Allergen-induced Asthmatic Responses Research Articles

Wheeze No More: Growing Out of Your Dopaminergic Nerves

In this issue of Immunity, Wang etal. identify a developmental transition of neural-immune interactions from postnatal to adult lung. Their findings implicate sympathetic nerve production of dopamine as a contributor to the susceptibility of children to allergen-induced asthmatic responses.

Effect of Inhaled TD-8236 on Allergen-induced Asthmatic Response

Effect of Inhaled TD-8236 on Allergen-induced Asthmatic Response

The effects of a CCR3 inhibitor, AXP1275, on allergen‐induced airway responses in adults with mild‐to‐moderate atopic asthma

CCR3 is the cognate receptor for major human eosinophil chemoattractants from the eotaxin family of proteins that are elevated in asthma and correlate with disease severity. This proof-of-mechanism study examined the effect of AXP1275, an oral, small-molecule inhibitor of CCR3, on airway responses to inhaled allergen challenge. Twenty-one subjects with mild atopic asthma and documented early and late asthmatic responses to an inhaled aeroallergen completed a randomized double-blind cross-over study to compare early and late allergen-induced asthmatic responses, methacholine PC20 , blood and sputum eosinophils and exhaled nitric oxide after 2weeks of treatment with once-daily doses of AXP1275 (50mg) or placebo. There was a significant increase in methacholine PC20 after 12days of AXP1275 treatment compared to placebo (increase of 0.92 doubling doses versus 0.17 doubling doses, P=.01), but this protection was lost post-allergen challenge. There was no effect of AXP1275 on allergen-induced late asthmatic responses, or eosinophils in blood and sputum. The early asthmatic response and exhaled nitric oxide levels were slightly lower with AXP1275, but this did not reach statistical significance. The number of subjects who experienced treatment-emergent adverse events while receiving AXP1275 was comparable placebo. AXP1275 50mg administered daily was safe and well tolerated, and there was no difference in the type, severity or frequency of treatment-emergent adverse events in subjects while receiving AXP1275 compared to placebo. AXP1275 increased the methacholine PC20 ; however, the low and variable exposure to APX1275 over a short treatment period may have contributed to poor efficacy on other outcomes.

T-cell inhibitors for atopic dermatitis

The management of atopic dermatitis is changing with the development of novel biologic agents to target specific molecules in the inflammatory cascade. Following the ability of dupilumab has proved its ability to act on the interleukin 4 receptor in treating atopic dermatitis. Thymic stromal lymphopoietin monoclonal antibody (AMG157/MEDI9929) and OX40 blocking antibody (GBR 830) were developed by targeting the same pathway as dupilumab further upstream. The clinical data on the efficacy for these drugs are not yet known. There is some early evidence that AMG157/MEDI9929 attenuates most measures of allergen-induced asthmatic responses. However, there are no public data on its ability to treat atopic dermatitis. In a phase 2a study, GBR 830 showed at least a 50% reduction in the Eczema Area and Severity Index scores of 17 of 23 patients, but it was not sufficiently powered for identification of statistical differences between GBR 830 versus placebo. Although there is potential for these 2 drugs to greatly improve the management of severe atopic dermatitis, significant clinical trials have not yet been completed to prove efficacy, and there are not yet any available phase 3 clinical trials, which are needed to truly evaluate their efficacy in affecting T-cells.

Randomized trial of allergen-induced asthmatic response in smokers andnon-smokers: effects of inhaled corticosteroids.

