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BACKGROUND Long-term trajectories of asthma with fixed airflow obstruction (FAO) may reveal links to inflammatory endotypes. OBJECTIVE We investigated whether measures of asthma control and airway inflammation and remodelling differed by long-term FAO status in moderate-to-severe asthma. METHODS Adults enrolled in the Difficult Asthma Study assessed initially using serial Asthma Control Questionnaire (ACQ), exacerbation history, spirometry and sputum cytology over 12 months, as well as endoscopic bronchial biopsy with airway smooth muscle (ASM) quantification, were revaluated three or more years later with questionnaires and spirometry. FAO was defined as a persistent post-bronchodilator forced expired volume in one second (FEV1 )-to-forced vital capacity ratio below 0.70. RESULTS Sixty-two participants (mean ± SD age 48 ± 11 years; 50% female; 75% atopic; asthma duration 24 ± 14 years) returned for follow-up assessment (median interval 7.9 years; IQR: 5.4-8.8 years). Compared to participants without FAO (n = 28), those with FAO at baseline and long-term follow-up (n = 18) had higher baseline sputum neutrophil content and ASM, and a higher exacerbation frequency that persisted at long-term follow-up. Sputum eosinophils, ACQ and long-term FEV1 decline did not differ. Participants with incident FAO at long-term follow-up (n = 16) had higher baseline exacerbation frequency, sputum eosinophil content, higher ACQ scores and greater decline in FEV1 , whereas baseline ASM was similar to those without FAO. CONCLUSION In moderate-to-severe asthma, long-term FAO is characterized by neutrophilic sputum inflammation and airway remodelling, but FEV1 decline is similar to those without FAO. Long-term incident FAO is preceded by higher exacerbation frequency, higher sputum eosinophil content and significant FEV1 decline.

Cystic fibrosis (CF) is a genetic disease that causes multiple airway abnormalities. Two major respiratory consequences of CF are airway hyperresponsiveness (AHR) and airway remodeling. Airway smooth muscle (ASM) is hypothesized to be responsible for the airway dysfunction, since their thickening is involved in remodeling, and excessive contraction by the ASM may cause AHR. It is unclear whether the ASM is intrinsically altered to favor increased contractility or proliferation or if microenvironmental influences induce pathological behavior in vivo. In this study, we examined the contractile and proliferative properties of ASM cells isolated from healthy donor and CF transplant lungs. Assays of proliferation showed that CF ASM proliferates at a higher rate than healthy cells. Through calcium analysis, no differences in contractile activation in response to histamine were found. However, CF ASM cells lagged in their reuptake of calcium in the sarcoplasmic reticulum. The combination CFTR corrector and potentiator, VX-809/770, used to restore CFTR function in CF ASM, resulted in a reduction in proliferation and in a normalization of calcium reuptake kinetics. These results show that impaired CFTR function in ASM cells causes intrinsic changes in their proliferative and contractile properties.

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates the metabolism of xenobiotics. There is growing evidence that the AhR is implicated in physiological processes such proliferation, differentiation, and immune responses. Recently, a role of the AhR in regulating allergic asthma has been suggested, but whether the AhR also regulates other type of asthma, particularly occupational/irritant-induced asthma, remains unknown. Using AhR-deficient (Ahr−/−) mice, we compared the function of the AhR in the response to ovalbumin (OVA; allergic asthma) vs. chlorine (Cl2; irritant-induced asthma) exposure. Lung inflammation and airway hyperresponsiveness were assessed 24h after exposure to Cl2 or OVA challenge in Ahr−/− and heterozygous (Ahr+/−) mice. After OVA challenge, absence of AhR was associated with significantly enhanced eosinophilia and lymphocyte influx into the airways of Ahr−/− mice. There were also increased levels of interleukin-4 (IL-4) and IL-5 in the airways. However, OVA-induced airway hyperresponsiveness was not affected. In the irritant-induced asthma model caused by exposure to Cl2, the AhR did not regulate the inflammatory response. However, absence of AhR reduced Cl2-induced airway hyperresponsiveness. Collectively, these results support a differential role for the AhR in regulating asthma outcomes in response to diverse etiological agents.

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a major transcription factor involved in redox homeostasis and in the response induced by oxidative injury. Nrf2 is present in an inactive state in the cytoplasm of cells. Its activation by internal or external stimuli, such as infections or pollution, leads to the transcription of more than 500 elements through its binding to the antioxidant response element. The lungs are particularly susceptible to factors that generate oxidative stress such as infections, allergens and hyperoxia. Nrf2 has a crucial protective role against these ROS. Oxidative stress and subsequent activation of Nrf2 have been demonstrated in many human respiratory diseases affecting the airways, including asthma and chronic obstructive pulmonary disease (COPD), or the pulmonary parenchyma such as acute respiratory distress syndrome (ARDS) and pulmonary fibrosis. Several compounds, both naturally occurring and synthetic, have been identified as Nrf2 inducers and enhance the activation of Nrf2 and expression of Nrf2-dependent genes. These inducers have proven particularly effective at reducing the severity of the oxidative stress-driven lung injury in various animal models. In humans, these compounds offer promise as potential therapeutic strategies for the management of respiratory pathologies associated with oxidative stress but there is thus far little evidence of efficacy through human trials. The purpose of this review is to summarize the involvement of Nrf2 and its inducers in ARDS, COPD, asthma and lung fibrosis in both human and in experimental models.

The quantification of airway compliance ( Caw) is essential to the study of airway alterations in disease models. However, the required measurements of airway pressure and volume are difficult to acquire in mice. We hypothesized that the inflation limb of full-range pressure-volume (PV) curves could be used to quantify Caw, as it contains a segment where only the airway tree is distended. The study objective was to assess the feasibility of the approach by analysis of full-range PV curves previously collected in three mouse models: an elastase model of emphysema, a genetic model spontaneously developing emphysema (leukotriene C4 synthase knockout; LTC4S-KO), and a bleomycin model of lung fibrosis. Attempts to validate results included Caw change relative to respiratory system compliance (Δ Caw/Δ C), the minute work of breathing (mWOB), and the elastance at 20.5 Hz ( Ers_20.5) from prior respiratory mechanics measurements in the same subjects. Caw was estimated at 3% of total compliance in healthy mice or 2.3 ± 1 μL/cmH2O ( n = 17). The technique detected changes in models of respiratory obstructive and restrictive diseases relative to control mice as well as differences in the two emphysema models studied. The changes in Caw were consistent with those seen in Δ Caw/Δ C, mWOB, or Ers_20.5, with some variations according to the model, as well as with results reported in the literature in humans and mice. Direct Caw measurements in subjects as small as mice could prove useful to further characterize other respiratory disease models associated with airway remodeling or to assess treatment effects.

