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Background In a previously reported Co FAR study, 55 subjects with egg allergy underwent randomized, placebo-controlled egg oral immunotherapy ( eOIT). Active treatment induced desensitization in most and sustained unresponsiveness ( SU) in a smaller subset. We hypothesized that component-resolved analysis of IgE, IgG4, IgA, IgA1, and IgA2 may identify potential biomarkers of SU in OIT subjects. Methods Longitudinal samples for 51 egg-allergic subjects (37 active and 14 placebo) were available. Egg white ( EW)-, ovalbumin ( OVA)-, and ovomucoid ( OVM)-specific levels of IgA, IgA1, and IgA2 were quantified by ELISA. IgE and IgG4 to these antigens were quantified using Immuno CAP ®. Clinical responders achieved SU to egg; all others were considered nonresponders. Between-group comparisons were made among active and placebo, as well as responders and nonresponders. Results No placebo subjects achieved responder status. Through month 48, among the 37 active subjects, baseline IgE- OVM was lower in responders (median 3.97 kU/l, n = 19) than in nonresponders (10.9 kU/l, n = 18, P = 0.010). Logistic regression analysis revealed that lower baseline IgE- EW ( P = 0.038), IgE- OVM ( P = 0.032), and a higher IgG4/IgE- OVM ratio ( P = 0.013) were associated with clinical response. Relative increases in IgG4- EW, IgA- EW, and IgA2- EW were observed in responders ( P = 0.024, 0.024, and 0.029, respectively). IgG4/IgE, IgA/IgE, and IgA2/IgE ratios for EW and IgA/IgE ratio for OVA were found to be significantly elevated among responders ( P = 0.004, 0.009, 0.028, and 0.008, respectively). Conclusions Increased IgG4- EW, IgA- EW, and IgA2- EW during eOIT are associated with clinical response to eOIT. Lower pretreatment IgE- EW and IgE- OVM are also associated with SU. Future studies are needed to evaluate and validate these potential biomarkers. [ABSTRACT FROM AUTHOR]

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., (Copyright © 2024 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Objectives: Peanut allergy in children is a population health problem. Evidence suggests early peanut introduction (EPI) for infants can reduce the development of peanut allergy. Primary care settings have not widely adopted guidelines recommending EPI. Peanut allergy prevention depends on primary care providers incorporating EPI guidelines into well-child check (WCC) encounters. We aimed to improve guideline adherence in a primary care setting by implementing a bundle of clinical decision support (CDS) tools., Methods: Using quality improvement methodology, the team developed a standardized work protocol and CDS tools within an electronic medical record (EMR) at 4, 6, and 9-month WCC encounters. The team executed changes and modifications through plan-do-study-act cycles and analyzed results with statistical process control charts., Results: We collected data from 445 WCC encounters from baseline through sustainability. EMR documentation of EPI guidance at 4, 6, and 9-month WCCs shifted from 13.9% to 83.5% over 12 months. Provider adoption of smart lists and templates increased from 2% to 73%, the distribution of home peanut introduction handouts increased from 5.2% to 54.1%, and caregiver-reported peanut ingestion increased from 0% to 34.6%. Diphtheria-tetanus-acellular pertussis vaccination rates remained at 100% for 6-month visits, and patient in-room time remained at 65 minutes., Conclusions: Quality improvement methodology improved documentation of EPI guidance and increased reported peanut ingestion at routine WCC encounters without impacting other measures. Broader use of bundled CDS tools and EMR standardization could further improve guideline adherence and increase early peanut introduction to prevent peanut allergy in infants., (Copyright © 2023 by the American Academy of Pediatrics.)

Background: Oral and sublingual immunotherapies for peanut allergy have demonstrated efficacy in small clinical trials; however, mechanisms and biomarkers correlating with clinical outcomes remain elusive. Previous studies have demonstrated a role for IgG in post-OIT plasma in the suppression of IgE-mediated mast cell reactions., Objective: The aim of this study was to characterize the role that peanut oral and sublingual immunotherapy-induced plasma factors play in the inhibition of ex vivo basophil activation and whether inhibitory activity is associated with clinical outcomes., Methods: Plasma samples from subjects on placebo, peanut oral immunotherapy (OIT) or peanut sublingual immunotherapy (SLIT), and IgG-depleted plasma or the IgG fraction were incubated with sensitized basophils, and the inhibition of basophil activation following stimulation with peanut extract was measured. Basophil inhibition results were compared between the two routes of immunotherapy, time on treatment and clinical outcomes., Results: Plasma from subjects after 12 months of active peanut OIT, but not placebo, inhibits basophil activation ex vivo. Depletion of IgG abrogated the blocking effect of OIT plasma, while the IgG fraction substantially blocked basophil activation. Basophils are inhibited to a similar extent by undiluted OIT and SLIT plasma; however, diluted OIT plasma from the time of desensitization challenge inhibited basophils more than diluted SLIT plasma from time of desensitization challenge. Plasma from subjects who experienced sustained unresponsiveness following OIT inhibited basophils to a greater extent than plasma from subjects who were desensitized, but this was not true for SLIT., Conclusions and Clinical Relevance: Peanut immunotherapy induces IgG-dependent functional changes in plasma that are associated with OIT but not SLIT clinical outcomes. Understanding the mechanisms of peanut OIT and SLIT may help derive informative biomarkers., (© 2018 John Wiley & Sons Ltd.)