It is thought that asthmatics who smoke cigarettes respond less well to inhaled corticosteroid (ICS) therapy than asthmatics who do not smoke. To evaluate the effects of smoking on allergen-induced airway responses in asthmatics treated with ICS. Randomized, double-blind, crossover study evaluating twice daily fluticasone propionate (FP) 100μg, FP 500μg and placebo, for 7days, on allergen-induced asthmatic responses in 18 non-smoking and 17 smoking atopic asthmatics (NCT01400906). At 1h post-morning dose on Day 6, forced expiratory volume in 1 sec (FEV1 ) was measured up to 10h post-challenge. Exhaled nitric oxide (eNO), induced sputum cell counts, and responsiveness to methacholine were assessed the following day. The late asthmatic response (LAR) was suppressed by FP in smokers and non-smokers; with placebo, the LAR was also attenuated in smokers versus non-smokers (adjusted mean minimum change in FEV1 (L) over 4-10h [95% CI] in non-smokers: placebo -1.01 [1.31, 0.70], FP 100μg -0.38 [0.54, 0.22], FP 500μg -0.35 [0.54-0.22]; and in smokers: placebo -0.63 [0.84, 0.43]; FP 100μg -0.44 [0.65, 0.23]; FP 500μg -0.46 [0.59-0.32]). The Early AR was suppressed by FP treatment in non-smokers, but was not impacted in smokers. The reduction in methacholine hyperresponsiveness after FP was greater in non-smokers (1.5- and twofold doubling dose difference from placebo after FP 100μg and FP 500μg) than smokers (1.0 and 1.3 difference, respectively). Allergen-induced increases in eNO and sputum eosinophils were lower in smokers than non-smokers and were suppressed in both groups by FP. Allergen-induced LARs were of a similar amplitude in both smoking and non-smoking atopic asthmatics at the end of ICS treatment, but attenuation of the LAR in smokers was only partly associated with ICS treatment. The marked attenuation of the LAR observed in smokers in the absence of ICS treatment is a novel observation.

IL-25 as a potential therapeutic target in allergic asthma.

Allergic asthma is a prevalent disease characterized by intermittent airway hyperresponsiveness resulting in airway narrowing, debilitating wheezing and shortness of breath that in severe cases can prove fatal. Notably, the number of sufferers, especially among children, has increased dramatically over recent decades and the WHO estimates that 235 million people worldwide suffer from this disorder. Asthma can be induced by a variety of provocative allergic stimuli and is associated with pulmonary inflammatory infiltrates including T helper 2 (Th2) cells and type-2 innate lymphoid cells (ILC2s) secreting the type-2 cytokines IL-4, IL-5 IL-9 and IL-13. These cytokines coordinate the inappropriate muscular contraction, immunoglobulin E production, eosinophilia and mucus hypersecretion that typify asthma. Despite being characterized for over a century, asthma is often underdiagnosed and there have been few therapeutic advances since the introduction of steroids in the 1950s (e.g., antileukotrienes and anti-IgE treatment). In part, this is due to the complexity of the disease with the existence of subtypes of asthma only now being fully realized. These recent improvements in our understanding have resulted in clinical trials establishing the potential of biological asthma treatments such as antibodies that neutralize IL-5 and IL-13. However, these therapies only work in subsets of asthma patients, leading to an unmet need for additional novel treatments. A triad of lung epithelium-derived cytokines, IL-25, IL-33 and thymic stromal lymphopoietin (TSLP), that lie upstream of the effector type-2 cytokines, have emerged as important mediators in asthma and are therefore potential treatment targets [1]. IL-25 was identified in 2001 and found to induce type-2 immune responses in human and animal studies [2]. It is a member of the IL-17 cytokine family and in contrast to IL-17A elicits type-2 cytokine production via its receptor IL17 receptor beta (IL-17RB, IL-25R) [3]. Although IL-25 is reported to be expressed by a range of structural (including bronchial epithelial cells and endothelial cells) and immune cells (Th cells, macrophages, dendritic cells, basophils and mast cells), it is generally difficult to detect IL-25 protein, presumably because it is produced in low amounts or consumed rapidly. Thus, the cellular sources of IL-25 and the mechanisms by which it is released during disease still remain unclear. A range of immune cells are responsive to IL-25, such as Th2 and Th9 cells, ILC2, monocytes, eosinophils and natural killer T cells; all of which have been shown to contribute to asthma pathogenesis. Mouse models have indicated that IL-25 may represent an important target in asthma, IL-25 as a potential therapeutic target in allergic asthma