Background Bronchial thermoplasty (BT) is a novel technique used in the treatment of subjects with severe refractory asthma. Radiofrequency is provided to airway walls during bronchoscopy in order to reduce airway remodeling. Several clinical studies have reported an improvement in subjects’ symptoms following BT. However, how BT affects the airway architectures and inflammatory mediators in the airways has not been yet fully elucidated. Methods Fourteen subjects with severe asthma were recruited in this study according to the criteria of ATS severe asthma definition. The study subjects undertook bronchial biopsy during the bronchoscopy procedure at baseline and 6 weeks after the initial BT treatment. The obtained samples were stained with antibodies for α-smooth muscle actin (α-SMA); protein gene product (PGP) 9.5, a specific nerve marker; von Willebrand factor (vWF), a marker for blood vessels; interleukin-17A (IL-17A) and transforming growth factor-β1 (TGF-β1). Results The expression of α-SMA and PGP9.5 were significantly reduced post-BT. There was no significant difference in the number of blood vessels between baseline and post-BT. In addition, BT did not affect the production of IL-17A and TGF-β1 in the airways. The changes in the expression of α-SMA and PGP9.5 had no significant correlation with the improvement of pulmonary function. Conclusion and Clinical Relevance: This study suggests that BT reduces airway smooth muscle mass and the airway innervation without affecting vasculature and the production of inflammatory mediators in the airways of subjects with severe asthma.

RationaleInvestigations on the mechanisms of airway smooth muscle remodeling, a prominent asthma feature contributing to its clinical manifestations and severity, have largely focused on its hyperplastic growth. Conversely, limited data and virtually no translational research have been produced on a plausible role of apoptosis in the homeostasis and remodeling of airway smooth muscle.ObjectivesWe aimed at demonstrating an involvement of apoptosis, an essential regulator of organ structure and cell turnover, in the pathophysiology of airway smooth muscle remodeling in asthma.MethodsMurine experimental asthma was modeled to analyze airway hyperresponsiveness, contractile tissue remodeling and apoptosis detection outcomes at early and late cutoffs, and under pharmacological inhibition of apoptosis by employing a caspase blocker. Clinical investigation followed through analyses on human bronchial biopsies.ResultsAirway hyperresponsiveness and contractile tissue remodeling were already established in early experimental asthma, and a subsequent upregulation of apoptosis limited the airway contractile tissue growth. Caspase inhibition elicited chaotic pulmonary mechanics and an unusual growth of airway smooth muscle that was structurally disorganized. In bronchial biopsies, airway smooth muscle increased from controls through subjects with intermittent and persistent moderate and severe asthma. Cleaved poly-ADP ribose polymerase (c-PARP, a byproduct of caspase activity) was increased in severe asthma.ConclusionsApoptosis is involved in airway contractile cell turnover and in shaping the size, structure and proper function of the airway smooth muscle layer. Apoptosis inhibitors may complicate concomitant asthma, whereas agents favouring airway contractile cell apoptosis may provide a novel pipeline of therapeutic development.Key messagesHow normal airway smooth muscle structure is preserved, and whether counteracting responses to remodeling are elicited in asthma, are outstanding questions not probed in vivo nor in the clinical setting.In this work, combined investigations on murine experimental asthma and human bronchial biopsies show that airway contractile cell apoptosis is involved in the homeostasis of airway smooth muscle, and apoptotic activity is upregulated as part of the remodeling process of this tissue in asthma.Apoptosis arises as a key regulator of the size and structure of the airway smooth muscle layer. This concept draws implications for clinical practice and drug development.

International audience; The 2019 Havemeyer Workshop brought together researchers and clinicians to discuss the latest information on Equine Asthma and provide future research directions. Current clinical and molecular asthma phenotypes and endotypes in humans were discussed and compared to asthma phenotypes in horses. The role of infectious and non-infectious causes of equine asthma, genetic factors and proposed disease pathophysiology were reviewed. Diagnostic limitations were evident by the limited number of tests and biomarkers available to field practitioners. The participants emphasized the need for more accessible, standardized diagnostics that would help identify specific phenotypes and endotypes in order to create more targeted treatments or management strategies. One important outcome of the workshop was the creation of the Equine Asthma Group that will facilitate communication between veterinary practice and research communities through published and easily accessible guidelines and foster research collaboration.

Membrane-associated RING-CH-1 (March1) is a member of the March family of E3 ubiquitin ligases. March1 downregulates cell surface expression of MHC II and CD86 by targeting them to lysosomal degradation. Given the key roles of MHC class II and CD86 in T cell activation and to get further insights into the development of allergic inflammation, we asked whether March1 deficiency exacerbates or attenuates features of allergic asthma in mice. Herein, we used an acute model of allergy to compare the asthmatic phenotype of March1-deficient and -sufficient mice immunized with ovalbumin (OVA) and later challenged by intranasal instillation of OVA in the lungs. We found that eosinophilic inflammation in airways and lung tissue was similar between WT and March1−/− allergic mice, whereas neutrophilic inflammation was significant only in March1−/− mice. Airway hyperresponsiveness as well as levels of IFN-γ, IL-13, IL-6, and IL-10 was lower in the lungs of asthmatic March1−/− mice compared to WT, whereas lung levels of TNF-α, IL-4, and IL-5 were not significantly different. Interestingly, in the serum, levels of total and ova-specific IgE were reduced in March1-deficient mice as compared to WT mice. Taken together, our results demonstrate a role of March1 E3 ubiquitin ligase in modulating allergic responses.

Objective To determine if inhaled and intranasal ciclesonide are superior to placebo at decreasing respiratory symptoms in adult outpatients with covid-19. Design Randomised, double blind, placebo controlled trial. Setting Three Canadian provinces (Quebec, Ontario, and British Columbia). Participants 203 adults aged 18 years and older with polymerase chain reaction confirmed covid-19, presenting with fever, cough, or dyspnoea. Intervention Participants were randomised to receive either inhaled ciclesonide (600 μg twice daily) and intranasal ciclesonide (200 μg daily) or metered dose inhaler and nasal saline placebos for 14 days. Main outcome measures The primary outcome was symptom resolution at day 7. Analyses were conducted on the modified intention-to-treat population (participants who took at least one dose of study drug and completed one follow-up survey) and adjusted for stratified randomisation by sex. Results The modified intention-to-treat population included 203 participants: 105 were randomly assigned to ciclesonide (excluding two dropouts and one loss to follow-up) and 98 to placebo (excluding three dropouts and six losses to follow-up). The median age was 35 years (interquartile range 27-47 years) and 54% were women. The proportion of participants with resolution of symptoms by day 7 did not differ significantly between the intervention group (42/105, 40%) and control group (34/98, 35%); absolute adjusted risk difference 5.5% (95% confidence interval −7.8% to 18.8%). Results might be limited to the population studied, which mainly included younger adults without comorbidities. The trial was stopped early, therefore could have been underpowered. Conclusion Compared with placebo, the combination of inhaled and intranasal ciclesonide did not show a statistically significant increase in resolution of symptoms among healthier young adults with covid-19 presenting with prominent respiratory symptoms. As evidence is insufficient to determine the benefit of inhaled and intranasal corticosteroids in the treatment of covid-19, further research is needed. Trial registration ClinicalTrials.gov NCT04435795 .