Background: Improved animal models are needed to understand the genetic and environmental factors that contribute to food allergy., Objective: We sought to assess food allergy phenotypes in a genetically diverse collection of mice., Methods: We selected 16 Collaborative Cross (CC) mouse strains, as well as the classic inbred C57BL/6J, C3H/HeJ, and BALB/cJ strains, for screening. Female mice were sensitized to peanut intragastrically with or without cholera toxin and then challenged with peanut by means of oral gavage or intraperitoneal injection and assessed for anaphylaxis. Peanut-specific immunoglobulins, T-cell cytokines, regulatory T cells, mast cells, and basophils were quantified., Results: Eleven of the 16 CC strains had allergic reactions to intraperitoneal peanut challenge, whereas only CC027/GeniUnc mice reproducibly experienced severe symptoms after oral food challenge (OFC). CC027/GeniUnc, C3H/HeJ, and C57BL/6J mice all mounted a T H 2 response against peanut, leading to production of IL-4 and IgE, but only the CC027/GeniUnc mice reacted to OFC. Orally induced anaphylaxis in CC027/GeniUnc mice was correlated with serum levels of Ara h 2 in circulation but not with allergen-specific IgE or mucosal mast cell protease 1 levels, indicating systemic allergen absorption is important for anaphylaxis through the gastrointestinal tract. Furthermore, CC027/GeniUnc, but not C3H/HeJ or BALB/cJ, mice can be sensitized in the absence of cholera toxin and react on OFC to peanut., Conclusions: We have identified and characterized CC027/GeniUnc mice as a strain that is genetically susceptible to peanut allergy and prone to severe reactions after OFC. More broadly, these findings demonstrate the untapped potential of the CC population in developing novel models for allergy research., (Copyright © 2018 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Mechanisms underlying oral immunotherapy (OIT) are unclear and the effects on immune cells at varying maintenance doses are unknown., Objective: We aimed to determine the immunologic changes caused by peanut OIT in preschool aged children and determine the effect on these immune responses in groups ingesting low or high-dose peanut OIT (300 mg or 3000 mg, respectively) as maintenance therapy., Methods: Blood was drawn at several time-points throughout the OIT protocol and PBMCs isolated and cultured with peanut antigens. Secreted cytokines were quantified via multiplex assay, whereas Treg and peanut-responsive CD4 T cells were studied with flow cytometry. Basophil activation assays were also conducted., Results: Th2-, Th1-, Th9- and Tr1-type cytokines decreased over the course of OIT in groups on high- and low-dose OIT. There were no significant differences detected in cytokine changes between the high- and low-dose groups. The initial increase in both the number of peanut-responsive CD4 T cells and the number of Tregs was transient and no significant differences were found between groups. Basophil activation following peanut stimulation was decreased over the course of OIT and associated with increased peanut-IgG4/IgE ratios. No differences were found between high- and low-dose groups in basophil activation at the time of desensitization or sustained unresponsiveness oral food challenges., Conclusions and Clinical Relevance: Peanut OIT leads to decreases in pro-allergic cytokines, including IL-5, IL-13, and IL-9 and decreased basophil activation. No differences in T cell or basophil responses were found between subjects on low or high-dose maintenance OIT, which has implications for clinical dosing strategies., (© 2018 John Wiley & Sons Ltd.)

B-cell receptors (BCRs) play a critical role in adaptive immunity as they generate highly diverse immunoglobulin repertoires to recognize a wide variety of antigens. To better understand immune responses, it is critically important to establish a quantitative and rapid method to analyze BCR repertoire comprehensively. Here, we developed "Bcrip", a novel approach to characterize BCR repertoire by sequencing millions of BCR cDNA using next-generation sequencer. Using this method and quantitative real-time PCR, we analyzed expression levels and repertoires of BCRs in a total of 17 peanut allergic subjects' peripheral blood samples before and after receiving oral immunotherapy (OIT) or placebo. By our methods, we successfully identified all of variable (V), joining (J), and constant (C) regions, in an average of 79.1% of total reads and 99.6% of these VJC-mapped reads contained the C region corresponding to the isotypes that we aimed to analyze. In the 17 peanut allergic subjects' peripheral blood samples, we observed an oligoclonal enrichment of certain immunoglobulin heavy chain alpha (IGHA) and IGH gamma (IGHG) clones (P = 0.034 and P = 0.027, respectively) in peanut allergic subjects after OIT. This newly developed BCR sequencing and analysis method can be applied to investigate B-cell repertoires in various research areas, including food allergies as well as autoimmune and infectious diseases.

