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Rationale: Social determinants of health underlie disparities in asthma. However, the effects of individual determinants likely interact, so a summary metric may better capture their impact. The Child Opportunity Index 2.0 (COI) is one such tool, yet its association with exacerbation-prone (EP) asthma is unknown., Objective: To investigate the association between the COI and EP asthma and clinical measures of asthma severity in children., Methods: We analyzed data from two prospective observational pediatric asthma cohorts (n = 193). Children were classified as EP (≥1 exacerbation in the past 12 months) or exacerbation-null (no exacerbations in the past 5 years). Spirometry, exhaled nitric oxide, IgE, and Composite Asthma Severity Index (CASI) were obtained. The association between COI and EP status was assessed with logistic regression. We fit linear and logistic regression models to test the association between COI and each clinical measure., Results: A 20-point COI decrease conferred 40% higher odds of EP asthma (OR 1.4; 95%CI 1.1-1.76). The effect was similar when adjusted for age and sex (OR 1.38, 95%CI 1.1-1.75) but was attenuated with additional adjustment for race and ethnicity (OR 1.19, 95%CI 0.92-1.54). A similar effect was seen for the Social/Economic and Education COI domains but not the Health/Environment Domain. A 20-point COI decrease was associated with an increase in CASI of 0.34. COI was not associated with other clinical measures., Conclusions: Lower COI was associated with greater odds of EP asthma. This highlights the potential use of the COI to understand neighborhood-level risk and identify community targets to reduce asthma disparities., (© 2024 Wiley Periodicals LLC.)

By incompletely understood mechanisms, type 2 (T2) inflammation present in the airways of severe asthmatics drives the formation of pathologic mucus which leads to airway mucus plugging. Here we investigate the molecular role and clinical significance of intelectin-1 (ITLN-1) in the development of pathologic airway mucus in asthma. Through analyses of human airway epithelial cells we find that ITLN1 gene expression is highly induced by interleukin-13 (IL-13) in a subset of metaplastic MUC5AC + mucus secretory cells, and that ITLN-1 protein is a secreted component of IL-13-induced mucus. Additionally, we find ITLN-1 protein binds the C-terminus of the MUC5AC mucin and that its deletion in airway epithelial cells partially reverses IL-13-induced mucostasis. Through analysis of nasal airway epithelial brushings, we find that ITLN1 is highly expressed in T2-high asthmatics, when compared to T2-low children. Furthermore, we demonstrate that both ITLN-1 gene expression and protein levels are significantly reduced by a common genetic variant that is associated with protection from the formation of mucus plugs in T2-high asthma. This work identifies an important biomarker and targetable pathways for the treatment of mucus obstruction in asthma., (© 2024. The Author(s).)

Studies of asthma and allergy are generating increasing volumes of omics data for analysis and interpretation. The National Institute of Allergy and Infectious Diseases (NIAID) assembled a workshop comprising investigators studying asthma and allergic diseases using omics approaches, omics investigators from outside the field, and NIAID medical and scientific officers to discuss the following areas in asthma and allergy research: genomics, epigenomics, transcriptomics, microbiomics, metabolomics, proteomics, lipidomics, integrative omics, systems biology, and causal inference. Current states of the art, present challenges, novel and emerging strategies, and priorities for progress were presented and discussed for each area. This workshop report summarizes the major points and conclusions from this NIAID workshop. As a group, the investigators underscored the imperatives for rigorous analytic frameworks, integration of different omics data types, cross-disciplinary interaction, strategies for overcoming current limitations, and the overarching goal to improve scientific understanding and care of asthma and allergic diseases., (Copyright © 2024 American Academy of Allergy, Asthma & Immunology. All rights reserved.)

Background: Albuterol is the first-line asthma medication used in diverse populations. Although DNA methylation (DNAm) is an epigenetic mechanism involved in asthma and bronchodilator drug response (BDR), no study has assessed whether albuterol could induce changes in the airway epithelial methylome. We aimed to characterize albuterol-induced DNAm changes in airway epithelial cells, and assess potential functional consequences and the influence of genetic variation and asthma-related clinical variables., Results: We followed a discovery and validation study design to characterize albuterol-induced DNAm changes in paired airway epithelial cultures stimulated in vitro with albuterol. In the discovery phase, an epigenome-wide association study using paired nasal epithelial cultures from Puerto Rican children (n = 97) identified 22 CpGs genome-wide associated with repeated-use albuterol treatment (p < 9 × 10 -8 ). Albuterol predominantly induced a hypomethylation effect on CpGs captured by the EPIC array across the genome (probability of hypomethylation: 76%, p value = 3.3 × 10 -5 ). DNAm changes on the CpGs cg23032799 (CREB3L1), cg00483640 (MYLK4-LINC01600), and cg05673431 (KSR1) were validated in nasal epithelia from 10 independent donors (false discovery rate [FDR] < 0.05). The effect on the CpG cg23032799 (CREB3L1) was cross-tissue validated in bronchial epithelial cells at nominal level (p = 0.030). DNAm changes in these three CpGs were shown to be influenced by three independent genetic variants (FDR < 0.05). In silico analyses showed these polymorphisms regulated gene expression of nearby genes in lungs and/or fibroblasts including KSR1 and LINC01600 (6.30 × 10 -14  ≤ p ≤ 6.60 × 10 -5 ). Additionally, hypomethylation at the CpGs cg10290200 (FLNC) and cg05673431 (KSR1) was associated with increased gene expression of the genes where they are located (FDR < 0.05). Furthermore, while the epigenetic effect of albuterol was independent of the asthma status, severity, and use of medication, BDR was nominally associated with the effect on the CpG cg23032799 (CREB3L1) (p = 0.004). Gene-set enrichment analyses revealed that epigenomic modifications of albuterol could participate in asthma-relevant processes (e.g., IL-2, TNF-α, and NF-κB signaling pathways). Finally, nine differentially methylated regions were associated with albuterol treatment, including CREB3L1, MYLK4, and KSR1 (adjusted p value < 0.05)., Conclusions: This study revealed evidence of epigenetic modifications induced by albuterol in the mucociliary airway epithelium. The epigenomic response induced by albuterol might have potential clinical implications by affecting biological pathways relevant to asthma., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: Type 1 (T1) inflammation (marked by IFN-γ expression) is now consistently identified in subsets of asthma cohorts, but how it contributes to disease remains unclear., Objective: We sought to understand the role of CCL5 in asthmatic T1 inflammation and how it interacts with both T1 and type 2 (T2) inflammation., Methods: CCL5, CXCL9, and CXCL10 messenger RNA expression from sputum bulk RNA sequencing, as well as clinical and inflammatory data were obtained from the Severe Asthma Research Program III (SARP III). CCL5 and IFNG expression from bronchoalveolar lavage cell bulk RNA sequencing was obtained from the Immune Mechanisms in Severe Asthma (IMSA) cohort and expression related to previously identified immune cell profiles. The role of CCL5 in tissue-resident memory T-cell (TRM) reactivation was evaluated in a T1 high murine severe asthma model., Results: Sputum CCL5 expression strongly correlated with T1 chemokines (P < .001 for CXCL9 and CXCL10), consistent with a role in T1 inflammation. CCL5 high participants had greater fractional exhaled nitric oxide (P = .009), blood eosinophils (P < .001), and sputum eosinophils (P = .001) in addition to sputum neutrophils (P = .001). Increased CCL5 bronchoalveolar lavage expression was unique to a previously described T1 high /T2 variable /lymphocytic patient group in the IMSA cohort, with IFNG trending with worsening lung obstruction only in this group (P = .083). In a murine model, high expression of the CCL5 receptor CCR5 was observed in TRMs and was consistent with a T1 signature. A role for CCL5 in TRM activation was supported by the ability of the CCR5 inhibitor maraviroc to blunt reactivation., Conclusion: CCL5 appears to contribute to TRM-related T1 neutrophilic inflammation in asthma while paradoxically also correlating with T2 inflammation and with sputum eosinophilia., (Copyright © 2023 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Whether children and people with asthma and allergic diseases are at increased risk for severe acute respiratory syndrome virus 2 (SARS-CoV-2) infection is unknown., Objective: Our aims were to determine the incidence of SARS-CoV-2 infection in households with children and to also determine whether self-reported asthma and/or other allergic diseases are associated with infection and household transmission., Methods: For 6 months, biweekly nasal swabs and weekly surveys were conducted within 1394 households (N = 4142 participants) to identify incident SARS-CoV-2 infections from May 2020 to February 2021, which was the pandemic period largely before a vaccine and before the emergence of SARS-CoV-2 variants. Participant and household infection and household transmission probabilities were calculated by using time-to-event analyses, and factors associated with infection and transmission risk were determined by using regression analyses., Results: In all, 147 households (261 participants) tested positive for SARS-CoV-2. The household SARS-CoV-2 infection probability was 25.8%; the participant infection probability was similar for children (14.0% [95% CI = 8.0%-19.6%]), teenagers (12.1% [95% CI = 8.2%-15.9%]), and adults (14.0% [95% CI = 9.5%-18.4%]). Infections were symptomatic in 24.5% of children, 41.2% of teenagers, and 62.5% of adults. Self-reported doctor-diagnosed asthma was not a risk factor for infection (adjusted hazard ratio [aHR] = 1.04 [95% CI = 0.73-1.46]), nor was upper respiratory allergy or eczema. Self-reported doctor-diagnosed food allergy was associated with lower infection risk (aHR = 0.50 [95% CI = 0.32-0.81]); higher body mass index was associated with increased infection risk (aHR per 10-point increase = 1.09 [95% CI = 1.03-1.15]). The household secondary attack rate was 57.7%. Asthma was not associated with household transmission, but transmission was lower in households with food allergy (adjusted odds ratio = 0.43 [95% CI = 0.19-0.96]; P = .04)., Conclusion: Asthma does not increase the risk of SARS-CoV-2 infection. Food allergy is associated with lower infection risk, whereas body mass index is associated with increased infection risk. Understanding how these factors modify infection risk may offer new avenues for preventing infection., (Copyright © 2022. Published by Elsevier Inc.)