Background and Purpose Cysteinyl leukotrienes (CysLTs) are pro-inflammatory lipid mediators that exacerbate disease state in several asthma phenotypes including asthma induced by allergen, virus and exercise. However, the role of CysLTs in irritant-induced airway disease is not well characterized. The purpose of the current study was to investigate the effect of montelukast, a CysLT1 receptor antagonist, on parameters of irritant-induced asthma induced by inhalation of chlorine in the mouse. Experimental Approach BALB/c mice were exposed to chlorine in air (100 ppm, for 5 min). Montelukast (3 mg·kg−1) or the vehicle (1% methylcellulose) was administered 24 and 1 h prior to chlorine exposure and 1 h prior to outcome measurements. Twenty-four hours after exposure, responses to inhaled aerosolized methacholine, cell composition and an array of cytokines/chemokines in bronchoalveolar lavage (BAL) fluid were measured. Neutralizing antibodies against IL-6 and VEGF were administered prior to exposures. Key Results Montelukast reduced chlorine -induced airway hyperresponsiveness (AHR) to methacholine in the peripheral lung compartment as estimated from dynamic elastance, but not in large conducting airways. Montelukast treatment attenuated chlorine-induced macrophage influx, neutrophilia and eosinophilia in BAL fluid. Chlorine exposure increased VEGF, IL-6, the chemokines KC and CCL3 in BAL fluid. Montelukast treatment prevented chlorine-induced increases in VEGF and IL-6. Anti-IL-6 antibody inhibited chlorine-induced neutrophilia and reduced AHR. Conclusions and Implications Pre-treatment with montelukast attenuated chlorine-induced neutrophilia and AHR in mice. These effects are mediated, in part, via IL-6.

Omalizumab, a recombinant humanized monoclonal antibody targeting the IgE molecule, is the first biologic approved for moderate-to-severe allergic asthmatics, who remain uncontrolled despite high dose inhaled corticosteroid and bronchodilators. Steroid-sparing effect of omalizumab has not been demonstrated in asthmatics with persistent airway eosinophilia in a randomised controlled trial till date. From this double-blind, placebo-controlled, multi-centred, randomized parallel group design, we report that omalizumab is possibly inadequate to control sputum eosinophilia, and therefore may not have a steroid-sparing effect, especially in those maintained on oral corticosteroids daily. This needs to be confirmed or refuted in a larger trial, which may be a challenge with respect to recruitment, since there are currently three additional biologics available to prescribe.Trial registration Clinicaltrials.gov, NCT02049294, Registered 30th January 2014, https://clinicaltrials.gov/ct2/show/NCT02049294

Occupational asthma (OA) is a unique phenotype of asthma. Depending on the type of sensitizers to which the subjects are exposed, different pathophysiological mechanisms lead to the development of OA. This chapter reviews our current understanding of the mechanisms of occupational sensitization according to the different types of sensitizers. Several host and environmental factors predisposing to the development of sensitizer-induced OA have been identified. Atopy, rhinitis, and genetic markers are the main host risk factors predisposing to development of OA, whereas the degree of exposure to the causal agent is the main environmental risk factor predisposing to development of OA. An accurate diagnosis of OA is crucial because of the socioeconomic implication of this diagnosis for the workers. Not only does the diagnosis of asthma need to be confirmed, but the causality between the exposure to a specific agent at the workplace and the occurrence of asthma needs to be established.

International audience; The term "equine asthma" has been proposed as a unifying descriptor of inflammatory airway disease (IAD), recurrent airway obstruction (RAO), and summer pasture-associated obstructive airway disease. Whilst the term will increase comprehensibility for both the lay and scientific communities, its biologic relevance must be compared and contrasted to asthma in human medicine, recognizing the limited availability of peer-reviewed equine-derived data, which are largely restricted to clinical signs, measures of airway obstruction and inflammation and response to therapy. Such limitations constrain meaningful comparisons with human asthma phenotypes. Suggested minimum inclusion criteria supporting the term asthma, as well as similarities and differences between IAD, RAO, and multiple human asthma phenotypes are discussed. Furthermore, differences between phenotype and severity are described, and typical features for equine asthma subcategories are proposed. Based on shared features, we conclude that mild/moderate (IAD) and severe (RAO) equine asthma are biologically appropriate models for both allergic and non-allergic human asthma, with RAO (severe equine asthma) also being an appropriate model for late-onset asthma. With the development of new biologic treatments in humans and the application of more targeted therapeutic approaches in the horse, it would appear appropriate to further investigate the allergic (Th-2) and non-allergic (non-Th-2) phenotypes of equine asthma. Further research is required to more fully determine the potential clinical utility of phenotype classification.

SummaryBackground Airway inflammatory phenotyping is increasingly applied to subjects with asthma. However, its relationship to clinical outcomes in difficult asthma is incompletely elucidated. Objective The goal of our study was to determine the relationship between exacerbation rates and phenotypes of difficult asthma based on the longitudinal measures of sputum eosinophils and neutrophils. Methods Subjects in the longitudinal observational study from two tertiary care centres that completed 1 year of observation and provided at least three sputum samples were classified by inflammatory phenotypes using previously established thresholds. Kaplan–Meier curves and univariable and multivariable Cox proportional hazard models were used to determine the association between inflammatory phenotypes and exacerbation rate. Results During the study, 115 exacerbations occurred in 73 severe asthmatic subjects. Subjects with the persistently eosinophilic phenotype had a significantly shorter time to first exacerbation and greater risk of exacerbation over a 1-year period than those with the non-eosinophilic phenotype based on the univariable and multivariable Cox proportional hazard model (hazard ratio [HR], 3.24; 95% confidence interval [CI], 1.35–7.72; adjusted HR, 3.90; 95% CI, 1.34–11.36). No significant differences in time to first exacerbation or exacerbation risk over a 1-year period were observed among the neutrophilic phenotypes. Conclusions The persistent eosinophilic phenotype is associated with increased exacerbation risk compared with the non-eosinophilic phenotype in severe asthma. No differences in time to first exacerbation or exacerbation risk over a 1-year period were detected among neutrophilic phenotypes.

