RESUMEN
BACKGROUND: The development of peanut allergy is due to a combination of genetic and environmental factors, although specific genes have proven difficult to identify. Previously, we reported that peanut-sensitized Collaborative Cross strain CC027/GeniUnc (CC027) mice develop anaphylaxis upon oral challenge to peanut, in contrast to C3H/HeJ (C3H) mice. OBJECTIVE: This study aimed to determine the genetic basis of orally induced anaphylaxis to peanut in CC027 mice. METHODS: A genetic mapping population between CC027 and C3H mice was designed to identify the genetic factors that drive oral anaphylaxis. A total of 356 CC027xC3H backcrossed mice were generated, sensitized to peanut, then challenged to peanut by oral gavage. Anaphylaxis and peanut-specific IgE were quantified for all mice. T-cell phenotyping was conducted on CC027 mice and 5 additional Collaborative Cross strains. RESULTS: Anaphylaxis to peanut was absent in 77% of backcrossed mice, with 19% showing moderate anaphylaxis and 4% having severe anaphylaxis. There were 8 genetic loci associated with variation in response to peanut challenge-6 associated with anaphylaxis (temperature decrease) and 2 associated with peanut-specific IgE levels. There were 2 major loci that impacted multiple aspects of the severity of acute anaphylaxis, at which the CC027 allele was associated with worse outcome. At one of these loci, CC027 has a private genetic variant in the Themis gene. Consistent with described functions of Themis, we found that CC027 mice have more immature T cells with fewer CD8+, CD4+, and CD4+CD25+CD127- regulatory T cells. CONCLUSIONS: Our results demonstrate a key role for Themis in the orally reactive CC027 mouse model of peanut allergy.
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Anafilaxia , Arachis , Inmunoglobulina E , Ratones Endogámicos C3H , Hipersensibilidad al Cacahuete , Animales , Anafilaxia/inmunología , Anafilaxia/genética , Hipersensibilidad al Cacahuete/inmunología , Hipersensibilidad al Cacahuete/genética , Ratones , Arachis/inmunología , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Administración Oral , Mutación , Femenino , MasculinoRESUMEN
Gene editing technology has emerged as a powerful tool in all aspects of health research and continues to advance our understanding of critical and essential elements in disease pathophysiology. The clustered regularly interspaced short palindromic repeats (CRISPR) gene editing technology has been used with precision to generate gene knockouts, alter genes, and identify genes that cause disease. The full spectrum of allergic/atopic diseases, in part because of shared pathophysiology, is ripe for studies with this technology. In this way, novel culprit genes are being identified and allow for manipulation of triggering allergens to reduce allergenicity and disease. Notwithstanding current limitations on precision and potential off-target effects, newer approaches are rapidly being introduced to more fully understand specific gene functions as well as the consequences of genetic manipulation. In this review, we examine the impact of editing technologies of novel genes relevant to peanut allergy and asthma as well as how gene modification of common allergens may lead to the deletion of allergenic proteins.
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Alérgenos , Sistemas CRISPR-Cas , Edición Génica , Humanos , Alérgenos/inmunología , Alérgenos/genética , Animales , Hipersensibilidad/genética , Hipersensibilidad/inmunología , Eliminación de Gen , Asma/genética , Asma/inmunología , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/inmunologíaRESUMEN
Examining the genetics of peanut allergy (PA) in the context of clinical trial interventions and outcomes provides an opportunity to not only understand gene-environment interactions for PA risk but to also understand the benefit of allergen immunotherapy. A consistent theme in the genetics of food allergy is that in keeping with the dual allergen exposure hypothesis, barrier- and immune-related genes are most commonly implicated in food allergy and tolerance. With a focus on PA, we review how genetic risk factors across 3 genes (FLG, MALT1, and HLA-DQA1) have helped delineate distinct allergic characteristics and outcomes in the context of environmental interventions in the Learning Early about Peanut Allergy (LEAP) study and other clinical trials. We specifically consider and present a framework for genetic risk prediction for the development of PA and discuss how genetics, age, and oral consumption intertwine to predict PA outcome. Although there is some promise in this proposed framework, a better understanding of the mechanistic pathways by which PA develops and persists is needed to develop targeted therapeutics for established disease. Only by understanding the mechanisms by which PA develops, persists, and resolves can we identify adjuvants to oral immunotherapy to make older children and adults immunologically similar to their younger, more malleable counterparts and thus more likely to achieve long-term tolerance.