Variability in response to short-acting β 2 -agonists (e.g., albuterol) among patients with asthma from diverse racial/ethnic groups may contribute to asthma disparities. We sought to identify genetic variants associated with bronchodilator response (BDR) to identify potential mechanisms of drug response and risk factors for worse asthma outcomes. Genome-wide association studies of bronchodilator response (BDR) were performed using TOPMed Whole Genome Sequencing data of the Asthma Translational Genomic Collaboration (ATGC), which corresponded to 1136 Puerto Rican, 656 Mexican and 4337 African American patients with asthma. With the population-specific GWAS results, a trans-ethnic meta-analysis was performed to identify BDR-associated variants shared across the three populations. Replication analysis was carried out in three pediatric asthma cohorts, including CAMP (Childhood Asthma Management Program; n = 560), GACRS (Genetics of Asthma in Costa Rica Study; n = 967) and HPR (Hartford-Puerto Rico; n = 417). A genome-wide significant locus (rs35661809; P = 3.61 × 10 -8 ) in LINC02220, a non-coding RNA gene, was identified in Puerto Ricans. While this region was devoid of protein-coding genes, capture Hi-C data showed a distal interaction with the promoter of the DNAH5 gene in lung tissue. In replication analysis, the GACRS cohort yielded a nominal association (1-tailed P < 0.05). No genetic variant was associated with BDR at the genome-wide significant threshold in Mexicans and African Americans. Our findings help inform genetic underpinnings of BDR for understudied minority patients with asthma, but the limited availability of genetic data for racial/ethnic minority children with asthma remains a paramount challenge., (© 2022. The Author(s).)

To identify genetic determinants of airway dysfunction, we performed a transcriptome-wide association study for asthma by combining RNA-seq data from the nasal airway epithelium of 681 children, with UK Biobank genetic association data. Our airway analysis identified 95 asthma genes, 58 of which were not identified by transcriptome-wide association analyses using other asthma-relevant tissues. Among these genes were MUC5AC, an airway mucin, and FOXA3, a transcriptional driver of mucus metaplasia. Muco-ciliary epithelial cultures from genotyped donors revealed that the MUC5AC risk variant increases MUC5AC protein secretion and mucus secretory cell frequency. Airway transcriptome-wide association analyses for mucus production and chronic cough also identified MUC5AC. These cis-expression variants were associated with trans effects on expression; the MUC5AC variant was associated with upregulation of non-inflammatory mucus secretory network genes, while the FOXA3 variant was associated with upregulation of type-2 inflammation-induced mucus-metaplasia pathway genes. Our results reveal genetic mechanisms of airway mucus pathobiology., (© 2022. The Author(s).)

Background: Pharmacogenetic studies in asthma cohorts, primarily made up of White people of European descent, have identified loci associated with response to inhaled beta agonists and corticosteroids (ICSs). Differences exist in how individuals from different ancestral backgrounds respond to long-acting beta agonist (LABA) and ICSs. Therefore, we sought to understand the pharmacogenetic mechanisms regulating therapeutic responsiveness in individuals of African descent., Methods: We did ancestry-based pharmacogenetic studies of children (aged 5-11 years) and adolescents and adults (aged 12-69 years) from the Best African Response to Drug (BARD) trials, in which participants with asthma uncontrolled with low-dose ICS (fluticasone propionate 50 μg in children, 100 μg in adolescents and adults) received different step-up combination therapies. The hierarchal composite outcome of pairwise superior responsiveness in BARD was based on asthma exacerbations, a 31-day difference in annualised asthma-control days, or a 5% difference in percentage predicted FEV 1 . We did whole-genome admixture mapping of 15 159 ancestral segments within 312 independent regions, stratified by the two age groups. The two co-primary outcome comparisons were the step up from low-dose ICS to the quintuple dose of ICS (5 × ICS: 250 μg twice daily in children and 500 μg twice daily in adolescents and adults) versus double dose (2-2·5 × ICS: 100 μg twice daily in children, 250 μg twice daily in adolescents and adults), and 5 × ICS versus 100 μg fluticasone plus a LABA (salmeterol 50 μg twice daily). We used a genome-wide significance threshold of p<1·6 × 10 -4 , and tested for replication using independent cohorts of individuals of African descent with asthma., Findings: We included 249 unrelated children and 267 unrelated adolescents and adults in the BARD pharmacogenetic analysis. In children, we identified a significant admixture mapping peak for superior responsiveness to 5 × ICS versus 100 μg fluticasone plus salmeterol on chromosome 12 (odds ratio [OR local African ] 3·95, 95% CI 2·02-7·72, p=6·1 × 10 -5 ) fine mapped to a locus adjacent to RNFT2 and NOS1 (rs73399224, OR allele dose 0·17, 95% CI 0·07-0·42, p=8·4 × 10 -5 ). In adolescents and adults, we identified a peak for superior responsiveness to 5 × ICS versus 2·5 × ICS on chromosome 22 (OR local African 3·35, 1·98-5·67, p=6·8 × 10 -6 ) containing a locus adjacent to TPST2 (rs5752429, OR allele dose 0·21, 0·09-0·52, p=5·7 × 10 -4 ). We replicated rs5752429 and nominally replicated rs73399224 in independent African American cohorts., Interpretation: BARD is the first genome-wide pharmacogenetic study of LABA and ICS response in clinical trials of individuals of African descent to detect and replicate genome-wide significant loci. Admixture mapping of the composite BARD trial outcome enabled the identification of novel pharmacogenetic variation accounting for differential therapeutic responses in people of African descent with asthma., Funding: National Institutes of Health, National Heart, Lung, and Blood Institute., Competing Interests: Declaration of interests VEO reports consulting fees from Sanofi and fees for serving on independent data monitoring committees for Sanofi and Regeneron Pharmaceuticals. SJS reports receiving consulting fees, paid to his institution, from AstraZeneca, GlaxoSmithKline, Moderna, Propeller Health, Regeneron, and Sanofi, as well as a research grant from Propeller Health. ERB reports receiving consulting fees and donated drugs from Boehringer Ingelheim, donated drugs from Merck and Teva Pharmaceuticals, consulting fees from AstraZeneca, MedImmune, GlaxoSmithKline, Novartis, and Sanofi–Regeneron, and participating in trials as an employee of Wake Forest School of Medicine and the University of Arizona for AstraZeneca, MedImmune, Boehringer Ingelheim, Cephalon–Teva Pharmaceuticals, Genentech, GlaxoSmithKline, Johnson & Johnson (Janssen), Novartis, and Sanofi–Regeneron. VMC reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals. WP reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals. DM reports receiving grant support and donated drugs from GlaxoSmithKline, Genentech, Vifor Pharma, Boehringer Ingelheim, and Teva Pharmaceuticals, grant support from Sanofi and AstraZeneca, fees for serving on a data and safety monitoring board from Novartis, and donated drugs from Merck. FDM reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals, grant support from Johnson & Johnson, and consulting fees from Copeval and Commence. EH-L reports a fellowship from the Spanish Ministry of Science, Innovation, and Universities. MP-Y reports grants from the Spanish Ministry of Economy, Industry, and Competitiveness, the State Research Agency and the European Regional Development Funds from the European Union (MICIU/AEI/FEDER, UE), and grant support from GlaxoSmithKline, Spain. SJK reports receiving donated drugs from Merck–Organon, Genentech, GlaxoSmithKline, and Regeneron and owning stock in Merck. LBB reports receiving consulting fees and lecture fees from Aerocrine, GlaxoSmithKline, Genentech–Novartis, and AstraZeneca, advisory board fees and donated drugs from Merck, fees for serving on a data safety monitoring board from DBV Technologies, consulting fees, lecture fees, and donated drugs from Teva Pharmaceuticals and Boehringer Ingelheim, honoraria from WebMD–Medscape, advisory board fees and lecture fees from Sanofi–Regeneron, advisory board fees and consulting fees from Vectura, and advisory board fees from Circassia. MDC reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals, and consulting fees from Genentech and Novartis. JCC reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals. MC reports receiving grant support, lecture fees, and donated drugs from Boehringer Ingelheim, donated drugs from Merck, consulting fees, lecture fees, and donated drugs from Teva Pharmaceuticals, consulting fees and lecture fees from Boston Scientific and Genentech, consulting fees from Nuvaira, Aviragen, 4D Pharma, VIDA Diagnostics, Mallinckrodt Pharmaceuticals, Theravance, Therabron, and Vectura, grant support, consulting fees, and lecture fees from Sanofi-Aventis, grant support and lecture fees from AstraZeneca and GlaxoSmithKline, grant support from Chiesi and Novartis, and lecture fees from Regeneron Pharmaceuticals. LCD reports receiving grant support and consulting fees from AstraZeneca, and consulting fees from Sanofi–Regeneron. FH reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals. DJJ reports grant support from GlaxoSmithKline, consulting fees from Novartis, Sanofi, Regeneron, Vifor Pharma, and AstraZeneca, and fees for serving on a data and safety monitoring board from Pfizer. NJ reports receiving honorarium for consulting from GlaxoSmithKline pharmaceuticals and Pulmocide. MK reports receiving grant support from Chiesi and Sanofi. JAK reports personal fees for independent data monitoring committee participation from Sanofi and research funding from the American Lung Association—Airway Clinical Research Centers Network. SCL reports grant funding from the American Lung Association—Airway Clinical Research Centers Network. RFL reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals, and lecture fees from Thermo Fisher Scientific. JJL reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals. NL reports receiving grant support, advisory board fees, and donated drugs from GlaxoSmithKline, grant support, consulting fees, and advisory board fees from AstraZeneca, consulting fees, advisory board fees, and donated drugs from Teva Pharmaceuticals, grant support from Genentech, grant support and advisory board fees from Sanofi–Regeneron, and donated drugs from Merck and Boehringer Ingelheim. WCM reports receiving grant support and donated drugs from Boehringer Ingelheim, donated drugs from Merck and Teva Pharmaceuticals, grant support and advisory board fees from AstraZeneca, GlaxoSmithKline, and Sanofi–Regeneron, and grant support from Novartis, Cumberland Pharmaceuticals, and Gossamer Bio. SPP reports receiving advisory board fees from AstraZeneca, GlaxoSmithKline, Mylan, Teva Pharmaceuticals, Sanofi–Regeneron, and Theravance, fees for serving as clinical trial adjudicator from Quintiles, fees for serving on a data and safety monitoring board from Genentech, fees for serving as chair of a data and safety monitoring board from Novartis, and honoraria from PRIME. JAP reports receiving donated drugs from Boehringer Ingelheim, Merck, Teva Pharmaceuticals, and GlaxoSmithKline. LJS reports receiving donated drugs from Boehringer Ingelheim and Teva Pharmaceuticals, and fees for serving on a data and safety monitoring board and donated drugs from Merck. JS reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals, advisory board fees from PulmOne Advanced Medical Devices, advisory board fees, honoraria, and travel support from Regeneron–Sanofi–Genzyme, holding patents #6 090 618, #6 114 311, #6 284 743, #6 291 211, #6 297 221, #6 331 527, and #7 169 764 on a smooth-muscle gene promoter (SM22 alpha), holding pending patent PCT/US2014/032186 on a method for determining respiratory physiological parameters, holding pending patent 62/872,980 on remodilins for airway remodelling and organ fibrosis, and holding pending patent 62/828,122 on remodilins to prevent or treat cancer metastasis, glaucoma, and hypoxia. CAS reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals. SW reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals, grant support and consulting fees from AstraZeneca and Sanofi, and consulting fees from Pieris Pharmaceuticals. DAM reports receiving donated drugs from Boehringer Ingelheim, Merck, and Teva Pharmaceuticals. EI reports receiving grant support and consulting fees from AstraZeneca, Novartis, and Genentech, consulting fees from Regeneron Pharmaceuticals, Bird Rock Bio, Nuvelution Pharmaceuticals, Vitaeris, Sanofi Genzyme, Entrinsic Health Solutions, Pneuma Respiratory, 4D Pharma, Sienna Biopharmaceuticals, and Equillium, grant support, consulting fees, and donated drugs from Merck, Teva Pharmaceutical Industries, and GlaxoSmithKline, serving as a consultant for Vorso, receiving grant support and donated drugs from Vifor Pharma, Boehringer Ingelheim, and Teva Pharmaceuticals, grant support from Sanofi and AstraZeneca, and donated drugs from Circassia. MEW reports receiving grant support and consulting fees from AstraZeneca, Novartis, Sanofi, and GlaxoSmithKline, consulting fees from Regeneron Pharmaceuticals, Mylan, Genentech, Restorbio, Equillium, Boston Scientific, Genzyme, Gala Therapeutics, and Pulmatrix, fees for serving on a data and safety monitoring board from Sentien Biotechnologies, grant support, consulting fees, advisory board fees, and donated drugs from Teva Pharmaceuticals, consulting fees and donated drugs from Boehringer Ingelheim and Merck. MD, GAH, EJA CC, CE, AMF, DH, AM, ETN, SPS, MAS, SRW, EGB, and KB declare no competing interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Repetitive exposure of Rag1-/- mice to the Alternaria allergen extract generated a form of memory that elicited an asthma-like response upon a subthreshold recall challenge 3-15 wk later. This memory was associated with lung ICOS+ST2+ ILC2s. Genetic, pharmacologic, and antibody-mediated inhibition and adoptive transfer established an essential role for ILC2s in memory-driven asthma. ATAC-seq demonstrated a distinct epigenetic landscape of memory ILC2s and identified Bach2 and AP1 (JunD and Fosl2) motifs as major drivers of altered gene accessibility. scRNA-seq, gene knockout, and signaling studies suggest that repetitive allergenic stress induces a gene repression program involving Nr4a2, Zeb1, Bach2, and JunD and a preparedness program involving Fhl2, FosB, Stat6, Srebf2, and MPP7 in memory ILC2s. A mutually regulated balance between these two programs establishes and maintains memory. The preparedness program (e.g., Fhl2) can be activated with a subthreshold cognate stimulation, which down-regulates repressors and activates effector pathways to elicit the memory-driven phenotype., Competing Interests: Disclosures: M. Gorska reported a book contract with Springer Nature. The book will describe methods and protocols to study asthma. The book is currently in preparation. No other disclosures were reported., (© 2021 Verma et al.)