SummaryBackground In severe asthmatics with persistent airway eosinophilia, blockade of interleukin-5 has significant steroid-sparing effects and attenuates blood and sputum eosinophilia. The contribution of local maturational processes of progenitors within the airways relative to the recruitment of mature cells from the peripheral circulation to the development of airway eosinophilia is not known. We hypothesize that local eosinophilopoiesis may be the predominant process that drives persistent airway eosinophilia and corticosteroid requirement in severe asthmatics. Objectives In a cross-sectional study, the number and growth potential of eosinophil-lineage-committed progenitors (EoP) were assayed in 21 severe eosinophilic asthmatics, 19 mild asthmatics, eight COPD patients and eight normal subjects. The effect of anti-IL-5 treatment on mature eosinophils and EoP numbers was made in severe eosinophilic asthmatics who participated in a randomized clinical trial of mepolizumab (substudy of a larger GSK sponsored global phase III trial, MEA115575) where subjects received mepolizumab (100 mg, n = 9) or placebo (n = 8), as six monthly subcutaneous injections. Results Mature eosinophil and EoP numbers were significantly greater in the sputum of severe asthmatics compared with all other subject groups. In colony-forming assays, EoP from blood of severe asthmatics demonstrated a greater response to IL-5 than mild asthmatics. Treatment of severe asthmatics with mepolizumab significantly attenuated blood eosinophils and increased EoP numbers consistent with blockade of systemic eosinophilopoiesis. There was however no significant treatment effect on mature eosinophils, sputum EoP numbers or the prednisone maintenance dose. Conclusions and Clinical Relevance Patients with severe eosinophilic asthma have an exaggerated eosinophilopoeitic process in their airways. Treatment with 100 mg subcutaneous mepolizumab significantly attenuated systemic differentiation of eosinophils, but did not suppress local airway eosinophil differentiation to mature cells. Targeting IL-5-driven eosinophil differentiation locally within the lung maybe of relevance for optimal control of airway eosinophilia and asthma.

The effect of remodeling on airway function is uncertain. It may affect airway compressibility during forced expirations differently than airflow resistance, providing a tool for its assessment. The aim of the current study was to compare the effects of acute and chronic antigen challenge on methacholine-induced bronchoconstriction assessed from resistance and maximal tidal expiratory flow. Balb/C mice were sensitized with ovalbumin (OVA) and challenged either daily for three days with intra-nasal OVA or daily for 5 days and three times a week for 5 subsequent weeks. Acute and chronic allergen challenge induced airway hyperresponsiveness (AHR) to methacholine. However the relationship between maximal tidal expiratory flow and resistance during methacholine challenge was different between the two conditions, suggesting that the determinants of AHR are not identical following acute and chronic allergen exposure. We conclude that the contrast of changes in maximal tidal expiratory flow and respiratory resistance during methacholine-induced bronchoconstriction may allow the detection of the mechanical consequences of airway remodeling.

BackgroundIn clinical trials, the two anti-interleukin (IL)-5 monoclonal antibodies (mAbs: mepolizumab and reslizumab) approved to treat severe eosinophilic asthma reduce exacerbations by ∼50–60%.ObjectiveTo observe response to anti-IL-5 mAbs in a real-life clinical setting, and to evaluate predictors of suboptimal response.MethodsIn four Canadian academic centres, predefined clinical end-points in 250 carefully characterised moderate-to-severe asthmatic patients were collected prospectively to assess response to the two anti-IL-5 mAbs. Suboptimal response was determined based on failure to reduce maintenance corticosteroid (MCS) or asthma symptoms scores (Asthma Control Questionnaire (ACQ)) or exacerbations, in addition to persistence of sputum/blood eosinophils. Worsening in suboptimal responders was assessed based on reduced lung function by 25% or increase in MCS/ACQ. A representative subset of 39 patients was evaluated for inflammatory mediators, autoantibodies and complement activation in sputum (by ELISA) and for immune-complex deposition by immunostaining formalin-fixed paraffin-embedded sputum plugs.ResultsSuboptimal responses were observed in 42.8% (107 out of 250) patients treated with either mepolizumab or reslizumab. Daily prednisone requirement, sinus disease and late-onset asthma diagnoses were the strongest predictors of suboptimal response. Asthma worsened in 13.6% (34 out of 250) of these patients. The majority (79%) of them were prednisone-dependent. Presence of sputum anti-eosinophil peroxidase immunoglobulin (Ig)G was a predictor of suboptimal response to an anti-IL-5 mAb. An increase in sputum C3c (marker of complement activation) and deposition of C1q-bound/IL-5-bound IgG were observed in the sputa of those patients who worsened on therapy, suggesting an underlying autoimmune-mediated pathology.ConclusionA significant number of patients who meet currently approved indications for anti-IL5 mAbs show suboptimal response to them in real-life clinical practice, particularly if they are on high doses of prednisone. Monitoring blood eosinophil count is not helpful to identify these patients. The concern of worsening of symptoms associated with immune-complex mediated complement activation in a small proportion of these patients highlights the relevance of recognising airway autoimmune phenomena and this requires further evaluation.

Philanthropy is often the life blood of academic institutions. Perhaps one of the most important and lasting contributions an individual can make takes the form of a university endowment. Dr Ronald V. Christie, Chief of the Department of Medicine and, subsequently Dean of the Faculty of Medicine at McGill University (1964–1972), met Dame Olga Leibovici, a wonderful philanthropist. After long discussion, she bestowed in her will in 1965, the sum of US $2 million to McGill University to establish the Louis and Artur Lucian Award for Research in Circulatory Diseases. Mme Leibovici wanted to honor and remember her brothers, Louis and Artur (Ing.), both engineers (ingenieurs, in French); their ashes are preserved in the columbarium of the Cimetiere Pere Lachaise in Paris, France. The award provisions were put in place after she died in 1974. It fell to Dr Christie’s successor, Dr Patrick Cronin, Dean (1972–1977) to bestow the first Lucian Award of $50 000 Canadian to Drs Nicolae Simionescu, MD, and Maya Simionescu, PhD, of Bucharest and Yale University, for their outstanding work on cellular biology and atherosclerosis in 1978. The terms of her will stated that: “…Seventy percent of the income fund will obligatorily be used to create an award named ‘Louis and Artur Lucian (certified Engineers)’ awarded annually by a jury nominated by the University for the best work published in the past year anywhere in the world RELATED TO DISEASES OF THE CARDIOVASCULAR SYSTEM” (Figure). Furthermore, “The Awardees will be scrupulously selected according to merit from any country, without regard to race, religion or nationality. The Jury has the right to share this award between two or more recipients or to defer giving the Award the next year or even two if judged appropriate.” Figure. Terms of the will bestowing the Lucian Award. Excerpt from the will of …