Allergen-Induced Asthmatic Responses Modified by a GATA3-Specific DNAzyme

BackgroundThe most prevalent phenotype of asthma is characterized by eosinophil-dominated inflammation that is driven by a type 2 helper T cell (Th2). Therapeutic targeting of GATA3, an important transcription factor of the Th2 pathway, may be beneficial. We evaluated the safety and efficacy of SB010, a novel DNA enzyme (DNAzyme) that is able to cleave and inactivate GATA3 messenger RNA (mRNA).MethodsWe conducted a randomized, double-blind, placebo-controlled, multicenter clinical trial of SB010 involving patients who had allergic asthma with sputum eosinophilia and who also had biphasic early and late asthmatic responses after laboratory-based allergen provocation. A total of 40 patients could be evaluated; 21 were assigned to receive 10 mg of SB010, and 19 were assigned to receive placebo, with each study drug administered by means of inhalation once daily for 28 days. An allergen challenge was performed before and after the 28-day period. The primary end point was the late asthmatic response as quantified by the change in the area under the curve (AUC) for forced expiratory volume in 1 second (FEV1).ResultsAfter 28 days, SB010 attenuated the mean late asthmatic response by 34%, as compared with the baseline response, according to the AUC for FEV1, whereas placebo was associated with a 1% increase in the AUC for FEV1 (P=0.02). The early asthmatic response with SB010 was attenuated by 11% as measured by the AUC for FEV1, whereas the early response with placebo was increased by 10% (P=0.03). Inhibition of the late asthmatic response by SB010 was associated with attenuation of allergen-induced sputum eosinophilia and with lower levels of tryptase in sputum and lower plasma levels of interleukin-5. Allergen-induced levels of fractional exhaled nitric oxide and airway hyperresponsiveness to methacholine were not affected by either SB010 or placebo.ConclusionsTreatment with SB010 significantly attenuated both late and early asthmatic responses after allergen provocation in patients with allergic asthma. Biomarker analysis showed an attenuation of Th2-regulated inflammatory responses. (Funded by Sterna Biologicals and the German Federal Ministry of Education and Research; ClinicalTrials.gov number, NCT01743768.)

Association Between IL-13 -1112 C/T Promoter Polymorphism and Patterns of Allergen-Induced Asthmatic Response in House Dust Mite Allergic Patients

Association Between IL-13 -1112 C/T Promoter Polymorphism and Patterns of Allergen-Induced Asthmatic Response in House Dust Mite Allergic Patients

Effects of ASM-024, a modulator of acetylcholine receptor function, on airway responsiveness and allergen-induced responses in patients with mild asthma.

To evaluate the safety, tolerability and clinical activity of ASM-024, a new cholinergic compound with dual nicotinic and muscarinic activity, in mild allergic asthma. The present study involved 24 stable, mild allergic asthmatic subjects. In a cross-over design, ASM-024 (50 mg or 200 mg) or placebo were administered once daily by nebulization over three periods of nine consecutive days separated by a three-week washout. The effect of each treatment on the forced expiratory volume in 1 s (FEV1), provocative concentration of methacholine causing a 20% decline in FEV1 (PC20), early and late asthmatic responses, and allergen-induced inflammation were measured. Seventeen subjects completed the study. During treatment with ASM-024 at 50 mg or 200 mg, the PC20 value increased respectively from a mean (± SD) 2.56±3.86 mg/mL to 4.11 mg/mL (P=0.007), and from 3.12±4.37 mg/mL to 5.23 mg/mL (P=0.005) (no change with placebo). On day 7 (day preceding allergen challenge), postdosing FEV1 increased by 2.0% with 50 mg (P=0.005) and 1.9% with 200 mg (P=0.008) (placebo -1.1%). ASM-24 had no inhibitory effect on early and late asthmatic responses, nor on sputum eosinophil or neutrophil levels. ASM-024 induced no serious adverse events, but caused cough in 22% and 48% of the subjects with 50 mg and 200 mg, respectively, compared with 10% who were on placebo. ASM-024 did not inhibit allergen-induced asthmatic response and related airway inflammation, but reduced methacholine airway responsiveness and slightly improved lung function. The mechanism by which ASM-024 improves these outcomes requires further study.