Rationale: Puerto Ricans have the highest childhood asthma prevalence in the United States (23.6%); however, the etiology is uncertain. Objectives: In this study, we sought to uncover the genetic architecture of lung function in Puerto Rican youth with and without asthma who were recruited from the island ( n  = 836). Methods: We used admixture-mapping and whole-genome sequencing data to discover genomic regions associated with lung function. Functional roles of the prioritized candidate SNPs were examined with chromatin immunoprecipitation sequencing, RNA sequencing, and expression quantitative trait loci data. Measurements and Main Results: We discovered a genomic region at 1q32 that was significantly associated with a 0.12-L decrease in the lung volume of exhaled air (95% confidence interval, -0.17 to -0.07; P  = 6.62 × 10 -8 ) with each allele of African ancestry. Within this region, two SNPs were expression quantitative trait loci of TMEM9 in nasal airway epithelial cells and MROH3P in esophagus mucosa. The minor alleles of these SNPs were associated with significantly decreased lung function and decreased TMEM9 gene expression. Another admixture-mapping peak was observed on chromosome 5q35.1, indicating that each Native American ancestry allele was associated with a 0.15-L increase in lung function (95% confidence interval, 0.08-0.21; P  = 5.03 × 10 -6 ). The region-based association tests identified four suggestive windows that harbored candidate rare variants associated with lung function. Conclusions: We identified common and rare genetic variants that may play a critical role in lung function among Puerto Rican youth. We independently validated an inflammatory pathway that could potentially be used to develop more targeted treatments and interventions for patients with asthma.

The type 2 cytokine-high asthma endotype (T2H) is characterized by IL-13-driven mucus obstruction of the airways. To further investigate this incompletely understood pathobiology, we characterize IL-13 effects on human airway epithelial cell cultures using single-cell RNA sequencing, finding that IL-13 generates a distinctive transcriptional state for each cell type. Specifically, we discover a mucus secretory program induced by IL-13 in all cell types which converts both mucus and defense secretory cells into a metaplastic state with emergent mucin production and secretion, while leading to ER stress and cell death in ciliated cells. The IL-13-remodeled epithelium secretes a pathologic, mucin-imbalanced, and innate immunity-depleted proteome that arrests mucociliary motion. Signatures of IL-13-induced cellular remodeling are mirrored by transcriptional signatures characteristic of the nasal airway epithelium within T2H versus T2-low asthmatic children. Our results reveal the epithelium-wide scope of T2H asthma and present candidate therapeutic targets for restoring normal epithelial function., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Rationale: Coronavirus disease (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). ACE2 (angiotensin-converting enzyme 2), and TMPRSS2 (transmembrane protease serine 2) mediate viral infection of host cells. We reasoned that differences in ACE2 or TMPRSS2 gene expression in sputum cells among patients with asthma may identify subgroups at risk for COVID-19 morbidity. Objectives: To determine the relationship between demographic features and sputum ACE2 and TMPRSS2 gene expression in asthma. Methods : We analyzed gene expression for ACE2 and TMPRSS2, and for ICAM-1 (intercellular adhesion molecule 1) (rhinovirus receptor as a comparator) in sputum cells from 330 participants in SARP-3 (Severe Asthma Research Program-3) and 79 healthy control subjects. Measurements and Main Results: Gene expression of ACE2 was lower than TMPRSS2, and expression levels of both genes were similar in asthma and health. Among patients with asthma, male sex, African American race, and history of diabetes mellitus were associated with higher expression of ACE2 and TMPRSS2. Use of inhaled corticosteroids (ICS) was associated with lower expression of ACE2 and TMPRSS2, but treatment with triamcinolone acetonide did not decrease expression of either gene. These findings differed from those for ICAM-1, where gene expression was increased in asthma and less consistent differences were observed related to sex, race, and use of ICS. Conclusions: Higher expression of ACE2 and TMPRSS2 in males, African Americans, and patients with diabetes mellitus provides rationale for monitoring these asthma subgroups for poor COVID-19 outcomes. The lower expression of ACE2 and TMPRSS2 with ICS use warrants prospective study of ICS use as a predictor of decreased susceptibility to SARS-CoV-2 infection and decreased COVID-19 morbidity.

