Mepolizumab Reduces Systemic Corticosteroid Use in Chronic Rhinosinusitis With Nasal Polyps.

BACKGROUND: Systemic corticosteroids (SCSs) are associated with short- and long-term adverse effects. OBJECTIVE: To assess mepolizumab efficacy according to prior SCS use and characterize mepolizumab's SCS-sparing capabilities, in patients with severe chronic rhinosinusitis with nasal polyps. METHODS: In the randomized, double-blind, phase III SYNAPSE trial (NCT03085797), adults with severe chronic rhinosinusitis with nasal polyps eligible for repeat sinus surgery despite standard of care treatment received mepolizumab (100 mg subcutaneously) or placebo every 4 weeks for 52 weeks. The impact of prior SCS courses (0/1/>1) on mepolizumab versus placebo treatment responses (changes from baseline in total endoscopic nasal polyp [week 52], nasal obstruction visual analog scale [weeks 49-52], and 22-item Sino-Nasal Outcome Test total [week 52] scores) was analyzed post hoc. To characterize mepolizumab's SCS-sparing capabilities, time-to-first SCS course for nasal polyps (prespecified) and total prednisolone-equivalent oral corticosteroid dose by patient baseline characteristics (post hoc, in patients with ≥1 SCS course during SYNAPSE) were assessed up to week 52. RESULTS: Mepolizumab versus placebo improved treatment responses, irrespective of prior SCS use. By week 52, the probability of requiring SCSs for nasal polyps (Kaplan-Meier estimate [95% CI]) was lower with mepolizumab (25.4% [20.0-32.1]) versus placebo (37.5% [31.1-44.6]). In patients requiring 1 or more dose of SCSs, total (mean ± SD mg/y) prednisolone-equivalent oral corticosteroid dose was lower with mepolizumab (438.9 ± 350.40) versus placebo (505.2 ± 455.091), overall and irrespective of prior sinus surgeries, blood eosinophil count, or comorbidities. CONCLUSIONS: Mepolizumab is associated with clinical benefits in patients with severe chronic rhinosinusitis with nasal polyps regardless of prior SCS use and has an SCS-sparing effect.

Dupilumab efficacy in subgroups of type 2 asthma with high-dose inhaled corticosteroids at baseline.

BACKGROUND AND OBJECTIVE: Dupilumab blocks the shared receptor component for interleukin (IL)-4/IL-13, key and central drivers of type 2 inflammation in multiple diseases. In phase 3 QUEST (NCT02414854), add-on dupilumab 200 and 300 mg every 2 weeks reduced severe exacerbations, improved pre-bronchodilator forced expiratory volume in 1 s (FEV1), and was generally well tolerated in patients with uncontrolled moderate-to-severe asthma. This post hoc analysis assessed dupilumab efficacy in subpopulations of patients with type 2 asthma and high-dose inhaled corticosteroids (ICS). METHODS: Adjusted annualized severe exacerbation rates over the treatment period, least squares (LS) mean change from baseline at Week 12 in pre-bronchodilator FEV1, and LS mean change from baseline at Week 24 in 5-item Asthma Control Questionnaire (ACQ-5) scores were analyzed in subgroups of patients receiving high-dose (>500 µg) ICS with baseline blood eosinophils ≥150 cells/µL and/or fractional exhaled nitric oxide ≥25 ppb. Subgroups included allergic phenotype (with/without), comorbid chronic rhinosinusitis and/or nasal polyposis (with/without), pre-bronchodilator FEV1/forced vital capacity (<70%/≥70%), blood eosinophil level, exacerbation history, median baseline pre-bronchodilator FEV1, age at asthma onset (≤40/>40 years), median FEV1 reversibility, body mass index (<30/≥30 kg/m2), and sex. RESULTS: Dupilumab vs placebo reduced exacerbations and improved pre-bronchodilator FEV1 at Week 12 and ACQ-5 at Week 24 across subgroups of patients with type 2 asthma and high-dose ICS at baseline. Dupilumab was also effective in patients receiving medium-dose ICS. CONCLUSION: Dupilumab reduced severe exacerbations and improved lung function and asthma control in subgroups of patients with type 2 asthma and high-dose ICS at baseline. CLINICAL TRIAL REGISTRATION NUMBER: NCT02414854.

Respiratory Symptoms among US Adults: a Cross-Sectional Health Survey Study.