Pathogen persistence in the respiratory tract is an important preoccupation, and of particular relevance to infectious diseases such as tuberculosis. The equilibrium between elimination of pathogens and the magnitude of the host response is a sword of Damocles for susceptible patients. The alveolar macrophage is the first sentinel of the respiratory tree and constitutes the dominant immune cell in the steady state. This immune cell is a key player in the balance between defense against pathogens and tolerance toward innocuous stimuli. This review focuses on the role of alveolar macrophages in limiting lung tissue damage from potentially innocuous stimuli and from infections, processes that are relevant to appropriate tolerance of potential causes of lung disease. Notably, the different anti-inflammatory strategies employed by alveolar macrophages and lung tissue damage control are explored. These two properties, in addition to macrophage manipulation by pathogens, are discussed to explain how alveolar macrophages may drive pathogen persistence in the airways.

Background Inhaled oxidative toxicants present in ambient air cause airway epithelial injury, inflammation, and airway hyperresponsiveness. Effective adaptation to such environmental insults is essential for the preservation of pulmonary function, whereas failure or incomplete adaptation to oxidative injury can render the host susceptible to the development of airway disease. Objective We sought to explore the mechanisms of airway adaptation to oxidative injury. Methods For a model to study pulmonary adaptation to oxidative stress–induced lung injury, we exposed mice to repeated nose-only chlorine gas exposures. Outcome measures were evaluated 24 hours after the last chlorine exposure. Lung mechanics and airway responsiveness to methacholine were assessed by using the flexiVent. Inflammation and antioxidant responses were assessed in both bronchoalveolar lavage fluid and lung tissue. Using both loss or gain of function and genomic approaches, we further dissected the cellular and molecular mechanisms involved in pulmonary adaptation. Results Repeated exposures to oxidative stress resulted in pulmonary adaptation evidenced by abrogation of neutrophilic inflammation and airway hyperresponsiveness. This adaptation was independent of antioxidant mechanisms and regulatory T cells but dependent on residential alveolar macrophages (AMs). Interestingly, 5% of AMs expressed forkhead box P3, and depletion of these cells abolished adaptation. Results from transcriptomic profiling and loss and gain of function suggest that adaptation might be dependent on TGF-β and prostaglandin E2. Conclusion Pulmonary adaptation during oxidative stress–induced lung injury is mediated by a novel subset of forkhead box P3–positive AMs that limits inflammation, favoring airway adaptation and host fitness through TGF-β and prostaglandin E2.

Background: Individuals with severe atopic asthma are poorly controlled with standard treatments, including corticosteroids. A humanized monoclonal antibody binding immunoglobulin E (IgE), omalizumab, is approved to treat patients that are managed poorly despite optimal therapy and that have elevated serum levels of IgE. Objective: The purpose of this study was to determine omalizumab’s effectiveness in a real-world setting. The primary outcome was the number of exacerbations of asthma requiring oral corticosteroid treatment in the 2 year pre-treatment period compared to 2 years post-treatment. The secondary outcome was cumulative dose of prednisone used before and after treatment. Other outcomes that were measured included: reduction in maintenance therapy, change in spirometry (FEV1) data, the stratification of patient population based on smoking status, and average exacerbation number and prednisone use as a function of IgE level and blood eosinophilia count. Methods: Patient data were retrieved (n=41) through the hospital records of patients treated at the Montreal Chest Institute of the McGill University Health Center. Data were gathered and analyzed for the 2 years before the treatment start date and compared to data 2 years after. Results: There was a significant reduction in average exacerbation number from 6.4 pre-treatment to 3.2 post-treatment (p=0.003). There was also a reduction in cumulative prednisone use from 2504mg to 1423mg (p=0.04) following the institution of omalizumab treatment. There was no correlation between either the initial IgE levels and blood eosinophilia and the reduction in exacerbations Conclusion: Omalizumab was effective in reducing exacerbation number and prednisone use for patients with severe refractory asthma.

Airway smooth muscle (ASM) plays a key role in airway hyperresponsiveness (AHR) but it is unclear whether its contractility is intrinsically changed in asthma.To investigate whether key parameters of ASM contractility are altered in subjects with asthma.Human trachea and main bronchi were dissected free of epithelium and connective tissues and suspended in a force-length measurement set-up. After equilibration each tissue underwent a series of protocols to assess its methacholine dose-response relationship, shortening velocity, and response to length oscillations equivalent to tidal breathing and deep inspirations.Main bronchi and tracheal ASM were significantly hyposensitive in subjects with asthma compared with control subjects. Trachea and main bronchi did not show significant differences in reactivity to methacholine and unloaded tissue shortening velocity (Vmax) compared with control subjects. There were no significant differences in responses to deep inspiration, with or without superimposed tidal breathing oscillations. No significant correlations were found between age, body mass index, or sex and sensitivity, reactivity, or Vmax.Our data show that, in contrast to some animal models of AHR, human tracheal and main bronchial smooth muscle contractility is not increased in asthma. Specifically, our results indicate that it is highly unlikely that ASM half-maximum effective concentration (EC50) or Vmax contribute to AHR in asthma, but, because of high variability, we cannot conclude whether or not asthmatic ASM is hyperreactive.

Introduction: Lung adaptation from pulmonary insults is an essential requirement for host fitness and survival. Lung epithelial injury and inflammation trigger oxidative stress which further damages the tracheobronchial tree. Failure or incomplete adaptation to oxidative injury favours the development of severe airway disease. Objectives: Establish a new model to explore airway adaptation to oxidative injury in order to elucidate key mechanisms for preserving lung function. Methods: To establish a model for the study of adaptation to oxidative stress induced-lung injury, we exposed mice to repeated chlorine gas exposures. Outcome measures were assessed 24h after the last chlorine exposure. Lung function mechanics were explored using FlexiVent. Inflammation and anti-oxidant responses were assessed in both bronchoalveolar lavage and lung tissue. Knock-out mice, depletion, adoptive transfer and gene array approaches were used to further explore the mechanistic. Results: Here we report a striking respiratory airway adaptation in mice after repeated chlorine exposures. Mice rapidly adapt by controlling the neutrophilic inflammation and airway hyperresponsiveness. After excluding antioxidant mechanisms and regulatory T cells, we found that adaptation was mediated by resident alveolar macrophages, programmed with a potent pro-phagocytic capacity. Notably, 5% of alveolar macrophages expressed Foxp3 and depletion of these cells abolished adaptation. Conclusions: This new model of adaptation to oxidative stress-induced lung injury lead us to discover a subset of alveolar macrophages Foxp3 + , which may provide new cellular mechanism in resolving inflammation leading to airway adaptation and host fitness. CIHR MOP-126131.

