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Key Points: Question: In people with asthma, compared with short-acting β agonists (SABA) alone, is the combination of SABA with inhaled corticosteroids (ICS-SABA) and the combination of formoterol with inhaled corticosteroids (ICS-formoterol) associated with better asthma outcomes? Findings: In this systematic review and network meta-analysis that included 27 randomized clinical trials (50 496 adult and pediatric patients), compared with SABA alone, ICS-SABA was associated with a 4.7% reduction in risk of severe exacerbations and ICS-formoterol was associated with a 10.3% reduction in severe exacerbations, without an increase in adverse events. Meaning: Both combined ICS with SABA and ICS with formoterol were associated with lower risks of severe asthma exacerbations compared with SABA alone. Importance: The optimal inhaled reliever therapy for asthma remains unclear. Objective: To compare short-acting β agonists (SABA) alone with SABA combined with inhaled corticosteroids (ICS) and with the fast-onset, long-acting β agonist formoterol combined with ICS for asthma. Data Sources: The MEDLINE, Embase, and CENTRAL databases were searched from January 1, 2020, to September 27, 2024, without language restrictions. Study Selection: Pairs of reviewers independently selected randomized clinical trials evaluating (1) SABA alone, (2) ICS with formoterol, and (3) ICS with SABA (combined or separate inhalers). Data Extraction and Synthesis: Two reviewers independently extracted data and assessed risk of bias. Random-effects meta-analyses synthesized outcomes. GRADE (Grading of Recommendations Assessment, Development, and Evaluation) was used to evaluate the certainty of evidence. Main Outcomes and Measures: Asthma symptom control (5-item Asthma Control Questionnaire; range, 0-6, lower scores indicate better asthma control; minimum important difference [MID], 0.5 points), asthma-related quality of life (Asthma Quality of Life Questionnaire; range, 1-7, higher scores indicate better quality of life; MID, 0.5 points), risk of severe exacerbations, and risk of serious adverse events. Results: A total of 27 randomized clinical trials (N = 50 496 adult and pediatric patients; mean age, 41.0 years; 20 288 male [40%]) were included. Compared with SABA alone, both ICS-containing relievers were associated with fewer severe exacerbations (ICS-formoterol risk ratio [RR], 0.65 [95% CI, 0.60-0.72]; risk difference [RD], −10.3% [95% CI, −11.8% to −8.3%]; ICS-SABA RR, 0.84 [95% CI, 0.73-0.95]; RD, −4.7% [95% CI, −8.0% to −1.5%]) with high certainty. Compared with SABA alone, both ICS-containing relievers were associated with improved asthma control (ICS-formoterol RR improvement [MID] in total score, 1.07 [95% CI, 1.04-1.10]; RD, 4.1% [95% CI, 2.3%-5.9%]; ICS-SABA RR, 1.09 [95% CI, 1.03-1.15]; RD, 5.4% [95% CI, 1.8%-8.5%]) with high certainty. In an indirect comparison with ICS-SABA, ICS-formoterol was associated with fewer severe exacerbations (RR, 0.78 [95% CI, 0.66-0.92]; RD, −5.5% [95% CI, −8.4% to −2.0%]) with moderate certainty. Compared with SABA alone, ICS-formoterol (RD, −0.6% [95% CI, −1.3% to 0%]) was not associated with increased risk of serious adverse events (high certainty) and ICS-SABA (RD, 0% [95% CI, −1.1% to 1.2%]) was not associated with increased risk of serious adverse events (moderate certainty). Conclusions and Relevance: In this network meta-analysis of patients with asthma, ICS combined with formoterol and ICS combined with SABA were each associated with reduced asthma exacerbations and improved asthma control compared with SABA alone. This systematic review and network meta-analysis investigates whether inhaled corticosteroids combined with either short-acting beta agonists or formoterol are more effective than short-acting beta agonists alone in reducing exacerbations and improving control in patients with asthma. [ABSTRACT FROM AUTHOR]