Baseline lung function, quantified as forced expiratory volume in the first second of exhalation (FEV 1 ), is a standard diagnostic criterion used by clinicians to identify and classify lung diseases. Using whole-genome sequencing data from the National Heart, Lung, and Blood Institute Trans-Omics for Precision Medicine project, we identified a novel genetic association with FEV 1 on chromosome 12 in 867 African American children with asthma ( P = 1.26 × 10 -8 , β = 0.302). Conditional analysis within 1 Mb of the tag signal (rs73429450) yielded one major and two other weaker independent signals within this peak. We explored statistical and functional evidence for all variants in linkage disequilibrium with the three independent signals and yielded nine variants as the most likely candidates responsible for the association with FEV 1 Hi-C data and expression QTL analysis demonstrated that these variants physically interacted with KITLG (KIT ligand, also known as SCF ), and their minor alleles were associated with increased expression of the KITLG gene in nasal epithelial cells. Gene-by-air-pollution interaction analysis found that the candidate variant rs58475486 interacted with past-year ambient sulfur dioxide exposure ( P = 0.003, β = 0.32). This study identified a novel protective genetic association with FEV 1 , possibly mediated through KITLG , in African American children with asthma. This is the first study that has identified a genetic association between lung function and KITLG , which has established a role in orchestrating allergic inflammation in asthma., (Copyright © 2020 by the Genetics Society of America.)

Rationale: Severe early-life respiratory illnesses, particularly those caused by respiratory syncytial virus (RSV) and human rhinovirus (HRV), are strongly associated with the development of asthma in children. Puerto Rican children in particular have a strikingly high asthma burden. However, prior studies of the potential associations between early-life respiratory illnesses and asthma in Puerto Rican and other minority populations have been limited., Objectives: We sought to determine whether early-life respiratory illness was associated with asthma in Puerto Rican, Mexican American, and African American children., Methods: Using a logistic regression analysis, we examined the association between early-life respiratory illnesses (report of upper respiratory infection (URI), pneumonia, bronchitis, and bronchiolitis/RSV) within the first two years of life and physician-diagnosed asthma after the age of two in a large cohort of Puerto Rican, Mexican American, and African American children., Measurements and Main Results: While early-life respiratory illnesses were associated with greater asthma odds in Puerto Ricans, Mexican Americans, and African Americans, these associations were stronger among Puerto Rican children. Specifically, in Puerto Ricans, the odds was 6.15 (95% CI: 4.21-9.05) if the child reported at least one of the following respiratory illness: URI, pneumonia, bronchitis or bronchiolitis. The odds were also higher in Puerto Ricans when considering these conditions separately., Conclusions: We observed population-specific associations between early-life respiratory illnesses and asthma, which were especially significant and stronger in Puerto Ricans. Taken together with the known high burden of RSV in Puerto Rico, our results may help explain the high burden of asthma in Puerto Ricans., Competing Interests: The authors have declared that no competing interests exist.

Type 2 (T2) inflammation plays a key role in the pathogenesis of asthma. IL-4, IL-5, and IL-13, along with other inflammatory mediators, lead to increased cellular eosinophilic inflammation. It is likely that around half of all patients with asthma have evidence of T2-high inflammation. Sputum and blood eosinophils, exhaled nitric oxide, blood IgE levels, and airway gene expression markers are frequently used biomarkers of T2-high asthma. Individuals with T2-high asthma tend to have several features of increased asthma severity, including reduced lung function and increased rates of asthma exacerbations, and T2-high patients demonstrate distinct pathologic features including increased airway remodeling and alterations in airway mucus production. Several monoclonal antibodies are now available to treat individuals with T2-high asthma and these medications significantly reduce asthma exacerbation rates., (Copyright © 2019. Published by Elsevier Inc.)

Background: Global gene expression levels are known to be highly dependent upon gross demographic features including age, yet identification of age-related genomic indicators has yet to be comprehensively undertaken in a disease and treatment-specific context., Methods: We used gene expression data from CD4+ lymphocytes in the Asthma BioRepository for Integrative Genomic Exploration (Asthma BRIDGE), an open-access collection of subjects participating in genetic studies of asthma with available gene expression data. Replication population participants were Puerto Rico islanders recruited as part of the ongoing Genes environments & Admixture in Latino Americans (GALA II), who provided nasal brushings for transcript sequencing. The main outcome measure was chronic asthma control as derived by questionnaires. Genomic associations were performed using regression of chronic asthma control score on gene expression with age in years as a covariate, including a multiplicative interaction term for gene expression times age., Results: The SMARCD1 gene (SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily D member 1) interacted with age to influence chronic asthma control on inhaled corticosteroids, with a doubling of expression leading to an increase of 1.3 units of chronic asthma control per year (95% CI [0.86, 1.74], p = 6 × 10 - 9 ), suggesting worsening asthma control with increasing age. This result replicated in GALA II (p = 3.8 × 10 - 8 ). Cellular assays confirmed the role of SMARCD1 in glucocorticoid response in airway epithelial cells., Conclusion: Focusing on age-dependent factors may help identify novel indicators of asthma medication response. Age appears to modulate the effect of SMARCD1 on asthma control with inhaled corticosteroids.

Background: Research in transformed immortalized cell lines indicates the cadherin-related family member 3 (CDHR3) protein serves as a receptor for human rhinovirus (HRV)-C. Similar experiments indicate that the CDHR3 coding variant rs6967330 increases CDHR3 protein surface expression., Objective: We sought to determine whether CDHR3 is necessary for HRV-C infection of primary airway epithelial cells (AECs) and to identify molecular mechanisms by which CDHR3 variants confer risk for asthma exacerbations., Methods: CDHR3 function and influence on HRV-C infection were investigated by using single-cell transcriptomics, CRISPR-Cas9 gene knockout, and genotype-specific donor experiments performed in primary AECs. Nasal airway epithelium cis-expression quantitative trait locus (eQTL) analysis of CDHR3 was performed, followed by association testing for asthma hospitalization in minority children., Results: CDHR3 lung expression is exclusive to ciliated AECs and associated with basal bodies during and after motile ciliogenesis. Knockout of CDHR3 in human AECs did not prevent ciliated cell differentiation but was associated with a decrease in transepithelial resistance and an 80% decrease in HRV-C infection of the mucociliary epithelium. AECs from subjects homozygous for the risk-associated rs6967330 single nucleotide polymorphism (SNP) exhibited greater HRV-C infection compared with cells homozygous for the nonrisk allele. AEC cis-eQTL analysis indicated that rs6967330 and other SNPs are eQTLs for CDHR3. Only the eQTL block containing the rs6967330 SNP showed a significant association with childhood asthma hospitalization., Conclusions: Genetic deletion and genotype-specific studies in primary AECs indicate CDHR3 is critical to HRV-C infection of ciliated cells. The rs6967330 SNP confers risk of severe childhood asthma exacerbations, likely through increasing HRV-C infection levels and protein surface localization., (Copyright © 2019 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Bacterial permeability family member A1 (BPIFA1), also known as short palate, lung, and nasal epithelium clone 1 (SPLUNC1), is a protein involved in the antiinflammatory response. The goal of this study was to determine whether BPIFA1 expression in asthmatic airways is regulated by genetic variations, altering epithelial responses to type 2 cytokines (e.g., IL-13). Nasal epithelial cells from patients with mild to severe asthma were collected from the National Heart, Lung, and Blood Institute Severe Asthma Research Program centers, genotyped for rs750064, and measured for BPIFA1. To determine the function of rs750064, cells were cultured at air-liquid interface and treated with IL-13 with or without recombinant human BPIFA1 (rhBPIFA1). Noncultured nasal cells with the rs750064 CC genotype had significantly less BPIFA1 mRNA expression than the CT and TT genotypes. Cultured CC versus CT and TT cells without stimulation maintained less BPIFA1 expression. With IL-13 treatment, CC genotype cells secreted more eotaxin-3 than CT and TT genotype cells. Also, rhBPIFA1 reduced IL-13-mediated eotaxin-3. BPIFA1 mRNA levels negatively correlated with serum IgE and fractional exhaled nitric oxide. Baseline FEV1% levels were lower in the asthma patients with the CC genotype (n = 1,016). Our data suggest that less BPIFA1 in asthma patients with the CC allele may predispose them to greater eosinophilic inflammation, which could be attenuated by rhBPIFA1 protein therapy.