Rationale: We investigated whether benralizumab targeted IL-5Rα+ cells involved in eosinophilopoietic processes that drive airway eosinophilia in severe asthma. Methods: In a Canadian substudy of ZONDA, 18 patients with severe, prednisone-dependent asthma received 28-week benralizumab 30 mg SC Q4W or Q8W (Q8W: first 3 doses every 4 weeks) or placebo (PBO) Q4W, after a steroid optimization phase (V4), followed by steroid taper (V14). Mature eosinophils, eosinophil-lineage committed progenitor cells (EoP), and IL-5Rα+ILC2s were enumerated by flow cytometry in blood and sputum. Protein granzyme B, tryptase, and relevant cytokines were examined in cell-free sputum supernatants. Outcomes for both regimens were combined (n=10) and compared with PBO (n=7). Data are medians and IQRs. Mann-Whitney U test compared changes with drug (V14–V6) vs. PBO (V14–V6). Results: Benralizumab vs. PBO significantly reduced blood eos (0.24 [0.1–0.43] to 0.005 [0–0.013] vs. 0.4 [0.21–0.59] to 0.34 [0.26–0.57] x 10 6 /ml; p p p 3 cells/ml; p p =0.2; p =0.24). Increased NK-cell cell activity was reflected by increases in granzyme B ( p =0.02) and interferon-γ ( p =0.03) with benralizumab vs. PBO. Conclusions: Benralizumab 30 mg SC for 28 weeks attenuated systemic and airway eos, EoP, and IL5Rα+ILC2.

Background Bronchial vascular remodelling may contribute to the severity of airway narrowing through mucosal congestion. Interleukin (IL)-17A is associated with the most severe asthmatic phenotype but whether it might contribute to vascular remodelling is uncertain. Objective To assess vascular remodelling in severe asthma and whether IL-17A directly or indirectly may cause endothelial cell activation and angiogenesis. Methods Bronchial vascularization was quantified in asthmatic subjects, COPD and healthy subjects together with the number of IL-17A+ cells as well as the concentration of angiogenic factors in the sputum. The effect of IL-17A on in vitro angiogenesis, cell migration and endothelial permeability was assessed directly on primary human lung microvascular endothelial cells (HMVEC-L) or indirectly with conditioned medium derived from normal bronchial epithelial cells (NHBEC), fibroblasts (NHBF) and airway smooth muscle cells (ASMC) after IL-17A stimulation. Results Severe asthmatics have increased vascularity compared to the other groups, which correlates positively with the concentrations of angiogenic factors in sputum. Interestingly, we demonstrated that increased bronchial vascularity correlates positively with the number of subepithelial IL-17A+ cells. However IL-17A had no direct effect on HMVEC-L function but it enhanced endothelial tube formation and cell migration through the production of angiogenic factors by NHBE and ASMC. Conclusions & clinical relevance Our results shed light on the role of IL-17A in vascular remodelling, most likely through stimulating the synthesis of other angiogenic factors. Knowledge of these pathways may aid in the identification of new therapeutic targets.

Asthmatic airways are inflamed and undergo remodelling. Inhaled corticosteroids and long-acting β2-agonist combinations are more effective than inhaled corticosteroid monotherapy in controlling disease exacerbations, but their effect on airway remodelling and inflammation remains ill-defined. This study evaluates the contribution of inhaled fluticasone and salmeterol, alone or combined, to the reversal of bronchial remodelling and inflammation. Severely asthmatic horses (6 horses/group) were treated with fluticasone, salmeterol, fluticasone/salmeterol, or with antigen avoidance for 12 weeks. Lung function, central and peripheral airway remodelling, and bronchoalveolar inflammation were assessed. Fluticasone/salmeterol and fluticasone monotherapy decreased peripheral airway smooth muscle remodelling after 12 weeks (p = 0.007 and p = 0.02, respectively). On average, a 30% decrease was observed with both treatments. In central airways, fluticasone/salmeterol reversed extracellular matrix remodelling after 12 weeks, both within the lamina propria (decreased thickness, p = 0.005) and within the smooth muscle layer (p = 0.004). Only fluticasone/salmeterol decreased bronchoalveolar neutrophilia (p = 0.03) to the same extent as antigen avoidance already after 8 weeks. In conclusion, this study shows that fluticasone/salmeterol combination decreases extracellular matrix remodelling in central airways and intraluminal neutrophilia. Fluticasone/salmeterol and fluticasone monotherapy equally reverse peripheral airway smooth muscle remodelling.

SummaryBackground Several chemokines, notably eotaxin, mediate the recruitment of eosinophils into tissues via the CCR3 receptor. Objective In this study, we investigated the role of CCR3 agonists in asthma by observing the effect of a small molecule antagonist of the CCR3 receptor (GW766994) on sputum eosinophil counts in patients with eosinophilic asthma. Methods Clinical and physiological outcomes, the chemotactic activity of sputum supernatant for eosinophils and the presence of eosinophil progenitors in sputum and blood samples were also studied. Results In a double-blind parallel group study, 60 patients with asthma were randomized to 300 mg of GW766994 twice daily or matching placebo for 10 days followed by prednisone 30 mg for 5 days. Of these patients, 53 had a sputum eosinophil count > 4.9% at baseline. Despite plasma concentrations of drug consistent with > 90% receptor occupancy during the dosing period, the CCR3 antagonist did not significantly reduce eosinophils or eosinophil progenitor cells (CD34+ 45+ IL-5Rα+) in sputum or in blood. The ex vivo chemotactic effect of sputum supernatants on eosinophils was attenuated by GW766944 compared to placebo. There was no improvement in FEV1; however, there was a modest but statistically significant improvement in PC20 methacholine (0.66 doubling dose) and ACQ scores, (0.43). Whilst the improvement in PC20 is statistically significant, it is not of clinical significance. Conclusions and Clinical Relevance In conclusion, this study calls into question the role of CCR3 in airway eosinophilia in asthma and suggests that other cellular mechanisms mediated by the CCR3 receptor may contribute to airway hyperresponsiveness.