Asunto(s)
Hipersensibilidad a los Alimentos , Hipersensibilidad al Cacahuete , Niño , Adulto , Humanos , Adolescente , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/terapia , Alérgenos , Factores de Riesgo , Hipersensibilidad a los Alimentos/etiología , Desensibilización Inmunológica/efectos adversos , Arachis/genéticaRESUMEN
BACKGROUND: Deleterious variation in the epidermal differentiation complex (EDC) on chromosome 1 is a well-known genetic determinant of atopic dermatitis (AD) and has been associated with risk of peanut allergy (PA) in population-based studies. OBJECTIVE: Our aim was to determine the effect of genetic variation in the EDC on AD trajectory and risk of PA in early life. METHODS: Genome sequencing was used to measure genetic variation in the EDC in the Learning Early about Peanut Allergy (LEAP) study participants. Association tests were done to identify gene- and variant-level predicted deleterious variation associated with AD severity by using the Scoring Atopic Dermatitis (SCORAD) tool (n = 559) at baseline and each follow-up visit, as well as PA and food allergy in peanut avoiders (n = 275). Predicted deleterious variants included missense variants that were frameshift insertions, frameshift deletions, stop-gain mutations, or stop-loss mutations. Associations between variant load, SCORAD score, and PA were tested by using linear and generalized linear regression models. RESULTS: The genes FLG, FLG2, HRNR, and TCHH1 harbored the most predicted deleterious variation (30, 6, 3, and 1 variant, respectively). FLG variants were associated with SCORAD score at all time points; 4 variants (R1798X, R501X, S126X, and S761fs) drove the association with SCORAD score at each time point, and higher variant load was associated with greater AD severity over time. There was an association between these variants and PA, which remained significant independent of baseline AD severity (odds ratio = 2.63 [95% CI = 1.11-6.01] [P = .02]). CONCLUSIONS: Variation in FLG predicted to be deleterious is associated with AD severity at baseline and longitudinally and has an association with PA independent of baseline severity.
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Dermatitis Atópica , Hipersensibilidad al Cacahuete , Humanos , Hipersensibilidad al Cacahuete/genética , Dermatitis Atópica/genética , Mutación del Sistema de Lectura , Mutación , Arachis/genéticaRESUMEN
Rationale: Previous studies identified an interaction between HLA and oral peanut exposure. HLA-DQA1*01:02 had a protective role with the induction of Ara h 2 epitope-specific IgG4 associated with peanut consumption during the LEAP clinical trial for prevention of peanut allergy, while it was a risk allele for peanut allergy in the peanut avoidance group. We have now evaluated this gene-environment interaction in two subsequent peanut oral immunotherapy (OIT) trials - IMPACT and POISED - to better understand the potential for the HLA-DQA1*01:02 allele as an indicator of higher likelihood of desensitization, sustained unresponsiveness, and peanut allergy remission. Methods: We determined HLA-DQA1*01:02 carrier status using genome sequencing from POISED (N=118, age: 7-55yr) and IMPACT (N=126, age: 12-<48mo). We tested for association with remission, sustained unresponsiveness (SU), and desensitization in the OIT groups, as well as peanut component specific IgG4 (psIgG4) using generalized linear models and adjusting for relevant covariates and ancestry. Results: While not quite statistically significant, a higher proportion of HLA-DQA1*01:02 carriers receiving OIT in IMPACT were desensitized (93%) compared to non-carriers (78%); odds ratio (OR)=5.74 (p=0.06). In this sample we also observed that a higher proportion of carriers achieved remission (35%) compared to non-carriers (22%); OR=1.26 (p=0.80). In POISED, carriers more frequently attained continued desensitization (80% versus 61% among non-carriers; OR=1.28, p=0.86) and achieved SU (52% versus 31%; OR=2.32, p=0.19). psIgG4 associations with HLA-DQA1*01:02 in the OIT arm of IMPACT which included younger study subjects recapitulated patterns noted in LEAP, but no associations of note were observed in the older POISED study subjects. Conclusions: Findings across three clinical trials show a pattern of a gene environment interaction between HLA and oral peanut exposure. Age, and prior sensitization contribute additional determinants of outcomes, consistent with a mechanism of restricted antigen recognition fundamental to driving protective immune responses to OIT.