Transcriptional networks in whole blood of asthmatics

Background Allergen inhalation challenge causes significant changes in the blood transcriptomes of mild atopic asthmatic individuals [1]. Systems biology approaches have been used to identify transcriptional networks that reflect underlying disease processes. Such networks provide insights into the correlation patterns among genes and may identify specific molecular processes associated with asthmatic responses. Transcriptional networks can be identified using blood expression data and are associated with allergen-induced asthmatic responses.

Science Translational Medicine Podcast: 2 July 2014

Jeffrey M. Harris and Lawren C. Wu describe how the drug quilizumab reduced allergen-induced asthmatic airway responses in mild asthmatics.

Effects of an Anti-TSLP Antibody on Allergen-Induced Asthmatic Responses

BackgroundThymic stromal lymphopoietin (TSLP) is an epithelial-cell–derived cytokine that may be important in initiating allergic inflammation. AMG 157 is a human anti-TSLP monoclonal immunoglobulin G2λ that binds human TSLP and prevents receptor interaction.MethodsIn this double-blind, placebo-controlled study, we randomly assigned 31 patients with mild allergic asthma to receive three monthly doses of AMG 157 (700 mg) or placebo intravenously. We conducted allergen challenges on days 42 and 84 to evaluate the effect of AMG 157 in reducing the maximum percentage decrease in the forced expiratory volume in 1 second (FEV1). We also measured the fraction of nitric oxide in exhaled air, blood and sputum eosinophils, and airway hyperresponsiveness. The primary end point was the late asthmatic response, as measured 3 to 7 hours after the allergen challenge.ResultsAMG 157 attenuated most measures of allergen-induced early and late asthmatic responses. The maximum percentage decrease in the FEV1 during the late response was 34.0% smaller in the AMG-157 group than in the placebo group on day 42 (P=0.09) and 45.9% smaller on day 84 (P=0.02). In addition, patients receiving AMG 157 had significant decreases in levels of blood and sputum eosinophils before and after the allergen challenge and in the fraction of exhaled nitric oxide. There were 15 adverse events in the AMG-157 group, as compared with 12 in the placebo group; there were no serious adverse events.ConclusionsTreatment with AMG 157 reduced allergen-induced bronchoconstriction and indexes of airway inflammation before and after allergen challenge. These findings are consistent with a key role for TSLP in allergen-induced airway responses and persistent airway inflammation in patients with allergic asthma. Whether anti-TSLP therapeutics will have clinical value cannot be determined from these data. (Funded by Amgen; ClinicalTrials.gov number, NCT01405963.)

Eculizumab for treatment of asthma

Introduction: Asthma is an inflammatory disease, which can be exacerbated by stimuli such as viral infections and exposure to allergens. Asthma continues to be a profound public health problem due to asthma exacerbation in a low proportion of patients in need of more effective medications.Areas covered: The C5 complement pathway has been proposed as a new target for the treatment of asthma, supported by clinical observations of increased C5a levels in asthmatic airways, constitutive expression of C5 receptors on bronchial epithelium and smooth muscle cells, and preclinical studies in mice demonstrating inhibition of C5 cleavage reduced established airway inflammation and improves lung function. Eculizumab is a monoclonal antibody, which binds to the complement protein C5, thereby preventing the formation of C5a and C5b-9. The research discussed in this review describes development of eculizumab for the treatment of paroxysmal nocturnal hemoglobinuria and the efficacy of eculizumab on allergen-induced asthmatic responses in a placebo-controlled study.Expert opinion: In an allergen-challenge model of asthma, there was a significant period effect with eculizumab, with inhibition of the late asthmatic response in subjects who received placebo treatment first. Although this study provides some evidence that eculizumab may be effective to attenuate allergen-induced responses, the role of C5 in asthma remains to be clarified.

