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INTRODUCTION: There is considerable research interest in the role of helminth infections in the development of allergic diseases. However, findings from previous studies are mixed. Existing systematic reviews of these studies are outdated. We performed a systematic review of the global literature on the association between helminth infections and development and clinical outcomes of allergic diseases. METHODS: We searched Cochrane Library, MEDLINE, EMBASE, ISI Web of Science, PubMed, Global Index Medicus, Scielo, KoreaMed, Google Scholar, and Lilacs for studies published up to January 2020. We included observational epidemiological studies (cohort, case-control and cross-sectional studies) of children and adults reporting associations between helminth infections and asthma, allergic rhinitis, eczema and atopy. We performed random-effects meta-analysis to summarize the effect estimates. RESULTS: We included 80 studies with 99,967 participants. In the meta-analyses, we did not observe an overall association between helminth infections and allergic diseases. There was, however, evidence that A. lumbricoides infections was associated with an increased risk of bronchial hyperreactivity in children (RR:1.41, 95%CI: 1.17-1.70; I2=50, p for I2=0.09), and was associated with an increased risk of atopy among helminth-infected adults (RR:1.37, 95%CI: 1.18-1.61; I2=52, p for I2=0.02). We found no study that addressed the association between helminth infection and clinical outcomes of allergic diseases. The overall strength of the underlying evidence was low to moderate. CONCLUSION: Helminth infections may increase the risk of bronchial hyperreactivity in children and atopy in adults. Well-designed longitudinal cohorts may help clarify potential causal associations between chronic helminth infections and allergic diseases.

Background Regulatory T cells attenuate development of asthma in wild-type (WT) mice, with both naturally occurring regulatory T (nTreg) cells and inducible regulatory T (iTreg) cells exhibiting suppressive activity. When transferred into CD8-deficient (CD8 −/− ) recipients, both cell types enhanced development of allergen-induced airway hyperresponsiveness. Objective We sought to determine whether the pathways leading to enhancement of lung allergic responses by transferred nTreg and iTreg cells differed. Methods nTreg cells (CD4 + CD25 + ) were isolated from WT mice and iTreg cells were generated from WT CD4 + CD25 − T cells after activation in the presence of TGF-β and transferred into sensitized CD8 −/− recipients before challenge. Development of airway hyperresponsiveness, cytokine levels, and airway inflammation were monitored. Results Transfer of nTreg cells enhanced lung allergic responses, as did transfer of iTreg cells. Although anti–IL-13 reduced nTreg cell–mediated enhancement, it was ineffective in iTreg cell–mediated enhancement; conversely, anti–IL-17, but not anti–IL-13, attenuated the enhancement by iTreg cells. Recovered iTreg cells from the lungs of CD8 −/− recipients were capable of IL-17 production and expressed high levels of signature genes of the T H 17 pathway, RORγt and Il17 , whereas reduced expression of the Treg cell key transcription factor forkhead box p3 (Foxp3) was observed. In vitro exogenous IL-6–induced IL-17 production in iTreg cells, and in vivo conversion of transferred iTreg cells was dependent on recipient IL-6. Conclusions iTreg cells, similar to nTreg cells, exhibit functional plasticity and can be converted from suppressor cells to pathogenic effector cells, enhancing lung allergic responses, but these effects were mediated through different pathways.

Background Asthma is a widespread, multifactorial chronic airway disease. The influence of regulatory B cells on airway hyperreactivity (AHR) and remodeling in asthma is poorly understood. Objective Our aim was to analyze the role of B cells in a house dust mite (HDM)-based murine asthma model. Methods The influence of B cells on lung function, tissue remodeling, and the immune response were analyzed by using wild-type and B-cell–deficient (μMT) mice and transfer of IL-10–proficient and IL-10–deficient B cells to μMT mice. Results After HDM-sensitization, both wild-type and μMT mice developed AHR, but the AHR was significantly stronger in μMT mice, as confirmed by 2 independent techniques: invasive lung function measurement in vivo and examination of precision-cut lung slices ex vivo. Moreover, airway remodeling was significantly increased in allergic μMT mice, as shown by enhanced collagen deposition in the airways, whereas the numbers of FoxP3+ and FoxP3– IL-10–secreting regulatory T cells were reduced. Adoptive transfer of IL-10–proficient but not IL-10–deficient B cells into μMT mice before HDM-sensitization attenuated AHR and lung remodeling. In contrast, FoxP3+ regulatory T cells were equally upregulated by transfer of IL-10–proficient and IL-10–deficient B cells. Conclusion Our data in a murine asthma model illustrate a central role of regulatory B cells in the control of lung function and airway remodeling and may support future concepts for B-cell–targeted prevention and treatment strategies for allergic asthma.

International audience; Two different transcription factors discriminate the-315C>T polymorphism of the Fc epsilon RI alpha gene: binding of Sp1 to-315C and of a high mobility grouprelated molecule to-315T.

Background Group 2 innate lymphoid cells (ILC2s) are the dominant innate lymphoid cell population in the lungs at steady state, and their release of type 2 cytokines is a central driver in responding eosinophil infiltration and increased airway hyperreactivity. Our laboratory has identified a unique subset of ILC2s in the lungs that actively produce IL-10 (ILC210s). Objective Our aim was to characterize the effector functions of ILC210s in the development and pathology of allergic asthma. Methods IL-4–stimulated ILC210s were isolated to evaluate cytokine secretion, transcription factor signaling, metabolic dependence, and effector functions in vitro. ILC210s were also adoptively transferred into Rag2–/–γc–/– mice, which were then challenged with IL-33 and assessed for airway hyperreactivity and lung inflammation. Results We have determined that the transcription factors cMaf and Blimp-1 regulate IL-10 expression in ILC210s. Strikingly, our results demonstrate that ILC210s can utilize both autocrine and paracrine signaling to suppress proinflammatory ILC2 effector functions in vitro. Further, this subset dampens airway hyperreactivity and significantly reduces lung inflammation in vivo. Interestingly, ILC210s demonstrated a metabolic dependency on the glycolytic pathway for IL-10 production, shifting from the fatty acid oxidation pathway conventionally utilized for proinflammatory effector functions. Conclusion These findings provide an important and previously unrecognized role of ILC210s in diseases associated with ILC2s such as allergic lung inflammation and asthma. They also provide new insights into the metabolism dependency of proinflammatory and anti-inflammatory ILC2 phenotypes.

Background The diagnosis of occupational asthma (OA) can be challenging and needs a stepwise approach. However, the predictive value of the methacholine challenge has never been addressed specifically in this context. Objective We sought to evaluate the sensitivity, specificity, and positive and negative predictive values of the methacholine challenge in OA. Methods A Canadian database was used to review 1012 cases of workers referred for a suspicion of OA between 1983 and 2011 and having had a specific inhalation challenge. We calculated the sensitivity, specificity, and positive and negative predictive values of methacholine challenges at baseline of the specific inhalation challenge, at the workplace, and outside work. Results At baseline, the methacholine challenge showed an overall sensitivity of 80.2% and a specificity of 47.1%, with positive and negative predictive values of 36.5% and 86.3%, respectively. Among the 430 subjects who were still working, the baseline measures displayed a sensitivity of 95.4%, a specificity of 40.1%, and positive and negative predictive values of 41.1% and 95.2%, respectively. Among the 582 subjects tested outside work, the baseline measures demonstrated a sensitivity and specificity of 66.7% and 52%, respectively, and positive and negative predictive values of 31.9% and 82.2%, respectively. When considering all subjects tested by a methacholine challenge at least once while at work (479), the sensitivity, specificity, and positive and negative predictive values were 98.1%, 39.1%, and 44.0% and 97.7%, respectively. Conclusion A negative methacholine challenge in a patient still exposed to the causative agent at work makes the diagnosis of OA very unlikely.

The Dutch hypothesis was first articulated in 1961, when many novel and advanced scientific techniques were not available, such as genomics techniques for pinpointing genes, gene expression, lipid and protein profiles, and the microbiome. In addition, computed tomographic scans and advanced analysis techniques to dissect (small) airways disease and emphysema were not available. At that time, the group of researchers under the visionary guidance of Professor N. G. M. Orie put forward that both genetic and environmental factors can determine whether one would have airway obstructive diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Moreover, they stipulated that the phenotype of obstructive airway disease could be affected by sex and changes with aging. Orie and colleagues' call to carefully phenotype patients with obstructive airways diseases has been adopted by many current researchers in an attempt to determine the heterogeneity of both asthma andCOPD to better define these diseases and optimize their treatment. The founders of the Dutch hypothesis were far ahead of their time, and we can learn from their insights. We should fully characterize all patients in our clinical practice and not just state that they have asthma, COPD, or asthma and COPD overlap syndrome. This detailed phenotyping can help in understanding these obstructive airway diseases and provide guidance for disease management.