Asunto(s)
Arachis , Hipersensibilidad al Cacahuete , Adolescente , Adulto , Niño , Humanos , Persona de Mediana Edad , Adulto Joven , Inmunoglobulina G , Factores Inmunológicos , Inmunoterapia , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/terapia , Ensayos Clínicos como AsuntoRESUMEN
BACKGROUND: Understanding risk factors for peanut allergy (PA) is essential to develop effective preventive measures. OBJECTIVE: The objective was to ascertain associates and predictors of PA, and the relationship between PA and asthma severity. METHODS: In a population-based birth cohort, we investigated the association between objectively confirmed PA with early-life environmental exposures, filaggrin (FLG)-loss-of-function mutations and other atopic disease. We then examined the association of PA with longitudinal trajectories of sensitization, wheeze and allergic comorbidities, which were previously derived using machine learning. Finally, we ascertained the relationship between PA and asthma severity. RESULTS: PA was confirmed in 30/959 participants with evaluable data. In the multivariate analysis, eczema in infancy (OR = 4.4, 95% CI 1.5-13.2, p = 0.007), egg sensitization at age 3 years (OR = 9.7, 95% CI 3.3-29.9, p < 0.001) and early-life cat ownership (OR = 3.0, 95% CI 1.1-8.4, p = 0.04) were independent associates of PA. In the stratified analysis among 700 participants with genetic information, in children with early-life eczema there was no difference in FLG mutations between children with and without PA (3/18 [16.7%] vs. 42/220 [19.1%], p = 1.00). In contrast, among children without eczema, those with PA were almost eight times more likely to have FLG mutations (2/6 [33.3%] vs. 27/456 [5.9%], p = 0.049). We observed associations between PA and multiple allergic sensitization profiles derived using machine learning, with ~60-fold increase in risk among individuals assigned to multiple early sensitization. PA was significantly associated with persistent wheeze (but not other wheeze phenotypes), and with trajectories of atopic disease characterized by co-morbid persistent eczema and wheeze (but not with transient phenotypes). Children with PA were more likely to have asthma, but among asthmatics we found no evidence of an association between PA and asthma severity. CONCLUSIONS: Peanut allergy is associated with multiple IgE sensitization and early-onset persistent eczema and wheeze. FLG loss-of-function mutations were associated with peanut allergy in children without eczema.
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Asma , Eccema , Hipersensibilidad al Cacahuete , Asma/etiología , Asma/genética , Cohorte de Nacimiento , Estudios de Cohortes , Eccema/complicaciones , Eccema/epidemiología , Eccema/genética , Humanos , Lactante , Proteínas de Filamentos Intermediarios/genética , Hipersensibilidad al Cacahuete/complicaciones , Hipersensibilidad al Cacahuete/epidemiología , Hipersensibilidad al Cacahuete/genética , Ruidos Respiratorios/genética , Factores de RiesgoRESUMEN
We investigated the interplay between genetics and oral peanut protein exposure in the determination of the immunological response to peanut using the targeted intervention in the LEAP clinical trial. We identified an association between peanut-specific IgG4 and HLA-DQA1*01:02 that was only observed in the presence of sustained oral peanut protein exposure. The association between IgG4 and HLA-DQA1*01:02 was driven by IgG4 specific for the Ara h 2 component. Once peanut consumption ceased, the association between IgG4-specific Ara h 2 and HLA-DQA1*01:02 was attenuated. The association was validated by observing expanded IgG4-specific epitopes in people who carried HLA-DQA1*01:02. Notably, we confirmed the previously reported associations with HLA-DQA1*01:02 and peanut allergy risk in the absence of oral peanut protein exposure. Interaction between HLA and presence or absence of exposure to peanut in an allergen- and epitope-specific manner implicates a mechanism of antigen recognition that is fundamental to driving immune responses related to allergy risk or protection.
