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.

Questions in Mild Asthma: An Official American Thoracic Society Research Statement.

Background: Patients with mild asthma are believed to represent the majority of patients with asthma. Disease-associated risks such as exacerbations, lung function decline, and death have been understudied in this patient population. There have been no prior efforts from major societies to describe research needs in mild asthma. Methods: A multidisciplinary, diverse group of 24 international experts reviewed the literature, identified knowledge gaps, and provided research recommendations relating to mild asthma definition, pathophysiology, and management across all age groups. Research needs were also investigated from a patient perspective, generated in conjunction with patients with asthma, caregivers, and stakeholders. Of note, this project is not a systematic review of the evidence and is not a clinical practice guideline. Results: There are multiple unmet needs in research on mild asthma driven by large knowledge gaps in all areas. Specifically, there is an immediate need for a robust mild asthma definition and an improved understanding of its pathophysiology and management strategies across all age groups. Future research must factor in patient perspectives. Conclusions: Despite significant advances in severe asthma, there remain innumerable research areas requiring urgent attention in mild asthma. An important first step is to determine a better definition that will accurately reflect the heterogeneity and risks noted in this group. This research statement highlights the topics of research that are of the highest priority. Furthermore, it firmly advocates the need for engagement with patient groups and for more support for research in this field.

Patterns of rescue and maintenance therapy claims surrounding a clinical encounter for an asthma exacerbation.

BACKGROUND: A "window of opportunity" has been proposed where anti-inflammatory therapy administration in response to symptoms could prevent exacerbation. OBJECTIVE: To evaluate rescue and maintenance therapy claims surrounding a severe asthma exacerbation serious enough to require a face-to-face clinical encounter. METHODS: Merative MarketScan research databases (US administrative claims 2011 to 2017) were analyzed for patients aged ≥4 years, with an asthma diagnosis code, who filled short-acting ß2-agonist (SABA) and Global Initiative for Asthma Steps 3 to 5 maintenance therapies. Patients were indexed on a random SABA claim and had 12 months' continuous health plan eligibility pre- and post-index. Serious exacerbations were severe exacerbations requiring systemic corticosteroids prescribed from an outpatient clinic, urgent care or emergency department, or hospitalization for asthma. SABA and maintenance claims 30 days pre- and post-event were analyzed. RESULTS: Of 319,342 patients (30% children 4 to 11 years; 70% adults or adolescents ≥12 years), 27.2% of children and 16.8% of adolescents or adults experienced ≥ 1 serious exacerbation (unadjusted odds ratio [OR], 1.85 [95% confidence interval, 1.81-1.88]). In the 30 days pre-event, 42.6% filled ≥1 SABA (children: 44.3%; adolescents or adults: 41.5%; OR, 1.12 [1.09-1.16]) and 57.4% filled maintenance (children: 59.0%; adolescents or adults: 56.3%; OR, 1.12 [1.08-1.15]). In the 30 days post-event, 61.4% filled SABA (children: 69.7%; adolescents or adults: 55.6%; OR, 1.84 [1.78-1.90]) and 94.8% filled maintenance (children: 98.6%; adolescents or adults: 92.2%; OR, 6.09 [5.45-6.81]). CONCLUSION: Many patients treated as having moderate-to-severe asthma escalate SABA claims before a serious exacerbation, but approximately 40% have no anti-inflammatory maintenance fill, highlighting a "window of opportunity" to prevent exacerbations using inhaled corticosteroids concomitantly with SABA as rescue.

Impact of mepolizumab in patients with high-burden severe asthma within a managed care population.

OBJECTIVE: To evaluate the real-world impact of mepolizumab on the incidence of asthma exacerbations, oral corticosteroid (OCS) use and asthma exacerbation-related costs in patients with high-burden severe asthma. METHODS: This was a retrospective study of the MarketScan Commercial and Medicare Databases in patients with high-burden severe asthma (≥80th percentile of total healthcare expenditure and/or significant comorbidity burden). Patients were ≥12 years of age upon mepolizumab initiation (index date November 1, 2015-December 31, 2018) and had ≥2 mepolizumab administrations during the 6 months post-index. Asthma exacerbation frequency (primary outcome), use of OCS (secondary outcome), and asthma exacerbation-related costs (exploratory outcome) were assessed during the 12 months pre-index (baseline) and post-index (follow-up). RESULTS: In total, 281 patients were analyzed. Mepolizumab significantly reduced the proportion of patients with any asthma exacerbation (P < 0.001) or exacerbations requiring hospitalization (P = 0.004) in the follow-up versus baseline period. The mean number of exacerbations decreased from 2.5 to 1.5 events/patient/year (relative reduction: 40.0%; P < 0.001). The proportion of patients with ≥1 OCS claim also decreased significantly from 94.0% to 81.9% (relative reduction: 12.9%; P < 0.001), corresponding to a decrease from 6.6 to 4.7 claims/person/year (P < 0.001). Of the 264 patients with ≥1 OCS claim during baseline, 191 (72.3%) showed a decrease in mean daily OCS use by ≥50% in 117 patients (61.3%). Total asthma exacerbation-related costs were significantly lower after mepolizumab was initiated (P < 0.001). CONCLUSIONS: Mepolizumab reduced exacerbation frequency, OCS use and asthma exacerbation-related costs in patients with high-cost severe asthma. Mepolizumab provides real-world benefits to patients, healthcare systems and payers.

