Hybrid immunity and SARS-CoV-2 antibodies: results of the HEROES-RECOVER prospective cohort study.

BACKGROUND: There are limited data on whether hybrid immunity differs by count and order of immunity-conferring events (SARS-CoV-2 infection or COVID-19 vaccination). From a cohort of health care personnel, first responders, and other frontline workers in six US states, we examined heterogeneity of the effect of hybrid immunity on SARS-CoV-2 antibody levels. METHODS: Exposures included event-count (sum of infections and vaccine doses) and event-order, categorized into seven permutations of vaccination and/or infection. Outcome was level of serum binding antibodies against receptor binding domain (RBD) of the ancestral SARS-CoV-2 spike protein (total RBD-binding Ig), measured by enzyme-linked immunosorbent assay. Mean antibody levels were examined up to 365 days after each of the 1st-7th events. RESULTS: Analysis included 5,793 participants measured from August 7, 2020 to April 15, 2023. Hybrid immunity from infection before one or two vaccine doses elicited modestly superior antibody responses after the 2nd and 3rd events (compared to infections or vaccine-doses alone). This superiority was not evident after the 4th and 5th events (additional doses). Among adults infected before vaccination, adjusted geometric mean ratios (95% CI) of anti-RBD early response (versus vaccinated-only) were 1.23 (1.14-1.33), 1.09 (1.03-1.14), 0.87 (0.81-0.94), and 0.99 (0.85-1.15) after the 2nd-5th events, respectively. Post-vaccination infections elicited superior responses: adjusted geometric mean ratios (95% CI) of anti-RBD early response (versus vaccinated-only) were: 0.93 (0.75-1.17), 1.11 (1.06-1.16), 1.17 (1.11-1.24), and 1.20 (1.07-1.34) after the 2nd-5th events, respectively. CONCLUSIONS AND RELEVANCE: Findings reflecting heterogeneity in antibody levels by permutations of infection and vaccination history could inform COVID-19 vaccination policy.

Genetic relationships between high blood eosinophil count, asthma susceptibility, and asthma severity.

OBJECTIVE: Genetic relationships between blood eosinophil count (BEC), asthma susceptibility, and severity are unclear. We sought to identify the genetic difference between type 2 (T2) and nontype 2 (non-T2) asthma (defined by BEC) and investigate genetic relationships between high BEC, asthma susceptibility, and severity. METHODS: Genome-wide association studies (GWASs) were performed for T2 (n = 9,064; BEC ≥ 300 cells/µL) versus non-T2 asthma (n = 14,379; BEC < 150 cells/µL) and asthma susceptibility (37,227 asthmatics vs. 124,132 nonasthma controls) in the UK Biobank and asthma severity (moderate-to-severe asthma [n = 2,153] vs. mild asthma [n = 5165]) in the All of Us Research Program (AoURP). Genetic causality between BEC, asthma susceptibility, and severity were dissected using Mendelian randomization (MR). RESULTS: High BEC was associated with asthma and decreased pulmonary function. GWASs revealed four sets of genetic variants (p < 5 × 10-8): genes associated with only BEC or asthma and genes associated with high BEC and asthma in the same or opposite direction. The C allele of rs653178 in ATXN2 was associated with high BEC, risk for autoimmune diseases, and protection for asthma. Genetic variants associated with BEC or asthma were not associated with asthma severity. MR indicated high BEC and asthma were in bidirectional causal relationship (p < .001); however, they were not causal for asthma severity. CONCLUSIONS: Genetic variants associated with asthma or BEC and asthma severity are distinctive. High BEC is a risk factor for asthma; however, it is neither necessary nor sufficient for asthma susceptibility and severity.

Low CC16 mRNA Expression Levels in Bronchial Epithelial Cells Are Associated with Asthma Severity.