Background IL-25 and IL-33 belong to distinct cytokine families, but experimental mouse studies suggest their immunologic functions in type 2 immunity are almost entirely overlapping. However, only polymorphisms in the IL-33 pathway ( IL1RL1 and IL33 ) have been significantly associated with asthma in large-cohort genome-wide association studies. Objective We sought to identify distinct pathways for IL-25 and IL-33 in the lung that might provide insight into their roles in asthma pathogenesis and potential for therapeutic intervention. Methods IL-25 receptor–deficient (Il17rb −/− ) , IL-33 receptor–deficient (ST2, Il1rl1 −/− ), and double-deficient (Il17rb −/− Il1rl1 −/− ) mice were analyzed in models of allergic asthma. Microarrays, an ex vivo lung slice airway contraction model, and Il13 +/eGFP mice were then used to identify specific effects of IL-25 and IL-33 administration. Results Comparison of IL-25 and IL-33 pathway–deficient mice demonstrates that IL-33 signaling plays a more important in vivo role in airways hyperreactivity than IL-25. Furthermore, methacholine-induced airway contraction ex vivo increases after treatment with IL-33 but not IL-25. This is dependent on expression of the IL-33 receptor and type 2 cytokines. Confocal studies with Il13 +/eGFP mice show that IL-33 more potently induces expansion of IL-13–producing type 2 innate lymphoid cells, correlating with airway contraction. This predominance of IL-33 activity is enforced in vivo because IL-33 is more rapidly expressed and released in comparison with IL-25. Conclusion Our data demonstrate that IL-33 plays a critical role in the rapid induction of airway contraction by stimulating the prompt expansion of IL-13–producing type 2 innate lymphoid cells, whereas IL-25–induced responses are slower and less potent.

Traditionally, asthma has been considered a disease that predominantly involves the large airways. Today, this concept is being challenged, and increasing evidence has become available showing that abnormalities in the small airways also contribute to the clinical expression of asthma. The small airways can be affected by inflammation, remodeling, and changes in the surrounding tissue, all contributing to small-airways dysfunction. In this article we have performed a systematic review of the literature on the association between small-airways dysfunction and clinical signs and symptoms of asthma. This review shows that small-airways dysfunction associates with worse control of asthma, higher numbers of exacerbations, the presence of nocturnal asthma, more severe bronchial hyperresponsiveness, exercise-induced asthma, and the late-phase allergic response. Importantly, small-airways dysfunction can already be present in patients with mild asthma. Our review provides suggestive evidence that a better response of the small airways to inhaled steroids or montelukast associates with better asthma control. For this reason, an early recognition of small-airways dysfunction is important because it enables the physician to start timely treatment to target the small airways. It is important to develop simpler and more reliable tools (eg, questionnaires or bronchial provocation tests with small-particle stimuli) to assess the presence and extent of small-airways dysfunction in daily clinical practice. (J Allergy Clin Immunol 2013;131:646-57.)

Background Genome-wide association studies have identified associations of genetic variants at 17q21 near ORMDL3 with childhood asthma. Objectives We sought to determine whether associations in this region are specific to particular asthma phenotypes and specific to ORMDL3 . Methods We examined associations between 244 independent single nucleotide polymorphisms (SNPs) plus 13 previously identified asthma-related SNPs in the region between 34 and 36 Mb on chromosome 17 and early wheezing phenotypes, doctor-diagnosed asthma and atopy at 7½ years, and bronchial hyperresponsiveness and lung function at 8½ years in 7045 children from the Avon Longitudinal Study of Parents and Children birth cohort study. With this, cis expression quantitative trait loci signals for the same SNPs were assessed in 875 samples across genes in the same region. Results The strongest evidence for phenotypic association was seen for persistent wheezing (rs8076131 near ORMDL3 : relative risk ratio [RRR], 1.60 [95% CI, 1.40-1.84], P = 1.4 × 10 −11 ; rs2305480 near GSDML : RRR, 1.60 [95% CI, 1.39-1.83], P = 1.5 × 10 −11 ; and rs9303277 near IKZF3 : RRR, 1.57 [95% CI, 1.37-1.79], P = 4.4 × 10 −11 ). Similar but less precisely estimated effects were seen for intermediate-onset wheeze, but there was little evidence of associations with other wheezing phenotypes. There was some evidence of associations with bronchial hyperresponsiveness. SNPs across the whole region show strong evidence of association with differential levels of expression at GSDML , IKZF3 , and MED24 , as well as ORMDL3. Conclusions Associations of SNPs in the 17q21 locus are specific to asthma and specific wheezing phenotypes and are not explained by associations with intermediate phenotypes, such as atopy or lung function.

Evidence from longitudinal cohort studies demonstrates that wheezing that begins in early life and continues into the school years generally persists into adulthood. This persistent wheezing is associated with lung function deficits and airways hyperresponsiveness that appear to be established in the first few years of life. Allergic sensitization early in life, early-life infection with rhinovirus, or colonization with any of a number of bacteria have been associated with increased risk of persistent wheeze. Early life, whether in utero or in the first few years of life, presents a window of vulnerability during which airway injury results in persistent airways dysfunction. Available data further suggest that a second such window of vulnerability might be present in the preadolescent and adolescent years. Lung function growth patterns established by age 6 years generally continue into early adulthood to middle adulthood, typically leaving groups of subjects with wheezing that persists into or relapses during adulthood with a mean FEV 1 of about 10% of predicted value less than their peers who do not wheeze. Subgroups of patients with persistent asthma, however, can have progressive decreases in lung function and enter adulthood with even lower lung function. The concern exists that these deficits in lung function apparent in early adulthood might put subjects at risk for the later development of chronic obstructive pulmonary disease.

Access to an electronic medical record is essential for personalized medicine. Currently, only 40% of US physicians have such access, but this is rapidly changing. It is expected that 100,000 Americans will have their whole genome sequenced in 2012. The cost of such sequencing is rapidly dropping, and is estimated to be $1000 by 2013. These technological advances will make interpretation of whole genome sequence data a major clinical challenge for the foreseeable future. At present, a relatively small number of genes have been identified to determine drug treatment response phenotypes for asthma. It is anticipated that this will dramatically increase over the next 10 years as personalized medicine becomes more of a reality for asthma patients.

Background Studies of selected patient groups have shown that airway hyperresponsiveness (AHR) to mannitol is more specific than methacholine for the diagnosis of asthma, as well as more closely associated with markers of airway inflammation in asthma. Objective We sought to compare AHR to mannitol and methacholine and exhaled nitric oxide (eNO) levels in a nonselected population sample. Methods In 238 young adults randomly drawn from the nationwide civil registration list in Copenhagen, Denmark, AHR to mannitol and methacholine, as well as levels of eNO, were determined, and the association with asthma was analyzed. Results In diagnosing asthma the specificity of methacholine and mannitol was 80.2% (95% CI, 77.1% to 82.9%) and 98.4% (95% CI, 96.2% to 99.4%), respectively, with a positive predictive value of 48.6% versus 90.4%, whereas the sensitivity was 68.6% (95% CI, 57.1% to 78.4%) and 58.8% (95% CI, 50.7% to 62.6%), respectively. In asthmatic subjects AHR to mannitol was associated with increased eNO levels (positive AHR to mannitol: median, 47 ppb [interquartile range, 35-68 ppb]; negative AHR to mannitol: median, 19 ppb [interquartile range, 13-30 ppb]; P = .001), whereas this was not the case for AHR to methacholine (median of 37 ppb [interquartile range, 26-51 ppb] vs 24 ppb [interquartile range, 15-39 ppb], P = .13). Conclusion In this random population sample, AHR to mannitol was less sensitive but more specific than methacholine in the diagnosis of asthma. Furthermore, AHR to mannitol was more closely associated with ongoing airway inflammation in terms of increased eNO levels.

The pathogenesis of bronchial asthma, a complex trait associated with a number of environmental factors (eg, allergens, infection, air pollution, exercise, and obesity), involves multiple cell types and several distinct cellular and molecular pathways. These pathways include adaptive and innate immunity and involve T(H)2 cells, mast cells, basophils, eosinophils, neutrophils, airway epithelial cells, and subsets of a newly described cell type called natural killer T (NKT) cells. A role for subsets of NKT cells in asthma has been suggested by extensive studies in animal models of asthma induced with allergen, viral infection, ozone exposure, or bacterial components, suggesting that NKT cells function in concert with T(H)2 cells or independently of adaptive immunity in causing airway hyperreactivity. The clinical relevance of NKT cells in human asthma is supported by the observation that NKT cells are present in the lungs of some patients with asthma, particularly patients with severe, poorly controlled asthma, although additional research is required to more precisely define the specific role of NKT cells in human asthma. These studies of NKT cells greatly expand our understanding of possible mechanisms that drive the development of asthma, particularly in the case of asthma associated with neutrophils, viral infection, and air pollution.

