Type 2 (T2) immune-mediated epithelial-driven diseases are characterized by dysregulated immune responses at epithelial barrier surfaces. A key mediator of these diseases is thymic stromal lymphopoietin (TSLP), an epithelial cytokine that acts as a regulator of both T2 and non-T2 inflammation. TSLP activates dendritic cells and other immune cells, promoting the release of proinflammatory cytokines, including interleukin (IL)-4, IL-5, and IL-13. Given its central role in initiating and amplifying T2 inflammation, TSLP has emerged as a promising therapeutic target in multiple epithelial-driven inflammatory diseases. Tezepelumab is a human monoclonal antibody that selectively blocks TSLP from interacting with its receptor complex, thereby interrupting this inflammatory cascade, and its study in various disease states has clarified the clinical importance of TSLP-driven inflammation. In this review, we examine preclinical and clinical evidence and enumerate the lessons learned to date regarding the role of TSLP in sustaining select T2 inflammatory diseases—specifically asthma, chronic rhinosinusitis with nasal polyps, chronic obstructive pulmonary disease, allergic rhinitis, atopic dermatitis, and chronic spontaneous urticaria. Tezepelumab is currently the only approved anti-TSLP therapy. Other TSLP-targeting agents, including ecleralimab, SHR-1905, bosakitug, verekitug, sunakiment, TAVO101, ocankitug, HBM9378, MG-ZG122, GB-0895, and solrikitug, are in clinical development.
Background Allergic bronchopulmonary aspergillosis (ABPA) is a complex allergic hypersensitivity reaction to Aspergillus species that can complicate and worsen concomitant asthma and is associated with an intense type 2 immune response in lower airways; there are no approved targeted therapies. Objective To investigate dupilumab, a fully human monoclonal antibody blocking interleukins 4/13 via the shared interleukin 4 receptor alpha, in patients with asthma and ABPA. Methods In this double-blind phase 2 trial, patients with asthma aged ≥12 years who met the clinical criteria for ABPA were randomized to dupilumab (n=35) or placebo (n=27) for 24 to 52 weeks; 37.1% were receiving chronic systemic corticosteroids (SCS). The primary endpoint was change from baseline in prebronchodilator forced expiratory volume in 1 second (FEV1) at 24 weeks. Additional endpoints included severe respiratory exacerbations and SCS use. Results At week 24, prebronchodilator FEV1 was significantly improved with dupilumab versus placebo (least squares mean change, 0.203 L vs 0.002 L; least squares mean treatment difference, 0.201 L; 95% confidence interval [CI], 0.08-0.33; P=0.002). The adjusted annualized severe respiratory exacerbation rate per person-year was 0.695 (95% CI, 0.35-1.36) with dupilumab and 1.551 (95% CI, 0.75-3.22) with placebo, a 55.2% reduction; nominal P=0.0627. At week 24, 71.4% of dupilumab recipients who required SCS at baseline no longer required SCS, compared with 14.3% receiving placebo. Overall safety was consistent with the known dupilumab safety profile. Conclusions In patients with asthma and ABPA, dupilumab significantly improved lung function compared with placebo, reduced severe respiratory exacerbations, and was well tolerated.
Background KIT D816V drives constitutive mast cell (MC) signaling and is central to the pathogenesis of clonal mast cell activation disorders including systemic mastocytosis. These conditions may present with severe anaphylaxis despite low KIT D816V mutation burden. Since neoplastic mast cells may co-express mutant and wild-type (WT) KIT, the functional relevance of ligand-dependent signaling and activation remains incompletely understood. Barzolvolimab has demonstrated efficacy in WT MC-driven diseases, but its effects on KIT-mutated MCs remain unclear. Objective To assess the effects of barzolvolimab on KIT D816V-mutated MCs. Methods We established and characterized primary-like human MC models, including isogenic hiPSC-derived WT and heterozygous KIT D816V MCs, PSC-derived MCs and HMC-1.2 cell line. Barzolvolimab effects on apoptosis, KIT signaling, and IgE-mediated activation were investigated using flow cytometry, Western blotting, and functional degranulation assays. Results Barzolvolimab induced dose-dependent apoptosis and inhibited SCF-induced KIT signaling in WT MCs, but had no effect on mutant MC viability or signaling. Notably, barzolvolimab effectively suppressed SCF-enhanced IgE-mediated MC activation across all primary-like models, including KIT D816V MCs, as evidenced by reduced β-hexosaminidase release and CD63 expression. This inhibitory effect occurred at low nanomolar concentrations and was independent of cytotoxicity. Conclusions Our findings demonstrate a functional dissociation between KIT-dependent survival and activation pathways in mutated MCs. While barzolvolimab does not reduce the viability of KIT-mutated MCs, it effectively suppresses SCF-dependent amplification of IgE-mediated activation, supporting its potential as a therapeutic option for symptomatic patients harboring KIT mutations, particularly for the control of mediator-related symptoms.