Rationale: CC16 is a protein mainly produced by nonciliated bronchial epithelial cells (BECs) that participates in host defense. Reduced CC16 protein concentrations in BAL and serum are associated with asthma susceptibility. Objectives: Few studies have investigated the relationship between CC16 and asthma progression, and none has focused on BECs. In this study, we sought to determine if CC16 mRNA expression levels in BECs are associated with asthma severity. Methods: Association analyses between CC16 mRNA expression levels in BECs (242 asthmatics and 69 control subjects) and asthma-related phenotypes in Severe Asthma Research Program were performed using a generalized linear model. Measurements and Main Results: Low CC16 mRNA expression levels in BECs were significantly associated with asthma susceptibility and asthma severity, high systemic corticosteroids use, high retrospective and prospective asthma exacerbations, and low pulmonary function. Low CC16 mRNA expression levels were significantly associated with high T2 inflammation biomarkers (fractional exhaled nitric oxide and sputum eosinophils). CC16 mRNA expression levels were negatively correlated with expression levels of Th2 genes (IL1RL1, POSTN, SERPINB2, CLCA1, NOS2, and MUC5AC) and positively correlated with expression levels of Th1 and inflammation genes (IL12A and MUC5B). A combination of two nontraditional T2 biomarkers (CC16 and IL-6) revealed four asthma endotypes with different characteristics of T2 inflammation, obesity, and asthma severity. Conclusions: Our findings indicate that low CC16 mRNA expression levels in BECs are associated with asthma susceptibility, severity, and exacerbations, partially through immunomodulation of T2 inflammation. CC16 is a potential nontraditional T2 biomarker for asthma development and progression.

Genetic analyses of chr11p15.5 region identify MUC5AC-MUC5B associated with asthma-related phenotypes.

OBJECTIVE: Genome-wide association studies (GWASs) have identified single nucleotide polymorphisms (SNPs) in chr11p15.5 region associated with asthma and idiopathic interstitial pneumonias (IIPs). We sought to identify functional genes for asthma by combining SNPs and mRNA expression in bronchial epithelial cells (BEC) in the Severe Asthma Research Program (SARP). METHODS: Correlation analyses of mRNA expression of six candidate genes (AP2A2, MUC6, MUC2, MUC5AC, MUC5B, and TOLLIP) and asthma phenotypes were performed in the longitudinal cohort (n = 156) with RNAseq in BEC, and replicated in the cross-sectional cohort (n = 155). eQTL (n = 114) and genetic association analysis of asthma severity (426 severe vs. 531 non-severe asthma) were performed, and compared with previously published GWASs of IIPs and asthma. RESULTS: Higher expression of AP2A2 and MUC5AC and lower expression of MUC5B in BEC were correlated with asthma, asthma exacerbations, and T2 biomarkers (P < 0.01). SNPs associated with asthma and IIPs in previous GWASs were eQTL SNPs for MUC5AC, MUC5B, or TOLLIP, however, they were not in strong linkage disequilibrium. The risk alleles for asthma or protective alleles for IIPs were associated with higher expression of MUC5AC and lower expression of MUC5B. rs11603634, rs12788104, and rs28415845 associated with moderate-to-severe asthma or adult onset asthma in previous GWASs were not associated with asthma severity (P > 0.8). CONCLUSIONS: SNPs associated with asthma in chr11p15.5 region are not associated with asthma severity neither with IIPs. Higher expression of MUC5AC and lower expression of MUC5B are risk for asthma but protective for IIPs.

Investigations of a combination of atopic status and age of asthma onset identify asthma subphenotypes.

OBJECTIVE: Subphenotypes of asthma may be determined by age onset and atopic status. We sought to characterize early or late onset atopic asthma with fungal or non-fungal sensitization (AAFS or AANFS) and non-atopic asthma (NAA) in children and adults in the Severe Asthma Research Program (SARP). SARP is an ongoing project involving well-phenotyped patients with mild to severe asthma. METHODS: Phenotypic comparisons were performed using Kruskal-Wallis or chi-square test. Genetic association analyses were performed using logistic or linear regression. RESULTS: Airway hyper-responsiveness, total serum IgE levels, and T2 biomarkers showed an increasing trend from NAA to AANFS and then to AAFS. Children and adults with early onset asthma had greater % of AAFS than adults with late onset asthma (46% and 40% vs. 32%; P < 0.00001). In children, AAFS and AANFS had lower % predicted FEV1 (86% and 91% vs. 97%) and greater % of patients with severe asthma than NAA (61% and 59% vs. 43%). In adults with early or late onset asthma, NAA had greater % of patients with severe asthma than AANFS and AAFS (61% vs. 40% and 37% or 56% vs. 44% and 49%). The G allele of rs2872507 in GSDMB had higher frequency in AAFS than AANFS and NAA (0.63 vs. 0.55 and 0.55), and associated with earlier age onset and asthma severity. CONCLUSIONS: Early or late onset AAFS, AANFS, and NAA have shared and distinct phenotypic characteristics in children and adults. AAFS is a complex disorder involving genetic susceptibility and environmental factors.