Physical activity is essential for young children to develop adequately and for quality of life. It can be lower in children with subclinical asthma, and therefore methods to reveal subclinical reduction in physical activity in young children are warranted.We sought to study an association between physical activity in preschool children and objectively assessed intermediary asthma phenotypes.We studied 253 five-year-old children (127 girls) participating in the Copenhagen Prospective Studies on Asthma in Childhood. The main outcome measure was level of physical activity assessed objectively with accelerometers worn on an ankle for 4 weeks. Objective assessment of asthma intermediary phenotypes included prebronchodilator and postbronchodilator specific airway resistance, bronchial responsiveness to cold dry-air hyperventilation, and exhaled nitric oxide levels. Analyses were performed with generalized linear model and principal component analysis.Physical activity was inversely associated with bronchial responsiveness (relative rate, 0.89; 95% CI, 0.83-0.95; P = .007) and significantly increased in the months of spring and summer (P.001) and in boys (relative rate, 1.16; 95% CI, 1.09-1.25; P.001). Physical activity was independent of asthma diagnosis, age, body mass index, baseline specific airway resistance, reversibility to beta(2)-agonist, sensitization, and exhaled nitric oxide level.Physical activity in preschool children was reduced with increasing bronchial responsiveness. The reduced physical activity was subclinical and not realized by parents or doctors despite daily diary cards and close clinical follow-up since birth. This observation warrants awareness of even very mild asthma symptoms in clinical practice.

Background Disturbance in the delicate balance between L-arginine–metabolizing enzymes such as nitric oxide synthase (NOS) and arginase may lead to decreased L-arginine availability to constitutive forms of NOS (endothelial NOS), thereby increasing the nitro-oxidative stress and airway hyperresponsiveness (AHR). Objective In this study, we investigated the effects of high doses of L-arginine on L-arginine–metabolizing enzymes and subsequent biological effects such as cyclic guanosine monophosphate production, lipid peroxidation, peroxynitrite, AHR, and airway inflammation in a murine model of asthma. Methods Different doses of L-arginine were administered to ovalbumin–sensitized and challenged mice. Exhaled nitric oxide, AHR, airway inflammation, T H 2 cytokines, goblet cell metaplasia, nitro-oxidative stress, and expressions of arginase 1, endothelial NOS, and inducible NOS in lung were determined. Results L-arginine significantly reduced AHR and airway inflammation including bronchoalveolar lavage fluid eosinophilia, T H 2 cytokines, TGF-β1, goblet cell metaplasia, and subepithelial fibrosis. Further, L-arginine increased ENO levels and cyclic guanosine monophosphate in lung and reduced the markers of nitro-oxidative stress such as nitrotyrosine, 8-isoprostane, and 8-hydroxy-2′-deoxyguanosine. This was associated with reduced activity and expression of arginase 1, increased expression of endothelial NOS, and reduction of inducible NOS in bronchial epithelia. Conclusion We conclude that L-arginine administration may improve disordered nitric oxide metabolism associated with allergic airway inflammation, and alleviates some features of asthma.

Leukotriene (LT) E 4 mediates many of the principal features of bronchial asthma, such as bronchial constriction, hyperresponsiveness, eosinophilia, and increased vascular permeability. Furthermore, it is the most stable of the cysteinyl leukotrienes (CysLTs) and can be active at the site of release for a prolonged time after its synthesis. There might be several reasons why LTE 4 has been forgotten. LTE 4 demonstrated low affinity for CysLT 1 and CysLT 2 receptors in equilibrium competition assays. It was less potent than other CysLTs in functional assays, such as calcium flux, in cells transfected with CysLT 1 and CysLT 2 . The introduction of CysLT 1 antagonists into clinical practice diverted interest into CysLT 1 -related mechanisms, which were mediated mainly by LTD 4 . However, experiments with animal models and human studies have revealed that LTE 4 has unique characteristics that cannot be explained by the current knowledge of CysLT 1 and CysLT 2 . These activities include its potency relative to other CysLTs to increase airway responsiveness to histamine, to enhance eosinophilic recruitment, and to increase vascular permeability. Asthmatic airways also demonstrate marked in vivo relative hyperresponsiveness to LTE 4 , especially in patients with aspirin-sensitive respiratory disease. This has stimulated a search for additional LT receptors that would respond preferentially to LTE 4 stimulation.

Background RNA interference is an endogenous cellular mechanism in which short interfering RNAs (siRNAs) direct the sequence specific degradation of a target mRNA. siRNAs can be synthesized with chemical modifications to increase stability and reduce double-stranded RNA–induced immune responses without affecting their ability to elicit degradation of target mRNA. Objectives This study examined the use of chemically modified siRNAs in a mouse model of allergen-induced airway hyperresponsiveness. Methods Chemically modified siRNAs were designed and screened in a cell-based reporter assay. The most potent siRNAs were then screened in bone marrow–derived mast cells to demonstrate efficacy in primary cells. Results A candidate siRNA was formulated and administered to sensitized mice just before airway challenge with allergen. Administration of the siRNA was shown to reduce airway resistance significantly in sensitized and challenged mice by 60%, whereas a control siRNA had no effect. Conclusion These data demonstrate the effectiveness of introducing targeted siRNAs to prevent induction of allergen-induced airway dysfunction and suggest potential therapeutic applications.

Background Although respiratory viral infections in early childhood can enhance the development of airway allergen sensitization, the exact mechanisms of the effects of viral infections on the adaptive immune response to inhaled allergens are controversial. Objective We sought to evaluate the effects of double-stranded RNA (dsRNA) on airway sensitization to inhaled allergens. Methods Novel mouse models were created through simultaneous airway sensitization to an allergen and low or high doses of dsRNA. The mouse models were applied to Toll-like receptor 3–, IL-13–, IL-4–, signal transducer and activator of transcription (STAT) 6–, IFN-γ–, and T-box expressed in T cells (T-bet)–deficient mice to evaluate underlying pathophysiologic mechanisms in the development of allergic lung inflammation. Results We found that airway allergen sensitization with dsRNA induced lung inflammation that was not present in Toll-like receptor 3–deficient mice. Moreover, lung inflammation enhanced by low-dose dsRNA was impaired in IL-13–deficient mice, whereas lung inflammation by high-dose dsRNA was impaired in IFN-γ–deficient mice. The models also demonstrated that low-dose dsRNA enhanced IL-4 expression during allergen sensitization and that inflammation enhanced by low-dose dsRNA was not present in IL-4– or STAT6-deficient mice. In contrast, the present study showed that high-dose dsRNA enhanced IFN-γ expression during allergen sensitization and that the development of lung inflammation enhanced by high-dose dsRNA was impaired in T-bet–deficient mice. Conclusion These findings suggest that airway allergen exposure during respiratory viral infections might induce asthma induced by both T H 1 and T H 2 immune responses to inhaled allergens. Clinical implications Targeting both T H 1 and T H 2 lung inflammation might be important in the treatment of virus-associated asthma.

Background Placebos are hypothesized to exert positive effects on medical conditions by enhancing patient expectancies. Recent reviews suggest that placebo benefits are restricted to subjective responses, like pain, but might be ineffective for objective physiologic outcomes. Nevertheless, mind-body links and placebo responsivity in asthma are widely believed to exist. Objective We carried out a randomized, double-blind investigation to (1) determine whether placebo can suppress airway hyperreactivity in asthmatic subjects, (2) quantify the placebo effect, (3) identify predictors of the placebo response, and (4) determine whether physician interventions modify the placebo response. Methods In a double-blind, crossover design investigation, 55 subjects with mild intermittent and persistent asthma with stable airway hyperreactivity were randomized to placebo or salmeterol before serial methacholine challenges. Subjects were additionally randomized to physician interactions that communicated either positive or neutral expectancies regarding drug effect. Results Placebo bronchodilator administration significantly reduced bronchial hyperreactivity compared with baseline (the calculated concentration of methacholine required to induce a 20% decrease in FEV 1 nearly doubled); 18% of subjects were placebo responders by using conservative definitions. Experimental manipulation of physician behavior altered perceptions of the physician but not the magnitude or frequency of the placebo response. Conclusions Objective placebo effects exist in asthma. These responses are of significant magnitude and likely to be meaningful clinically. The placebo response was not modulated by alterations in physician behavior in this study. Clinical implications The placebo response in patients with asthma is important in understanding the limitations of clinical research studies and in maximizing safe and effective therapies. This article confirms the existence of a strong placebo response in an objective and clinically relevant measure of disease activity.