Background Lung macrophages are central regulators of inflammatory responses in the airways and lung parenchyma. Macrophages function as conduits for cytokine function in the inflammatory milieu. We previously demonstrated that IL-9-responsive macrophages are essential for allergic lung inflammation in an arginase 1 (Arg1) pathway. Objective Define the IL-9/Arg1/polyamine pathway in human macrophages from model systems and asthmatic patient samples. Methods Using humanized NSG-Quad mice treated with intranasal IL-9 and patient bronchoalveolar lavage (BAL) samples, we evaluated macrophage phenotypes via flow cytometry, bulk RNA sequencing, and metabolic assays. Results Two distinct human lung macrophage populations were defined by the expression of CD43. IL-9 promoted the expansion of IL-9R+/Arg1+ CD43- macrophages in humanized mice. In parallel, greater proportions of IL-9R+/Arg1+ CD43- macrophages were observed in asthmatic patient BAL samples compared with healthy control patients. Higher concentrations of polyamines, downstream metabolites of Arg1 function, were detected in BAL of IL-9-treated humanized mice. There were increased concentrations of polyamines in asthmatic patient BAL, compared to control samples, and concentrations were positively correlated to BAL IL-9 concentration and increases of IL-9R+ and Arg1+ CD43- macrophages. Conclusions IL-9-responsive CD206+ CD43- macrophages alter the metabolites present in the lung milieu. These data provide evidence for an IL-9R/Arg1/polyamine lung macrophage axis that is active in asthma patients.
Background Chronic rhinosinusitis with nasal polyps (CRSwNP) features marked infiltration of diverse inflammatory cells. Cadherin-26 (CDH26) is an adhesion molecule associated with eosinophilic inflammation, but its role in CRSwNP remains undefined. Objective To investigate the expression, mechanisim, and function of CDH26 in CRSwNP. Methods Bulk and single-cell RNA sequencing and immunohistochemistry of human nasal tissues profiled CDH26 expression, localization, and its association with immune cells and inflammatory pathways in CRSwNP. Nasal epithelial cells were stimulated with cytokines to examine CDH26 expression, and were transfected to evaluate CDH26’s impact on JAK-STAT signaling. Adhesion and survival assays were conducted with isolated eosinophils and neutrophils. CDH26-/- mice were used to establish a CRSwNP model to determine CDH26’s role in disease development. Results CDH26 was elevated in eosinophilic CRSwNP (ECRSwNP) compared with control and non-eosinophilic CRSwNP (NECRSwNP) and correlated with intraepithelial infiltration of both eosinophils and neutrophils. Single-cell analysis showed its epithelial localization and co-expression with IL13RA1/STAT6 in basal cells. CDH26 was induced by IL-4/IL-13 via JAK-STAT signaling and, in turn, enhanced STAT6 phosphorylation. CDH26 mediated epithelial adhesion of eosinophils and neutrophils via integrin α4 (ITGA4) and enhanced their survival in vitro. CDH26-/- mice showed attenuated nasal polyp-like lesion formation and reduction in the infiltration of eosinophils, neutrophils, mast cells, and T cell subsets. Conclusion CDH26 is a type 2-inducible epithelial molecule that functions as an inflammatory mediator in CRSwNP by modulating JAK-STAT signaling and promoting eosinophil and neutrophil retention, thereby linking epithelial dysfunction to sustained inflammation and may represent a potential therapeutic target.
