Qingling Zhang

Summary: Asthma is underdiagnosed and undertreated in China, where treatment with dupilumab could be beneficial. In this industry‐funded post hoc exploratory analysis, dupilumab showed clinical efficacy in allergic and non‐allergic asthma.

Background: Birch pollen (Bet v 1) is a major trigger for allergic asthma, with lung CD4⁺ tissue-resident memory T cells (Trm) driving chronic exacerbations. However, the innate immune checkpoints initiating this adaptive memory remain unclear. We investigated whether macrophage ferroptosis links innate allergen stress to Trm-mediated memory, and evaluated its potential as a therapeutic target. Methods: Using murine models of allergic airway inflammation and bone marrow-derived macrophages (BMDMs), we evaluated the therapeutic efficacy of the ferroptosis inhibitor Ferrostatin-1 (Fer-1). Macrophage depletion, STAT1 silencing, and adoptive transfer of MHC-II-deficient (H2-Ab1^-/-) macrophages were employed to analyze macrophage-T cell crosstalk. Immune profiling and cellular dynamics were assessed via flow cytometry, immunofluorescence, and Western blot. Results: Bet v 1 exposure induced macrophage ferroptosis (elevated lipid ROS and Fe²⁺) both in vitro and in vivo. Pharmacological inhibition with Fer-1 attenuated airway inflammation and prevented lung CD4⁺ Trm expansion. Mechanistically, ferroptotic stress enhanced macrophage phagocytosis and MHC-II-mediated antigen presentation via the PI3K-AKT-Rac1 pathway. STAT1 was identified as a coregulator of both ferroptosis and MHC-II expression. Adoptive transfer and in vitro assays confirmed that pathogenic Trm proliferation required direct, MHC-II-dependent contact with ferroptotic macrophages. Conclusions: Macrophage ferroptosis serves as a critical bridge between innate allergen exposure and chronic adaptive immune memory. Targeting the macrophage ferroptosis-STAT1-Trm axis disrupts pathological antigen presentation, offering a promising therapeutic strategy for chronic allergic asthma.

Introduction: Neutrophilic asthma is a severe, steroid-resistant phenotype driven by T helper 17 (Th17) cells, but its upstream molecular checkpoints remain poorly defined. Aims and objectives: We investigated whether the immunoproteasome subunit PSMB8 modulates Th17 differentiation and drives neutrophilic asthma. Methods: Sputum proteomics from the multi-center C-BIOPRED asthma cohort were analyzed. An ovalbumin/lipopolysaccharide-induced mouse model evaluated the in vivo efficacy of the PSMB8 inhibitor PR-957. Naive CD4⁺ T cells were cultured under Th17-polarizing conditions with PR-957, followed by multi-omics and functional rescue experiments. Results: PSMB8 was upregulated in sputum from neutrophilic asthma patients, inversely correlating with lung function. In vivo, PR-957 significantly reduced airway hyperresponsiveness and lung neutrophil infiltration (from 15.8% to 5.96%, p<0.001), accompanied by decreased Th17 frequencies. In vitro, PR-957 dose-dependently inhibited Th17 differentiation. Multi-omics showed that PSMB8 inhibition triggered endoplasmic reticulum (ER) stress (upregulating ATF4 and CHOP) and downregulated Furin/Activin A. Exogenous Activin A restored STAT3 phosphorylation and rescued Th17 differentiation. Conclusions: PSMB8 drives neutrophilic asthma by promoting Th17 differentiation via ER stress and Furin/Activin A modulation, highlighting PSMB8 inhibition as a therapeutic strategy for this severe phenotype. erj;68/suppl_70/PA1603/F1 F1 F1

Purpose: Asthma affects approximately 46 million adults in China. The safety and efficacy of dupilumab, a monoclonal antibody which blocks the shared receptor component for interleukin (IL)-4 and IL-13, were evaluated in a phase 3 study in patients with moderate-to-severe asthma in the Asia–Pacific region (NCT03782532). This is a pre-specified subgroup analysis of patients in China derived from the Asia–Pacific trial. Patients and Methods: Patients (≥ 12 years) with inadequately controlled asthma despite medium/high-dose inhaled corticosteroids and ≥ 1 additional controller were included. Patients with type 2 inflammation (eosinophil counts ≥ 150 cells/μL or fractional exhaled nitric oxide ≥ 25 parts per billion) without maintenance oral corticosteroids (OCS) (type 2 non-OCS group, for primary efficacy analysis) were randomized 1:1 to receive 200-mg dupilumab every 2 weeks or placebo for 24 weeks. In this pre-specified subgroup analysis, primary efficacy endpoints examined included change from baseline in pre-bronchodilator forced expiratory volume in 1 second (FEV₁) to week 12. Additional outcomes assessed included asthma control measures, annualized severe exacerbation rates, and safety. Results: In a total of 412 patients randomized from China (206 per treatment group) 347 (84.2%) were included in the primary efficacy analysis. Changes from baseline to week 12 in FEV₁ were significantly greater for dupilumab vs placebo (least squares [LS] mean difference: 0.34 L [95% confidence interval (CI): 0.25, 0.43]), as were improvements in 5-Item Asthma Control Questionnaire scores at week 24 (LS mean difference: − 0.19 [95% CI: − 0.35, − 0.03]). Severe exacerbation risk was significantly reduced by 74.2% (risk ratio: 0.258 [95% CI: 0.127, 0.521], P = 0.0002) vs placebo. Treatment-emergent adverse event rates were similar across groups. Conclusion: In this 24-week subgroup analysis, dupilumab improved lung function, asthma control, and exacerbations, and was well tolerated in patients from China with type 2 asthma without maintenance OCS.