Background IL-13 is believed to be a central mediator of asthma, and TGF-β1 is a key downstream mediator in the development of IL-13–mediated asthma phenotypes. Objective To evaluate the biological roles of basic fibroblast growth factor (FGF2) in phenotype expression in transgenic (TG) mice overexpressing lung-specific TGF-β1, and the therapeutic effects of recombinant FGF2 in the development of asthma phenotypes. Methods To evaluate the roles of FGF2 in airway hyperresponsiveness (AHR) expression induced by high levels of TGF-β1, TGF-β1 TG (+) mice were bred with FGF2-deficient mice. To evaluate the therapeutic effects of recombinant FGF2 (rFGF2) in the development of asthma, mice were given 10 μg of rFGF2 subcutaneously once a day, 1 hour before the allergen challenge in an asthma mouse model. AHR was evaluated using noninvasive whole-body plethysmography, mucus production by diastase-resistant periodic acid Schiff (DPAS) staining, and lung inflammation using bronchoalveolar lavage (BAL) cellularity and lung histology. Results AHR decreased in TGF-β1 TG (+) mice and was accompanied by the upregulation of FGF2 mRNA expression in lung tissues, when compared with littermate wild-type control mice. Interestingly, AHR was enhanced markedly in TGF-β1 (+) mice with homozygous FGF2 gene disruption. In an asthma mouse model, AHR, mucus production, and lung inflammation were inhibited markedly by rFGF2 treatment. This inhibition was accompanied by downregulation of the allergen-induced proliferation of T cells from regional lymph nodes. Conclusion FGF2 seems to be a key inhibitor in the development of AHR, and rFGF2 treatment constrains the development of asthma phenotypes.

Background TNF is thought to contribute to airway hyperreactivity (AHR) and airway inflammation in asthma. However, studies with TNF-deficient or TNF receptor–deficient mice have not produced a clear picture of the role of TNF in the AHR associated with allergic inflammation in the mouse. Objective We used a genetic approach to investigate the contributions of TNF to antigen-induced AHR and airway inflammation in mice on the C57BL/6 background. Methods We analyzed features of airway allergic inflammation, including antigen-induced AHR, in C57BL/6 wild-type and TNF −/− mice, using 2 different methods for sensitizing the mice to ovalbumin (OVA). Results In mice sensitized to OVA administered with the adjuvant aluminum hydroxide (alum), which develop IgE-independent and mast cell–independent allergic inflammation and AHR, we found no significant differences in OVA-induced AHR in C57BL/6-TNF −/− versus wild-type mice. By contrast, in mice sensitized to OVA without alum, which develop allergic inflammation that is significantly mast cell–dependent, C57BL/6-TNF −/− mice exhibited significant reductions versus wild-type mice in OVA-induced AHR to methacholine; numbers of lymphocytes, neutrophils, and eosinophils in bronchoalveolar lavage fluid; levels of myeloperoxidase, eosinophil peroxidase, and the cytokines IL-4, IL-5, and IL-17 in lung tissue; and histologic evidence of pulmonary inflammation. Conclusion In pulmonary allergic inflammation induced in mice immunized with OVA without alum, TNF significantly contributes to several features of the response, including antigen-induced inflammation and AHR. Clinical implications Our findings in mice support the hypothesis that TNF can promote the allergic inflammation and AHR associated with asthma.

Background TNF-α is a pivotal proinflammatory cytokine increased in asthmatic airways. The TNF-α gene family might be linked to asthma or bronchial hyperresponsiveness (BHR), and TNF-α production might be modulated by CD14 + cells. Objective We investigated the association between asthma susceptibility or asthma-related phenotypes and TNF-α ( −308G/A ) polymorphism and examined the combined effect with CD14 ( −159T/C ) polymorphism in Korean children. Methods Asthmatic (n = 788) and control (n = 153) children were evaluated for asthma phenotypes. Genotypes were determined by using the single-base extension method and PCR–restriction fragment length polymorphism. Results There was no difference between asthmatic children and control subjects in terms of the allele frequencies of TNF-α ( −308G/A ) and CD14 ( −159T/C ). Significantly lower PC 20 values were seen in asthmatic ( P = .016) children with the TNF-α risk allele ( −308A ). Higher frequencies of 1 or 2 copies of the risk allele were found in asthmatic children with moderate-to-severe BHR to methacholine and exercise compared with control children (adjusted odds ratio of 2.57 [95% CI, 1.30-5.08] and adjusted odds ratio of 2.04 [95% CI 0.99-4.20], respectively). In addition, asthmatic children with risk alleles at both loci had significantly greater BHR than those homozygous for the common alleles ( P = .018). Conclusion The TNF-α promoter polymorphism ( −308G/A ) might be associated with severe BHR in Korean children with asthma. In addition, these children show a synergistic effect between the TNF-α promoter ( −308A ) and CD14 promoter ( −159C ) polymorphisms in terms of BHR. Clinical implications The TNF-α polymorphism might be a disease-modifying gene in asthma and modulated by the CD14 gene.

Background The use of combination inhaled budesonide and formoterol as maintenance and reliever therapy significantly improves the risk and the time to exacerbations in asthma. Objectives To explore the mechanisms underlying the effect of the reliever dose on exacerbations by examining the effect of combination therapy on the allergen challenge model when given after allergen exposure. Methods In a randomized, double-blind crossover study, single doses of budesonide/formoterol (400/12 μg), formoterol (12 μg), budesonide (400 μg), or placebo were administered during the acute bronchoconstriction response (early airway response) immediately after allergen inhalation in 15 patients with mild asthma. Allergen-induced late airway response (LAR), sputum inflammatory markers, airway hyperresponsiveness, and exhaled nitric oxide were measured. Results All active treatments significantly attenuated the LAR, with budesonide/formoterol significantly better than its monocomponents (maximum FEV 1 fall: placebo, [mean ± SEM] 21.2% ± 3.1%; budesonide/formoterol, 4.2% ± 1.4%; formoterol, 7.5% ± 1.7%; budesonide, 10.4% ± 1.6%). Allergen-induced change in methacholine PC 20 was significantly attenuated by budesonide/formoterol, but not by its monocomponents. Sputum cell counts and exhaled nitric oxide increased significantly after all allergen challenges, with no significant attenuation by any of the treatments. Therapy with combination and formoterol alone, but not budesonide, significantly reduced the early airway response. Conclusion A single dose of budesonide/formoterol was superior to its monocomponents in attenuating the allergen-induced LAR and airway hyperresponsiveness. These effects may represent the contribution of the reliever dose to the budesonide/formoterol maintenance and reliever regimen. Clinical implications The protective effect against allergic airway responses with a single reliever dose of budesonide/formoterol is predominantly related to greater functional antagonism of airway smooth muscles.

Background Bronchial asthma is characterized by inflammation of the airways, which is usually accompanied by increased vascular permeability, resulting in plasma exudation. Vascular endothelial growth factor (VEGF) has been implicated in contributing to asthmatic tissue edema through its effect on vascular permeability. Many cellular responses of VEGF are regulated by the lipid products of phosphoinositide 3-kinase (PI3K). However, the effect of PI3K catalytic subunit p110δ on VEGF-mediated signaling is unknown. Recently, an isoform-specific small molecule inhibitor, IC87114, which is selective for p110δ catalytic activity, has been identified. Objective We have sought to investigate the role of PI3K-δ, more specifically in the increase of vascular permeability. Methods Female BALB/c mice were sensitized and challenged with ovalbumin. We have investigated the effect of IC87114 on airway inflammation, T H 2 cytokines expression, airway hyperresponsiveness, plasma extravasation, hypoxia-inducible factor 1α expression, and VEGF expression in a murine model of asthma. Results Our current study has revealed that IC87114 reduces antigen-induced airway infiltration of inflammatory cells, secretion of T H 2 cytokines in lungs, airway hyperresponsiveness, and vascular permeability. Moreover, we have found that inhibition of p110δ reduces ovalbumin-induced upregulation of VEGF level. Conclusion These results suggest that PI3K-δ inhibitor attenuates antigen-induced airway inflammation and hyperresponsiveness by preventing vascular leakage in mice. Clinical implications These findings provide a crucial molecular mechanism for the potential role of PI3K-δ in asthma and other airway inflammatory disorders.

Background Epidemiologic data indicate an increased incidence of asthma in the obese. Objective Because serum levels of the insulin-sensitizing and anti-inflammatory adipokine adiponectin are reduced in obese individuals, we sought to determine whether exogenous adiponectin can attenuate allergic airway responses. Methods We sensitized and challenged BALB/cJ mice with ovalbumin (OVA). Alzet micro-osmotic pumps were implanted in the mice to deliver continuous infusions of buffer or adiponectin (1.0 μg/g/d), which resulted in an approximate 60% increase in serum adiponectin levels. Two days later, mice were challenged with aerosolized saline or OVA once per day for 3 days. Mice were examined 24 hours after the last challenge. Results OVA challenge increased airway responsiveness to intravenous methacholine, bronchoalveolar lavage fluid cells, and T H 2 cytokine levels. Importantly, each of these responses to OVA was reduced in adiponectin- versus buffer-treated mice. OVA challenge caused a 30% reduction in serum adiponectin levels and a corresponding decrease in adipose tissue adiponectin mRNA expression. OVA challenge also decreased pulmonary mRNA expression of each of 3 proposed adiponectin-binding proteins, adiponectin receptor 1, adiponectin receptor 2, and T-cadherin. Conclusion Our results indicate that serum adiponectin is reduced during pulmonary allergic reactions and that adiponectin attenuates allergic airway inflammation and airway hyperresponsiveness in mice. Clinical implications The data suggest that adiponectin might play a role in the relationship between obesity and asthma.