Background Non-communicable inflammatory skin diseases (ncISDs) comprise over 100 conditions with overlapping clinical features. Current classification systems are largely based on morphology and do not adequately reflect underlying molecular mechanisms, limiting the implementation of precision therapies. Objective To establish a data-driven, molecular framework for stratifying ncISDs independent of conventional diagnostic categories. Methods We integrated 727 skin transcriptomes with clinical metadata from 390 patients across 22 ncISDs and applied unsupervised and machine-learning approaches to identify molecular endotypes and develop a predictive classifier. Results We identified thirteen distinct molecular endotypes, which segregated into two major groups: seven driven by immune response programs and six by metabolic and epidermal structural pathways. Common diseases such as psoriasis and eczema distributed across multiple endotypes, highlighting substantial molecular heterogeneity. Psoriasis-dominated endotypes showed differential responses to IL-23-, IL-17-, and TNF-targeted therapies, underscoring clinical relevance. A multi-endotype classifier achieved 81.4% accuracy and was validated in independent cohorts. Conclusion These findings define a molecularly informed framework for disease stratification that transcends traditional diagnostic boundaries and enables more precise, mechanism-based therapeutic decision-making across inflammatory diseases.
Background Peanut allergy is an increasingly prevalent condition without curative treatment. Oral immunotherapy (OIT) can induce desensitization, but its mechanisms are not fully understood. Administration of oral short-chain fatty acids (SCFAs) in murine models induces favorable immunomodulation that overlaps with processes observed in OIT. We hypothesized that in human populations, oral SCFA levels change during OIT and are associated with systemic downregulation of Type 2 processes. Methods Within a clinical trial of children age 4-14 years with high-threshold peanut allergy randomized to OIT or avoidance, we profiled oral SCFA levels, the oral microbiome, and peripheral blood transcriptome over the course of OIT or avoidance. Statistical and network analyses were carried out to test our hypotheses. Results Among the 56 children in the clinical trial with complete multi-omic profiles over the trial duration, 29 were randomized to OIT and 27 to avoidance. 100% of the participants in the OIT group achieved desensitization compared to 18.5% in the avoidance group. Oral levels of the SCFA propionate increased with OIT but not avoidance (FDR=0.042) and remained elevated with sustained unresponsiveness. Oral propionate levels positively correlated with the relative abundances of several oral microbes, including known propionate producers Prevotella spp. (r=0.47, FDR 3.75x 10-3) and Veillonella (r=0.39, FDR 1.45x10-2). Oral propionate levels negatively correlated with peripheral blood transcript expression of OIT-associated Fcγ receptors (FDR≤ 0.05), IL-4 & IL-13 signaling (FDR≤ 0.05), and neutrophil degranulation pathways (FDR≤ 0.05). Conclusions This study raises the intriguing possibility of oral propionate serving as an important immunoregulatory bridge between local and systemic processes in peanut OIT. Trial Registration ClinicalTrials.gov NCT03907397.
Background The ability of barrier epithelia to sense environmental perturbations and initiate local inflammation is essential for progenitor-mediated epithelial repair and restoration of tissue integrity. Objective To characterize human esophageal epithelial progenitor cell heterogeneity and identify molecular mechanisms regulating epithelial regeneration in eosinophilic esophagitis (EoE). Methods Single-cell RNA sequencing of the adult human esophagus was integrated with spatial characterization of epithelial cell populations and functional analyses using primary human esophageal organoids and air-liquid interface cultures. Results Using NGFR and P73, we defined a layer of human basal progenitor cells spanning both papillary and interpapillary regions of the human esophageal epithelium. Proliferating basal progenitor cells were enriched within the papillary epithelium, and a subset of papillary basal progenitor cells displayed active YAP signaling, revealing spatially organized heterogeneity within the progenitor compartment. NGFR-positive basal cells exhibited enhanced organoid-forming capacity and suppressed NOTCH signaling to maintain basal identity. During epithelial regeneration, IL1A was induced in primary human organoids, and an intraepithelial apical-to-basal IL1A signaling axis was identified in patients with EoE. IL1A activated NF-κB-dependent transcription, promoted basal progenitor expansion, and enhanced epithelial barrier function. Although IL13 selectively rewired IL1A-dependent transcriptional and regenerative programs, IL1A signaling remained active under inflammatory conditions. Conclusion These findings demonstrate that IL1A coordinates epithelial inflammatory and regenerative responses in the human esophagus. They further show that the outcome of IL1A signaling is determined by the surrounding inflammatory milieu, providing a framework for understanding epithelial remodeling in eosinophilic esophagitis.