Asunto(s)
Albuminas 2S de Plantas/inmunología , Alelos , Formación de Anticuerpos , Antígenos de Plantas/inmunología , Arachis , Cadenas alfa de HLA-DQ , Inmunoglobulina G/inmunología , Hipersensibilidad al Cacahuete , Formación de Anticuerpos/genética , Formación de Anticuerpos/inmunología , Niño , Femenino , Cadenas alfa de HLA-DQ/genética , Cadenas alfa de HLA-DQ/inmunología , Humanos , Masculino , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/inmunologíaRESUMEN
The rising incidence of food allergy in children underscores the importance of environmental exposures; however, genetic factors play a major role. How the environment and genetics interact to cause food allergy remains unclear. The landmark Learning Early About Peanut Allergy (LEAP) clinical trial established that early peanut introduction protects high-risk infants, consistent with the tolerizing effects of gut exposure. In this issue of the JCI, Kanchan et al. leveraged the LEAP trial data to examine molecular genetic mechanisms of early sensitization. A previously identified HLA risk allele for peanut allergy (DQA1*01:02) was associated with peanut-specific IgG4 levels in consumers. Notably, IgG4 antibodies likely provide protection by reducing the binding of allergen to IgE. The association of the same allele with peanut allergy in avoiders while potentially conferring protection in consumers reinforces the need to integrate genetic information toward a personalized therapeutic strategy for the best outcome in addressing food allergies.
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Arachis , Hipersensibilidad al Cacahuete , Alelos , Alérgenos , Arachis/genética , Arachis/inmunología , Niño , Cadenas alfa de HLA-DQ , Humanos , Lactante , Hipersensibilidad al Cacahuete/genéticaRESUMEN
Food allergy affects an estimated 8% of children in the United States. Oral immunotherapy (OIT) is a recently approved treatment, with outcomes ranging from sustained tolerance to food allergens to no apparent benefit. The immunological underpinnings that influence clinical outcomes of OIT remain largely unresolved. Using single-cell RNA-Seq and paired T cell receptor α/ß (TCRα/ß) sequencing, we assessed the transcriptomes of CD154+ and CD137+ peanut-reactive T helper (Th) cells from 12 patients with peanut allergy longitudinally throughout OIT. We observed expanded populations of cells expressing Th1, Th2, and Th17 signatures that further separated into 6 clonally distinct subsets. Four of these subsets demonstrated a convergence of TCR sequences, suggesting antigen-driven T cell fates. Over the course of OIT, we observed suppression of Th2 and Th1 gene signatures in effector clonotypes but not T follicular helper-like (Tfh-like) clonotypes. Positive outcomes were associated with stronger suppression of Th2 signatures in Th2A-like cells, while treatment failure was associated with the expression of baseline inflammatory gene signatures that were present in Th1 and Th17 cell populations and unmodulated by OIT. These results demonstrate that differential clinical responses to OIT are associated with both preexisting characteristics of peanut-reactive CD4+ T cells and suppression of a subset of Th2 cells.
Asunto(s)
Arachis , Desensibilización Inmunológica , Hipersensibilidad al Cacahuete , RNA-Seq , Receptores de Antígenos de Linfocitos T alfa-beta , Análisis de la Célula Individual , Linfocitos T Colaboradores-Inductores/inmunología , Niño , Femenino , Humanos , Masculino , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/inmunología , Hipersensibilidad al Cacahuete/terapia , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores de Antígenos de Linfocitos T alfa-beta/inmunologíaRESUMEN
BACKGROUND: The etiology of food allergy is poorly understood; mouse models are powerful systems to discover immunologic pathways driving allergic disease. C3H/HeJ mice are a widely used model for the study of peanut allergy because, unlike C57BL/6 or BALB/c mice, they are highly susceptible to oral anaphylaxis. However, the immunologic mechanism of this strain's susceptibility is not known. OBJECTIVE: We aimed to determine the mechanism underlying the unique susceptibility to anaphylaxis in C3H/HeJ mice. We tested the role of deleterious Toll-like receptor 4 (Tlr4) or dedicator of cytokinesis 8 (Dock8) mutations in this strain because both genes have been associated with food allergy. METHODS: We generated C3H/HeJ mice with corrected Dock8 or Tlr4 alleles and sensitized and challenged them with peanut. We then characterized the antibody response to sensitization, anaphylaxis response to both oral and systemic peanut challenge, gut microbiome, and biomarkers of gut permeability. RESULTS: In contrast to C3H/HeJ mice, C57BL/6 mice were resistant to anaphylaxis after oral peanut challenge; however, both strains undergo anaphylaxis with intraperitoneal challenge. Restoring Tlr4 or Dock8 function in C3H/HeJ mice did not protect from anaphylaxis. Instead, we discovered enhanced gut permeability resulting in ingested allergens in the bloodstream in C3H/HeJ mice compared to C57BL/6 mice, which correlated with an increased number of goblet cells in the small intestine. CONCLUSIONS: Our work highlights the potential importance of gut permeability in driving anaphylaxis to ingested food allergens; it also indicates that genetic loci outside of Tlr4 and Dock8 are responsible for the oral anaphylactic susceptibility of C3H/HeJ mice.