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.

Allergic and eosinophilic asthma in the era of biomarkers and biologics: similarities, differences and misconceptions.

OBJECTIVE: Severe asthma is associated with substantial personal and economic burden; maintaining disease control is the key management goal. Increased understanding of asthma heterogeneity and development of type 2 (T2)-targeting biologics has substantially advanced disease management and outcomes; however, despite both being driven by T2 inflammation, allergic and eosinophilic asthma have different treatment recommendations. We sought to better understand the similarities and differences between allergic and eosinophilic asthma and highlight where misconceptions may arise. DATA SOURCES: Published articles, pivotal trials, post hoc analyses, and asthma clinical guidelines sourced from PubMed. STUDY SELECTIONS: Sources reporting allergic and eosinophilic asthma classifications, disease mechanisms, and biomarkers associated with treatment response. RESULTS: This review highlights that severe allergic and eosinophilic asthma are both driven by T2 inflammation with eosinophils playing a cardinal role. Despite this overlap, treatment recommendations differ based on asthma classification. T2 cytokine gene expression is a reasonably well-established research tool, but not a well-established biomarker in clinical practice, unlike blood eosinophil counts, fractional exhaled nitric oxide, and immunoglobulin E; the clinical relevance of immunoglobulin E as a predictive biomarker remains unclear. CONCLUSION: Asthma classifications that can be easily characterized at patient level to ensure accurate diagnosis, predict disease trajectory, and treatment response are required. The current dichotomy of allergic and eosinophilic asthma classifications is likely too simplistic, given the similar eosinophil-mediated disease pathophysiology in both classifications. Our results provide future directions to guide clinically meaningful interpretation of asthma endophenotypes, which may improve understanding of severe asthma characterization and aid future advances in defining responders more precisely with personalized medicine approaches.

Phenotyping, Precision Medicine, and Asthma.

The traditional one-size-fits all approach based on asthma severity is archaic. Asthma is a heterogenous syndrome rather than a single disease entity. Studies evaluating observable characteristics called phenotypes have elucidated this heterogeneity. Asthma clusters demonstrate overlapping features, are generally stable over time and are reproducible. What the identification of clusters may have failed to do, is move the needle of precision medicine meaningfully in asthma. This may be related to the lack of a straightforward and clinically meaningful way to apply what we have learned about asthma clusters. Clusters are based on both clinical factors and biomarkers. The use of biomarkers is slowly gaining popularity, but phenotyping based on biomarkers is generally greatly underutilized even in subspecialty care. Biomarkers are more often used to evaluate type 2 (T2) inflammatory signatures and eosinophils (sputum and blood), fractional exhaled nitric oxide (FeNO) and serum total and specific immunoglobulin (Ig) E reliably characterize the underlying inflammatory pathways. Biomarkers perform variably and clinicians must be familiar with their advantages and disadvantages to accurately apply them in clinical care. In addition, it is increasingly clear that clinical features are critical in understanding not only phenotypic characterization but in predicting response to therapy and future risk of poor outcomes. Strategies for asthma management will need to leverage our knowledge of biomarkers and clinical features to create composite scores and risk prediction tools that are clinically applicable. Despite significant progress, many questions remain, and more work is required to accurately identify non-T2 biomarkers. Adoption of phenotyping and more consistent use of biomarkers is needed, and we should continue to encourage this incorporation into practice.

Neutrophil extracellular traps and thrombosis in COVID-19.

Studies of patients with COVID-19 have demonstrated markedly dysregulated coagulation and a high risk of morbid arterial and venous thrombotic events. Elevated levels of blood neutrophils and neutrophil extracellular traps (NETs) have recently been described in patients with COVID-19. However, their potential role in COVID-19-associated thrombosis remains incompletely understood. In order to elucidate the potential role of hyperactive neutrophils and NET release in COVID-19-associated thrombosis, we conducted a case-control study of patients hospitalized with COVID-19 who developed thrombosis, as compared with gender- and age-matched COVID-19 patients without clinical thrombosis. We found that remnants of NETs (cell-free DNA, myeloperoxidase-DNA complexes, and citrullinated histone H3) and neutrophil-derived S100A8/A9 (calprotectin) in patient sera were associated with higher risk of morbid thrombotic events in spite of prophylactic anticoagulation. These observations underscore the need for urgent investigation into the potential relationship between NETs and unrelenting thrombosis in COVID-19, as well as novel approaches for thrombosis prevention.