Quantitative CT Characteristics of Cluster Phenotypes in the Severe Asthma Research Program Cohorts.

Background Clustering key clinical characteristics of participants in the Severe Asthma Research Program (SARP), a large, multicenter prospective observational study of patients with asthma and healthy controls, has led to the identification of novel asthma phenotypes. Purpose To determine whether quantitative CT (qCT) could help distinguish between clinical asthma phenotypes. Materials and Methods A retrospective cross-sectional analysis was conducted with the use of qCT images (maximal bronchodilation at total lung capacity [TLC], or inspiration, and functional residual capacity [FRC], or expiration) from the cluster phenotypes of SARP participants (cluster 1: minimal disease; cluster 2: mild, reversible; cluster 3: obese asthma; cluster 4: severe, reversible; cluster 5: severe, irreversible) enrolled between September 2001 and December 2015. Airway morphometry was performed along standard paths (RB1, RB4, RB10, LB1, and LB10). Corresponding voxels from TLC and FRC images were mapped with use of deformable image registration to characterize disease probability maps (DPMs) of functional small airway disease (fSAD), voxel-level volume changes (Jacobian), and isotropy (anisotropic deformation index [ADI]). The association between cluster assignment and qCT measures was evaluated using linear mixed models. Results A total of 455 participants were evaluated with cluster assignments and CT (mean age ± SD, 42.1 years ± 14.7; 270 women). Airway morphometry had limited ability to help discern between clusters. DPM fSAD was highest in cluster 5 (cluster 1 in SARP III: 19.0% ± 20.6; cluster 2: 18.9% ± 13.3; cluster 3: 24.9% ± 13.1; cluster 4: 24.1% ± 8.4; cluster 5: 38.8% ± 14.4; P < .001). Lower whole-lung Jacobian and ADI values were associated with greater cluster severity. Compared to cluster 1, cluster 5 lung expansion was 31% smaller (Jacobian in SARP III cohort: 2.31 ± 0.6 vs 1.61 ± 0.3, respectively, P < .001) and 34% more isotropic (ADI in SARP III cohort: 0.40 ± 0.1 vs 0.61 ± 0.2, P < .001). Within-lung Jacobian and ADI SDs decreased as severity worsened (Jacobian SD in SARP III cohort: 0.90 ± 0.4 for cluster 1; 0.79 ± 0.3 for cluster 2; 0.62 ± 0.2 for cluster 3; 0.63 ± 0.2 for cluster 4; and 0.41 ± 0.2 for cluster 5; P < .001). Conclusion Quantitative CT assessments of the degree and intraindividual regional variability of lung expansion distinguished between well-established clinical phenotypes among participants with asthma from the Severe Asthma Research Program study. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Verschakelen in this issue.

Genetic analyses identify GSDMB associated with asthma severity, exacerbations, and antiviral pathways.

BACKGROUND: The Chr17q12-21.2 region is the strongest and most consistently associated region with asthma susceptibility. The functional genes or single nucleotide polymorphisms (SNPs) are not obvious due to linkage disequilibrium. OBJECTIVES: We sought to comprehensively investigate whole-genome sequence and RNA sequence from human bronchial epithelial cells to dissect functional genes/SNPs for asthma severity in the Severe Asthma Research Program. METHODS: Expression quantitative trait loci analysis (n = 114), correlation analysis (n = 156) of gene expression and asthma phenotypes, and pathway analysis were performed in bronchial epithelial cells and replicated. Genetic association for asthma severity (426 severe vs 531 nonsevere asthma) and longitudinal asthma exacerbations (n = 273) was performed. RESULTS: Multiple SNPs in gasdermin B (GSDMB) associated with asthma severity (odds ratio, >1.25) and longitudinal asthma exacerbations (P < .05). Expression quantitative trait loci analyses identified multiple SNPs associated with expression levels of post-GPI attachment to proteins 3, GSDMB, or gasdermin A (3.1 × 10-9 

Autoimmunity to Vimentin Is Associated with Outcomes of Patients with Idiopathic Pulmonary Fibrosis.