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Mucosa Intestinal/metabolismo , Anafilaxis Cutánea Pasiva , Hipersensibilidad al Cacahuete/metabolismo , Administración Oral , Animales , Arachis/inmunología , Modelos Animales de Enfermedad , Femenino , Microbioma Gastrointestinal , Predisposición Genética a la Enfermedad , Factores de Intercambio de Guanina Nucleótido/genética , Masculino , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Mutación , Anafilaxis Cutánea Pasiva/genética , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/microbiología , Permeabilidad , Especificidad de la Especie , Receptor Toll-Like 4/genéticaRESUMEN
Peanut allergy can result in life-threatening reactions and is a major public health concern. Oral immunotherapy (OIT) induces desensitization to food allergens through administration of increasing amounts of allergen. To dissect peanut-specific immunoglobulin E (IgE) and IgG responses in subjects undergoing OIT, we have developed AllerScan, a method that leverages phage-display and next-generation sequencing to identify the epitope targets of peanut-specific antibodies. We observe a striking diversification and boosting of the peanut-specific IgG repertoire after OIT and a reduction in pre-existing IgE levels against individual epitopes. High-resolution epitope mapping reveals shared recognition of public epitopes in Ara h 1, 2, 3, and 7. In individual subjects, OIT-induced IgG specificities overlap extensively with IgE and exhibit strikingly similar antibody footprints, suggesting related clonal lineages or convergent evolution of peanut-specific IgE and IgG B cells. Individual differences in epitope recognition identified via AllerScan could inform safer and more effective personalized immunotherapy.
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Desensibilización Inmunológica/métodos , Mapeo Epitopo/métodos , Epítopos/química , Inmunoglobulina E/sangre , Inmunoglobulina G/sangre , Omalizumab/uso terapéutico , Hipersensibilidad al Cacahuete/terapia , Albuminas 2S de Plantas/administración & dosificación , Albuminas 2S de Plantas/química , Antígenos de Plantas/administración & dosificación , Antígenos de Plantas/química , Arachis/química , Arachis/inmunología , Linfocitos B/inmunología , Linfocitos B/patología , Estudios de Casos y Controles , Epítopos/inmunología , Secuenciación de Nucleótidos de Alto Rendimiento , Ensayos Analíticos de Alto Rendimiento , Humanos , Proteínas de la Membrana/administración & dosificación , Proteínas de la Membrana/química , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/inmunología , Hipersensibilidad al Cacahuete/patología , Biblioteca de Péptidos , Proteínas de Plantas/administración & dosificación , Proteínas de Plantas/química , Medicina de Precisión , Proteínas de Almacenamiento de SemillasRESUMEN
BACKGROUND: Peanut oral immunotherapy (POIT) has provided desensitization to peanut allergic individuals. Limited immunological evaluation exists during the first 24-weeks of POIT. OBJECTIVE: Regulatory T-cells (Tregs) are antigen induced immunosuppressive T-cells important in establishing tolerance. Delineation of early immunologic changes contributing to the development of peanut desensitization would help clarify the mechanism of action in POIT. We performed single-cell RNA sequencing (scRNAseq) on Tregs in pediatric subjects undergoing POIT during the first 24-weeks of therapy to evaluate early immunological changes induced by POIT. METHODS: PBMC samples from peanut allergic subjects between 5 and 12 years of age enrolled in a Phase 1/2a POIT study were collected and analyzed at 0, 6, and 24-weeks after POIT initiation and samples were compared to healthy non-peanut allergic controls. Tregs were enriched from PBMCs and scRNAseq analysis performed. Cell Ranger 3.1.0 (10× Genomics) was utilized to identify cell clusters and differentially expressed genes, and results were analyzed with Seurat suite version 3.0.0. RESULTS: Gene analysis revealed 10 major clusters corresponding to different cell types observed to change during POIT when compared to the healthy, non-peanut-allergic state. scRNAseq analysis of Tregs revealed strong CD3G expression correlating with gdTregs. scRNAseq analysis of gdTregs revealed dynamic changes occurring within the first 6-weeks of treatment and cell frequencies of naïve and memory gdTregs at 24-weeks of treatment reducing to levels similar to healthy controls. Analysis of transcriptomic cell identity analysis using SingleR showed gene expression in gdTregs similar to healthy control after 24-weeks of POIT treatment. scRNAseq analysis revealed alterations in gene expression for memory and naïve gdTregs during this timeframe. Specifically, expression of OX40R (TNFRSF4), GITR (TNFRSF18), TGFB1, CTLA4, ISG20, CD69 were upregulated in memory gdTregs compared to naive gdTregs by 24-weeks of POIT, while IL7R and SELL were downregulated in memory gdTregs compared to naïve gdTregs. CONCLUSIONS: There are specific expression profiles of peripheral naïve and mature gdTreg cells in peanut allergic patients undergoing POIT in the first 24-weeks of treatment implicating pathways involved in maintenance of immune homeostasis. gdTreg cells may contribute to the tolerogenic effect of POIT within the first 24-weeks of POIT treatment. These findings suggest that gdTregs cells may be an early marker of desensitization in subjects undergoing POIT.