Background Dendritic cells are the most powerful of the antigen-presenting cells and are known to play important roles in sensitization and inflammation in allergen-specific asthma. Various cytokines and chemokines are involved in the maturation and activation of dendritic cells. Among them is CC chemokine ligand (CCL)21, a key chemokine in the entry of naive T cells and antigen-stimulated dendritic cells into the T-cell zones of secondary lymphoid organs, which is a critical process in antigen-specific T-cell activation. Objective We studied the role of CCL21 in airway inflammation in asthma by using BALB/c-plt/plt (plt) mice, which possess genetic defects in expression of both CCL21 and CCL19. Methods Plt and control BALB/c mice were immunized with ovalbumin and alum 4 times and thereafter were subjected to a 2-week regimen of ovalbumin inhalation. Results In plt mice, ovalbumin-specific IgE response was delayed compared with control BALB/c mice, but they had the same level of response after final immunization. Although airway inflammation and response to acetylcholine were significantly reduced compared with BALB/c mice, significant eosinophilic inflammation and hyperresponsiveness were also observed in plt mice after 2 weeks of inhalation. Four weeks after cessation of inhalation, airway inflammation and hyperresponsiveness in plt mice were greater than in BALB/c mice. At the time of resolution of airway inflammation, IL-10 production was enhanced in BALB/c mice but not in plt mice. Conclusion The chemokines CCL21 and CCL19 were critical for resolution of airway inflammation. Clinical implications The findings about the chemokines for induction and resolution of inflammation are key to establishing a new strategy for asthma immunotherapy.

Background Patients with allergic asthma have symptoms of a predominant T H 2 response, including airway eosinophilic inflammation and increased mucous production in the lungs. This accompanies increased airways responsiveness, which can be life threatening. Because T H 2 cells and cytokines have been implicated in contributing to these symptoms, pathways that control the development of these cells or that regulate their cytokine production represent good targets for controlling this disease. Objective We have previously shown that mice lacking the tyrosine kinase inducible T-cell kinase (ITK) have drastically reduced airway inflammation in a model of allergic asthma. However, it was not clear whether this translated into reduced airways hyperresponsiveness. We have analyzed tracheal responsiveness and airways hyperresponsiveness of wild-type (WT) and ITK null mice during induction of experimental allergic asthma. Methods Experimental allergic asthma was induced in WT and ITK knockout mice. Tracheal responses to carbachol, acetylcholine, and potassium chloride were analyzed. Airways hyperresponsiveness to methacholine challenge was also analyzed in allergen-challenged mice, along with lung and bronchoalveolar lavage fluid T H 2 cytokine message and protein. Results ITK null mice have reduced tracheal responses to cholinergic challenge in vitro before as well as after allergen challenge. These mice also have reduced airways hyperresponsiveness in response to allergen challenge, which could be rescued by transferring WT splenocytes or purified WT CD4 + T cells. This reduced airways response was preferentially accompanied by reduced expression of T H 2 cytokines in the lungs. Conclusion Our results indicate that the tyrosine kinase ITK and its function in T cells represent an attractive target for antiasthmatic drugs. Clinical implications Modulating the expression or activity of ITK may be a novel strategy to block allergic airway inflammation.

Background A new asthma susceptibility gene, the G protein–coupled receptor for asthma susceptibility ( GPRA, GPR154 ), has recently been identified and the association was replicated in 2 white populations, but not in a Korean population. Objective To test the association between GPR154 gene polymorphisms and airway responsiveness to methacholine in a Chinese population. Methods Eight single nucleotide polymorphisms (SNPs) in the GPR154 gene were genotyped in 451 cases and 232 controls in stage I. The association of 1 SNP, rs324981, was tested in an additional 264 case and 241 control subjects in stage II. Both single marker and haplotype associations were tested. Results In stage I, we found that airway hyperresponsiveness to methacholine was associated with 2 single SNPs, rs324981 and rs324987, but not with the haplotypes of GPR154 . The minor allele homozygotes of rs324981 (AA) and rs324987 (TT) were at a significantly lower risk of hyperresponsiveness to methacholine with odds ratios of 0.59 ( P = .02) and 0.56 ( P = .01), respectively. In stage II, we found a similar trend of association between rs324981 and airway hyperresponsiveness ( P = .09). In the pooled analysis, the odds ratio of the AA homozygote of rs324981 was 0.61 ( P = .004). The permutation test resulted in a study-wide empirical P value of .023, which meant that the association remained significant after adjustment for multiple tests. Conclusions Our study supports a role of the GPR154 gene in asthma susceptibility and suggests that the AA homozygote of rs324981 is a protective factor for airway hyperresponsiveness to methacholine in a Chinese population. Clinical implications Our findings confirmed a role of GPR154 in the genetic susceptibility of asthma and suggest that GPR154 polymorphism should be taken into consideration to improve the assessment of an individual's risk of asthma.

Background Matrix metalloproteinase 9 (MMP-9) and its tissue inhibitor of metalloproteinase 1 (TIMP-1) are hypothesized to play a role in the pathogenesis of airway remodeling in asthma. Objective We have used a mouse model of airway remodeling to determine the pattern of expression of MMP-9 and TIMP-1 in airway epithelium and peribronchial cells, and assess whether TIMP-1, an inhibitor of MMP-9, is expressed at the same sites in the airway. In addition, we have investigated whether immunostimulatory sequences (ISSs) of DNA modulate levels of expression of MMP-9, TIMP-1, and peribronchial fibrosis. Methods Levels of lung MMP-9 and TIMP-1 were assessed by zymography, ELISA, and immunohistochemistry. Results Repetitive ovalbumin challenge induced a significant increase in levels of MMP-9, TIMP-1, and peribronchial collagen deposition. The pattern of expression of MMP-9 and TIMP-1 in the remodeled airway was significantly different. MMP-9 but not TIMP-1 was expressed in airway epithelium, whereas both MMP-9 and TIMP-1 were expressed in peribronchial inflammatory cells. ISS significantly reduced expression of MMP-9 in airway epithelium (which immunostained positive for Toll receptor 9), as well as in peribronchial inflammatory cells. In vitro studies demonstrated that ISS inhibited bone marrow macrophage generation of MMP-9. Conclusion Allergen-induced peribronchial fibrosis is associated with expression of MMP-9 and TIMP-1 at different anatomical sites in the remodeled airway. The ability of ISS to inhibit the expression of MMP-9 in airway epithelium (a site where its inhibitor TIMP-1 is not induced by allergen challenge) may be important in determining whether ISS contributes to reductions in airway remodeling by reducing levels of MMP-9. Clinical implications Immunostimulatory sequences of DNA, which are being investigated as novel therapeutics in asthma, inhibit airway remodeling in mice as well as epithelial expression of MMP-9, an enzyme that degrades the extracellular matrix proteins surrounding the airway.

Background: Sex hormones may contribute to the higher prevalence and severity of adult asthma in women compared with men.Objective: Sequence variants in the estrogen receptor a gene (ESRI) may alter estrogen action in asthma.Methods: Two hundred asthma probands and their families (n = 1249) were genotyped for 5 single nucleotide polymorphisms (SNPs) in the ESRI gene (intervening sequence 1 [IVS1]-1505A/G, IVS1-1415T/C, IVS1-397C/T, IVS1-351G/A and exon 1 +30T/C). Association with asthma and bronchial hyperresponsiveness (BHR) were tested. In the asthma probands, association of SNPs with BHR severity and annual FEV1 decline were determined.Results: No SNP was associated with asthma. IVS1-397 was significantly associated with the presence of BHR (P =.02) and interacted with sex; female subjects with the CT or TT genotype were at risk (P =.01). In asthma probands, all SNPs were associated with FEV1 decline. Exon1 +30 CT and TT group had an excess decline of 11.6 mL/y (P =.03) and 15.7 mL/y (P =.01), respectively, compared with the CC group. Of the IVS1 polymorphisms, IVS1-351G/A showed the strongest association, with the AA group having excess decline of 16.1 mL/y (P =.01) compared with the GG group. In subanalyses by sex, these associations were significant only in female subjects.Conclusion: ESR1 gene variants may affect development of BHR, particularly in female subjects. They may also lead to a more rapid lung function loss in patients with asthma, and in female subjects specifically. This may result from altered estrogen action, which affects lung development and/or airway remodeling. Further studies on ESR1 gene variations are important to understand better the origin of sex differences in asthma. Clinical implications: Variations in the gene encoding estrogen receptor a are associated with BHR and a more rapid annual lung function decline., especially in female subjects. Even though this has no diagnostic or clinical implication, it may open avenues for future sex-specific treatment in asthma.