The Toll-like Receptor (TLR) adaptor proteins Myeloid Differentiating Factor 88 (MyD88) and Toll, interleukin-1 Receptor and Resistance protein (TIR) domain-containing adaptor inducing interferon-β (TRIF) comprise the two principal limbs of the TLR signaling network. We studied the role of these adaptors in the TLR4-dependent inhibition of allergic airway disease and induction of CD4+ICOS+ T cells by nasal application of Protollin™, a mucosal adjuvant composed of TLR2 and 4 agonists. Wild-type (wt), Trif -/- or Myd88 -/- mice were sensitized to birch pollen extract (BPEx), then received intranasal Protollin followed by consecutive BPEx challenges. Protollin's protection against allergic airway disease was TRIF-dependent and MyD88-independent. TRIF-deficiency diminished the CD4+ICOS+ T cell subsets in the lymph nodes draining the nasal mucosa, as well as their recruitment to the lungs. Overall, TRIF-deficiency reduced the proportion of cervical lymph node and lung CD4+ICOS+Foxp3- cells, in particular. Adoptive transfer of cervical lymph node cells supported a role for Protollin-induced CD4+ICOS+ cells in the TRIF-dependent inhibition of AHR. Thus, our data demonstrate that stimulation of the TLR4-TRIF pathway can protect against the development of allergic airway disease and that a TRIF-dependent adjuvant effect on CD4+ICOS+ T cell responses may be a contributing mechanism. This article is protected by copyright. All rights reserved.

Omalizumab, a recombinant humanized monoclonal antibody targeting the IgE molecule, is the first biologic approved for moderate-to-severe allergic asthmatics, who remain uncontrolled despite high dose inhaled corticosteroid and bronchodilators. Steroid-sparing effect of omalizumab has not been demonstrated in asthmatics with persistent airway eosinophilia in a randomised controlled trial till date. From this double-blind, placebo-controlled, multi-centred, randomized parallel group design, we report that omalizumab is possibly inadequate to control sputum eosinophilia, and therefore may not have a steroid-sparing effect, especially in those maintained on oral corticosteroids daily. This needs to be confirmed or refuted in a larger trial, which may be a challenge with respect to recruitment, since there are currently three additional biologics available to prescribe. Trial registration Clinicaltrials.gov, NCT02049294, Registered 30th January 2014, https://clinicaltrials.gov/ct2/show/NCT02049294

Background Although the heterogeneous nature of asthma has prompted asthma phenotyping with physiological or biomarker data, these studies have been mostly cross-sectional. Longitudinal studies that assess the stability of phenotypes based on a combination of physiological, clinical and biomarker data are currently lacking. Our objective was to assess the longitudinal stability of clusters derived from repeated measures of airway and physiological data over a 1-year period in moderate and severe asthmatics. Methods A total of 125 subjects, 48 with moderate asthma (MA) and 77 with severe asthma (SA) were evaluated every 3 months and monthly, respectively, over a 1-year period. At each 3-month time point, subjects were grouped into 4 asthma clusters (A, B, C, D) based on a combination of clinical (duration of asthma), physiological (FEV1 and BMI) and biomarker (sputum eosinophil count) variables, using k-means clustering. Results Majority of subjects in clusters A and C had severe asthma (93 % of subjects in cluster A and 79.5 % of subjects in cluster C at baseline). Overall, a total of 59 subjects (47 %) had stable cluster membership, remaining in clusters with the same subjects at each evaluation time. Cluster A was the least stable (21 % stability) and cluster B was the most stable cluster (71 % stability). Cluster stability was not influenced by changes in the dosage of inhaled corticosteroids. Conclusion Asthma phenotyping based on clinical, physiologic and biomarker data identified clusters with significant differences in longitudinal stability over a 1-year period. This finding indicates that the majority of patients within stable clusters can be phenotyped with reasonable accuracy after a single measurement of lung function and sputum eosinophilia, while patients in unstable clusters will require more frequent evaluation of these variables to be properly characterized.

Modulation of adaptive immune responses via the innate immune pattern recognition receptors, such as the TLRs, is an emerging strategy for vaccine development. We investigated whether nasal rather than intrapulmonary application of Protollin, a mucosal adjuvant composed of TLR2 and TLR4 ligands, is sufficient to elicit protection against murine allergic lower airway disease. Wild-type, Tlr2−/−, or Tlr4−/− BALB/c mice were sensitized to a birch pollen allergen extract (BPEx), then received either intranasal or intrapulmonary administrations of Protollin or Protollin admixed with BPEx, followed by consecutive daily BPEx challenges. Nasal application of Protollin or Protollin admixed with BPEx was sufficient to inhibit allergic lower airway disease with minimal collateral lung inflammation. Inhibition was dependent on TLR4 and was associated with the induction of ICOS in cells of the nasal mucosa and on both CD4+Foxp3+ and CD4+Foxp3− T cells of the draining lymph nodes (LNs), as well as their recruitment to the lungs. Adoptive transfer of cervical LN CD4+ICOS+, but not CD4+ICOS−, cells inhibited BPEx-induced airway hyperresponsiveness and bronchoalveolar lavage eosinophilia. Thus, our data indicate that expansion of resident ICOS-expressing CD4+ T cells of the cervical LNs by nasal mucosal TLR4 stimulation may inhibit the development of allergic lower airway disease in mice.

Increased airway smooth muscle (ASM) mass is a hallmark of airway remodeling in severe asthma. Th17-associated cytokines, particularly IL-17A, IL-17F, and IL-22, have been postulated to play a role in the pathogenesis of asthma. To investigate the in vitro effect of Th17 cytokines on the proliferation and survival of airway smooth muscle cells (ASMCs), human ASMCs from asthmatic and nonasthmatic subjects were incubated with IL-17A, IL-17F, or IL-22. The aforementioned cytokines demonstrated an ability to promote proliferation and survival of ASMCs from asthmatic and nonasthmatic subjects, which were mediated by selective activation of their corresponding receptors on ASMCs, including IL-17RA, IL-17RC, or IL-22R1, respectively. IL-17A and IL-17F-induced proliferation of ASMCs was dependent on ERK1/2 MAPK pathway, while IL-22-induced proliferation involved both ERK1/2 MAPK and NF-κB pathways. The involvement of signaling pathways was further confirmed by the inhibition of proliferation by knockdown of ERK1/2 MAPK or NF-κB p65 expression with pathway-specific siRNA. Together, our results show that Th17-associated cytokines promote proliferation and reduce the apoptotic rate of human ASMCs, raising the possibility that Th17 cytokines may contribute to increasing airway smooth muscle mass and airway remodeling in asthma.