Autoimmunity has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF); however, the repertoire of autoantigens involved in this disease and the clinical relevance of these autoimmune responses are still being explored. Our initial discovery assays demonstrated that circulating and intrapulmonary vimentin levels are increased in IPF patients. Subsequent studies showed native vimentin induced HLA-DR-dependent in vitro proliferation of CD4 T cells from IPF patients and enhanced the production of IL-4, IL-17, and TGF-ß1 by these lymphocytes in contrast to normal control specimens. Vimentin supplementation of IPF PBMC cultures also resulted in HLA-DR-dependent production of IgG with anti-vimentin specificities. Circulating anti-vimentin IgG autoantibody levels were much greater in IPF subjects from the University of Alabama at Birmingham (n = 102) and the University of Pittsburgh (U. Pitt., n = 70) than in normal controls. Anti-vimentin autoantibody levels in IPF patients were HLA biased and inversely correlated with physiological measurements of lung function (i.e., forced expiratory volumes and diffusing capacities). Despite considerable intergroup differences in transplant-free survival between these two independent IPF cohorts, serious adverse outcomes were most frequent among the patients within each population that had the highest anti-vimentin autoantibody levels (University of Alabama at Birmingham: hazard ratio 2.5, 95% confidence interval 1.2-5.3, p = 0.012; University of Pittsburgh: hazard ratio 2.7, 95% confidence interval 1.3-5.5, p = 0.006). These data show that anti-vimentin autoreactivity is prevalent in IPF patients and is strongly associated with disease manifestations. These findings have implications with regard to the pathogenesis of this enigmatic disease and raise the possibility that therapies specifically directed at these autoimmune processes could have therapeutic efficacy.

Low-dose cadmium exposure induces peribronchiolar fibrosis through site-specific phosphorylation of vimentin.

Exposure to cadmium (Cd) has been associated with development of chronic obstructive lung disease (COPD). The mechanisms and signaling pathways whereby Cd causes pathological peribronchiolar fibrosis, airway remodeling, and subsequent airflow obstruction remain unclear. We aimed to evaluate whether low-dose Cd exposure induces vimentin phosphorylation and Yes-associated protein 1 (YAP1) activation leading to peribronchiolar fibrosis and subsequent airway remodeling. Our data demonstrate that Cd induces myofibroblast differentiation and extracellular matrix (ECM) deposition around small (<2 mm in diameter) airways. Upon Cd exposure, α-smooth muscle actin (α-SMA) expression and the production of ECM proteins, including fibronectin and collagen-1, are markedly induced in primary human lung fibroblasts. Cd induces Smad2/3 activation and the translocation of both Smad2/3 and Yes-associated protein 1 (YAP1) into the nucleus. In parallel, Cd induces AKT and cdc2 phosphorylation and downstream vimentin phosphorylation at Ser39 and Ser55, respectively. AKT and cdc2 inhibitors block Cd-induced vimentin fragmentation and secretion in association with inhibition of α-SMA expression, ECM deposition, and collagen secretion. Furthermore, vimentin silencing abrogates Cd-induced α-SMA expression and decreases ECM production. Vimentin-deficient mice are protected from Cd-induced peribronchiolar fibrosis and remodeling. These findings identify two specific sites on vimentin that are phosphorylated by Cd and highlight the functional significance of vimentin phosphorylation in YAP1/Smad3 signaling that mediates Cd-induced peribronchiolar fibrosis and airway remodeling.

Expression of asthma susceptibility genes in bronchial epithelial cells and bronchial alveolar lavage in the Severe Asthma Research Program (SARP) cohort.

OBJECTIVE: Genome-wide association studies (GWASs) have identified genes associated with asthma, however expression of these genes in asthma-relevant tissues has not been studied. This study tested expression and correlation between GWAS-identified asthma genes and asthma or asthma severity. METHODS: Correlation analyses of expression levels of GWAS-identified asthma genes and asthma-related biomarkers were performed in cells from human bronchial epithelial biopsy (BEC, n = 107) and bronchial alveolar lavage (BAL, n = 94). RESULTS: Expression levels of asthma genes between BEC and BAL and with asthma or asthma severity were weakly correlated. The expression levels of IL18R1 were consistently higher in asthma than controls or in severe asthma than mild/moderate asthma in BEC and BAL (p < 0.05). In RAD50-IL13 region, the expression levels of RAD50, not IL4, IL5, or IL13, were positively correlated between BEC and BAL (ρ = 0.53, P = 4.5 × 10(-6)). The expression levels of IL13 were positively correlated with IL5 in BEC (ρ = 0.35, P = 1.9 × 10(-4)) and IL4 in BAL (ρ = 0.42, P = 2.5 × 10(-5)), respectively. rs3798134 in RAD50, a GWAS-identified SNP, was correlated with IL13 expression and the expression levels of IL13 were correlated with asthma (P = 0.03). rs17772583 in RAD50 was significantly correlated with RAD50 expression in BAL and BEC (P = 7.4 × 10(-7) and 0.04) but was not associated with asthma. CONCLUSIONS: This is the first report studying the expression of GWAS-identified asthma genes in BEC and BAL. IL13, rather than RAD50, IL4, or IL5, is more likely to be the asthma susceptibility gene. Our study illustrates tissue-specific expression of asthma-related genes. Therefore, whenever possible, disease-relevant tissues should be used for transcription analysis.