Eosinophilic granulomatosis with polyangiitis (EGPA) and severe eosinophilic asthma (SEA) share a Type 2 (T2) inflammatory signature but exhibit distinct pathophysiology. We hypothesized that EGPA involves additional inflammatory mechanisms, beyond T2 immunity, that drive its systemic manifestations and treatment resistance. Using single-cell RNA sequencing, we identify interferon (IFN-I)-driven inflammation in EGPA, in contrast to TNF predominant pathway activation in SEA. IL1B⁺MX1⁺ neutrophils in EGPA express IFN-stimulated genes and promote tertiary lymphoid structure formation with autoantibody production. In addition, other IFN-activated granulocytes, including APOC1⁺ eosinophils, SCN7A⁺ mast cells, and basophils, further contribute to immune dysregulation in EGPA, unlike TNF activated granulocytes in SEA. Longitudinal single-cell analysis of EGPA reveals an IGF1⁺ macrophage population linked to EGPA relapse. In animal models of both conditions, IGF1 blockade attenuates T2 inflammation, mucin production, and goblet cell hyperplasia, highlighting IGF1 as a possible therapeutic target in T2 inflammation disease.

Severe asthma exhibits heterogeneity in airflow obstruction, driven by airway remodeling and air trapping, which can be noninvasively assessed via quantitative computed tomography (qCT). This study aimed to identify asthma phenotypes by clustering qCT measurements of airway dimensions, lung volumes, and densitometry, and to elucidate the underlying molecular pathways through sputum proteomics. We applied consensus clustering to qCT data from 239 asthma patients (severe and mild/moderate) and 68 healthy controls from the Chinese C‐BIOPRED cohort. Four distinct qCT clusters emerged: cluster 1, characterized by luminal dilation, severe air trapping, and reduced lung density; cluster 2, with thickened airway walls and luminal narrowing without air trapping; cluster 3, showing mild luminal dilation, preserved lung volumes, and optimal spirometry; and cluster 4, featuring airway wall thickening, luminal narrowing, severe air trapping, and profound airflow obstruction. Sputum eosinophilia was elevated in clusters 1 and 4. Proteomics revealed upregulated pathways in apoptosis execution and cornified envelope formation in cluster 1, while clusters 2 and 4 exhibited enhanced complement activation, fibrin formation, plasma lipoprotein assembly, and insulin‐like growth factor (IGF) transport regulation. These findings delineate qCT‐derived phenotypes and their associated underlying mechanisms of airway remodeling and airflow obstruction in severe asthma.

Background: We investigated the role of the complement system, particularly complement C5, in severe asthma defined from an analysis of sputum proteomics. Although there has been evidence of complement activation in asthma, its role in severe asthma remains unclear. Method: Sputum protein expression profiles were analyzed from healthy controls and severe asthma patients using data‐dependent acquisition mass spectrometry. Weighted correlation network analysis (WGCNA) was used to define the unique modules that were highly correlated with clinical, physiologic, and inflammatory traits. Differential analysis was performed for the complement C5 pathway protein levels and eosinophilic protein expression as influenced by C5. Asthmatic mouse models were used to verify the effect of complement C5 administration and inhibition. Results: The WGCNA “brown” module related to the complement system activation was positively correlated with eosinophilic inflammation. Specifically, C5 and downstream complement proteins were up‐regulated in patients with high sputum eosinophil levels (≥ 3%) compared to low sputum eosinophils (< 3%). Patients with reduced C5 expression had less eosinophilic inflammation and better lung function. Using single‐cell RNA sequencing and immunofluorescence staining led to identification of macrophages as the main source of C5. In vivo experiments confirmed that inhibiting C5 reduced inflammation in allergic mouse models, while direct stimulation with recombinant C5 in IL‐5 transgenic mice increased eosinophilic inflammation. Conclusion: We demonstrate a direct role for complement C5 in exacerbating eosinophilic inflammation in severe asthma.