The effect of C5 inhibition by eculizumab on allergen-induced asthmatic responses in patients

The effect of C5 inhibition by eculizumab on allergen-induced asthmatic responses in patients

Hyaluronidase Expression and Activity Is Regulated by Pro-Inflammatory Cytokines in Human Airway Epithelial Cells

Hyaluronan (HA) is present at the apical surface of airway epithelium as a high-molecular-weight polymer. Since HA depolymerization initiates a cascade of events that results in kinin generation and growth factor processing, in the present work we used primary cultures of human bronchial epithelial (HBE) cells grown at the air-liquid interface (ALI) to assess hyaluronidase (Hyal) activity by HA zymography, gene expression by quantitative real-time PCR, and localization by confocal microscopy. Because TNF-alpha and IL-1beta induce Hyals in other cells, we tested their effects on Hyals expression and activity. We found that Hyal-like activity is present in the apical and basolateral secretions from HBE cells where Hyals 1, 2, and 3 are expressed, and that IL-1beta acts synergistically with TNF-alpha to increase gene expression and activity. Confocal microscopy showed that Hyals 1, 2, and 3 were localized intracellularly, while Hyal2 was also expressed at the apical pole associated with the plasma membrane, and in a soluble form on the apical secretions. Tissue sections from normal individuals and from individuals with asthma showed a Hyal distribution pattern similar to that observed on nontreated HBE cells or exposed to cytokines, respectively. In addition, increased expression and activity were observed in tracheal sections and in bronchoalveolar lavage (BAL) obtained from subjects with asthma when compared with normal lung donors and healthy volunteers. Our observations indicate that Hyal 1, 2, and 3 are expressed in airway epithelium and may operate in a coordinated fashion to depolymerize HA during inflammation associated with up-regulation of TNF-alpha and IL-1beta, such as allergen-induced asthmatic responses.

Th1- and Th2-Dependent Endothelial Progenitor Cell Recruitment and Angiogenic Switch in Asthma

Increased numbers of submucosal vessels are a consistent pathologic component of asthmatic airway remodeling. However, the relationship between new vessel formation and asthmatic inflammatory response is unknown. We hypothesized that angiogenesis is a primary event during the initiation of airway inflammation and is linked to the recruitment of bone marrow-derived endothelial progenitor cells (EPC). To test this hypothesis, circulating EPC and EPC-derived endothelial cell colony formation of individuals with asthma or allergic rhinitis and health controls was evaluated. Circulating EPC were increased in asthma, highly proliferative, and exhibited enhanced incorporation into endothelial cell tubes as compared with controls. In an acute allergen challenge murine asthma model, EPC mobilization occurred within hours of challenge and mobilized EPC were selectively recruited into the challenged lungs of sensitized animals, but not into other organs. EPC recruitment was Th1 and Th2 dependent and was temporally associated with an increased microvessel density that was noted within 48 h of allergen challenge, indicating an early switch to an angiogenic lung environment. A chronic allergen challenge model provided evidence that EPC recruitment to the lung persisted and was associated with increasing microvessel density over time. Thus, a Th1- and Th2-dependent angiogenic switch with EPC mobilization, recruitment, and increased lung vessel formation occurs early but becomes a sustained and cumulative component of the allergen-induced asthmatic response.