Sputum neutrophil counts are associated with more severe asthma phenotypes using cluster analysis.

BACKGROUND: Clinical cluster analysis from the Severe Asthma Research Program (SARP) identified 5 asthma subphenotypes that represent the severity spectrum of early-onset allergic asthma, late-onset severe asthma, and severe asthma with chronic obstructive pulmonary disease characteristics. Analysis of induced sputum from a subset of SARP subjects showed 4 sputum inflammatory cellular patterns. Subjects with concurrent increases in eosinophil (≥2%) and neutrophil (≥40%) percentages had characteristics of very severe asthma. OBJECTIVE: To better understand interactions between inflammation and clinical subphenotypes, we integrated inflammatory cellular measures and clinical variables in a new cluster analysis. METHODS: Participants in SARP who underwent sputum induction at 3 clinical sites were included in this analysis (n = 423). Fifteen variables, including clinical characteristics and blood and sputum inflammatory cell assessments, were selected using factor analysis for unsupervised cluster analysis. RESULTS: Four phenotypic clusters were identified. Cluster A (n = 132) and B (n = 127) subjects had mild-to-moderate early-onset allergic asthma with paucigranulocytic or eosinophilic sputum inflammatory cell patterns. In contrast, these inflammatory patterns were present in only 7% of cluster C (n = 117) and D (n = 47) subjects who had moderate-to-severe asthma with frequent health care use despite treatment with high doses of inhaled or oral corticosteroids and, in cluster D, reduced lung function. The majority of these subjects (>83%) had sputum neutrophilia either alone or with concurrent sputum eosinophilia. Baseline lung function and sputum neutrophil percentages were the most important variables determining cluster assignment. CONCLUSION: This multivariate approach identified 4 asthma subphenotypes representing the severity spectrum from mild-to-moderate allergic asthma with minimal or eosinophil-predominant sputum inflammation to moderate-to-severe asthma with neutrophil-predominant or mixed granulocytic inflammation.

Biomarker surrogates do not accurately predict sputum eosinophil and neutrophil percentages in asthmatic subjects.

BACKGROUND: Sputum eosinophil percentages are a strong predictor of airway inflammation and exacerbations and aid asthma management, whereas sputum neutrophil percentages indicate a different severe asthma phenotype that is potentially less responsive to TH2-targeted therapy. Variables, such as blood eosinophil counts, total IgE levels, fraction of exhaled nitric oxide (Feno) levels, or FEV1 percent predicted, might predict airway eosinophil percentages, whereas age, FEV1 percent predicted, or blood neutrophil counts might predict sputum neutrophil percentages. Availability and ease of measurement are useful characteristics, but accuracy in predicting airway eosinophil and neutrophil percentages either individually or combined is not established. OBJECTIVES: We sought to determine whether blood eosinophil counts, Feno levels, and IgE levels accurately predict sputum eosinophil percentages and whether age, FEV1 percent predicted, and blood neutrophil counts accurately predict sputum neutrophil percentages. METHODS: Subjects in the Wake Forest Severe Asthma Research Program (n = 328) were characterized by blood and sputum cell counts, health care use, lung function, Feno levels, and IgE levels. Multiple analytic techniques were used. RESULTS: Despite significant association with sputum eosinophil percentages, blood eosinophil counts, Feno levels, and total IgE levels did not accurately predict sputum eosinophil percentages, and combinations of these variables did not improve prediction. Age, FEV1 percent predicted, and blood neutrophil counts were similarly unsatisfactory for the prediction of sputum neutrophil percentages. Factor analysis and stepwise selection found Feno levels, IgE levels, and FEV1 percent predicted, but not blood eosinophil counts, correctly predicted 69% of sputum eosinophil percentages of less than 2% or 2% and greater. Likewise, age, asthma duration, and blood neutrophil counts correctly predicted 64% of sputum neutrophil percentages of less than 40% or 40% and greater. A model to predict both sputum eosinophil and neutrophil percentages accurately assigned only 41% of samples. CONCLUSION: Despite statistically significant associations, Feno levels, IgE levels, blood eosinophil and neutrophil counts, FEV1 percent predicted, and age are poor surrogates, both separately and combined, for accurately predicting sputum eosinophil and neutrophil percentages.