Background Respiratory viruses induce asthma exacerbations and airway hyperresponsiveness (AHR). Atopy is an important risk factor for asthma persistence. Objective We sought to evaluate whether atopy is a risk factor for prolonged AHR after upper respiratory tract infections (URIs). Methods Twenty-five children (13 atopic and 12 nonatopic children) with intermittent virus-induced asthma were studied. Clinical evaluation, skin prick tests, methacholine bronchoprovocation, questionnaires, and a nasal wash specimen were obtained at baseline. For 9 months, subjects completed diary cards with respiratory symptoms. During their first reported cold, a nasal wash specimen was obtained. Methacholine provocation was performed 10 days and 5, 7, 9, and 11 weeks later. In case a new cold developed, the provocation schedule was followed from the beginning. Results Viruses were detected in 17 (68%) of 25 patients during their first cold, with rhinovirus being most commonly identified (82%). AHR increased significantly 10 days after the URI, equally in both groups ( P =.67), and remained so up to the fifth week. Duration of AHR in subjects experiencing a single URI ranged from 5 to 11 weeks, without a significant difference between groups. In the duration of the study, atopic children experienced more colds and asthma exacerbations than nonatopic children. Thus for duration of AHR, significant prolongation was noted in the atopic group when assessed cumulatively. Conclusion In asthmatic children the duration of AHR after a single natural cold is 5 to 11 weeks. However, an increased rate of symptomatic cold and asthma episodes in atopic children is associated with considerable cumulative prolongation of AHR, which might help explain the role of atopy as a risk factor for asthma persistence.

Background (R)- and (S)-Enantiomers of albuterol likely exert differential effects in patients with asthma. The (R)-enantiomer binds to the β 2 -adrenergic receptor with greater affinity than the (S)-enantiomer and is responsible for albuterol's bronchodilating activity. (S)-Albuterol augments bronchospasm and has proinflammatory actions. Objective The study aim was to determine whether the (S)-enantiomer, in contrast to the (R)-enantiomer, has adverse effects on allergic airway inflammation and hyperresponsiveness in a mouse asthma model. Methods Mice sensitized to ovalbumin (OVA) intraperitoneally on days 0 and 14 were challenged with OVA intranasally on days 14, 25, and 35. On day 36, 24 hours after the final allergen challenge, the effect of the (R)- and (S)-enantiomers of albuterol (1 mg · kg −1 · d −1 administered by means of a miniosmotic pump from days 13-36) on airway inflammation and hyperreactivity was determined. Results In OVA-sensitized/OVA-challenged mice, (R)-albuterol significantly reduced the influx of eosinophils into the bronchoalveolar lavage fluid and airway tissue. (R)-Albuterol also significantly decreased airway goblet cell hyperplasia and mucus occlusion and levels of IL-4 in bronchoalveolar lavage fluid and OVA-specific IgE in plasma. Although (S)-albuterol significantly reduced airway eosinophil infiltration, goblet cell hyperplasia, and mucus occlusion, it increased airway edema and responsiveness to methacholine in OVA-sensitized/OVA-challenged mice. Allergen-induced airway edema and pulmonary mechanics were unaffected by (R)-albuterol. Conclusion Both (R)- and (S)-enantiomers of albuterol reduce airway eosinophil trafficking and mucus hypersecretion in a mouse model of asthma. However, (S)-albuterol increases allergen-induced airway edema and hyperresponsiveness. These adverse effects of the (S)-enantiomer on lung function might limit the clinical efficacy of racemic albuterol.

Background House dust mite allergen exposure is a key risk factor for the development of allergic asthma. Beyond provoking immune cell-mediated allergic responses, house dust mite allergens were recently shown to exert direct effects on airway structural cells secondary to their intrinsic protease activities. Objective This study tested the hypothesis that house dust mite allergen exposure can produce changes in airway responsiveness through a direct effect on airway smooth muscle (ASM). Methods Isolated rabbit ASM tissues were exposed to the house dust mite allergen, Der p 1, and induced changes in ASM responsiveness and activation of mitogen-activated protein kinase (MAPK) signaling pathways were examined under different experimental conditions. Results The observations demonstrated the following: (1) Der p 1 exposure elicited enhanced constrictor responses and impaired relaxation responses in the ASM tissues, (2) these proasthmatic-like effects of Der p 1 were attributed to its intrinsic cysteine protease activity, and (3) the induced changes in ASM responsiveness were associated with activation of both the extracellular signal-regulated kinase (ERK) 1/2 and the p38 MAPK signaling pathways. Additionally, specific blockade of ERK1/2 signaling was found to prevent the Der p 1–induced changes in ASM responsiveness, whereas inhibition of p38 MAPK signaling enhanced the proasthmatic-like action of Der p 1, with the latter effect a result of augmented activation of ERK1/2. Conclusion These findings are the first to demonstrate that the dust mite allergen, Der p 1, can directly elicit changes in ASM responsiveness that are associated with activation of MAPK signaling, wherein proasthmatic effects induced by Der p 1 are attributed to activation of ERK1/2, whereas coactivation of p38 MAPK exerts a homeostatic action by negatively regulating ERK1/2 signaling.

Background: Asthma is a common respiratory disease caused by the interaction of genetic susceptibility and exposure to various environmental factors. Passive smoke exposure, characterized by parental smoking, has been shown to be a risk factor for the development of atopy and asthma.Objective: We sought to perform a genome-wide linkage screen for asthma and bronchial hyperresponsiveness (BHR) and to determine the influence of passive tobacco smoke exposure during childhood on the results of genetic linkage studies to investigate gene-environment interactions.Methods: A genome-wide linkage screen for asthma and BHR was performed in 200 families ascertained through a parent with asthma. Analyses were performed separately for the entire sample and for the smoking-exposed and nonexposed families.Results: For asthma and BHR, the strongest evidence for linkage was observed for chromosomes 3p and 5q. The families in which the children were exposed to passive smoking accounted for the evidence for linkage of BHR to 5q (P Conclusion: The results from this study demonstrate that the influence of susceptibility genes for a common disease such as asthma might not be apparent unless there is the appropriate exposure to environmental stimuli, such as passive exposure to cigarette smoke. This approach should be useful for identification of asthma susceptibility genes.

Background Treatment with inhaled steroids is an effective method of reducing bronchoconstriction and airway inflammation after allergen challenge. However, the durationof the protective effects of inhaled steroids after discontinuation of therapy has not been established. Objective We sought to evaluate the protective effect of 1 week of inhaled steroid therapy against inhaled allergen challenge 12 hours after discontinuation of therapy. Methods In this randomized, double-blind, placebo-controlled crossover trial, 26 asthmatic subjects (>18 years old) not using inhaled steroids were administered 200 μg of budesonide twice daily, 200 μg of fluticasone twice daily, or placebo twice daily for 1 week. Twelve hours after discontinuation of therapy, subjects were administered an inhaled allergen challenge. Each treatment period was separated by a 3-week washout period. Results When compared with placebo (26% ± 14%), there was a slight but significant protection against the allergen-induced early response after fluticasone treatment (19% ± 10%, P =.001) but not after budesonide treatment (23% ± 13%, P =.08). However, when the area under the curve for the early airway response was examined, there was no difference between the 2 drugs in the amount of protection ( P =.62). Partial protection was demonstrated against the late-response allergen-induced sputum eosinophilia with both treatments ( P =.001). By contrast, no protection was observed against allergen-induced airway hyperresponsiveness for either treatment. Conclusions The protective effects of inhaled steroids against allergen-induced early responses, airway eosinophilia, and allergen-induced airway hyperresponsiveness are partially or completely lost as early as 12 hours after discontinuation of therapy.

Asthma is a disorder characterized by common features of reversible airflow obstruction and bronchial hyperreactivity in the setting of airway mucosal and submucosal inflammation. However, the clinical manifestations are syndromic and not unimodal. There is marked variability in severity of symptoms, natural history, risks of adverse outcomes, pathologic characteristics, and response to therapy. Understanding the relationship between these factors has been complicated by the variability of outcomes and the lack of correlation between them. There is a striking absence of correlation among the pathologic, physiologic, and clinical manifestations of the asthmatic disorders. Lung function tends to correlate poorly with clinical outcomes, and there is only modest correlation between clinical outcomes. Response to therapy is variable both externally (between patients) and internally, depending on which outcome is evaluated. A more complete understanding of the variability of disease and the genetic and environmental causes of the variability likely will change how we approach asthma and its therapy.