Oral Glucocorticoid-Sparing Effect of Benralizumab in Severe Asthma.

BACKGROUND: Many patients with severe asthma rely on oral glucocorticoids to manage their disease. We investigated whether benralizumab, a monoclonal antibody directed against the alpha subunit of the interleukin-5 receptor that significantly reduces the incidence of asthma exacerbations, was also effective as an oral glucocorticoid-sparing therapy in patients relying on oral glucocorticoids to manage severe asthma associated with eosinophilia. METHODS: In a 28-week randomized, controlled trial, we assessed the effects of benralizumab (at a dose of 30 mg administered subcutaneously either every 4 weeks or every 8 weeks [with the first three doses administered every 4 weeks]) versus placebo on the reduction in the oral glucocorticoid dose while asthma control was maintained in adult patients with severe asthma. The primary end point was the percentage change in the oral glucocorticoid dose from baseline to week 28. Annual asthma exacerbation rates, lung function, symptoms, and safety were assessed. RESULTS: Of 369 patients enrolled, 220 underwent randomization and started receiving benralizumab or placebo. The two benralizumab dosing regimens significantly reduced the median final oral glucocorticoid doses from baseline by 75%, as compared with a reduction of 25% in the oral glucocorticoid doses in the placebo group (P<0.001 for both comparisons). The odds of a reduction in the oral glucocorticoid dose were more than 4 times as high with benralizumab as with placebo. Among the secondary outcomes, benralizumab administered every 4 weeks resulted in an annual exacerbation rate that was 55% lower than the rate with placebo (marginal rate, 0.83 vs. 1.83, P=0.003), and benralizumab administered every 8 weeks resulted in an annual exacerbation rate that was 70% lower than the rate with placebo (marginal rate, 0.54 vs. 1.83, P<0.001). At 28 weeks, there was no significant effect of either benralizumab regimen on the forced expiratory volume in 1 second (FEV1), as compared with placebo. The effects on various measures of asthma symptoms were mixed, with some showing significant changes in favor of benralizumab and others not showing significant changes. Frequencies of adverse events were similar between each benralizumab group and the placebo group. CONCLUSIONS: Benralizumab showed significant, clinically relevant benefits, as compared with placebo, on oral glucocorticoid use and exacerbation rates. These effects occurred without a sustained effect on the FEV1. (Funded by AstraZeneca; ZONDA ClinicalTrials.gov number, NCT02075255 .).

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).

Rapid onset of effect of benralizumab on morning peak expiratory flow in severe, uncontrolled asthma.

BACKGROUND: Benralizumab is a unique eosinophil-depleting monoclonal antibody that significantly reduces asthma exacerbations, improves lung function and asthma symptoms, and permits the reduction of maintenance oral corticosteroid dosage for patients with severe, uncontrolled eosinophilic asthma. OBJECTIVE: To assess benralizumab's onset of action and efficacy by examining change in morning peak expiratory flow (PEF) after initiation of treatment in the phase 3 clinical trials SIROCCO, CALIMA, and ZONDA. METHODS: Mixed-model repeated-measures analysis was used to calculate PEF using daily least squares mean changes from baseline in morning PEF as well as differences between the benralizumab every 8 weeks (first 3 doses every 4 weeks) and placebo groups. A Bayesian nonlinear mixed-effects approach with an exponential relationship was used to model trial data to determine time to clinically meaningful improvement in morning PEF (defined as ≥25 L/min). RESULTS: Least squares mean morning PEF improvement from baseline was numerically greater by Day 2 after initiation of benralizumab therapy in all 3 trials. The Bayesian nonlinear mixed-effects model indicated that PEF improvement reached the clinically meaningful threshold within 3 weeks in SIROCCO and CALIMA and 2 weeks in ZONDA. CONCLUSION: In 3 phase 3 randomized clinical trials, benralizumab provided notable improvement in morning PEF 2 days after initiation and clinically meaningful improvements within 3 weeks for patients with severe, uncontrolled eosinophilic asthma. The rapid improvement in PEF demonstrated in these trials suggests that benralizumab's unique mechanism of action rapidly improves lung function for patients with severe, eosinophilic asthma. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: NCT01928771 (SIROCCO), NCT01914757 (CALIMA), and NCT02075255 (ZONDA).

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.

Impact of Age and Sex on Response to Asthma Therapy.