Background Integrated pest management (IPM) is thought to improve asthma symptoms through reduced mouse allergen exposure. Whether IPM acts through changes in mouse-associated microbes remains unknown. Objectives To examine the effects of school-based IPM on the classroom microbiome, and to determine the association between intervention microbiome signatures and student asthma morbidity. Methods In this ancillary study based on a randomized placebo-controlled clinical trial of school IPM and classroom high efficiency air purifiers (ClinicalTrials.gov NCT02291302), we performed deep metagenomics sequencing of longitudinally collected dust samples from 208 classrooms in 41 schools of 236 children with active, physician-diagnosed asthma with prospective follow-up of asthma severity during the school year. We assessed the effect of the interventions on classroom microbial communities in intention-to-treat analyses. Sparse Partial Least Squares models were used to identify microbial signatures of the interventions and the association between these microbial signatures and asthma morbidity was assessed using mixed effects models, controlling for covariates including mouse allergen exposure. Results IPM significantly altered classroom bacterial and phage community structure and increased bacterial, archaeal, and fungal diversity. A classroom microbiome signature of IPM was identified (AUC=0.84) and was associated with lower odds of any asthma symptom days in the past two weeks (OR 0.47, 95% CI [0.22, 0.97], p=0.043) and lower Composite Asthma Severity Index (β -0.92, 95% CI [-1.51, -0.33], p=0.002), adjusting for mouse allergen levels and student characteristics. Conclusion IPM-associated changes in the classroom microbiome are associated with lower asthma morbidity independent of mouse allergen exposure.
RATIONALE:Aspirin therapy after desensitization is a unique treatment option for patients with aspirin-exacerbated respiratory disease (AERD). However, biomarkers predicting response are lacking, and the effects of high-dose aspirin remain unclear. OBJECTIVES:We sought to determine clinical response to aspirin therapy after desensitization, identify predictive biomarkers, and compare aspirin-related molecular effects between AERD patients and healthy controls. METHODS:We conducted an 18-week, randomized, double-blind, placebo-controlled crossover trial of aspirin (600 mg/d) in patients with AERD (n = 14) and controls (n = 13). Each treatment arm lasted 8 weeks with a 2-week washout. Blood, induced sputum, nasal lavage, and urine samples were collected at 4 time points. Clinical outcomes, transcriptional profiles, cytology, and levels of eicosanoids, cytokines and chemokines were assessed. RESULTS:At baseline, AERD patients had higher blood eosinophils and elevated leukotriene E4 in plasma, nasal lavage, and urine, with reduced eoxin C4 in sputum supernatant and lower prostaglandin E2 and 12-hydroxyeicosatetraenoic acid in nasal lavage compared to controls. No differences in sputum gene expression were observed. SERPINB9 expression correlated with IL4RA in both groups and with PTGS2 in AERD. The disease of 8 patients (57.1%) responded to aspirin; however, the same number responded to placebo, with substantial overlap between treatments. Higher baseline SERPINB9 expression predicted response (odds ratio = 62.3; Padj = .03). After aspirin, SERPINB9 correlations with IL4RA and PTGS2 were lost in AERD but persisted in controls. No consistent molecular changes were observed after either treatment. CONCLUSION:Clinical improvement during aspirin therapy after desensitization was comparable to placebo. However, elevated baseline sputum SERPINB9 was associated with clinical improvement, highlighting potential as a candidate biomarker.