Asunto(s)
Arachis/inmunología , Desensibilización Inmunológica/métodos , Genes Codificadores de la Cadena delta de los Receptores de Linfocito T , Genes Codificadores de la Cadena gamma de los Receptores de Linfocito T , Hipersensibilidad al Cacahuete/terapia , Linfocitos T Reguladores/inmunología , Administración Oral , Alérgenos/administración & dosificación , Niño , Preescolar , Humanos , Memoria Inmunológica , Familia de Multigenes , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/inmunología , RNA-Seq , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Análisis de la Célula Individual , Factores de Tiempo , TranscriptomaRESUMEN
DNA methylation (DNAm) has been shown to play a role in mediating food allergy; however, the mechanism by which it does so is poorly understood. In this study, we used targeted next-generation bisulfite sequencing to evaluate DNAm levels in 125 targeted highly informative genomic regions containing 602 CpG sites on 70 immune-related genes to understand whether DNAm can differentiate peanut allergy (PA) versus nonallergy (NA). We found PA-associated DNAm signatures associated with 12 genes (7 potentially novel to food allergy, 3 associated with Th1/Th2, and 2 associated with innate immunity), as well as DNAm signature combinations with superior diagnostic potential compared with serum peanut-specific IgE for PA versus NA. Furthermore, we found that, following peanut protein stimulation, peripheral blood mononuclear cell (PBMCs) from PA participants showed increased production of cognate cytokines compared with NA participants. The varying responses between PA and NA participants may be associated with the interaction between the modification of DNAm and the interference of environment. Using Euclidean distance analysis, we found that the distances of methylation profile comprising 12 DNAm signatures between PA and NA pairs in monozygotic (MZ) twins were smaller than those in randomly paired genetically unrelated individuals, suggesting that PA-related DNAm signatures may be associated with genetic factors.
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Metilación de ADN , Epigénesis Genética , Hipersensibilidad al Cacahuete/genética , Islas de CpG , Citocinas/inmunología , Perfilación de la Expresión Génica , Humanos , Células Th2/inmunologíaAsunto(s)
Hipersensibilidad a los Alimentos/sangre , Proteína 1 Similar al Receptor de Interleucina-1/sangre , Niño , Preescolar , Hipersensibilidad al Huevo/sangre , Hipersensibilidad al Huevo/genética , Femenino , Hipersensibilidad a los Alimentos/genética , Humanos , Lactante , Proteína 1 Similar al Receptor de Interleucina-1/genética , Masculino , Hipersensibilidad a la Leche/sangre , Hipersensibilidad a la Leche/genética , Hipersensibilidad al Cacahuete/sangre , Hipersensibilidad al Cacahuete/genética , Polimorfismo de Nucleótido Simple , Isoformas de Proteínas/sangreRESUMEN
Oral immunotherapy (OIT) can successfully desensitize allergic individuals to offending foods such as peanut. Our recent clinical trial (NCT02103270) of peanut OIT allowed us to monitor peanut-specific CD4+ T cells, using MHC-peptide Dextramers, over the course of OIT. We used a single-cell targeted RNAseq assay to analyze these cells at 0, 12, 24, 52, and 104 weeks of OIT. We found a transient increase in TGFß-producing cells at 52 weeks in those with successful desensitization, which lasted until 117 weeks. We also performed clustering and identified 5 major clusters of Dextramer+ cells, which we tracked over time. One of these clusters appeared to be anergic, while another was consistent with recently described TFH13 cells. The other 3 clusters appeared to be Th2 cells by their coordinated production of IL-4 and IL-13, but they varied in their expression of STAT signaling proteins and other markers. A cluster with high expression of STAT family members also showed a possible transient increase at week 24 in those with successful desensitization. Single cell TCRαß repertoire sequences were too diverse to track clones over time. Together with increased TGFß production, these changes may be mechanistic predictors of successful OIT that should be further investigated.