Background T H 2-mediated allergic asthma is characterized by eosinophilia, mucus overproduction, and airway hyperresponsiveness (AHR). Although it is clear that T H 2 cells and their cytokines play an important role in AHR, the roles of T H 1 cells and neutrophils in AHR are controversial. Objective We sought to determine the roles of T H 1 cells and neutrophils in AHR. Methods Ovalbumin-specific CD4 + T cells were purified from DO11.10 mice, differentiated into T H 1 cells, and injected into naive BALB/c, IL-4RαKO, or IL-8RKO mice. After ovalbumin antigen challenge, cytokine mRNA levels in lung samples, as well as inflammatory cell types and numbers in bronchoalveolar lavage fluid (BALF), were determined. AHR was assessed by measuring resistance in tracheostomized mice and enhanced pause in freely moving mice. Results T H 1 cells induced AHR as robust as T H 2 cells. They also induced lung inflammation dominated by neutrophils. Neither AHR nor inflammation were reduced when T H 1 cells were transferred into IL-4RαKO mice. When IL-8RKO mice were used as recipients of T H 1 cells, neutrophilia was greatly reduced, but the AHR was as strong as that seen in wild-type mice. On the other hand, dexamethasone treatment had no effect on neutrophilia but has significantly reduced AHR. Reduction in AHR was accompanied by a reduction in the numbers of lymphocytes and macrophages in BALF. Conclusions T H 1 cells can induce strong AHR independent of IL-4 and IL-13. The AHR is associated with the presence of lymphocytes and macrophages, but not neutrophils, in BALF. Our results point to a pathway whereby T H 1 cells mediate AHR independent of neutrophilic inflammation.

Background Dendritic cells are important antigen-presenting cells. After an allergen inhalation, their numbers rapidly decrease in circulation and increase in the airway mucosa. Objective To investigate whether allergen-induced changes in the number of circulating dendritic cells are mediated by cysteinyl leukotrienes. Methods In a randomized, double-blind, crossover study, we examined the effects of 2 weeks of treatment with pranlukast (a cysteinyl leukotriene 1 [CysLT 1 ] receptor antagonist) 300 mg twice daily and placebo on allergen-induced changes in airway responses and circulating dendritic cells in 15 subjects with mild asthma. We examined by flow cytometry, before and at 3 hours and 24 hours after allergen inhalation, the proportion of myeloid (CD33 + ) and plasmacytoid (CD123 + ) dendritic cells (HLA-DR + , CD14 – , CD16 – ) among all peripheral blood mononuclear cells. The fraction of dendritic cells expressing CysLT 1 receptor was also determined. Results Compared with placebo, pranlukast significantly attenuated both the maximum early (by 55%) and the late (by 39%) asthma responses, the allergen-induced methacholine airway hyperresponsiveness, and the increase in macrophage inflammatory protein 1α and 3α in induced sputum. A significantly greater proportion of CD33 + cells (55%) expressed CysLT 1 receptor compared with CD123 + cells (11%). Consistent with this, pranlukast prevented the allergen-induced decrease in CD33 + dendritic cells at 3 hours postallergen (mean Δ from baseline, +4.4%) compared with placebo (mean Δ, −8.4; P + cells. Conclusion Pretreatment with pranlukast attenuated allergen-induced airway responses and the decrease in circulating myeloid dendritic cells, demonstrating a novel role of cysteinyl leukotrienes in dendritic cell trafficking.

In a recent study, the difference between asthma and eosinophilic bronchitis (a condition characterized by cough but not airway hyperresponsiveness or airflow obstruction) was infiltration of airway smooth muscle (ASM) by mast cells. Mast cells produce a variety of lipid mediators, chemokines, cytokines, and enzymes that may interact with ASM cells to cause hyperreactivity to constrictive stimuli and proliferation, and activated ASM can produce stem cell factor and other chemokines, cytokines, and growth factors that may act in recruitment, differentiation, and retention of mast cells. Mast cell infiltration of the airways in asthma is T-cell-dependent, and TH2 cytokines from T cells and other sources act in mast cell expansion from circulating and tissue precursors. The recent data on interactions of mast cells and ASM suggest that this could be an important contributor to airway hyperresponsiveness in asthma. Why this occurs in asthma and how it is sustained remain to be established.

Nasal polyposis (NP) is frequently associated with asthma. In this disease, asymptomatic bronchial hyperresponsiveness (BHR) is thought to precede the development of asthma. IL-9 and its receptor have been reported as candidate genes for asthma and to be associated with BHR.The objective of this study was to assess the contribution of 11-9 to the pathogenesis of BHR in NP by comparing the expression of IL-9 and its receptor in bronchial biopsy specimens from three groups of patients with NP: NP without BHR, NP with asymptomatic BHR, and NP with BHR and asthma.Bronchial biopsy specimens were examined in terms of cellular infiltration and in terms of expression of IL-9 protein and mRNA as well as of its receptor by using immunohistochemistry and in situ hybridization.Patients with NP with asthma as compared with the two other groups exhibited an increased bronchial infiltration of basophils, eosinophils, and T cells that correlated with the asthma score. The two groups of patients with NP with BHR showed an increased expression in IL-9 protein and mRNA as well as an increase in the expression of IL-9R mRNA at the epithelial level. These modifications were inversely correlated with the airway responsiveness to methacholine, producing a 20% fall in FEV1. There was a close association between IL-9+ cells, IL-5 mRNA expression, and eosinophil infiltration that correlated with each other.These results suggest an important role for IL-9 in the pathogenesis of BHR and a causal relation between IL-9 and the development of bronchial eosinophilia in asthma.

Background Although asthma and rhinitis often occur together, the reason for this common comorbidity is still a matter of debate. Objective We sought to assess whether the coexistence of asthma and rhinitis could be explained by common risk factors. Methods International cross-sectional study of representative samples of young adults, who completed a detailed questionnaire and underwent lung function tests, bronchoprovocation challenge, IgE measurements, and skin prick tests. Results In all countries, asthma and bronchial hyperreactivity were more frequent in subjects with rhinitis than in those without (odds ratio [OR], 6.63; 95% CI, 5.44-8.08; and OR, 3.02 95% CI, 2.66-3.43, respectively). Seventy-four percent to 81% of subjects with asthma reported rhinitis, depending on sensitization to specific allergens. Conversely, the risk of asthma increased from 2.0% in subjects without rhinitis to 6.7% in subjects with rhinitis only when exposed to pollen, 11.9% in subjects with rhinitis when exposed to animals, and 18.8% in subjects with rhinitis either when exposed to pollen or to animals. The association between rhinitis and asthma remained significant after adjustment for total IgE, parental history of asthma, and allergen sensitization (OR, 3.41; 95% CI, 2.75-4.2 suggesting that the coexistence of asthma and rhinitis is not solely due to atopic predisposition to these 2 diseases. Conclusions Although there were some variations in the association between asthma and rhinitis according to sensitization to individual allergens, the strong association between asthma and rhinitis was not fully explained by shared risk factors, including atopy. Our findings are consistent with the hypothesis that rhinitis might increase the risk of asthma.

Background Airway obstruction, perhaps the most relevant clinical feature of asthma, is typically assessed in allergic asthma models as airway hyperresponsiveness. Excess secretion of airway glycoproteins also contributes to airway obstruction in asthma but is not measured as part of most experimental models. Objective The purposes of this study were to develop a reliable, quantitative assay for detecting secreted airway glycoproteins and to assess the secretion of airway glycoproteins in comparison with other markers of airway obstruction resulting from allergic lung inflammation. Methods Two microtiter plate–based glycoprotein-detecting methods were developed, one using an antiglycoprotein antibody and the other using the glycoprotein-binding plant lectin, jacalin. Both methods were used to assess airway glycoprotein secretion in response to 2 defined agonists given intranasally, IL-13 and an allergen derived from Aspergillus fumigatus . Glycoprotein secretion was assessed concomitant with another measure of airway obstruction, airway hyperresponsiveness provoked by acetylcholine challenge, and a histologic method for quantitating glycoprotein production. Results Both assays were sufficient for quantitating airway glycoproteins over the full range of values encountered from murine bronchoalveolar lavage and yielded highly reproducible data. Secretion of airway glycoproteins increased commensurate with the detection of both airway hyperresponsiveness and airway glycoprotein production induced by IL-13 and allergen. Conclusion Airway glycoprotein secretion is a consistent feature of the allergic lung phenotype and likely contributes to airway obstruction induced by allergen in both humans and rodents.