Background: Asthma is a common but complex disease with racial/ethnic differences in prevalence, morbidity, and response to therapies., Objective: We sought to perform an analysis of genetic ancestry to identify new loci that contribute to asthma susceptibility., Methods: We leveraged the mixed ancestry of 3902 Latinos and performed an admixture mapping meta-analysis for asthma susceptibility. We replicated associations in an independent study of 3774 Latinos, performed targeted sequencing for fine mapping, and tested for disease correlations with gene expression in the whole blood of more than 500 subjects from 3 racial/ethnic groups., Results: We identified a genome-wide significant admixture mapping peak at 18q21 in Latinos (P = 6.8 × 10 -6 ), where Native American ancestry was associated with increased risk of asthma (odds ratio [OR], 1.20; 95% CI, 1.07-1.34; P = .002) and European ancestry was associated with protection (OR, 0.86; 95% CI, 0.77-0.96; P = .008). Our findings were replicated in an independent childhood asthma study in Latinos (P = 5.3 × 10 -3 , combined P = 2.6 × 10 -7 ). Fine mapping of 18q21 in 1978 Latinos identified a significant association with multiple variants 5' of SMAD family member 2 (SMAD2) in Mexicans, whereas a single rare variant in the same window was the top association in Puerto Ricans. Low versus high SMAD2 blood expression was correlated with case status (13.4% lower expression; OR, 3.93; 95% CI, 2.12-7.28; P < .001). In addition, lower expression of SMAD2 was associated with more frequent exacerbations among Puerto Ricans with asthma., Conclusion: Ancestry at 18q21 was significantly associated with asthma in Latinos and implicated multiple ancestry-informative noncoding variants upstream of SMAD2 with asthma susceptibility. Furthermore, decreased SMAD2 expression in blood was strongly associated with increased asthma risk and increased exacerbations., (Copyright © 2018. Published by Elsevier Inc.)

Background: Type 2 (T2) inflammation drives airway dysfunction in many patients with asthma; yet, we lack a comprehensive understanding of the airway immune cell types and networks that sustain this inflammation. Moreover, defects in the airway immune system in patients with asthma without T2 inflammation are not established., Objectives: To determine the gene networks that sustain T2 airway inflammation in T2-high asthma and to explore the gene networks that characterize T2-low asthma., Methods: Network analysis of sputum cell transcriptome expression data from 84 subjects with asthma and 27 healthy control subjects was used to identify immune cell type-enriched networks that underlie asthma subgroups., Results: Sputum T2 gene expression was characterized by an immune cell network derived from multiple innate immune cells, including eosinophils, mast cells/basophils, and inflammatory dendritic cells. Clustering of subjects within this network stratified subjects into T2-high and T2-low groups, but it also revealed a subgroup of T2-high subjects with uniformly higher expression of the T2 network. These "T2-ultrahigh subjects" were characterized clinically by older age and more severe airflow obstruction and pathologically by a second T2 network derived from T2-skewed, CD11b + /CD103 - /IRF4 + classical dendritic cells. Subjects with T2-low asthma were differentiated from healthy control subjects by lower expression of a cytotoxic CD8 + T-cell network, which was negatively correlated with body mass index and plasma IL-6 concentrations., Conclusions: Persistent airway T2 inflammation is a complex construct of innate and adaptive immunity gene expression networks that are variable across individuals with asthma and persist despite steroid treatment. Individuals with T2-low asthma exhibit an airway deficiency in cytotoxic T cells associated with obesity-driven inflammation.

Rationale: Albuterol, a bronchodilator medication, is the first-line therapy for asthma worldwide. There are significant racial/ethnic differences in albuterol drug response., Objectives: To identify genetic variants important for bronchodilator drug response (BDR) in racially diverse children., Methods: We performed the first whole-genome sequencing pharmacogenetics study from 1,441 children with asthma from the tails of the BDR distribution to identify genetic association with BDR., Measurements and Main Results: We identified population-specific and shared genetic variants associated with BDR, including genome-wide significant (P < 3.53 × 10 -7 ) and suggestive (P < 7.06 × 10 -6 ) loci near genes previously associated with lung capacity (DNAH5), immunity (NFKB1 and PLCB1), and β-adrenergic signaling (ADAMTS3 and COX18). Functional analyses of the BDR-associated SNP in NFKB1 revealed potential regulatory function in bronchial smooth muscle cells. The SNP is also an expression quantitative trait locus for a neighboring gene, SLC39A8. The lack of other asthma study populations with BDR and whole-genome sequencing data on minority children makes it impossible to perform replication of our rare variant associations. Minority underrepresentation also poses significant challenges to identify age-matched and population-matched cohorts of sufficient sample size for replication of our common variant findings., Conclusions: The lack of minority data, despite a collaboration of eight universities and 13 individual laboratories, highlights the urgent need for a dedicated national effort to prioritize diversity in research. Our study expands the understanding of pharmacogenetic analyses in racially/ethnically diverse populations and advances the foundation for precision medicine in at-risk and understudied minority populations.

Background: Respiratory illness caused by viral infection is associated with the development and exacerbation of childhood asthma. Little is known about the effects of respiratory viral infections in the absence of illness. Using quantitative PCR (qPCR) for common respiratory viruses and for two genes known to be highly upregulated in viral infections (CCL8/CXCL11), we screened 92 asthmatic and 69 healthy children without illness for respiratory virus infections., Results: We found 21 viral qPCR-positive and 2 suspected virus-infected subjects with high expression of CCL8/CXCL11. We applied a dual RNA-seq workflow to these subjects, together with 25 viral qPCR-negative subjects, to compare qPCR with sequencing-based virus detection and to generate the airway transcriptome for analysis. RNA-seq virus detection achieved 86% sensitivity when compared to qPCR-based screening. We detected additional respiratory viruses in the two CCL8/CXCL11-high subjects and in two of the qPCR-negative subjects. Viral read counts varied widely and were used to stratify subjects into Virus-High and Virus-Low groups. Examination of the host airway transcriptome found that the Virus-High group was characterized by immune cell airway infiltration, downregulation of cilia genes, and dampening of type 2 inflammation. Even the Virus-Low group was differentiated from the No-Virus group by 100 genes, some involved in eIF2 signaling., Conclusions: Respiratory virus infection without illness is not innocuous but may determine the airway function of these subjects by driving immune cell airway infiltration, cellular remodeling, and alteration of asthmogenic gene expression.

Background: Younger maternal age at birth is associated with increased risk of asthma in offspring in European descent populations, but has not been studied in Latino populations., Objectives: We sought to examine the relationship between maternal age at birth and prevalence of asthma in a nationwide study of Latino children., Methods: We included 3473 Latino children aged 8-21 years (1696 subjects with physician-diagnosed asthma and 1777 healthy controls) from five US centres and Puerto Rico recruited from July 2008 through November 2011. We used multiple logistic regression models to examine the effect of maternal age at birth on asthma in offspring overall and in analyses stratified by ethnic subgroup (Mexican American, Puerto Rican and other Latino). Secondary analyses evaluated the effects of siblings, acculturation and income on this relationship., Results: Maternal age < 20 years was significantly associated with decreased odds of asthma in offspring, independent of other risk factors (OR = 0.73, 95% CI: 0.57-0.93). In subgroup analyses, the protective effect of younger maternal age was observed only in Mexican Americans (OR = 0.53, 95% CI: 0.36, 0.79). In Puerto Ricans, older maternal age was associated with decreased odds of asthma (OR = 0.65, 95% CI: 0.44-0.97). In further stratified models, the protective effect of younger maternal age in Mexican Americans was seen only in children without older siblings (OR = 0.44, 95% CI: 0.23-0.81)., Conclusion and Clinical Relevance: In contrast to European descent populations, younger maternal age was associated with decreased odds of asthma in offspring in Mexican American women. Asthma is common in urban minority populations but the factors underlying the varying prevalence among different Latino ethnicities in the United States is not well understood. Maternal age represents one factor that may help to explain this variability., (© 2016 John Wiley & Sons Ltd.)

Genome-wide association studies of asthma have identified genetic variants in the IL1RL1 gene, but the molecular mechanisms conferring risk are unknown. IL1RL1 encodes the ST2 receptor (ST2L) for IL-33 and an inhibitory decoy receptor (sST2). IL-33 promotes type 2 inflammation, which is present in some but not all asthmatics. We find that two single nucleotide polymorphisms (SNPs) in IL1RL1 - rs1420101 and rs11685480 - are strongly associated with plasma sST2 levels, though neither is an expression quantitative trait locus (eQTL) in whole blood. Rather, rs1420101 and rs11685480 mark eQTLs in airway epithelial cells and distal lung parenchyma, respectively. We find that the genetically determined plasma sST2 reservoir, derived from the lung, neutralizes IL-33 activity, and these eQTL SNPs additively increase the risk of airway type 2 inflammation among asthmatics. These risk variants define a population of asthmatics at risk of IL-33-driven type 2 inflammation.