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Alérgenos/inmunología , Arachis/inmunología , Linfocitos T CD4-Positivos/inmunología , Desensibilización Inmunológica , Hipersensibilidad al Cacahuete , Administración Oral , Adolescente , Adulto , Niño , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/inmunología , Hipersensibilidad al Cacahuete/terapia , RNA-Seq , Transcripción Genética , Factor de Crecimiento Transformador beta1/genética , Adulto JovenRESUMEN
Food allergy is a potentially fatal disease affecting 8% of children and has become increasingly common in the past two decades. Despite the prevalence and severe nature of the disease, the mechanisms underlying sensitization remain to be further elucidated. The Collaborative Cross is a genetically diverse panel of inbred mice that were specifically developed to study the influence of genetics on complex diseases. Using this panel of mouse strains, we previously demonstrated CC027/GeniUnc mice, but not C3H/HeJ mice, develop peanut allergy after oral exposure to peanut in the absence of a Th2-skewing adjuvant. Here, we investigated factors associated with sensitization in CC027/GeniUnc mice following oral exposure to peanut, walnut, milk, or egg. CC027/GeniUnc mice mounted antigen-specific IgE responses to peanut, walnut and egg, but not milk, while C3H/HeJ mice were not sensitized to any antigen. Naïve CC027/GeniUnc mice had markedly lower total fecal IgA compared to C3H/HeJ, which was accompanied by stark differences in gut microbiome composition. Sensitized CC027/GeniUnc mice had significantly fewer CD3+ T cells but higher numbers of CXCR5+ B cells and T follicular helper cells in the mesenteric lymph nodes compared to C3H/HeJ mice, which is consistent with their relative immunoglobulin production. After oral challenge to the corresponding food, peanut- and walnut-sensitized CC027/GeniUnc mice experienced anaphylaxis, whereas mice exposed to milk and egg did not. Ara h 2 was detected in serum collected post-challenge from peanut-sensitized mice, indicating increased absorption of this allergen, while Bos d 5 and Gal d 2 were not detected in mice exposed to milk and egg, respectively. Machine learning on the change in gut microbiome composition as a result of food protein exposure identified a unique signature in CC027/GeniUnc mice that experienced anaphylaxis, including the depletion of Akkermansia. Overall, these results demonstrate several factors associated with enteral sensitization in CC027/GeniUnc mice, including diminished total fecal IgA, increased allergen absorption and altered gut microbiome composition. Furthermore, peanuts and tree nuts may have inherent properties distinct from milk and eggs that contribute to allergy.