Genome-wide association study identifies TH1 pathway genes associated with lung function in asthmatic patients.

BACKGROUND: Recent meta-analyses of genome-wide association studies in general populations of European descent have identified 28 loci for lung function. OBJECTIVE: We sought to identify novel lung function loci specifically for asthma and to confirm lung function loci identified in general populations. METHODS: Genome-wide association studies of lung function (percent predicted FEV1 [ppFEV1], percent predicted forced vital capacity, and FEV1/forced vital capacity ratio) were performed in 4 white populations of European descent (n = 1544), followed by meta-analyses. RESULTS: Seven of 28 previously identified lung function loci (HHIP, FAM13A, THSD4, GSTCD, NOTCH4-AGER, RARB, and ZNF323) identified in general populations were confirmed at single nucleotide polymorphism (SNP) levels (P < .05). Four of 32 loci (IL12A, IL12RB1, STAT4, and IRF2) associated with ppFEV1 (P < 10(-4)) belong to the TH1 or IL-12 cytokine family pathway. By using a linear additive model, these 4 TH1 pathway SNPs cumulatively explained 2.9% to 7.8% of the variance in ppFEV1 values in 4 populations (P = 3 × 10(-11)). Genetic scores of these 4 SNPs were associated with ppFEV1 values (P = 2 × 10(-7)) and the American Thoracic Society severe asthma classification (P = .005) in the Severe Asthma Research Program population. TH2 pathway genes (IL13, TSLP, IL33, and IL1RL1) conferring asthma susceptibility were not associated with lung function. CONCLUSION: Genes involved in airway structure/remodeling are associated with lung function in both general populations and asthmatic subjects. TH1 pathway genes involved in anti-virus/bacterial infection and inflammation modify lung function in asthmatic subjects. Genes associated with lung function that might affect asthma severity are distinct from those genes associated with asthma susceptibility.

Multivariate Cluster Analyses to Characterize Asthma Heterogeneity and Benralizumab Responsiveness.

BACKGROUND: An improved understanding of how severe asthma heterogeneity affects response could inform treatment decisions. OBJECTIVES: Characterize heterogeneity and benralizumab responsiveness in patients grouped by predefined Severe Asthma Research Program clusters using a multivariate approach. METHODS: In post-hoc analyses of the randomized, double-blind, placebo-controlled phase III SIROCCO (NCT01928771) and CALIMA (NCT01914757) studies, patients with severe asthma who received benralizumab or placebo were assigned to clusters using an established discriminant function to analyze 11 clinical characteristics simultaneously. The annualized asthma exacerbation rate, exacerbation incidence, and lung function were analyzed across clusters. RESULTS: Patients (n = 2,281) met criteria for four of five clusters: cluster 2 (early-onset moderate asthma, n = 393), cluster 4 (early-onset severe asthma, n = 386), cluster 3 (late-onset severe asthma, n = 641), and cluster 5 (late-onset severe, obstructed asthma, n = 861); no patients met cluster 1 criteria. Exacerbation rate reductions were significant in late-onset severe asthma (-48% [95% CI, -61% to -31%]; P < .0001) and late-onset severe, obstructed asthma (-50% [95% CI, -59% to -38%]; P < .0001), with nonsignificant reductions in early-onset clusters. These differences could not be fully explained by blood eosinophil count differences. Values for improvements in FEV1 were significant in late-onset severe asthma (+133 mL [95% CI, 66-200]; P = .0001) and late-onset severe, obstructed asthma (+160 mL [95% CI, 85-235]; P < .0001) while maintaining acute bronchodilator responsiveness. CONCLUSIONS: Benralizumab reduced exacerbations and improved lung function, primarily in late-onset asthma clusters. This multivariate approach to identify subphenotypes, potentially reflecting pathobiological mechanisms, can guide therapy beyond univariate approaches.