INTRODUCTION: Data collected through ongoing, state-based, cross-sectional health surveys could be used to better understand the contribution of respiratory symptoms to impaired health among the US adult population. METHODS: We used the 2015 Behavioral Risk Factor Surveillance System telephone health survey in four states (Kentucky, Florida, South Carolina, Texas) to describe the relationship between symptoms, associated factors such as tobacco smoking, and health impairments. Self-reported productive cough, shortness of breath (SOB), and dyspnea on exertion (DOE) were categorized as minimal, moderate, or severe. Data were analyzed using multiple logistic regression models with age as a covariate to assess relationships of symptoms with other factors. RESULTS: Among adults ≥ 18 years, respiratory impairment [current asthma, chronic obstructive pulmonary disease (COPD), or a current moderate or severe symptom] occurred in 39.1% of the population. More than half of adults reporting moderate or severe symptoms had not been diagnosed with asthma or COPD, particularly with DOE and productive cough. Subjects were at greater risk of moderate and severe SOB or productive cough with increasing age, prolonged smoking duration (≥ 20 years), being an ever-smoker, or if reporting COPD, current asthma, or any other comorbidity except cancer. Morbid obesity [body mass index (BMI) > 35 kg/m2] was associated with severe DOE at a rate similar to current asthma or COPD (25.6%, 95% CI 20.9-30.3%; 20.8%, 95% CI 16.4-25.1%; 21.3%, 95% CI 17.5-25.1%, respectively); it was the most common cause of DOE. SOB was associated with worse general health impairment and limited ambulation compared with other symptoms. Tobacco smoking prevalence and race varied among states, affecting symptom prevalence. CONCLUSION: In the largest US survey in decades, we provide a current perspective of respiratory symptoms among adults of all ages. While known risk factors were apparent, low-risk persons also frequently reported symptoms and impairments.

Benralizumab improves symptoms of patients with severe, eosinophilic asthma with a diagnosis of nasal polyposis.

BACKGROUND: Clinically meaningful improvement in the Sino-Nasal Outcome Test-22 (SNOT-22) was observed in patients with severe, eosinophilic asthma, and nasal polyposis (NP) treated with benralizumab in the ANDHI trial. A post hoc assessment of the effects of benralizumab on SNOT-22 response and asthma efficacy measures in these patients was conducted for further characterization of the efficacy and safety of benralizumab for patients with severe asthma and NP. METHODS: Adults with severe, eosinophilic asthma who had experienced ≥2 prior-year exacerbations despite high-dosage inhaled corticosteroid plus additional controller[s] were randomized to 24 weeks of benralizumab or placebo. Patients with physician-diagnosed chronic rhinosinusitis with NP of any severity ongoing at baseline who consented to participate were included in the current ANDHI NP substudy population. Effect on NP symptoms was assessed by the SNOT-22, with an improvement of at least 8.9 defined as clinically significant (responder). Effects on chronic asthma outcomes were assessed by means of annualized asthma exacerbation rate (AER), St. George's Respiratory Questionnaire (SGRQ) total score, forced expiratory volume in one second (FEV1 ), and Asthma Control Questionnaire-6 (ACQ-6). All p-values were nominal. RESULTS: Of the ANDHI population (n = 656), 23% (n = 153) participated in the NP substudy (n = 96 benralizumab; n = 57 placebo). Patients were 50% female, with mean age of 53 years, had prior-year AER = 3.3; mean pre-bronchodilator FEV1  = 55% predicted; and median blood eosinophil count â€‹= 510 cells/µl. For patients with high baseline SNOT-22 scores (>30), benralizumab treatment improved symptoms of NP as measured by SNOT-22 from baseline to Week 24 compared with placebo (Week 24: -10.44 [p = .0176]). Percentage of responders to SNOT-22 was greater for benralizumab vs. placebo (71.3% vs. 45.5%; p = .0036), and effect was enhanced for patients with high baseline SNOT-22 scores (>30). A 69% reduction vs. placebo in annualized AER (0.77 vs. 2.47; p < .0001) and greater clinically meaningful improvements from baseline in SGRQ total score (-16.7), FEV1 (+0.32 L), and ACQ-6 (-0.88) were observed (p < .0001). Benralizumab was well-tolerated. Frequency of adverse events (AEs) was similar for benralizumab (76.0%) and placebo (73.7%) groups. Most common AEs (frequency ≥5%) reported at a greater frequency in benralizumab vs. placebo included headache, sinusitis, pyrexia, and influenza. CONCLUSIONS: These substudy data from ANDHI demonstrated the efficacy profile of benralizumab for patients with severe, eosinophilic asthma and NP, with improvement in SNOT-22 and asthma outcomes.