Animal models of disease enable the study of the pathology, biomarkers, and treatments for the disease being studied. These models become particularly useful in the study of diseases, such as peanut allergy, that currently have no FDA-approved therapy options. Here, we describe a mouse model of peanut allergy using a peanut extract and cholera toxin that can be applied to both BALB/c and C3H/HeJ mouse strains. Sensitization is induced through the gastrointestinal tract resulting in elevated levels of peanut-specific IgE and anaphylaxis upon challenge with peanut proteins. This model has been used to study the cells and molecules involved in the development of peanut allergy and to evaluate novel immunotherapy approaches and the underlying mechanisms of immunotherapy. Potential utilities of this model are numerous and may include studies on microbial influences on peanut allergy and discovery of biomarkers of anaphylaxis.

Background: Oral immunotherapy (OIT) is an investigational therapeutic approach for the treatment of food allergies. Characterization of the drug product used in oral immunotherapy trials for peanut allergy has not been reported., Objective: To quantify relative amounts of the major peanut allergens and microbial load present in peanut flour used in OIT trials and assess whether these parameters change over a 12-month period. We also anticipate that this report will serve as a guide for investigators seeking to conduct OIT trials under Food and Drug Administration-approved Investigational New Drug applications., Methods: Densitometric scanning of Ara h 1 and Ara h 2 resolved on SDS-PAGE gels was used to assess allergen content in peanut flour extracts. Microbial testing was conducted on peanut flour under US Pharmacopeia guidelines for the presence of Escherichia coli, salmonella, yeast, mold, and total aerobic bacteria. In addition, aflatoxin was quantified in peanut flour. Reported results were obtained from 4 unique lots of peanut flour., Results: Relative amounts of the major peanut allergens were similar between different lots of peanut flour and remained stable over a 12-month period. E coli and salmonella were absent from all lots of flour. Yeast, mold, total aerobic bacteria, and aflatoxin were within established US Pharmacopeia guidelines on all lots tested and remained within the criteria over a 12-month period., Conclusions: Peanut flour used as a drug product contains the major peanut allergens and has low levels of potentially harmful microbes. Both these parameters remain stable over a 12-month period., (Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Doxorubicin (DOXO) induces significant, but transient, increases in apoptosis in the stem cell zone of the jejunum, followed by mucosal damage involving a decrease in crypt proliferation, crypt number, and villus height. The gastrointestinal tract is home to a vast population of commensal bacteria and numerous studies have demonstrated a symbiotic relationship between intestinal bacteria and intestinal epithelial cells (IEC) in maintaining homeostatic functions of the intestine. However, whether enteric bacteria play a role in DOXO-induced damage is not well understood. We hypothesized that enteric bacteria are necessary for induction of apoptosis and damage associated with DOXO treatment. Conventionally raised (CONV) and germ free (GF) mice were given a single injection of DOXO, and intestinal tissue was collected at 6, 72, and 120 h after treatment and from no treatment (0 h) controls. Histology and morphometric analyses quantified apoptosis, mitosis, crypt depth, villus height, and crypt density. Immunostaining for muc2 and lysozyme evaluated Paneth cells, goblet cells or dual stained intermediate cells. DOXO administration induced significant increases in apoptosis in jejunal epithelium regardless of the presence of enteric bacteria; however, the resulting injury, as demonstrated by statistically significant changes in crypt depth, crypt number, and proliferative cell number, was dependent upon the presence of enteric bacteria. Furthermore, we observed expansion of Paneth and goblet cells and presence of intermediate cells only in CONV and not GF mice. These findings provide evidence that manipulation and/or depletion of the enteric microbiota may have clinical significance in limiting chemotherapy-induced mucositis.

Food allergies have increased in prevalence over the past 20 years, now becoming an important public health concern. Although there are no therapies currently available for routine clinical care, recent reports have indicated that immunotherapies targeting the mucosal immune system may be effective. Oral immunotherapy is conducted by administering small, increasing amounts of food allergen; it has shown promise for desensitizing individuals with peanut, egg, or milk allergies. Sublingual immunotherapy also desensitizes allergic patients to foods-two major studies have examined the effects of sublingual immunotherapy in subjects with peanut allergies. We review the complex nature of IgE-mediated food allergies and the therapies being evaluated in clinical trials. We focus on the diagnosis and management of food allergies and investigational therapies.