A mouse model of Zhu-Tokita-Takenouchi-Kim syndrome reveals indispensable SON functions in organ development and hematopoiesis.

Rare diseases are underrepresented in biomedical research, leading to insufficient awareness. Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome is a rare disease caused by genetic alterations that result in heterozygous loss of function of SON. While patients with ZTTK syndrome live with numerous symptoms, the lack of model organisms hampers our understanding of SON and this complex syndrome. Here, we developed Son haploinsufficiency (Son+/-) mice as a model of ZTTK syndrome and identified the indispensable roles of Son in organ development and hematopoiesis. Son+/- mice recapitulated clinical symptoms of ZTTK syndrome, including growth retardation, cognitive impairment, skeletal abnormalities, and kidney agenesis. Furthermore, we identified hematopoietic abnormalities in Son+/- mice, including leukopenia and immunoglobulin deficiency, similar to those observed in human patients. Surface marker analyses and single-cell transcriptome profiling of hematopoietic stem and progenitor cells revealed that Son haploinsufficiency shifted cell fate more toward the myeloid lineage but compromised lymphoid lineage development by reducing genes required for lymphoid and B cell lineage specification. Additionally, Son haploinsufficiency caused inappropriate activation of erythroid genes and impaired erythropoiesis. These findings highlight the importance of the full gene expression of Son in multiple organs. Our model serves as an invaluable research tool for this rare disease and related disorders associated with SON dysfunction.

The IL6R variation Asp(358)Ala is a potential modifier of lung function in subjects with asthma.

BACKGROUND: The IL6R single nucleotide polymorphism (SNP) rs4129267 has recently been identified as an asthma susceptibility locus in subjects of European ancestry but has not been characterized with respect to asthma severity. The SNP rs4129267 is in linkage disequilibrium (r(2) = 1) with the IL6R coding SNP rs2228145 (Asp(358)Ala). This IL6R coding change increases IL-6 receptor (IL-6R) shedding and promotes IL-6 transsignaling. OBJECTIVES: We sought to evaluate the IL6R SNP rs2228145 with respect to asthma severity phenotypes. METHODS: The IL6R SNP rs2228145 was evaluated in subjects of European ancestry with asthma from the Severe Asthma Research Program (SARP). Lung function associations were replicated in the Collaborative Study on the Genetics of Asthma (CSGA) cohort. Serum soluble IL-6R levels were measured in subjects from SARP. Immunohistochemistry was used to qualitatively evaluate IL-6R protein expression in bronchoalveolar lavage cells and endobronchial biopsies. RESULTS: The minor C allele of IL6R SNP rs2228145 was associated with a lower percent predicted FEV(1) in the SARP cohort (P= .005), the CSGA cohort (P= .008), and in a combined cohort analysis (P= .003). Additional associations with percent predicted forced vital capacity (FVC), FEV(1)/FVC ratio, and PC(20) were observed. The rs2228145 C allele (Ala(358)) was more frequent in severe asthma phenotypic clusters. Elevated serum soluble IL-6R levels were associated with lower percent predicted FEV(1) (P= .02) and lower percent predicted FVC (P= .008) (n= 146). IL-6R protein expression was observed in bronchoalveolar lavage macrophages, airway epithelium, vascular endothelium, and airway smooth muscle. CONCLUSIONS: The IL6R coding SNP rs2228145 (Asp(358)Ala) is a potential modifier of lung function in subjects with asthma and might identify subjects at risk for more severe asthma. IL-6 transsignaling might have a pathogenic role in the lung.

Genome-wide association studies of asthma indicate opposite immunopathogenesis direction from autoimmune diseases.