Patients with severe asthma have asthma symptoms which are difficult to control, require high dosages of medication, and continue to experience persistent symptoms, asthma exacerbations or airflow obstruction. Epidemiological and clinical evidences point to the fact that severe asthma is not a single phenotype. Cluster analyses have identified subclasses of severe asthma using parameters such as patient characteristics, and cytokine profiles have also been useful in classifying moderate and severe asthma. The IL-4/IL-13 signalling pathway accounts for the symptoms experienced by a subset of severe asthmatics with allergen-associated symptoms and high serum immunoglobulin E (IgE) levels, and these patients are generally responsive to anti-IgE treatment. The IL-5/IL-33 signalling pathway is likely to play a key role in the disease pathogenesis of those who are resistant to high doses of inhaled corticosteroid but responsive to systemic corticosteroids and anti-IL5 therapy. The IL-17 signalling pathway is thought to contribute to 'neutrophilic asthma'. Although traditionally viewed as players in the defence mechanism against viral and intracellular bacterial infection, mounting evidence supports a role for Th1 cytokines such as IL-18 and IFN-γ in severe asthma pathogenesis. Furthermore, these cytokine signalling pathways interact to contribute to the spectrum of clinical pathological outcomes in severe asthma. To date, glucocorticoids are the most effective anti-asthma drugs available, yet severe asthma patients are typically resistant to the effects of glucocorticoids. Glucocorticoid receptor dysfunction and histone deacetylase activity reduction are likely to contribute to glucocorticoid resistance in severe asthma patients. This review discusses recent development in different cytokine signalling pathways, their interactions and steroid resistance, in the context of severe asthma pathogenesis.

Recent studies suggest that airway smooth muscle remodeling is an early event in asthma, but whether it remains a dynamic process late in the course of the disease is unknown. Moreover, little is known about the effects of an antigenic exposure on chronically established smooth muscle remodeling. We measured the effects of antigenic exposure on airway smooth muscle in the central and peripheral airways of horses with heaves, a naturally occurring airway disease that shares similarities with chronic asthma. Heaves-affected horses (n = 6) and age-matched control horses (n = 5) were kept on pasture before being exposed to indoor antigens for 30 days to induce airway inflammation and bronchoconstriction. Peripheral lung and endobronchial biopsies were collected before and after antigenic exposure by thoracoscopy and bronchoscopy, respectively. Immunohistochemistry and enzymatic labeling were used for morphometric analyses of airway smooth muscle mass and proliferative and apoptotic myocytes. In the peripheral airways, heaves-affected horses had twice as much smooth muscle as control horses. Remodeling was associated with smooth muscle hyperplasia and in situ proliferation, without reduced apoptosis. Further antigenic exposure had no effect on the morphometric data. In central airways, proliferating myocytes were increased compared with control horses only after antigenic exposure. Peripheral airway smooth muscle mass is stable in chronically affected animals subjected to antigenic exposure. This increased mass is maintained in a dynamic equilibrium by an elevated cellular turnover, suggesting that targeting smooth muscle proliferation could be effective at decreasing chronic remodeling.

Asthma is a chronic disorder of the airways associated in many instances with structural changes of the airways, termed airway remodelling. Irritant and allergen-induced murine models have been used to further understand the mechanisms of airway remodelling. The infiltration of the airways by inflammatory cells, such as T lymphocytes, mast cells, eosinophils, neutrophils and macrophages after repeated allergen challenges may be important effectors in the initiation and perpetuation of airway remodelling through the release of inflammatory mediators and growth factors. Interleukins-4 and -13 have been widely studied in experimental models, and have been shown to play a significant role in airway remodelling. Recently, a role for Th17 cells has been established. Other mediators involved in this process are ligands of the epidermal growth factor receptor, matrix metalloproteases and cysteinyl leukotrienes. A better understanding of the mechanisms leading to airway remodelling in allergic diseases may lead to the identification of novel therapeutic strategies but validation in human subjects is required for potential targets.

BACKGROUND: Noneosinophilic asthma has been regarded as a distinct phenotype characterized by a poor response to inhaled corticosteroids (ICS).OBJECTIVE: To determine whether noneosinophilic, steroid-naive asthmatic subjects show an improvement in asthma control, asthma symptoms and spirometry after four weeks of treatment with ICS, and whether they further benefit from the addition of a long-acting beta-2 agonists to ICS.METHODS: A randomized, double-blind, placebo-controlled, multicentre study comparing the efficacy of placebo versus inhaled fluticasone propionate 250 μg twice daily for four weeks in mildly uncontrolled, steroid-naive asthmatic subjects with a sputum eosinophil count ≤2%. This was followed by an open-label, four-week treatment period with fluticasone propionate 250 μg/salmeterol 50 μg, twice daily for all subjects.RESULTS: After four weeks of double-blind treatment, there was a statistically significant and clinically relevant improvement in the mean (± SD) Asthma Control Questionnaire score in the ICS-treated group (n=6) (decrease of 1.0±0.5) compared with the placebo group (n=6) (decrease of 0.09±0.4) (P=0.008). Forced expiratory volume in 1 s declined in the placebo group (−0.2±0.2 L) and did not change in the ICS group (0.04±0.1 L) after four weeks of treatment (P=0.02). The open-label treatment with fluticasone propionate 250 μg/salmeterol 50 μg did not produce additional improvements in those who were previously treated for four weeks with inhaled fluticasone alone.CONCLUSION: A clinically important and statistically significant response to ICS was observed in mildly uncontrolled noneosinophilic asthmatic subjects.

Neutrophils are potent contributors to the lung pathophysiological changes occurring in allergic airway inflammation, which typically involve T helper type 2 (Th2) cytokine overexpression. We have previously reported that equine pulmonary endothelial cells are activated by the Th2 cytokine IL-4 and express chemotactic factors for neutrophils after stimulation. We have further explored the possible mechanisms linking Th2-driven inflammation and neutrophilia by studying the effects of recombinant equine IL-4, a prototypical Th2 cytokine, on peripheral blood neutrophils (PBN) isolated from normal animals and from horses with asthmatic airway inflammation (equine heaves). We found that IL-4 induced morphological changes in PBN, dose- and time-dependent expression of IL-8 mRNA, as well as the release of chemotactic factors for neutrophils in culture supernatants. Also, IL-4 induced a mixed inflammatory response in PBN from control and asthmatic-animals with increased expression of proinflammatory IL-8 and TNF-α but a marked inhibition of IL-1β. IL-4 type I receptor (IL-4Rα) and CD23 (FcϵRII) expression were also upregulated by IL-4. Importantly, disease as well as chronic antigenic exposure modified gene expression by PBN. Finally, we found that activation of equine neutrophils with IL-4 involved STAT6 phosphorylation and p38 MAPK and phosphatidylinositol 3-kinase (PI3K); the pharmacological inhibitors, SB-203580 and LY-294002, respectively, significantly reversed IL-4-induced gene modulation in PBN. Overall, results from this study add to the link between Th2-driven inflammation and neutrophilia in the equine model and further extend the characterization of IL-4 effects on neutrophils.