Background Eotaxin-2 is a member of the eotaxin subfamily of CC chemokines that display eosinophil-specific, chemotactic properties and has been associated with allergic disorders. However, the contribution of eotaxin-2 to the development of defined pathogenic features of allergic disease remains to be defined. Objective We sought to determine whether eotaxin-2 was a cofactor with IL-5 for the regulation of pulmonary eosinophilia and to identify the combined role of these molecules in the induction of phenotypic characteristics of allergic lung disease. Methods We instilled recombinant eotaxin-2 into the airways of wild-type mice that had been treated systemically with IL-5 or into IL-5-transgenic mice and characterized pulmonary eosinophil numbers, IL-13 production, and airway hyperreactivity (AHR) to methacholine. Mice deficient in the IL-4 receptor α-chain, IL-13, and signal transducers and activators of transcription 6 or mice treated with anti-CCR3 monoclonal antibody were also used. Results Eotaxin-2 and IL-5 cooperatively promoted eosinophil accumulation, IL-13 production, and AHR to methacholine. Neither eotaxin-2 nor IL-5 alone induced these features of allergic disease. IL-13 production was critically dependent on eotaxin-2- and IL-5-regulated eosinophilia, which predisposed to the development of AHR. AHR was dependent on IL-13 and signaling through the IL-4R α-chain and signal transducers and activators of transcription 6 pathways and the presence of eosinophils in the lung. Conclusion These investigations demonstrate important cooperativity between eotaxin-2, IL-5, and IL-13 signaling systems and eosinophils for the development of hallmark features of allergic disease of the lung.

Background: It has been demonstrated that both cysteinyl leukotrienes (cysLTs) and cytokines are involved in the pathophysiology of bronchial asthma. Nonetheless, the exact mechanism involved in the interaction between these 2 molecules has yet to be determined. Objective: The aim of the present study was to determine the effects of cysLTs on allergic airway inflammation and allergen-specific cytokine production in a murine model of asthma. Methods: Four groups of BALB/c mice (control mice, Dermatophagoides farinae allergen-sensitized mice, pranlukast cysLT receptor antagonist-treated allergen-sensitized mice, and dexamethasone-treated allergen-sensitized mice) were examined. Results: Allergen-sensitized mice exhibited increased airway responsiveness and inflammation. Pranlukast-treated mice showed significant attenuation of these changes concomitant with reduction of T H 2 cytokine and IFN-γ production by isolated lung mononuclear cells (MNCs). A much stronger inhibition of all cytokines was noted in dexamethasone-treated mice. Pranlukast also significantly inhibited production of RANTES and activation of nuclear factor κB (NF-κB) in the isolated lung MNCs. Leukotriene D 4 stimulated isolated lung MNCs to produce RANTES but not any other cytokines and also activated NF-κB in these cells. Conclusions: Our results suggest that cysLTs activate NF-κB and induce RANTES production from isolated lung MNCs, which in turn might cause migration of eosinophils and activated T lymphocytes into the airway. (J Allergy Clin Immunol 2003;112:369-74.)

We sought to identify factors associated with wheezing symptoms in children found to have bronchial hyperresponsiveness (BHR) at 10 years of age.Children were seen at birth, 1, 2, 4 and 10 years of age in an entire population birth cohort study (n = 1456). At each stage information was collected prospectively on genetic and environmental risk factors for BHR. Skin prick testing was performed at 4 and 10 years of age. Spirometry and methacholine bronchial challenge were conducted at 10 years of age when BHR was considered present if PC(20) FEV(1) was4.0 mg/mL. In children with BHR at 10 years of age, factors independently associated with current wheezing were determined by logistic regression.BHR was identified in 169 10-year-olds at bronchial challenge, 55.6% of whom manifested current wheeze. In children with BHR, current wheezers had higher Log(10) total IgE and greater BHR than those who had never wheezed. Symptomatic BHR was independently associated with atopic sensitization (P.001) and maternal asthma (P =.011) at 10 years of age. If only factors present in the first 4 years of life were considered, parental smoking at 4 years of age (P =.021), maternal asthma (P =.017), and atopic sensitization at 4 years of age (P =.004) were independently associated with symptomatic BHR at 10 years of age.Symptomatic BHR is associated with greater degrees of BHR and higher total IgE. Heredity, atopy, and environmental exposure might influence symptom expression in children with BHR.

Exposure to high levels of allergens in sensitized asthmatic patients causes worsening of pulmonary function in experimental studies. Chronic exposure to lower, naturally occurring levels of allergens might increase the severity of asthma.We sought to study the associations between sensitization and exposure to common indoor allergens (dust mite, cat, and dog) in the home on pulmonary function, exhaled nitric oxide (eNO), and airway reactivity in asthmatic patients.Dust samples were collected from the living room carpet and mattress of 311 subject's homes, and Der p 1, Fel d 1, and Can f 1 concentrations were measured by using ELISAs. Spirometry, nonspecific bronchial reactivity, and eNO were measured.Subjects both sensitized and exposed to high levels of sensitizing allergen had significantly lower FEV(1) percent predicted values (mean, 83.7% vs 89.3%; mean difference, 5.6%; 95% CI, 0.6%-10.6%; P =.03), higher eNO values (geometric mean [GM], 12.8 vs 8.7 ppb; GM ratio, 0.7; 95% CI, 0.5-0.8; P =.001), and more severe airways reactivity (PD(20) GM, 0.25 vs 0.73 mg; GM ratio, 2.9; 95% CI, 1.6-5.0; P.001) compared with subjects not sensitized and exposed. No significant effect of the interaction between sensitization and exposure was found for FEV(1) percent predicted and eNO values. However, there was a significant effect of the interaction between sensitization and exposure to any allergen (P =.05) and between sensitization and exposure to cat allergen (P =.04) for nonspecific bronchial reactivity.Asthmatic subjects who are exposed in their homes to allergens to which they are sensitized have a more severe form of the disease.

Background: RANTES promoter polymorphisms were found associated with asthma/atopy in some studies but not others, possibly reflecting the genetic heterogeneity among different ethnicities and different asthma severity. Objective: The purpose of this investigation was to test the genetic association between the RANTES −28C/G and −403G/A polymorphisms and asthma/atopy in a cohort of Chinese children, with particular emphasis on those patients who had experienced life-threatening asthma attacks. Methods: Forty-eight children with near-fatal asthma, 134 children with mild-to-moderate asthma, 69 children with allergic disorders but no asthma, and 107 nonasthmatic nonatopic control children were genotyped through use of a PCR-based assay. Results: No significant difference was demonstrated for frequency of the RANTES −28C/G polymorphism when the mild-to-moderate asthma, atopic/nonasthmatic, and normal control groups were compared. The RANTES −28G allele was present in a significantly higher proportion of the children with near-fatal asthma compared with the nonasthmatic nonatopic controls (odds ratio, 2.93 [1.41-6.06]; P = .006) and the children with mild-to-moderate asthma (odds ratio, 3.52 [1.73-7.16]; P = .001). The frequency of −28G allele carriage correlated with asthma severity. The RANTES −28G allele was also associated with an increased blood eosinophil count and a higher degree of bronchial hyperresponsiveness. The RANTES −403G/A polymorphism did not influence asthma/atopy susceptibility, blood eosinophil count, or bronchial hyperresponsiveness. Interestingly, a higher frequency of −403A allele carriage was observed in the moderate asthma subgroup compared with the mild asthma analog. Conclusions: We conclude that the RANTES −28C/G polymorphism exacerbates asthma severity, representing a genetic risk factor for life-threatening asthma attacks in Chinese children. In addition, the linkage disequilibrium between these 2 polymorphisms is a potential confounder that must be considered in the design and interpretation of RANTES gene association studies. (J Allergy Clin Immunol 2003;111:1285-92.)

Bronchial asthma is a chronic inflammatory disease characterized mainly by infiltration of the airway mucosa by various inflammatory cells, notably eosinophils. T(H)2-type cytokines are suggested to be deeply involved in the pathogenesis of asthma.We sought to determine the suppressive effects of suplatast tosilate, an inhibitor of T(H)2-type cytokines, on eosinophilic inflammation of the bronchial mucosa in patients with mild asthma.Airway hyperresponsiveness tests, pulmonary function tests, eosinophil measurements in induced sputum, and bronchial mucosa biopsies were performed before and after treatment with suplatast tosilate for 6 weeks in 15 patients with mild asthma and in 13 control patients with mild asthma not receiving suplatast tosilate. This study was performed as a case-controlled open study.In the treatment group a significant improvement in the provocation concentration of histamine was observed (P.05). Improvements in peak expiratory flow (P.01) and in symptom score (P.05) were also noted in the suplatast tosilate-treated group. Moreover, the average number of infiltrating eosinophils and EG2(+) cells significantly decreased (both P.05), as did the ratios of eosinophils and EG2(+) cells in sputum (both P.01). The average number of CD4(+) and CD25(+) T lymphocytes also decreased (both P.05).Suplatast tosilate appears to inhibit allergic airway inflammation mediated by T(H)2-type cytokine and to improve clinical symptoms in patients with mild asthma.