HuR-Targeted Inhibition Impairs Th2 Proinflammatory Responses in Asthmatic CD4+ T Cells.

RNA-binding protein HuR (ELAVL1) is a master regulator of gene expression in human pathophysiology. Its dysregulation plays an important role in many diseases. We hypothesized that HuR plays an important role in Th2 inflammation in asthma in both mouse and human. To address this, we used a model of airway inflammation in a T cell-specific knockout mouse model, distal lck-Cre HuRfl/fl, as well as small molecule inhibitors in human peripheral blood-derived CD4+ T cells. Peripheral CD4+ T cells were isolated from 26 healthy control subjects and 45 asthmatics (36 type 2 high and 9 non-type 2 high, determined by blood eosinophil levels and fraction of exhaled NO). Our mouse data showed conditional ablation of HuR in T cell-abrogated Th2 differentiation, cytokine production, and lung inflammation. Studies using human T cells showed that HuR protein levels in CD4+ T cells were significantly higher in asthmatics compared with healthy control subjects. The expression and secretion of Th2 cytokines were significantly higher in asthmatics compared with control subjects. AMP-activated protein kinase activator treatment reduced the expression of several cytokines in both type 2 high and non-type 2 high asthma groups. However, the effects of CMLD-2 (a HuR-specific inhibitor) were more specific to endotype-defining cytokines in type 2 high asthmatics. Taken together, these data suggest that HuR plays a permissive role in both allergen and non-allergen-driven airway inflammation by regulating key genes, and that interfering with its function may be a novel method of asthma treatment.

Neutrophil calprotectin identifies severe pulmonary disease in COVID-19.

Severe cases of coronavirus disease 2019 (COVID-19) are regularly complicated by respiratory failure. Although it has been suggested that elevated levels of blood neutrophils associate with worsening oxygenation in COVID-19, it is unknown whether neutrophils are drivers of the thrombo-inflammatory storm or simple bystanders. To better understand the potential role of neutrophils in COVID-19, we measured levels of the neutrophil activation marker S100A8/A9 (calprotectin) in hospitalized patients and determined its relationship to severity of illness and respiratory status. Patients with COVID-19 (n = 172) had markedly elevated levels of calprotectin in their blood. Calprotectin tracked with other acute phase reactants including C-reactive protein, ferritin, lactate dehydrogenase, and absolute neutrophil count, but was superior in identifying patients requiring mechanical ventilation. In longitudinal samples, calprotectin rose as oxygenation worsened. When tested on day 1 or 2 of hospitalization (n = 94 patients), calprotectin levels were significantly higher in patients who progressed to severe COVID-19 requiring mechanical ventilation (8039 ± 7031 ng/ml, n = 32) as compared to those who remained free of intubation (3365 ± 3146, P < 0.0001). In summary, serum calprotectin levels track closely with current and future COVID-19 severity, implicating neutrophils as potential perpetuators of inflammation and respiratory compromise in COVID-19.

Onset of effect and impact on health-related quality of life, exacerbation rate, lung function, and nasal polyposis symptoms for patients with severe eosinophilic asthma treated with benralizumab (ANDHI): a randomised, controlled, phase 3b trial.