Background: Plasminogen activator inhibitor-1 (PAI-1) is induced in airways by virus and may mediate asthmatic airway remodeling. We sought to evaluate if genetic variants and early life lower respiratory infections jointly affect asthma risk., Methods: We included Latino children, adolescents, and young adults aged 8-21 years (1736 subjects with physician-diagnosed asthma and 1747 healthy controls) from five U.S. centers and Puerto Rico after excluding subjects with incomplete clinical or genetic data. We evaluated the independent and joint effects of a PAI-1 gain of function polymorphism and bronchiolitis / Respiratory Syncytial Virus (RSV) or other lower respiratory infections (LRI) within the first 2 years of life on asthma risk, asthma exacerbations and lung function., Results: RSV infection (OR 9.9, 95%CI 4.9-20.2) and other LRI (OR 9.1, 95%CI 7.2-11.5) were independently associated with asthma, but PAI-1 genotype was not. There were joint effects on asthma risk for both genotype-RSV (OR 17.7, 95% CI 6.3-50.2) and genotype-LRI (OR 11.7, 95% CI 8.8-16.4). A joint effect of genotype-RSV resulted in a 3.1-fold increased risk for recurrent asthma hospitalizations. In genotype-respiratory infection joint effect analysis, FEV1% predicted and FEV1/FVC % predicted were further reduced in the genotype-LRI group (β -2.1, 95% CI -4.0 to -0.2; β -2.0, 95% CI -3.1 to -0.8 respectively). Similarly, lower FEV1% predicted was noted in genotype-RSV group (β -3.1, 95% CI -6.1 to -0.2) with a trend for lower FEV1/FVC % predicted., Conclusions: A genetic variant of PAI-1 together with early life LRI such as RSV bronchiolitis is associated with an increased risk of asthma, morbidity, and reduced lung function in this Latino population., Competing Interests: The authors have declared that no competing interests exist.

Type 2 inflammation occurs in a large subgroup of asthmatics, and novel cytokine-directed therapies are being developed to treat this population. In mouse models, interleukin-33 (IL-33) activates lung resident innate lymphoid type 2 cells (ILC2s) to initiate airway type 2 inflammation. In human asthma, which is chronic and difficult to model, the role of IL-33 and the target cells responsible for persistent type 2 inflammation remain undefined. Full-length IL-33 is a nuclear protein and may function as an "alarmin" during cell death, a process that is uncommon in chronic stable asthma. We demonstrate a previously unidentified mechanism of IL-33 activity that involves alternative transcript splicing, which may operate in stable asthma. In human airway epithelial cells, alternative splicing of the IL-33 transcript is consistently present, and the deletion of exons 3 and 4 (Δ exon 3,4) confers cytoplasmic localization and facilitates extracellular secretion, while retaining signaling capacity. In nonexacerbating asthmatics, the expression of Δ exon 3,4 is strongly associated with airway type 2 inflammation, whereas full-length IL-33 is not. To further define the extracellular role of IL-33 in stable asthma, we sought to determine the cellular targets of its activity. Comprehensive flow cytometry and RNA sequencing of sputum cells suggest basophils and mast cells, not ILC2s, are the cellular sources of type 2 cytokines in chronic asthma. We conclude that IL-33 isoforms activate basophils and mast cells to drive type 2 inflammation in chronic stable asthma, and novel IL-33 inhibitors will need to block all biologically active isoforms.

Background: Pest allergen sensitization is associated with asthma morbidity in urban youth but minimally explored in Latino populations. Specifically, the effect of mouse sensitization on the risk of asthma exacerbation has been unexplored in Latino subgroups., Objective: To evaluate whether pest allergen sensitization is a predictor of asthma exacerbations and poor asthma control in urban minority children with asthma., Methods: Latino and African American children (8-21 years old) with asthma were recruited from 4 sites across the United States. Logistic regression models evaluated the association of mouse or cockroach sensitization with asthma-related acute care visits or hospitalizations., Results: A total of 1,992 children with asthma in the Genes-environments and Admixture in Latino American (GALA-II) and Study of African-Americans, Asthma, Genes, and Environments (SAGE-II) cohorts were studied. Asthmatic children from New York had the highest rate of pest allergen sensitization (42% mouse, 56% cockroach), with the lowest rate in San Francisco (4% mouse, 8% cockroach). Mouse sensitization, more than cockroach, was associated with increased odds of acute care visits (adjusted odds ratio [aOR], 1.47; 95% CI, 1.07-2.03) or hospitalizations (aOR, 3.07; 95% CI, 1.81-5.18), even after controlling for self-reported race and site of recruitment. In stratified analyses, Mexican youth sensitized to mouse allergen did not have higher odds of asthma exacerbation. Other Latino and Puerto Rican youth sensitized to mouse had higher odds of hospitalization for asthma (aORs, 4.57 [95% CI, 1.86-11.22] and 10.01 [95% CI, 1.77-56.6], respectively) but not emergency department visits., Conclusion: Pest allergen sensitization is associated with a higher odds of asthma exacerbations in urban minority youth. Puerto Rican and Other Latino youth sensitized to mouse were more likely to have asthma-related hospitalizations than Mexican youth., (Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Rationale: Adverse effects of exposures to ambient air pollution on lung function are well documented, but evidence in racial/ethnic minority children is lacking., Objectives: To assess the relationship between air pollution and lung function in minority children with asthma and possible modification by global genetic ancestry., Methods: The study population consisted of 1,449 Latino and 519 African American children with asthma from five different geographical regions in the mainland United States and Puerto Rico. We examined five pollutants (particulate matter ≤10 μm and ≤2.5 μm in diameter, ozone, nitrogen dioxide, and sulfur dioxide), derived from participant residential history and ambient air monitoring data, and assessed over several time windows. We fit generalized additive models for associations between pollutant exposures and lung function parameters and tested for interaction terms between exposures and genetic ancestry., Measurements and Main Results: A 5 μg/m(3) increase in average lifetime particulate matter less than or equal to 2.5 μm in diameter exposure was associated with a 7.7% decrease in FEV1 (95% confidence interval = -11.8 to -3.5%) in the overall study population. Global genetic ancestry did not appear to significantly modify these associations, but percent African ancestry was a significant predictor of lung function., Conclusions: Early-life particulate exposures were associated with reduced lung function in Latino and African American children with asthma. This is the first study to report an association between exposure to particulates and reduced lung function in minority children in which racial/ethnic status was measured by ancestry-informative markers.

Severe infection with respiratory syncytial virus (RSV) during infancy is strongly associated with the development of asthma. To identify genetic variation that contributes to asthma following severe RSV bronchiolitis during infancy, we sequenced the coding exons of 131 asthma candidate genes in 182 European and African American children with severe RSV bronchiolitis in infancy using anonymous pools for variant discovery, and then directly genotyped a set of 190 nonsynonymous variants. Association testing was performed for physician-diagnosed asthma before the 7th birthday (asthma) using genotypes from 6,500 individuals from the Exome Sequencing Project (ESP) as controls to gain statistical power. In addition, among patients with severe RSV bronchiolitis during infancy, we examined genetic associations with asthma, active asthma, persistent wheeze, and bronchial hyperreactivity (methacholine PC20) at age 6 years. We identified four rare nonsynonymous variants that were significantly associated with asthma following severe RSV bronchiolitis, including single variants in ADRB2, FLG and NCAM1 in European Americans (p = 4.6x10-4, 1.9x10-13 and 5.0x10-5, respectively), and NOS1 in African Americans (p = 2.3x10-11). One of the variants was a highly functional nonsynonymous variant in ADRB2 (rs1800888), which was also nominally associated with asthma (p = 0.027) and active asthma (p = 0.013) among European Americans with severe RSV bronchiolitis without including the ESP. Our results suggest that rare nonsynonymous variants contribute to the development of asthma following severe RSV bronchiolitis in infancy, notably in ADRB2. Additional studies are required to explore the role of rare variants in the etiology of asthma and asthma-related traits following severe RSV bronchiolitis.

Purpose of Review: This review will cover advances over the past year in defining airway endotypes in asthma by gene expression and the relationship between these endotypes and clinical traits., Recent Findings: Expression profiling studies of asthmatic airway samples continue to reveal significant heterogeneity in airway inflammation and dysfunction. Recent studies have indicated multiple distinct, but related Th2 inflammatory asthma endotypes. Moreover, novel biomarkers of Th2 inflammation are being identified in more accessible nasal brushing and induced sputum cell samples. New data suggest the presence of multiple non-Th2-driven asthma molecular endotypes, including ones related to neutrophilic inflammation, airway remodeling, and chemosensory dysfunction. Many of these endotypes are associated with clinical disease features and treatment response., Summary: Molecular endotyping of asthmatic patients using gene expression profiling of airway samples is helping to uncover disease mechanisms and potential novel treatment targets. The advancement of endotyping methods holds the promise of future personalized treatment for asthma.

Inhaled short-acting beta-agonist (SABA) medication is commonly used in asthma patients to rapidly reverse airway obstruction and improve acute symptoms. We performed a genome-wide association study of SABA medication response using gene-based association tests. A linear mixed model approach was first used for single-nucleotide polymorphism associations, and the results were later combined using GATES to generate gene-based associations. Our results identified SPATA13-AS1 as being significantly associated with SABA bronchodilator response in 328 healthy African Americans. In replication, this gene was associated with SABA response among the two separate groups of African Americans with asthma (n=1073, P=0.011 and n=1968, P=0.014), 149 healthy African Americans (P=0.003) and 556 European Americans with asthma (P=0.041). SPATA13-AS1 was also associated with longitudinal SABA medication usage in the two separate groups of African Americans with asthma (n=658, P=0.047 and n=1968, P=0.025). Future studies are needed to delineate the precise mechanism by which SPATA13-AS1 may influence SABA response.