BACKGROUND:IgE-mediated mast cell activation drives food-induced anaphylaxis in mouse models of food allergy (FA), but C57BL/6J mice are relatively resistant, whether to allergic diarrhea or systemic oral anaphylaxis. It is unclear whether this reflects a defect in mast cell activation, because these mice can produce allergen-specific IgE and respond to nonenteral allergens. OBJECTIVE:We sought to determine whether tape-stripping-induced dermal injury could promote FA in systemically sensitized C57BL/6J mice and define the contributions of mucosal mast cells (MMCs) and connective tissue mast cells (CTMCs). METHODS:C57BL/6J mice, wild-type littermates, and Mcpt5-Cre/DTA mice were subjected to systemic sensitization alone or combined tape-stripping/systemic sensitization. Anaphylaxis, mast cell hyperplasia, and mediator release were measured following oral allergen challenge. RESULTS:Systemically sensitized mice showed no impairment in IgE responses or MMC activation. However, food-induced intestinal and lethal oral anaphylaxis were observed only in tape-stripped mice. Dermal injury drove heterogeneous mast cell hyperplasia in multiple tissues, along with increased CD4 T cell- and innate lymphoid cell 2-derived IL-4 and intestinal cysteinyl leukotriene (CysLT) pathway genes. MMC and CTMC contributions were dose-dependent: repeated low-dose challenges favored leukotriene-dependent MMC responses, whereas a single high-dose challenge triggered CTMC-dependent systemic anaphylaxis. IL-4 further amplified CysLT gene expression and MMC hyperplasia, leading to CTMC-independent hypothermia. Arachidonate 5-lipoxygenase blockade reduced MMC-associated intestinal and oral anaphylaxis but did not affect CTMC-dependent systemic anaphylaxis. CONCLUSIONS:Overall, dermal injury combined with systemic sensitization promotes context-dependent FA in C57BL/6J mice through distinct mast cell subsets, with IL-4 and CysLTs shaping disease severity and phenotype.
BACKGROUND:Asthma is characterized by airway inflammation and bronchoconstriction. Recent therapies have addressed inflammation but not bronchoconstriction. S-Nitrosoglutathione (GSNO) is an endogenous smooth muscle relaxant that also affects β2-adrenergic response. Airway GSNO levels are often low in asthma. OBJECTIVE:We studied the effects of inhaled GSNO (iGSNO) in human asthma. METHODS:We measured the effects and metabolism of iGSNO, with a focus on forced expiratory volume in 1 second, β2-adrenergic agonist response and fractional exhaled nitric oxide, and expression of GSNO metabolic genes from bronchoscopic biopsy samples using spatial transcriptomics. RESULTS:iGSNO increased forced expiratory volume in 1 second and β2-adrenergic receptor response; the magnitude of increase was related, and additive, to the receptor response (P < .001). SCoR2 (AKR1A1 gene), encoding a GSNO degrading enzyme, was upregulated in airway epithelium, and higher SCoR2 expression was associated with reduced iGSNO bronchodilation. Sustained elevation in fractional exhaled nitric oxide after iGSNO, indicating reduced GSNO catabolism, was a biomarker for iGSNO effect. CONCLUSION:iGSNO could represent personalized asthma therapy, augmenting β2-adrenergic receptor agonist benefit.
BACKGROUND:Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous inflammatory disease with variable outcomes after functional endoscopic sinus surgery (FESS). Predictive biomarkers for post-FESS CRSwNP recurrence remain poorly defined. OBJECTIVE:We sought to identify tissue-based predictors of CRSwNP recurrence after FESS and assess dupilumab-induced modifications. METHODS:From a cohort of patients with CRSwNP (including nonsteroidal anti-inflammatory drug-exacerbated respiratory disease) who underwent FESS, we retrospectively identified 91 who could be dichotomized by clinical outcome as post-FESS rapid recurrence (<1 year) or slow/no recurrence (>2 years without recurrence). Nasal polyp tissue was analyzed for 69 inflammatory mediators via proteomics and ELISA. Logistic regression with least absolute shrinkage and selection operator (aka LASSO) feature selection identified candidate predictors. In an independent, second prospective cohort of 17 CRSwNP patients initiating dupilumab, nasal fluid was collected at baseline and after 2 months of dupilumab therapy and profiled for the same mediators. RESULTS:Twenty-three tissue mediators strongly predicted rapid CRSwNP recurrence (area under the curve > 0.70), including markers of type 2 (T2) inflammation (IL-4, IL-13, IL-5Rα, eosinophil cationic protein, IgE) and innate inflammation and/or myeloid involvement (CCL3/4/7/8/13, CSF2, IL-1β, IL-6, oncostatin M, MMP12, HIF-1α, TNF-α, TNFSF14). Of these, dupilumab significantly reduced IL-5Rα and several chemokines (CCL3, CCL4, CCL13) but had no effect on key myeloid mediators (CCL8, CSF2, IL-1β, MMP12, HIF-1α). CONCLUSIONS:Both T2 and non-T2 mediators play a role in rapid post-FESS recurrence in CRSwNP. T2 blockade with dupilumab reduces T2-associated mediators but does not suppress a parallel innate/myeloid inflammatory axis.