BACKGROUND: ANDHI was done to assess the efficacy of benralizumab, including onset of effect and impact on health-related quality of life (HRQOL), exacerbation rate, lung function, and nasal polyposis symptoms. METHODS: This phase 3b, randomised, double-blind, parallel-group, placebo-controlled ANDHI study was completed in adults (aged 18-75 years) with severe eosinophilic asthma with at least 2 exacerbations in the previous year, despite high-dose inhaled corticosteroid plus additional controllers, screening blood eosinophil counts of at least 150 cells per µL, and an Asthma Control Questionnaire 6 (ACQ-6) score of 1·5 or more. Patients who met eligibility criteria were randomly assigned (2:1; stratified by previous exacerbation count [two, or three or more], maintenance oral corticosteroid use, and region), using an integrated web-based response system, to receive benralizumab at 30 mg every 8 weeks (first three doses given 4 weeks apart) or matched placebo for 24 weeks. Primary efficacy measure was annualised asthma exacerbation rate, with rate ratio (RR) calculated over the approximate 24-week follow-up. Secondary efficacy measures included change from baseline to end of treatment (week 24) in St George's Respiratory Questionnaire (SGRQ) total score (key secondary endpoint), FEV1, peak expiratory flow (PEF), ACQ-6, Predominant Symptom and Impairment Assessment (PSIA), Clinician Global Impression of Change (CGI-C), Patient Global Impression of Change (PGI-C), and Sino-Nasal Outcome Test-22 (SNOT-22). All efficacy analyses, except for SNOT-22, were summarised and analysed using the full analysis set on an intention-to-treat population (all randomly assigned patients receiving investigational product, regardless of protocol adherence or continued participation in the study). SNOT-22 was summarised for the subgroup of patients with physician-diagnosed nasal polyposis with informed consent. This study is registered with ClinicalTrials.gov, NCT03170271. FINDINGS: Between July 7, 2017, and Sept 25, 2019, 656 patients received benralizumab (n=427) or placebo (n=229). Baseline characteristics were consistent with severe eosinophilic asthma. Benralizumab significantly reduced exacerbation risk by 49% compared with placebo (RR estimate 0·51, 95% CI 0·39-0·65; p<0·0001) over the 24-week treatment period and provided clinically meaningful and statistically significant improvement from baseline to week 24 in SGRQ total score versus placebo (least squares mean change from baseline -8·11 (95% CI -11·41 to -4·82; p<0·0001), with similar differences at earlier timepoints. Benralizumab improved FEV1, PEF, ACQ-6, CGI-C, PGI-C, PSIA, and SNOT-22 at week 24 versus placebo, with differences observed early (within weeks 1 to 4). Adverse events were reported for 271 (63%) of 427 patients on benralizumab versus 143 (62%) of 229 patients on placebo. The most commonly reported adverse events for the 427 patients receiving benralizumab (frequency >5%) were nasopharyngitis (30 [7%]), headache (37 [9%]), sinusitis (28 [7%]), bronchitis (22 [5%]), and pyrexia (26 [6%]). Fewer serious adverse events were reported for benralizumab (23 [5%]) versus placebo (25 [11%]), and the only common serious adverse event (experienced by >1% of patients) was worsening of asthma, which was reported for nine (2%) patients in the benralizumab group and nine (4%) patients in the placebo group. INTERPRETATION: Our results extend the efficacy profile of benralizumab for patients with severe eosinophilic asthma, showing early clinical benefits in patient-reported outcomes, HRQOL, lung function, and nasal polyposis symptoms. FUNDING: AstraZeneca.

Blood eosinophil count group shifts and kinetics in severe eosinophilic asthma.

BACKGROUND: Blood eosinophil count (BEC) measurements are a noninvasive, relatively reliable surrogate marker for eosinophilic airway inflammation. Single measurements of peripheral BEC greater than or equal to 150 cells/µL predict the response to anti-eosinophil therapies for patients with characteristics of severe eosinophilic asthma. OBJECTIVE: To describe how BECs shift over time for patients with severe, uncontrolled asthma receiving placebo in 2 large, randomized, placebo-controlled clinical trials of benralizumab (SIROCCO and CALIMA). METHODS: Our analysis included all adult patients who were randomized to placebo in the SIROCCO and CALIMA phase III benralizumab studies. Patients were categorized into baseline BEC groups of less than 150 cells/µL, greater than or equal to 150 cells/µL but less than 300 cells/µL, and greater than or equal to 300 cells/µL. The timing of the initial shift from baseline to a different group was evaluated at weeks 4, 8, 24, and 40 and at the end of treatment. Baseline characteristics, including oral corticosteroid use, were described based on the presence or absence of a BEC group shift. RESULTS: Of the 734 evaluable patients, 65% (n = 474) shifted BEC groups during the study, and most patients (86% [n = 410]) shifted by week 24. Patients who started in the less than 150 cells/µL group tended to shift groups earlier, with 59% shifting by week 4 compared with 38% to 55% for other groups in the same time frame. Patients who shifted BEC groups vs those who did not tend to have lower BECs, more oral corticosteroid use, and less incidence of nasal polyps or past polypectomy. CONCLUSION: A single BEC measurement, particularly when low, may be inadequate to help establish a phenotype of severe eosinophilic asthma. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers NCT01928771 (SIROCCO trial) and NCT01914757 (CALIMA trial).

