inhibited the IFN-gamma responses to IL-12, IL-12 plus IL-18, IL-2, and poly(I.C). DEP treatment had little effect on the percentages of NK and NKT cells in the spleen, but inhibited LPS-induced IFN-gamma production by splenic NK and NKT cells. In contrast, DEP failed to inhibit the IFN-gamma response by anti-CD3 mAb-activated NKT cells. Taken together, these observations suggest that DEP inhibit Toll-like receptor ligand-induced IFN-gamma responses by interfering with cytokine signaling pathways that stimulate NK and NKT cells to produce IFN-gamma. Our observations also suggest that DEP may promote a Th2 response by stimulating production of inflammatory cytokines while simultaneously inhibiting production of IFN-gamma, and raise the possibility that the same mechanisms contribute to the association between DEP exposure and asthma.

CD56+Cells Induce Steroid Resistance in B Cells Exposed to IL-15

Interleukin-2 can induce steroid resistance in T cells. IL-15 shares biological activities with IL-2, as both cytokines use IL-2Rgamma for signal transduction. We therefore sought to determine whether IL-15 contributes to induction of PBMC corticosteroid resistance. Surprisingly, we found that incubation of unfractionated PBMC with IL-15 for 48 h resulted in the inhibition of glucocorticoid receptor (GCR) nuclear translocation in response to dexamethasone (DEX) treatment in CD19-positive B cells significantly greater than CD19-negative non-B cells (p < 0.01). However, pure B cells incubated with IL-15 responded normally with nuclear translocation of GCR in response to steroids, but failed to translocate GCR when they were grown in the presence of CD19(-) cells. Coculture of B cells with CD3(+) (T cells), CD14(+) (monocytes), or CD56(+) (NK and NKT cells) in the presence of IL-15 revealed that only CD56(+) cells contributed to the steroid insensitivity of B cells. IL-15 stimulation significantly increased production of IL-4 by CD56(+) cells (p < 0.02). Treatment of purified B cells with combination IL-15/IL-4 resulted in abrogation of glucocorticoid receptor nuclear translocation and the inability of DEX to suppress cytokine production by B cells. In the presence of IL-4-neutralizing Ab, when B cells were cocultured with CD56(+) cells and IL-15, the B cells were found to be steroid sensitive, i.e., DEX induced GCR nuclear translocation. This study demonstrates that B cells develop steroid resistance in the presence of CD56(+) cells after IL-15 stimulation. Furthermore, IL-15 and IL-4 have the capacity to induce B cell insensitivity to steroids.

Increased levels of hypoxia-sensitive proteins in allergic airway inflammation

In this study we investigated the alterations in protein levels that are induced by allergic eosinophilic lung inflammation. Lung tissue eosinophilia and sequestration of inflammatory cells in airspaces were provoked by systemic sensitization with ovalbumin followed by repeated inhalation challenge with aerosolized ovalbumin. Proteome alterations in lung tissue and bronchoalveolar lavage fluid, respectively, were examined by two-dimensional gel electrophoresis followed by identification of proteins by mass spectrometry. Several proteins were markedly increased in inflamed tissue. In particular, several proteins that are known to be associated with hypoxia were elevated, for example, glycolytic enzymes, glucose-regulated protein 78 kD, prolyl-4-hydroxylase, peroxiredoxin 1, and arginase. Out of the identified proteins, Ym2 displayed the clearest increase, present at high levels in animals with lung eosinophilia, while being undetectable in control subjects. Furthermore, the levels of cathepsin S were markedly increased in inflamed tissue. Taken together, this study identifies a number of marker proteins associated with the pathogenesis of allergic lung inflammation and indicates a link between allergic airway inflammation and induction of hypoxia-related gene products.

Lymphocyte subsets in healthy children from birth through 18 years of age

BACKGROUND

Peripheral blood lymphocyte subsets need to be determined in a large, urban, minority-predominant cohort of healthy children to serve as suitable control subjects for the interpretation of the appearance of these cells in several disease conditions, notably pediatric HIV-1 infection.

OBJECTIVE

We sought to determine the distribution of lymphocyte subsets in healthy urban-dwelling infants, children, and adolescents in the United States.

METHODS

Lymphocyte subsets were determined by means of 3-color flow cytometry in a cross-sectional study of 807 HIV-unexposed children from birth through 18 years of age.

RESULTS

Cell-surface marker analysis demonstrated that age was an extremely important variable in 24 lymphocyte subset distributions measured as percentages or absolute counts--eg, the CD4 (helper) T cell, CD8 (cytotoxic) T cell, CD19 B cell, CD4CD45RACD62L (naive helper) T cell, CD3CD4CD45RO (memory helper) T cell, CD8HLA-DRCD38 (activated cytotoxic) T cell, and CD8CD28 (activation primed cytotoxic) T cell. The testing laboratory proved to be an important variable, indicating the need for using the same laboratory or group of laboratories to assay an individual's blood over time and to assay control and ill or treated populations. Sex and race-ethnicity were much less important.

CONCLUSION

The results of this study provide a control population for assessment of the effects of HIV infection on the normal development and distribution of lymphocyte subsets in children of both sexes, all races, and all ethnic backgrounds from birth through 18 years of age in an urban population. This study's findings will also prove invaluable in interpreting the immune changes in children with many other chronic diseases, such as primary immunodeficiency, malignancy, rheumatoid arthritis, and asthma.