Background: Bronchial airway expression profiling has identified inflammatory subphenotypes of asthma, but the invasiveness of this technique has limited its application to childhood asthma., Objectives: We sought to determine whether the nasal transcriptome can proxy expression changes in the lung airway transcriptome in asthmatic patients. We also sought to determine whether the nasal transcriptome can distinguish subphenotypes of asthma., Methods: Whole-transcriptome RNA sequencing was performed on nasal airway brushings from 10 control subjects and 10 asthmatic subjects, which were compared with established bronchial and small-airway transcriptomes. Targeted RNA sequencing nasal expression analysis was used to profile 105 genes in 50 asthmatic subjects and 50 control subjects for differential expression and clustering analyses., Results: We found 90.2% overlap in expressed genes and strong correlation in gene expression (ρ = .87) between the nasal and bronchial transcriptomes. Previously observed asthmatic bronchial differential expression was strongly correlated with asthmatic nasal differential expression (ρ = 0.77, P = 5.6 × 10(-9)). Clustering analysis identified TH2-high and TH2-low subjects differentiated by expression of 70 genes, including IL13, IL5, periostin (POSTN), calcium-activated chloride channel regulator 1 (CLCA1), and serpin peptidase inhibitor, clade B (SERPINB2). TH2-high subjects were more likely to have atopy (odds ratio, 10.3; P = 3.5 × 10(-6)), atopic asthma (odds ratio, 32.6; P = 6.9 × 10(-7)), high blood eosinophil counts (odds ratio, 9.1; P = 2.6 × 10(-6)), and rhinitis (odds ratio, 8.3; P = 4.1 × 10(-6)) compared with TH2-low subjects. Nasal IL13 expression levels were 3.9-fold higher in asthmatic participants who experienced an asthma exacerbation in the past year (P = .01). Several differentially expressed nasal genes were specific to asthma and independent of atopic status., Conclusion: Nasal airway gene expression profiles largely recapitulate expression profiles in the lung airways. Nasal expression profiling can be used to identify subjects with IL13-driven asthma and a TH2-skewed systemic immune response., (Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Rationale: The function of the P2X(7) nucleotide receptor protects against exacerbation in people with mild-intermittent asthma during viral illnesses, but the impact of disease severity and maintenance therapy has not been studied., Objectives: To evaluate the association between P2X(7), asthma exacerbations, and incomplete symptom control in a more diverse population., Methods: A matched P2RX7 genetic case-control was performed with samples from Asthma Clinical Research Network trial participants enrolled before July 2006, and P2X(7) pore activity was determined in whole blood samples as an ancillary study to two trials completed subsequently., Measurements and Main Results: A total of 187 exacerbations were studied in 742 subjects, and the change in asthma symptom burden was studied in an additional 110 subjects during a trial of inhaled corticosteroids (ICS) dose optimization. African American carriers of the minor G allele of the rs2230911 loss-of-function single nucleotide polymorphism were more likely to have a history of prednisone use in the previous 12 months, with adjustment for ICS and long-acting β(2)-agonists use (odds ratio, 2.7; 95% confidence interval, 1.2-6.2; P = 0.018). Despite medium-dose ICS, attenuated pore function predicted earlier exacerbations in incompletely controlled patients with moderate asthma (hazard ratio, 3.2; confidence interval, 1.1-9.3; P = 0.033). After establishing control with low-dose ICS in patients with mild asthma, those with attenuated pore function had more asthma symptoms, rescue albuterol use, and FEV(1) reversal (P < 0.001, 0.03, and 0.03, respectively) during the ICS adjustment phase., Conclusions: P2X(7) pore function protects against exacerbations of asthma and loss of control, independent of baseline severity and the maintenance therapy.

Background: Asthma is a common disease of children with a complex genetic origin. Understanding the genetic basis of asthma susceptibility will allow disease prediction and risk stratification., Objective: We sought to identify asthma susceptibility genes in children., Methods: A nested case-control genetic association study of children of Caucasian European ancestry from a birth cohort was conducted. Single nucleotide polymorphisms (SNPs, n = 116,024) were genotyped in pools of DNA samples from cohort children with physician-diagnosed asthma (n = 112) and normal controls (n = 165). A genomic region containing the ATPAF1 gene was found to be significantly associated with asthma. Additional SNPs within this region were genotyped in individual samples from the same children and in 8 independent study populations of Caucasian, African American, Hispanic, or other ancestries. SNPs were also genotyped or imputed in 2 consortia control populations. ATPAF1 expression was measured in bronchial biopsies from asthmatic patients and controls., Results: Asthma was found to be associated with a cluster of SNPs and SNP haplotypes containing the ATPAF1 gene, with 2 SNPs achieving significance at a genome-wide level (P = 2.26 × 10(-5) to 2.2 × 10(-8)). Asthma severity was also found to be associated with SNPs and SNP haplotypes in the primary population. SNP and/or gene-level associations were confirmed in the 4 non-Hispanic populations. Haplotype associations were also confirmed in the non-Hispanic populations (P = .045-.0009). ATPAF1 total RNA expression was significantly (P < .01) higher in bronchial biopsies from asthmatic patients than from controls., Conclusion: Genetic variation in the ATPAF1 gene predisposes children of different ancestries to asthma., (Published by Mosby, Inc.)

Rationale: Acute asthma exacerbations, precipitated by viral infections, are a significant cause of morbidity, but not all patients with asthma are equally susceptible., Objectives: To explore susceptibility factors for asthma exacerbations, we considered a role for histoblood group antigens because they are implicated in mechanisms of gastrointestinal viral infection, specifically the O-secretor mucin glycan phenotype. We investigated if this phenotype is associated with susceptibility to asthma exacerbation., Methods: We performed two consecutive case-control studies in subjects with asthma who were either prone or resistant to asthma exacerbations. Exacerbation-prone cases had frequent use of prednisone for an asthma exacerbation and frequent asthma-related healthcare utilization, whereas exacerbation-resistant control subjects had rarely reported asthma exacerbations. The frequency of different mucin glycan phenotypes, defined by the presence or absence of H (O), A, B, or AB antigens, was compared in cases and control subjects., Measurements and Main Results: In an initial study consisting of 49 subjects with asthma (23 cases and 26 control subjects), we found that having the O-secretor phenotype was associated with a 5.8-fold increase in the odds of being a case (95% confidence interval, 1.7-21.0; P = 0.006). In a replication study consisting of 204 subjects with asthma (101 cases and 103 control subjects), we found that having the O-secretor phenotype was associated with a 2.3-fold increased odds of being a case (95% confidence interval, 1.2-4.4; P = 0.02)., Conclusions: The O-secretor mucin glycan phenotype is associated with susceptibility to asthma exacerbation. Clinical trial registered at www.clinicaltrials.gov (NCT00201266).

Background: Asthma is a chronic inflammatory disease with a strong genetic predisposition. A major challenge for candidate gene association studies in asthma is the selection of biologically relevant genes., Methodology/principal Findings: Using epithelial RNA expression arrays, HapMap allele frequency variation, and the literature, we identified six possible candidate susceptibility genes for childhood asthma including ADCY2, DNAH5, KIF3A, PDE4B, PLAU, SPRR2B. To evaluate these genes, we compared the genotypes of 194 predominantly tagging SNPs in 790 asthmatic, allergic and non-allergic children. We found that SNPs in all six genes were nominally associated with asthma (p<0.05) in our discovery cohort and in three independent cohorts at either the SNP or gene level (p<0.05). Further, we determined that our selection approach was superior to random selection of genes either differentially expressed in asthmatics compared to controls (p = 0.0049) or selected based on the literature alone (p = 0.0049), substantiating the validity of our gene selection approach. Importantly, we observed that 7 of 9 SNPs in the KIF3A gene more than doubled the odds of asthma (OR = 2.3, p<0.0001) and increased the odds of allergic disease (OR = 1.8, p<0.008). Our data indicate that KIF3A rs7737031 (T-allele) has an asthma population attributable risk of 18.5%. The association between KIF3A rs7737031 and asthma was validated in 3 independent populations, further substantiating the validity of our gene selection approach., Conclusions/significance: Our study demonstrates that KIF3A, a member of the kinesin superfamily of microtubule associated motors that are important in the transport of protein complexes within cilia, is a novel candidate gene for childhood asthma. Polymorphisms in KIF3A may in part be responsible for poor mucus and/or allergen clearance from the airways. Furthermore, our study provides a promising framework for the identification and evaluation of novel candidate susceptibility genes.

Common lung diseases such as asthma, COPD, and pulmonary fibrosis cause significant morbidity and mortality in the U.S. and worldwide. Research investigating the mechanisms of disease etiology has clearly indicated that genetic attributes and environmental exposures each play important roles in the development of these diseases. Emerging evidence underscores the importance of the interplay between genetic predisposition and environmental factors in fully understanding the development of lung disease. Herein we discuss recent advances in knowledge and technology surrounding the role of genetics, the environment, and gene-environment interactions in these common lung diseases.