Role of Matrix Metalloproteinases-1 and -2 in Interleukin-13-Suppressed Elastin in Airway Fibroblasts in Asthma.

Elastin synthesis and degradation in the airway and lung parenchyma contribute to airway mechanics, including airway patency and elastic recoil. IL-13 mediates many features of asthma pathobiology, including airway remodeling, but the effects of IL-13 on elastin architecture in the airway wall are not known. We hypothesized that IL-13 modulates elastin expression in airway fibroblasts from subjects with allergic asthma. Twenty-five subjects with mild asthma (FEV1, 89 ± 3% predicted) and 30 normal control subjects (FEV1, 102 ± 2% predicted) underwent bronchoscopy with endobronchial biopsy. Elastic fibers were visualized in airway biopsy specimens using Weigert's resorcin-fuchsin elastic stain. Airway fibroblasts were exposed to IL-13; a pan-matrix metalloproteinase (MMP) inhibitor (GM6001); specific inhibitors to MMP-1, -2, -3, and -8; and combinations of IL-13 with MMP inhibitors in separate conditions in serum-free media for 48 hours. Elastin (ELN) expression as well as MMP secretion and activity were quantified. Results of this study show that elastic fiber staining of airway biopsy tissue was significantly associated with methacholine PC20 (i.e., the provocative concentration of methacholine resulting in a 20% fall in FEV1 levels) in patients with asthma. IL-13 significantly suppressed ELN expression in asthmatic airway fibroblasts as compared with normal control fibroblasts. The effect of IL-13 on ELN expression was significantly correlated with postbronchodilator FEV1/FVC in patients with asthma. MMP inhibition significantly stimulated ELN expression in patients with asthma as compared with normal control subjects. Specific inhibition of MMP-1 and MMP-2, but not MMP-3 or MMP-8, reversed the IL-13-induced suppression of ELN expression. In asthma, MMP-1 and MMP-2 mediate IL-13-induced suppression of ELN expression in airway fibroblasts.

Alveolar macrophages from overweight/obese subjects with asthma demonstrate a proinflammatory phenotype.

RATIONALE: Obesity is associated with increased prevalence and severity of asthma. Adipose tissue macrophages can contribute to the systemic proinflammatory state associated with obesity. However, it remains unknown whether alveolar macrophages have a unique phenotype in overweight/obese patients with asthma. OBJECTIVES: We hypothesized that leptin levels would be increased in the bronchoalveolar lavage fluid from overweight/obese subjects and, furthermore, that leptin would alter the response of alveolar macrophages to bacterial LPS. METHODS: Forty-two subjects with asthma and 46 healthy control subjects underwent research bronchoscopy. Bronchoalveolar lavage fluid from 66 was analyzed for the level of cellular inflammation, cytokines, and soluble leptin. Cultured primary macrophages from 22 subjects were exposed to LPS, leptin, or leptin plus LPS. Cytokines were measured in the supernatants. MEASUREMENTS AND MAIN RESULTS: Leptin levels were increased in overweight/obese subjects, regardless of asthma status (P = 0.013), but were significantly higher in overweight/obese subjects with asthma. Observed levels of tumor necrosis factor-α were highest in overweight/obese subjects with asthma. Ex vivo studies of primary alveolar macrophages indicated that the response to LPS was most robust in alveolar macrophages from overweight/obese subjects with asthma and that preexposure to high-dose leptin enhanced the proinflammatory response. Leptin alone was sufficient to induce production of proinflammatory cytokines from macrophages derived from overweight/obese subjects with asthma. CONCLUSIONS: Ex vivo studies indicate that alveolar macrophages derived from overweight/obese subjects with asthma are uniquely sensitive to leptin. This macrophage phenotype, in the context of higher levels of soluble leptin, may contribute to the pathogenesis of airway disease associated with obesity.

Mast cell TNF receptors regulate responses to Mycoplasma pneumoniae in surfactant protein A (SP-A)-/- mice.