Metalloproteinase-9 in Induced Sputum Correlates with the Severity of the Late Allergen-Induced Asthmatic Response

Background: Asthma is characterized by airway inflammation and remodeling in which matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMP) play an important role. Allergen exposure activates the inflammatory/repair process in sensitized subjects. Induced-sputum analysis is a non-invasive method that allows the assessment of changes in inflammatory and remodeling mediators implicated in asthma. Objectives: To evaluate the changes in MMP-9 and its principal inhibitor (TIMP-1) in sputum and plasma of mild allergic asthmatic subjects after whole-lung allergen challenge. Methods: Induced sputum and blood samples were obtained at baseline, and 6 and 24 h after challenge. MMP-9 and TIMP-1 levels in sputum and plasma were measured by ELISA. Results: Allergen challenge increased the percentage of sputum eosinophils and MMP-9 levels 6 and 24 h after the challenge compared to baseline levels, but TIMP-1 levels did not vary significantly. A significant correlation was observed between MMP-9 levels at 6 h and the maximum percent fall in FEV₁ during the late response. Throughout the study, MMP-9 levels correlated significantly with the number of neutrophils in sputum. Conclusions: This study shows that analysis of induced sputum is a useful tool to study the variations in MMP-9 and TIMP-1 levels following allergen challenge, therefore allowing to evaluate their role in allergen-induced airway damage and repair.

Alterations in exhaled gas profile during allergen-induced asthmatic response.

The source of exhaled carbon monoxide (CO) and the relationship to airway inflammation are not clear. If CO is produced by the inflamed airway, we hypothesized that inflammation induced by allergen challenge would increase exhaled CO of atopic asthmatics. Eight atopic asthmatics underwent whole lung allergen challenge. CO, nitric oxide (NO), oxygen, and carbon dioxide (CO(2)) were measured simultaneously in exhaled breath which was collected into Mylar balloons before (baseline), immediately after, and at subsequent times after allergen. NO was higher in asthmatics than control subjects at baseline, increased further in seven of the eight asthmatics after allergen, and was inversely correlated to specific conductance. In contrast, exhaled CO of asthmatics was not higher than that of control individuals at baseline, decreased immediately after allergen, and returned to baseline levels during the late asthmatic response. Thus, allergen-induced airway inflammation did not lead to increased exhaled CO in asthma.

Aspergillus fumigatus-induced allergic airway inflammation alters surfactant homeostasis and lung function in BALB/c mice.

The differential regulation of pulmonary surfactant proteins (SPs) is demonstrated in a murine model of Aspergillus fumigatus (Af )-induced allergic airway inflammation and hyperresponsiveness. BALB/c mice were sensitized intraperitoneally and challenged intranasally with Af extract. Enzyme-linked immunosorbent assay analysis of serum immunoglobulin (Ig) levels in these mice showed markedly increased total IgE and Af-specific IgE and IgG1. This was associated with peribronchial/perivascular tissue inflammation, airway eosinophilia, and secretion of interleukin (IL)-4 and IL-5 into the bronchoalveolar lavage fluid (BALF). Functional analysis revealed that in comparison with nonsensitized mice, allergic sensitization and challenge resulted in significant increases in acetylcholine responsiveness. To analyze levels of SPs, the cell-free supernate of the BALF was further fractionated by high-speed (20,000 x g) centrifugation. After sensitization and challenges, the pellet (large-aggregate fraction) showed a selective downregulation of hydrophobic SPs SP-B and SP-C by 50%. This reduction was reflected by commensurate decreases in SP-B and SP-C messenger RNA (mRNA) expression of the lung tissue of these animals. In contrast, there was a 9-fold increase in SP-D protein levels in the 20,000 x g supernate without changes in SP-D mRNA. The increased levels of SP-D showed a significant positive correlation with serum IgE (r = 0.85, P < 0.001). Tissue mRNA and protein levels of SP-A in either the large- or the small-aggregate fractions were unaffected. Our data indicate that allergic airway inflammation induces selective inhibition of hydrophobic SP synthesis accompanied by marked increases in the lung collectin SP-D protein content of BALF. These changes may contribute significantly to the pathophysiology of Af-induced allergic airway hyperresponsiveness.

496 Regular albuterol increases allergen-induced asthmatic responses and serum tryptase

496 Regular albuterol increases allergen-induced asthmatic responses and serum tryptase