Rationale: In asthma, sputum group 2 innate lymphoid cells (ILC2s) are activated within 7 hours after allergen challenge. Neuroimmune interactions mediate rapid host responses at mucosal interfaces. In murine models of asthma, lung ILC2s colocalize to sensory neuronal termini expressing the neuropeptide neuromedin U (NMU), which stimulates type 2 (T2) cytokine secretion by ILC2s, with additive effects to alarmins in vitro. Objectives: To investigate the effect of the NMU/NMUR1 (NMU receptor 1) axis on early activation of ILC2s in asthma. Methods: Subjects with mild asthma (n = 8) were enrolled in a diluent-controlled allergen inhalation challenge study. Sputum ILC2 expression of NMUR1 and T2 cytokines was enumerated by flow cytometry, and airway NMU levels were assessed by ELISA. This was compared with samples from subjects with moderate to severe asthma (n = 9). Flow sort–purified and ex vivo–expanded ILC2s were used for functional assays and transcriptomic analyses. Measurements and Main Results: Significant increases in sputum ILC2s expressing NMUR1 were detected 7 hours after allergen versus diluent challenge whereby the majority of NMUR1+ ILC2s expressed IL-5/IL-13. Sputum NMUR1+ ILC2 counts were significantly greater in mild versus moderate to severe asthma, and NMUR1+ ILC2s correlated inversely with the dose of inhaled corticosteroid in the latter group. Coculturing with alarmins upregulated NMUR1 in ILC2s, which was attenuated by dexamethasone. NMU-stimulated T2 cytokine expression by ILC2s, maximal at 6 hours, was abrogated by dexamethasone or specific signaling inhibitors for mitogen-activated protein kinase 1/2 and phosphoinositol 3-kinase but not the IL-33 signaling moiety MyD88 in vitro. Conclusions: The NMU/NMUR1 axis stimulates rapid effects on ILC2s and may be an important early activator of these cells in eosinophilic inflammatory responses in asthma. [ABSTRACT FROM AUTHOR]

This article examines the protein expression of ACE2 and TMPRSS2 receptors in the airways of individuals with allergic asthma and allergic rhinitis after allergen challenge. The study found that allergen challenge led to a significant reduction in the number of cells expressing ACE2 and TMPRSS2 receptors in the bronchial tissue of individuals with allergic asthma. However, no significant changes were observed in the nasal tissue of individuals with allergic rhinitis. The authors hypothesized that elevated levels of IL-13, a type 2 cytokine, after allergen challenge may regulate ACE2 protein expression in the airways. The study suggests that while IL-13 may dampen ACE2 and TMPRSS2 receptor expression, other factors contribute to the rate of SARS-CoV-2 infectivity and hospitalization in individuals with asthma. [Extracted from the article]

Background: Similar immune responses in the nasal and bronchial mucosa implies that nasal allergen challenge (NAC) is a suitable early phase experimental model for drug development targeting allergic rhinitis (AR) and asthma. We assessed NAC reproducibility and the effects of intranasal corticosteroids (INCS) on symptoms, physiology, and inflammatory mediators. Methods: 20 participants with mild atopic asthma and AR underwent three single blinded nasal challenges each separated by three weeks (NCT03431961). Cohort A (n = 10) underwent a control saline challenge, followed by two allergen challenges. Cohort B (n = 10) underwent a NAC with no treatment intervention, followed by NAC with 14 days pre‐treatment with saline nasal spray (placebo), then NAC with 14 days pre‐treatment with INCS (220 μg triamcinolone acetonide twice daily). Nasosorption, nasal lavage, blood samples, forced expiratory volume 1 (FEV1), total nasal symptom score (TNSS), peak nasal inspiratory flow (PNIF) were collected up to 24 h after NAC. Total and active tryptase were measured as early‐phase allergy biomarkers (≤30 min) and IL‐13 and eosinophil cell counts as late‐phase allergy biomarkers (3–7 h) in serum and nasal samples. Period‐period reproducibility was assessed by intraclass correlation coefficients (ICC), and sample size estimates were performed using effect sizes measured after INCS. Results: NAC significantly induced acute increases in nasosorption tryptase and TNSS and reduced PNIF, and induced late increases in nasosorption IL‐13 with sustained reductions in PNIF. Reproducibility across NACs varied for symptoms and biomarkers, with total tryptase 5 min post NAC having the highest reproducibility (ICC = 0.91). Treatment with INCS inhibited NAC‐induced IL‐13 while blunting changes in TNSS and PNIF. For a similar crossover study, 7 participants per treatment arm are needed to detect treatment effects comparable to INCS for TNSS. Conclusion: NAC‐induced biomarkers and symptoms are reproducible and responsive to INCS. NAC is suitable for assessing pharmacodynamic activity and proof of mechanism for drugs targeting allergic inflammation. [ABSTRACT FROM AUTHOR]