BACKGROUND: Mycoplasma pneumoniae (Mp) frequently colonizes the airways of patients with chronic asthma and likely contributes to asthma exacerbations. We previously reported that mice lacking surfactant protein A (SP-A) have increased airway hyperresponsiveness (AHR) during M pneumoniae infection versus wild-type mice mediated by TNF-α. Mast cells (MCs) have been implicated in AHR in asthma models and produce and respond to TNF-α. OBJECTIVE: Determine the contribution of MC/TNF interactions to AHR in airways lacking functional SP-A during Mp infection. METHODS: Bronchoalveolar lavage fluid was collected from healthy and asthmatic subjects to examine TNF-α levels and M pneumoniae positivity. To determine how SP-A interactions with MCs regulate airway homeostasis, we generated mice lacking both SP-A and MCs (SP-A(-/-)Kit(W-sh/W-sh)) and infected them with M pneumoniae. RESULTS: Our findings indicate that high TNF-α levels correlate with M pneumoniae positivity in human asthmatic patients and that human SP-A inhibits M pneumoniae-stimulated transcription and release of TNF-α by MCs, implicating a protective role for SP-A. MC numbers increase in M pneumoniae-infected lungs, and airway reactivity is dramatically attenuated when MCs are absent. Using SP-A(-/-)Kit(W-sh/W-sh) mice engrafted with TNF-α(-/-) or TNF receptor (TNF-R)(-/-) MCs, we found that TNF-α activation of MCs through the TNF-R, but not MC-derived TNF-α, leads to augmented AHR during M pneumoniae infection when SP-A is absent. Additionally, M pneumoniae-infected SP-A(-/-)Kit(W-sh/W-sh) mice engrafted with TNF-α(-/-) or TNF-R(-/-) MCs have decreased mucus production compared with that seen in mice engrafted with wild-type MCs, whereas burden was unaffected. CONCLUSION: Our data highlight a previously unappreciated but vital role for MCs as secondary responders to TNF-α during the host response to pathogen infection.

SHP-1 as a critical regulator of Mycoplasma pneumoniae-induced inflammation in human asthmatic airway epithelial cells.

Asthma is a chronic inflammatory disease in which airway epithelial cells are the first line of defense against exposure of the airway to infectious agents. Src homology protein (SHP)-1, a protein tyrosine phosphatase, is a negative regulator of signaling pathways that are critical to the development of asthma and host defense. We hypothesize that SHP-1 function is defective in asthma, contributing to the increased inflammatory response induced by Mycoplasma pneumoniae, a pathogen known to exacerbate asthma. M. pneumoniae significantly activated SHP-1 in airway epithelial cells collected from nonasthmatic subjects by bronchoscopy with airway brushing but not in cells from asthmatic subjects. In asthmatic airway epithelial cells, M. pneumoniae induced significant PI3K/Akt phosphorylation, NF-κB activation, and IL-8 production compared with nonasthmatic cells, which were reversed by SHP-1 overexpression. Conversely, SHP-1 knockdown significantly increased IL-8 production and PI3K/Akt and NF-κB activation in the setting of M. pneumoniae infection in nonasthmatic cells, but it did not exacerbate these three parameters already activated in asthmatic cells. Thus, SHP-1 plays a critical role in abrogating M. pneumoniae-induced IL-8 production in nonasthmatic airway epithelial cells through inhibition of PI3K/Akt and NF-κB activity, but it is defective in asthma, resulting in an enhanced inflammatory response to infection.

Surfactant protein A is defective in abrogating inflammation in asthma.

Surfactant protein A (SP-A) regulates a variety of immune cell functions. We determined the ability of SP-A derived from normal and asthmatic subjects to modulate the inflammatory response elicited by Mycoplasma pneumoniae, a pathogen known to exacerbate asthma. Fourteen asthmatic and 10 normal control subjects underwent bronchoscopy with airway brushing and bronchoalveolar lavage (BAL). Total SP-A was extracted from BAL. The ratio of SP-A1 to total SP-A (SP-A1/SP-A) and the binding of total SP-A to M. pneumoniae membranes were determined. Airway epithelial cells from subjects were exposed to either normal or asthmatic SP-A before exposure to M. pneumoniae. IL-8 protein and MUC5AC mRNA were measured. Total BAL SP-A concentration did not differ between groups, but the percentage SP-A1 was significantly increased in BAL of asthmatic compared with normal subjects. SP-A1/SP-A significantly correlated with maximum binding of total SP-A to M. pneumoniae, but only in asthma. SP-A derived from asthmatic subjects did not significantly attenuate IL-8 and MUC5AC in the setting of M. pneumoniae infection compared with SP-A derived from normal subjects. We conclude that SP-A derived from asthmatic subjects does not abrogate inflammation effectively, and this dysfunction may be modulated by SP-A1/SP-A.

Airway fibroblasts in asthma manifest an invasive phenotype.