RATIONALE: Age and sex are associated with differences in asthma prevalence and morbidity. OBJECTIVES: To determine if age and sex associate with distinct phenotypes and a variable response to therapy in subjects with mild to moderate asthma. METHODS: We used Asthma Clinical Research Network data to determine the impact of age and sex on phenotypes and treatment failures among subjects participating in 10 trials from 1993 to 2003. MEASUREMENTS AND MAIN RESULTS: A total of 1,200 subjects were identified (median age, 30.4 yr; male, 520 [43.3%]; female, 680 [56.7%]) and analyzed. A higher proportion of subjects greater than or equal to 30 years old experienced treatment failures (17.3% vs. 10.3%; odds ratio [OR], 1.82; confidence interval [CI], 1.30-2.54; P < 0.001), and rates increased proportionally with increasing age older than 30 across the cohort (OR per yr, 1.02 [CI, 1.01-1.04]; OR per 5 yr, 1.13 [CI, 1.04-1.22]; P < 0.001). Lower lung function and longer duration of asthma were associated with a higher risk of treatment failures. A higher proportion of subjects greater than or equal to 30 years old receiving controller therapy experienced treatment failures. When stratified by specific therapy, treatment failures increased consistently for every year older than age 30 in subjects on inhaled corticosteroids (OR per year, 1.03; CI, 1.01-1.07). Females had a slightly higher FEV1 % predicted (84.5% vs. 81.1%; P < 0.001) but similar asthma control measures. There was not a statistically significant difference in treatment failures between females and males (15.2% vs. 11.7%; P = 0.088). CONCLUSIONS: Older age is associated with an increased risk of treatment failure, particularly in subjects taking inhaled corticosteroids. There was no significant difference in treatment failures between sexes.

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.

Association of Sputum Eosinophilia With Easily Measured Type-2 Inflammatory Biomarkers in Untreated Mild Persistent Asthma.

BACKGROUND: A multicenter clinical trial in patients with mild persistent asthma indicated that response to inhaled corticosteroids (ICS) is limited to those with sputum eosinophilia. However, testing for sputum eosinophilia is impractical in most clinical settings. OBJECTIVE: We examined associations between sputum eosinophilia and type 2 inflammatory biomarkers in untreated mild persistent asthma. METHODS: Induced sputum, blood eosinophil count (BEC), fractional exhaled nitric oxide (FeNO), and serum periostin were obtained twice during the 6-week run-in period in a clinical trial that enrolled patients 12 years and older with symptomatic, mild persistent asthma without controller therapy. The optimal threshold for each biomarker was based on achieving 80% or greater sensitivity. Performance of biomarkers (area under the receiver operating characteristics curve [AUC], range 0.0-1.0) in predicting sputum eosinophilia 2% or greater was determined; AUCs of 0.8 to 0.9 and more than 0.9 define excellent and outstanding discrimination, respectively. RESULTS: Of 564 participants, 27% were sputum eosinophilic, 83% were atopic, 70% had BEC of 200/uL or higher or FeNO of 25 ppb or greater; 64% of participants without sputum eosinophilia had elevated BEC or FeNO. The AUCs for BEC, FeNO, and both together in predicting sputum eosinophilia were all below the threshold for excellent discrimination (AUC 0.75, 0.78, and 0.79, respectively). Periostin (in adults) had poor discrimination (AUC 0.59; P = .02). CONCLUSIONS: In untreated mild persistent asthma, there is substantial discordance between sputum eosinophilia, BEC, and FeNO. Until prospective trials test the ability of alternative biomarkers to predict ICS response, BEC or FeNO phenotyping may be an option to consider ICS through a shared decision-making process with consideration of other clinical features.

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.

Mild asthma: Lessons learned and remaining questions.

Patients living with mild disease represent the largest proportion of asthma patients. There are significant challenges in proposing a definition that would best describe these patients, while also accurately identifying at-risk individuals. Current literature suggests considerable inflammatory and clinical heterogeneity within this group. Research has shown that these patients are at risk of poor control, exacerbations, lung function decline, and death. Despite conflicting data on its prevalence, eosinophilic inflammation appears to be a predictor of poorer outcomes in mild asthma. There is an immediate need to better understand phenotypic clusters in mild asthma. It is also important to understand factors that influence disease progression and remission, as it is evident that both vary in mild asthma. Guided by robust literature that supports inhaled corticosteroid-based strategies over short-acting beta-agonist (SABA) reliant regimens, the management of these patients has evolved considerably. Unfortunately, SABA use remains high in clinical practice despite strong advocacy from the Global Initiative for Asthma. Future mild asthma research should explore the role of biomarkers, develop prediction tools based on composite risk scores, and explore targeted therapies at least for at-risk individuals.

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.