BACKGROUND: Genome-wide association studies (GWASs) of asthma have consistently implicated the ORM1-like 3 and gasdermin B (ORMDL3-GSDMB), IL33, IL-1 receptor-like 1 and IL-18 receptor 1 (IL1RL1-IL18R1), RAD50-IL13, thymic stromal lymphopoietin and WD repeat domain 36 region (TSLP-WDR36), and HLA-DR/DQ regions. OBJECTIVE: A GWAS of asthma was performed in a non-Hispanic white population. METHODS: A GWAS was performed in 813 Severe Asthma Research Program/Collaborative Studies on the Genetics of Asthma/Chicago Asthma Genetics Study cases and 1564 control subjects. The GWAS results were compared with those of the published GWASs of autoimmune diseases. RESULTS: Multiple single nucleotide polymorphisms in the TNFAIP3 interacting protein 1 (TNIP1) gene, which interacts with TNFAIP3 and inhibits the TNF-α-induced nuclear factor κB inflammation pathway, were associated with asthma: rs1422673 (P = 3.44 × 10(-7)) and rs10036748 (P = 1.41 × 10(-6), r(2) = 0.67). rs1422673 was also associated with asthma in the published GABRIEL (P = .018) and EVE (P = 1.31 × 10(-5)) studies. The minor allele T of rs20541 in IL13 is the risk allele for asthma but the protective allele for psoriasis. The minor allele T of rs2395185 in HLA-DRA is the risk allele for asthma but the protective allele for ulcerative colitis. The minor allele A of rs2872507 in GSDMB is the protective allele for asthma but the risk allele for rheumatoid arthritis, Crohn disease, and ulcerative colitis. The T allele of rs10036748 in the TNIP1 gene is the minor protective allele for asthma but the minor or major risk allele for systemic lupus erythematosus and systemic sclerosis in non-Hispanic white or Chinese subjects, respectively. CONCLUSIONS: Our study suggests that single nucleotide polymorphisms associated with both asthma and autoimmune diseases might have opposite effects on immunopathogenesis.

Clinical Implications of Longitudinal Blood Eosinophil Counts in Patients With Severe Asthma.

BACKGROUND: The stability and variability of blood eosinophil counts (BECs) to phenotype patients with severe asthma is not fully understood. OBJECTIVE: This post hoc, longitudinal, pooled analysis of placebo-arm patients from 2 phase 3 studies evaluated the clinical implications of BEC stability and variability in moderate-to-severe asthma. METHODS: This analysis included patients from SIROCCO and CALIMA who received maintenance medium- to high-dosage inhaled corticosteroids plus long-acting ß2-agonists; 2:1 patients with BECs of 300 cells/µL or higher and less than 300 cells/µL were enrolled. The BECs were measured 6 times over 1 year in a centralized laboratory. Exacerbations, lung function, and Asthma Control Questionnaire 6 scores were documented across patients grouped by BEC (<300 cells/µL or ≥300 cells/µL) and variability (<80% or ≥80% BECs less than or greater than 300 cells/µL). RESULTS: Among 718 patients, 42.2% (n = 303) had predominantly high, 30.9% (n = 222) had predominantly low, and 26.9% (n = 193) had variable BECs. Prospective exacerbation rates (mean ± SD) were significantly greater in patients with predominantly high (1.39 ± 2.20) and variable (1.41 ± 2.09) BECs versus predominantly low (1.05 ± 1.66) BECs. Similar results were observed for the number of exacerbations while on placebo. CONCLUSIONS: Although patients with variable BECs had intermittently high and low BECs, they experienced similar exacerbation rates to the predominantly high group, which were greater than those in the predominantly low group. A high BEC supports an eosinophilic phenotype in clinical settings without additional measurements, whereas a low BEC requires repeated measurements because it could reflect intermittently high or predominantly low BECs.

A mouse model of ZTTK syndrome reveals indispensable SON functions in organ development and hematopoiesis.

Rare diseases are underrepresented in biomedical research, leading to insufficient awareness. Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome is a rare disease caused by genetic alterations that result in heterozygous loss-of-function of SON. While ZTTK syndrome patients suffer from numerous symptoms, the lack of model organisms hamper our understanding of both SON and this complex syndrome. Here, we developed Son haploinsufficiency (Son+/-) mice as a model of ZTTK syndrome and identified the indispensable roles of Son in organ development and hematopoiesis. Son+/- mice recapitulated clinical symptoms of ZTTK syndrome, including growth retardation, cognitive impairment, skeletal abnormalities, and kidney agenesis. Furthermore, we identified hematopoietic abnormalities in Son+/- mice, similar to those observed in human patients. Surface marker analyses and single-cell transcriptome profiling of hematopoietic stem and progenitor cells revealed that Son haploinsufficiency inclines cell fate toward the myeloid lineage but compromises lymphoid lineage development by reducing key genes required for lymphoid and B cell lineage specification. Additionally, Son haploinsufficiency causes inappropriate activation of erythroid genes and impaired erythroid maturation. These findings highlight the importance of the full gene dosage of Son in organ development and hematopoiesis. Our model serves as an invaluable research tool for this rare disease and related disorders associated with SON dysfunction.