Asunto(s)
Alérgenos/inmunología , Heces/microbiología , Microbioma Gastrointestinal/inmunología , Inmunoglobulina A/inmunología , Absorción Intestinal/inmunología , Hipersensibilidad al Cacahuete , Alérgenos/genética , Animales , Microbioma Gastrointestinal/genética , Predisposición Genética a la Enfermedad , Inmunoglobulina A/genética , Absorción Intestinal/genética , Ratones , Ratones Transgénicos , Hipersensibilidad al Cacahuete/genética , Hipersensibilidad al Cacahuete/inmunología , Hipersensibilidad al Cacahuete/microbiologíaRESUMEN
BACKGROUND: Unexpected allergic reactions to peanut are the most common cause of fatal food-related anaphylaxis. Mechanisms underlying the variable severity of peanut-allergic reactions remain unclear. OBJECTIVES: We sought to expand mechanistic understanding of reaction severity in peanut allergy. METHODS: We performed an integrated transcriptomic and epigenomic study of peanut-allergic children as they reacted in vivo during double-blind, placebo-controlled peanut challenges. We integrated whole-blood transcriptome and CD4+ T-cell epigenome profiles to identify molecular signatures of reaction severity (ie, how severely a peanut-allergic child reacts when exposed to peanut). A threshold-weighted reaction severity score was calculated for each subject based on symptoms experienced during peanut challenge and the eliciting dose. Through linear mixed effects modeling, network construction, and causal mediation analysis, we identified genes, CpGs, and their interactions that mediate reaction severity. Findings were replicated in an independent cohort. RESULTS: We identified 318 genes with changes in expression during the course of reaction associated with reaction severity, and 203 CpG sites with differential DNA methylation associated with reaction severity. After replicating these findings in an independent cohort, we constructed interaction networks with the identified peanut severity genes and CpGs. These analyses and leukocyte deconvolution highlighted neutrophil-mediated immunity. We identified NFKBIA and ARG1 as hubs in the networks and 3 groups of interacting key node CpGs and peanut severity genes encompassing immune response, chemotaxis, and regulation of macroautophagy. In addition, we found that gene expression of PHACTR1 and ZNF121 causally mediates the association between methylation at corresponding CpGs and reaction severity, suggesting that methylation may serve as an anchor upon which gene expression modulates reaction severity. CONCLUSIONS: Our findings enhance current mechanistic understanding of the genetic and epigenetic architecture of reaction severity in peanut allergy.
Asunto(s)
Anafilaxia/genética , Linfocitos T CD4-Positivos/fisiología , Hipersensibilidad al Cacahuete/genética , Adolescente , Alérgenos/inmunología , Arachis/inmunología , Niño , Estudios de Cohortes , Metilación de ADN , Progresión de la Enfermedad , Epigénesis Genética , Femenino , Redes Reguladoras de Genes , Humanos , Inmunidad/genética , Inmunización , Masculino , TranscriptomaAsunto(s)
Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Hipersensibilidad al Cacahuete/genética , Alérgenos/inmunología , Arachis/inmunología , Niño , Femenino , Sitios Genéticos , Predisposición Genética a la Enfermedad , Humanos , Inmunoglobulina E/inmunología , Masculino , RiesgoRESUMEN
Baseline eosinophils reside in the gastrointestinal tract; however, in several allergic disorders, excessive eosinophils accumulate in the blood as well in the tissues. Recently, we showed in vitro that interleukin (IL)-18 matures and transforms IL-5-generated eosinophils into the pathogenic eosinophils that are detected in human allergic diseases. To examine the role of local induction of IL-18 in promoting eosinophil-associated intestinal disorders, we generated enterocyte IL-18-overexpressing mice using the rat intestinal fatty acid-binding promoter (Fabpi) and analysed tissue IL-18 overexpression and eosinophilia by performing real-time polymerase chain reaction, Enzyme-Linked Immunosorbent Assay and anti-major basic protein immunostaining. Herein we show that Fabpi-IL-18 mice display highly induced IL-18 mRNA and protein in the jejunum. IL-18 overexpression in enterocytes promotes marked increases of eosinophils in the blood and jejunum. Our analysis shows IL-18 overexpression in the jejunum induces a specific population of CD101+ CD274+ tissue eosinophils. Additionally, we observed comparable tissue eosinophilia in IL-13-deficient-Fabpi-IL-18 mice, and reduced numbers of tissue eosinophils in eotaxin-deficient-Fabpi-IL-18 and IL-5-deficient-Fabpi-IL-18 mice compared with Fabpi-IL-18 transgenic mice. Notably, jejunum eosinophilia in IL-5-deficient-Fabpi-IL-18 mice is significantly induced compared with wild-type mice, which indicates the direct role of induced IL-18 in the tissue accumulation of eosinophils and mast cells. Furthermore, we also found that overexpression of IL-18 in the intestine promotes eosinophil-associated peanut-induced allergic responses in mice. Taken together, we provide direct in vivo evidence that induced expression of IL-18 in the enterocytes promotes eotaxin-1, IL-5 and IL-13 independent intestinal eosinophilia, which signifies the clinical relevance of induced IL-18 in eosinophil-associated gastrointestinal disorders (EGIDs) to food allergens.