Background: African American patients disproportionately experience uncontrolled asthma. Treatment with an inhaled corticosteroid (ICS) is considered first-line therapy for persistent asthma., Objective: We sought to determine the degree to which African American patients respond to ICS medication and whether the level of response is influenced by other factors, including genetic ancestry., Methods: Patients aged 12 to 56 years who received care from a large health system in southeast Michigan and who resided in Detroit were recruited to participate if they had a diagnosis of asthma. Patients were treated with 6 weeks of inhaled beclomethasone dipropionate, and pulmonary function was remeasured after treatment. Ancestry was determined by genotyping ancestry-informative markers. The main outcome measure was ICS responsiveness defined as the change in prebronchodilator FEV(1) over the 6-week course of treatment., Results: Among 147 participating African American patients with asthma, average improvement in FEV(1) after 6 weeks of ICS treatment was 11.6%. The mean proportion of African ancestry in this group was 78.4%. The degree of baseline bronchodilator reversibility was the only factor consistently associated with ICS responsiveness, as measured by both an improvement in FEV(1) and patient-reported asthma control (P = .001 and P = .021, respectively). The proportion of African ancestry was not significantly associated with ICS responsiveness., Conclusions: Although baseline pulmonary function parameters appear to be associated with the likelihood to respond to ICS treatment, the proportion of genetic African ancestry does not. This study suggests that genetic ancestry might not contribute to differences in ICS controller response among African American patients with asthma., (Copyright © 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Background: Inhaled corticosteroids (ICSs) are considered first-line treatment for persistent asthma, yet there is significant variability in treatment response. Dual-specificity phosphatase 1 (DUSP1) appears to mediate the anti-inflammatory action of corticosteroids., Objective: We sought to determine whether variants in the DUSP1 gene are associated with clinical response to ICS treatment., Methods: Study participants with asthma were drawn from the following multiethnic cohorts: the Genetics of Asthma in Latino Americans (GALA) study; the Study of African Americans, Asthma, Genes & Environments (SAGE); and the Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-ethnicity (SAPPHIRE). We screened GALA study participants for genetic variants that modified the relationship between ICS use and bronchodilator response. We then replicated our findings in SAGE and SAPPHIRE participants. In a group of SAPPHIRE participants treated with ICSs for 6 weeks, we examined whether a DUSP1 polymorphism was associated with changes in FEV(1) and self-reported asthma control., Results: The DUSP1 polymorphisms rs881152 and rs34507926 localized to different haplotype blocks and appeared to significantly modify the relationship between ICS use and bronchodilator response among GALA study participants. This interaction was also seen for rs881152 among SAPPHIRE but not SAGE participants. Among the group of SAPPHIRE participants prospectively treated with ICSs for 6 weeks, rs881152 genotype was significantly associated with changes in self-reported asthma control but not FEV(1)., Conclusion: DUSP1 polymorphisms were associated with clinical response to ICS therapy and therefore might be useful in the future to identify asthmatic patients more likely to respond to this controller treatment., (Copyright (c) 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Background: Leukotrienes play an important role in allergic and inflammatory diseases, but reports on the involvement of arachidonate 5-lipoxygenase-activating protein (ALOX5AP) and leukotriene A(4) hydrolase (LTA4H) in asthma have been inconclusive., Objective: To determine whether polymorphisms in ALOX5AP and LTA4H genes are risk factors for asthma in two different Latino groups: Mexicans and Puerto Ricans., Methods: The LTA4H gene was sequenced in individuals from both groups to identify novel polymorphisms. Single-nucleotide polymorphisms (SNPs) in the ALOX5AP and LTA4H genes were analysed for associations with asthma and asthma-related phenotypes in 687 parent-child trios of Mexican and Puerto Rican origin., Results: In LTA4H, five previously unknown polymorphisms were identified. Two SNPs within LTA4H (rs17525488 and rs2540493) were protective for asthma in Latinos (P=0.007 and 0.05, respectively). Among the Mexican patients, LTA4H polymorphisms were associated with baseline lung function and IgE levels. For ALOX5AP, the minor allele at SNP rs10507391 was associated with protection from asthma (odds ratio=0.78, P=0.02) and baseline lung function (P=0.018) in Puerto Ricans. A gene-gene interaction was identified between LTA4H (rs17525488) and ALOX5AP (rs10507391), (P=0.003, in the combined sample)., Conclusion: Our results support the role of LTA4H and ALOX5AP variants as risk factors for asthma in Latino populations.

Background: Chitinolytic enzymes play important roles in the pathophysiology of allergic airway responses in mouse models of asthma. Acidic mammalian chitinase (AMCase) and chitotriosidase (CHIT1) have chitinolytic activity, but relatively little is known about their expression in human asthma., Objective: We sought to determine the expression and activity of AMCase and CHIT1 in healthy subjects, subjects with asthma, and habitual smokers, taking account of the null 24-bp duplication in the CHIT1 gene., Methods: We measured chitinase activity in bronchoalveolar lavage (BAL) fluid at multiple pHs by using a synthetic chitin substrate. We also determined AMCase and CHIT1 gene expression in epithelial brushings and BAL fluid macrophages by means of real time RT-PCR. Paired DNA samples were genotyped for the CHIT1 duplication., Results: In all subgroups the pH profile of chitinase activity in BAL fluid matched that of CHIT1, but not AMCase, and chitinase activity was absent in subjects genetically deficient in active CHIT1. Although AMCase protein was detectable in lavage fluid, AMCase transcripts in macrophages were consistent with an isoform lacking enzymatic activity. Median chitinase activity in BAL fluid tended to be lower than normal in asthmatic subjects but was increased 7-fold in habitual smokers, where CHIT1 gene expression in macrophages was increased., Conclusions: Chitinase activity in the lung is the result of CHIT1 activity. Although AMCase protein is detectable in the lung, our data indicate that it is inactive. Chitinase activity is not increased in subjects with asthma and in fact tends to be decreased. The high levels of chitinase activity in habitual smokers result from upregulation of CHIT1 gene expression, especially in macrophages.

A highly heritable and reproducible measure of asthma severity is baseline pulmonary function. Pulmonary function is largely determined by airway smooth muscle (ASM) tone and contractility. The large conductance, voltage and calcium-activated potassium (BK) channel negatively regulates smooth muscle tone and contraction in ASM. The modulatory subunit of BK channels, the beta1-subunit, is critical for proper activation of BK channels in smooth muscle and has shown sex hormone specific regulation. We hypothesized that KCNMB1 genetic variants in African Americans may underlie differences in bronchial smooth muscle tone and thus pulmonary function, possibly in a sex-specific manner. Through resequencing of the KCNMB1 gene we identified several common variants including a novel African-specific coding polymorphism (C818T, R140W). The C818T SNP and four other KCNMB1 variants were genotyped in two independent groups of African American asthmatics (n = 509) and tested for association with the pulmonary function measure--forced expiratory volume (FEV(1)) % of predicted value. The 818T allele is associated with a clinically significant decline (-13%) in FEV(1) in both cohorts of asthmatics among males but not females (P(combined) = 0.0003). Patch clamp electrophysiology studies of the BK channel expressed with the 140Trp variant of the beta1-subunit demonstrated significantly reduced channel openings, predicted by the loss of pulmonary function observed. African American male asthmatics carrying the 818T allele (10% of population) are potentially at risk for greater airway obstruction and increased asthma morbidity. Female asthmatics may be insulated from the deleterious effects of the 818T allele by estrogen-mediated upregulation in BK channel activity.

Asthma is a common but complex respiratory ailment; current data indicate that interaction of genetic and environmental factors lead to its clinical expression. In the United States, asthma prevalence, morbidity, and mortality vary widely among different Latino ethnic groups. The prevalence of asthma is highest in Puerto Ricans, intermediate in Dominicans and Cubans, and lowest in Mexicans and Central Americans. Independently, known socioeconomic, environmental, and genetic differences do not fully account for this observation. One potential explanation is that there may be unique and ethnic-specific gene-environment interactions that can differentially modify risk for asthma in Latino ethnic groups. These gene-environment interactions can be tested using genetic ancestry as a surrogate for genetic risk factors. Latinos are admixed and share varying proportions of African, Native American, and European ancestry. Most Latinos are unaware of their precise ancestry and report their ancestry based on the national origin of their family and their physical appearance. The unavailability of precise ancestry and the genetic complexity among Latinos may complicate asthma research studies in this population. On the other hand, precisely because of this rich mixture of ancestry, Latinos present a unique opportunity to disentangle the clinical, social, environmental, and genetic underpinnings of population differences in asthma prevalence, severity, and bronchodilator drug responsiveness.

BackgroundPAI-1 gain-of-function variants promote airway fibrosis and are associated with asthma and with worse lung function in subjects with asthma.ObjectiveWe sought to determine whether the association of a gain-of-function polymorphism in plasminogen activator inhibitor-1 (PAI-1) with airway obstruction is modified by asthma status, and whether any genotype effect persists after accounting for common exposures that increase PAI-1 level.MethodsWe studied 2070 Latino children (8-21y) with genotypic and pulmonary function data from the GALA II cohort. We estimated the relationship of the PAI-1 risk allele with FEV1/FVC by multivariate linear regression, stratified by asthma status. We examined the association of the polymorphism with asthma and airway obstruction within asthmatics via multivariate logistic regression. We replicated associations in the SAPPHIRE cohort of African Americans (n=1056). Secondary analysis included the effect of the at-risk polymorphism on postbronchodilator lung function.ResultsThere was an interaction between asthma status and the PAI-1 polymorphism on FEV1 /FVC (P=.03). The gain-of-function variants, genotypes (AA/AG), were associated with lower FEV1 /FVC in subjects with asthma (β=-1.25, CI: -2.14,-0.35, P=.006), but not in controls. Subjects with asthma and the AA/AG genotypes had a 5% decrease in FEV1 /FVC (P