Background Restoring durable allergen tolerance remains a challenge in the treatment of allergic asthma. Regulatory T cells (Tregs) represent attractive therapeutic targets since they can potently restrain allergen-specific type 2 effector T cell (Th2) responses. Agents that expand Tregs and enhance their function, such as interleukin-2 (IL-2)-based therapies, have been explored, but limited specificity has constrained their efficacy. IL-2 muteins have been engineered to preferentially target Tregs but have not been studied in the context of allergic inflammation. Objective We explored the effects of the IL-2 mutein Fc.mut24 on allergen-induced type 2 airway inflammation. Methods C57BL/6 mice were injected subcutaneously with Fc.mut24 in a house dust mite model of allergic airway inflammation, and clinical, cellular, and molecular biomarkers of the disease were assessed. Results In naïve mice, Fc.mut24 induced a rapid and transient expansion of activated Tregs in the lung. Fc.mut24 treatment prior to allergen sensitization abrogated the emergence of allergen-specific Th2 cells in the lung and prevented allergic airway inflammation and airway hyperreactivity. Further, Fc.mut24-pretreated mice failed to mount a Th2 recall response and did not develop lung inflammation upon allergen rechallenge during the memory phase, suggesting long-term protection. Maintenance of this protection required Tregs, as deletion of Tregs abolished the protective effect of Fc.mut24. In contrast, Fc.mut24 administered during the memory phase did not suppress the Th2 recall response and did not prevent allergic airway inflammation following rechallenge. Conclusion Fc.mut24 therapy prevented allergic airway inflammation when delivered before Th2 cell priming but was insufficient to overcome established allergen-specific type 2 responses, defining a time-dependent window for effective Treg-directed intervention.
BACKGROUND:The congenital ichthyoses are rare hereditary epidermal differentiation disorders characterized by severely impaired skin barrier function. Patients with atopic dermatitis and one form of congenital ichthyosis, Netherton syndrome, are known to be at increased risk of atopy, presumably linked to barrier impairment. However, an increased risk of atopy has not been assessed in individuals with other congenital ichthyoses despite their severe barrier impairment. OBJECTIVE:Our aim was to explore rates of atopy in patients with congenital ichthyoses versus in a control population. METHODS:This cross-sectional survey study enrolled patients and parents of children aged 6 to 11 years with a physician-confirmed diagnosis of congenital ichthyosis and self-reported ichthyosis subtype. Designation of having food allergy, allergic rhinitis, or allergic asthma required a physician's diagnosis and affirmative responses about signs and symptoms. The ichthyosis survey results were compared with 2021 National Health Interview Survey data for each form of atopy. RESULTS:Overall, 115 of 130 invited subjects completed surveys. At least 1 physician-diagnosed atopic disorder was reported by 68.2% of the subjects, including 64.3% of the children and 72.5% of the adults. Significantly higher rates of allergic rhinitis, food allergy, and allergic asthma were found in those with congenital ichthyosis than in the age-matched population data. The highest rates were found not only those in with erythrodermic types (Netherton syndrome, ichthyosis with confetti, and harlequin ichthyosis), which is consistent with their higher levels of barrier impairment, but also in those with X-linked ichthyosis (which is characterized by barrier impairment similar to that in atopic dermatitis). CONCLUSION:Compared with the general population, patients with congenital ichthyosis have an increased risk of developing allergic disorders, suggesting the value of querying about comorbid allergies as part of routine care.