RATIONALE: Invasive cell phenotypes have been demonstrated in malignant transformation, but not in other diseases, such as asthma. Cellular invasiveness is thought to be mediated by transforming growth factor (TGF)-ß1 and matrix metalloproteinases (MMPs). IL-13 is a key T(H)2 cytokine that directs many features of airway remodeling through TGF-ß1 and MMPs. OBJECTIVES: We hypothesized that, in human asthma, IL-13 stimulates increased airway fibroblast invasiveness via TGF-ß1 and MMPs in asthma compared with normal controls. METHODS: Fibroblasts were cultured from endobronchial biopsies in 20 subjects with mild asthma (FEV(1): 90 ± 3.6% pred) and 17 normal control subjects (FEV(1): 102 ± 2.9% pred) who underwent bronchoscopy. Airway fibroblast invasiveness was investigated using Matrigel chambers. IL-13 or IL-13 with TGF-ß1 neutralizing antibody or pan-MMP inhibitor (GM6001) was added to the lower chamber as a chemoattractant. Flow cytometry and immunohistochemistry were performed in a subset of subjects to evaluate IL-13 receptor levels. MEASUREMENTS AND MAIN RESULTS: IL-13 significantly stimulated invasion in asthmatic airway fibroblasts, compared with normal control subjects. Inhibitors of both TGF-ß1 and MMPs blocked IL-13-induced invasion in asthma, but had no effect in normal control subjects. At baseline, in airway tissue, IL-13 receptors were expressed in significantly higher levels in asthma, compared with normal control subjects. In airway fibroblasts, baseline IL-13Rα2 was reduced in asthma compared with normal control subjects. CONCLUSIONS: IL-13 potentiates airway fibroblast invasion through a mechanism involving TGF-ß1 and MMPs. IL-13 receptor subunits are differentially expressed in asthma. These effects may result in IL-13-directed airway remodeling in asthma.

S-nitrosoglutathione reductase: an important regulator in human asthma.

RATIONALE: Nitric oxide bioactivity, mediated through the formation of S-nitrosothiols (SNOs), has a significant effect on bronchomotor tone. S-Nitrosoglutathione is an endogenous bronchodilator that is decreased in children with asthmatic respiratory failure and in adults with asthma undergoing segmental airway challenge. Recently we showed that S-nitrosoglutathione reductase (GSNOR) regulates endogenous SNOs. Mice with genetic deletion of GSNOR are protected from airway hyperresponsivity in an allergic asthma model. OBJECTIVES: We hypothesized that GSNOR is increased in human asthma and correlates with lung SNO content and airway reactivity. METHODS: We recruited 36 subjects with mild asthma with FEV(1) 88.5 +/- 2.3% predicted and 34 healthy control subjects with FEV(1) 100.7 +/- 2.5% predicted. Bronchoalveolar lavage (BAL) was performed in all subjects. Cell counts, differentials, GSNOR activity, and SNO levels were determined in BAL. MEASUREMENTS AND MAIN RESULTS: SNO content was decreased in asthmatic BAL compared with control BAL and correlated inversely with GSNOR expression in BAL cell lysates. Furthermore, GSNOR activity measured from BAL samples was significantly increased in subjects with asthma compared with control subjects and correlated inversely with the provocative concentration of methacholine causing a 20% decrease in FEV(1). CONCLUSIONS: These findings suggest that GSNOR is an important regulator of airway SNO content and airways hyperresponsiveness in human asthma.

Genetic profiling and tailored therapy in asthma: are we there yet?

Asthma is characterized by reversible bronchial hyper-responsiveness and airway inflammation, and encompasses a wide variety of patients with different clinical phenotypes that display variable responses to therapy. The definition of genomic variation presented in the Human Genome Project has facilitated the development of genetic-guided therapy in various diseases, including asthma. Tailored therapy is a reality in many types of malignancies where specific gene mutations or molecular profiles are identified and used to make critical therapeutic decisions. Despite the identification of beta-adrenergic receptor polymorphisms by Liggett and colleagues during the 1990s, the pharmacogenetics of asthma is still in its infancy. There have been great advances in asthma pharmacogenetics and pharmacotherapy with the completion of several large trials highlighting the effects of genotype on response to asthma therapy. This review focuses on research articles that serve to emphasize the potential role of using genotyping as a tool to develop individualized patient treatment regimens for asthma, thus improving outcomes and limiting adverse effects of certain therapies.