Fast impedimetric immunosensing of IgGs associated with peanut and hazelnut allergens
Food allergies trigger a variety of clinical adverse symptoms and clinical evidence suggests that the presence of food allergy-related IgG can be helpful in the diagnosis when analyzed at the peptide-epitope level. To validate and select the peptides based on their specificity toward hazelnut or peanut epitopes, the authors of this study developed a silicon-based microchip coupled with click-chemistry bound peptides identified by the Fraunhofer Institute for Cell Therapy and Immunology. Peptides related to hazelnut and peanut allergies were identified and used to develop a silicon-based microchip. Peptides were coupled with click-chemistry to the sensor surface. The immunosensor was developed by electrografting diazotized amino phenylacetic acid and subsequently, dibenzocyclooctyne-amine (DBCO-NH2) was used as click-chemistry to allow coupling of the peptides with a C-terminal linker and azide structure. Energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy (EIS), and fluorescence microscopy techniques have been used to analyze the bio-functionalization of the developed electrode. The peptide-epitope recognition was studied for seven allergen-derived peptides. The electrochemical responses were studied with sera from rabbits immunized with hazelnut and peanut powder. The microchips functionalized with the chosen peptides (peanut peptides T12 and EO13 and hazelnut peptides S4 and EO14 with an RSD of 4%, 3%, 9%, and 1% respectively) demonstrated their ability to specifically detect prevalent anti-nut related IgGs in rabbit sera in a range of dilutions from 1:500000 (0.0002%) until 1:50000 (0.002%). In addition, the other peptides showed promising differentiation abilities which can be further studied to perform multivariable detection fingerprint of anti-allergens in blood sera. https://doi.org/10.1016/j.bios.2023.115612
Desensitization and remission after peanut sublingual immunotherapy in 1- to 4-year-old peanut-allergic children: A randomized, placebo-controlled trial
Background: Prior studies of peanut sublingual immunotherapy (SLIT) have suggested a potential advantage with younger age at treatment initiation. Objective: We studied the safety and efficacy of SLIT for peanut allergy in 1- to 4-year-old children. Methods: Peanut-allergic 1- to 4-year-old children were randomized to receive 4 mg peanut SLIT versus placebo. Desensitization was assessed by double-blind, placebo-controlled food challenge (DBPCFC) after 36 months of treatment. Participants desensitized to at least 443 mg peanut protein discontinued therapy for 3 months and then underwent DBPCFC to assess for remission. Biomarkers were measured at baseline and longitudinally during treatment. Results: Fifty participants (25 peanut SLIT, 25 placebo) with a median age of 2.4 years were enrolled across 2 sites. The primary end point of desensitization was met with actively treated versus placebo participants having a significantly greater median cumulative tolerated dose (4443 mg vs 143 mg), higher likelihood of passing the month 36 DBPCFC (60% vs 0), and higher likelihood of demonstrating remission (48% vs 0). The highest rate of desensitization and remission was seen in 1- to 2-year-olds, followed by 2- to 3-year-olds and 3- to 4-year-olds. Longitudinal changes in peanut skin prick testing, peanut-specific IgG4, and peanut-specific IgG4/IgE ratio were seen in peanut SLIT but not placebo participants. Oropharyngeal itching was more commonly reported by peanut SLIT than placebo participants. Skin, gastrointestinal, upper respiratory, lower respiratory, and multisystem adverse events were similar between treatment groups. Conclusion: Peanut SLIT safely induces desensitization and remission in 1- to 4-year-old children, with improved outcomes seen with younger age at initiation. Keywords: Peanut allergy; SLIT; desensitization; food allergy; food immunotherapy; remission; sublingual immunotherapy. https://doi.org/10.1016/j.jaci.2023.08.032
A phase II study of Bruton's tyrosine kinase inhibition for the prevention of anaphylaxis
BACKGROUND. IgE-mediated anaphylaxis is a potentially fatal systemic allergic reaction for which there are no currently FDA-approved preventative therapies. Bruton’s tyrosine kinase (BTK) is an essential enzyme for IgE-mediated signaling pathways and is an ideal pharmacologic target to prevent allergic reactions. In this open-label trial, we evaluated the safety and efficacy of acalabrutinib, a BTK inhibitor that is FDA approved to treat some B cell malignancies, in preventing clinical reactivity to peanut in adults with peanut allergy. METHODS. After undergoing graded oral peanut challenge to establish their baseline level of clinical reactivity, 10 patients had a 6-week rest period, then received 4 standard doses of 100 mg acalabrutinib twice daily and underwent repeat food challenge. The primary endpoint was the change in patients’ threshold dose of peanut protein to elicit an objective clinical reaction. RESULTS. At baseline, patients tolerated a median of 29 mg of peanut protein before objective clinical reaction. During subsequent food challenge on acalabrutinib, patients’ median tolerated dose significantly increased to 4,044 mg (range 444–4,044 mg). 7 patients tolerated the maximum protocol amount (4,044 mg) of peanut protein with no clinical reaction, and the other 3 patients’ peanut tolerance increased between 32- and 217-fold. 3 patients experienced a total of 4 adverse events that were considered to be possibly related to acalabrutinib; all events were transient and nonserious. CONCLUSION. Acalabrutinib pretreatment achieved clinically relevant increases in patients’ tolerance to their food allergen, thereby supporting the need for larger, placebo-controlled trials.
https://doi.org/10.1172/JCI172335
Phase 3 Trial of Epicutaneous Immunotherapy in Toddlers with Peanut Allergy
Background: No approved treatment for peanut allergy exists for children younger than 4 years of age, and the efficacy and safety of epicutaneous immunotherapy with a peanut patch in toddlers with peanut allergy are unknown. Methods: We conducted this phase 3, multicenter, double-blind, randomized, placebo-controlled trial involving children 1 to 3 years of age with peanut allergy confirmed by a double-blind, placebo-controlled food challenge. Patients who had an eliciting dose (the dose necessary to elicit an allergic reaction) of 300 mg or less of peanut protein were assigned in a 2:1 ratio to receive epicutaneous immunotherapy delivered by means of a peanut patch (intervention group) or to receive placebo administered daily for 12 months. The primary end point was a treatment response as measured by the eliciting dose of peanut protein at 12 months. Safety was assessed according to the occurrence of adverse events during the use of the peanut patch or placebo. Results: Of the 362 patients who underwent randomization, 84.8% completed the trial. The primary efficacy end point result was observed in 67.0% of children in the intervention group as compared with 33.5% of those in the placebo group (risk difference, 33.4 percentage points; 95% confidence interval, 22.4 to 44.5; P<0.001). Adverse events that occurred during the use of the intervention or placebo, irrespective of relatedness, were observed in 100% of the patients in the intervention group and 99.2% in the placebo group. Serious adverse events occurred in 8.6% of the patients in the intervention group and 2.5% of those in the placebo group; anaphylaxis occurred in 7.8% and 3.4%, respectively. Serious treatment-related adverse events occurred in 0.4% of patients in the intervention group and none in the placebo group. Treatment-related anaphylaxis occurred in 1.6% in the intervention group and none in the placebo group. Conclusions: In this trial involving children 1 to 3 years of age with peanut allergy, epicutaneous immunotherapy for 12 months was superior to placebo in desensitizing children to peanuts and increasing the peanut dose that triggered allergic symptoms. (Funded by DBV Technologies; EPITOPE ClinicalTrials.gov number, NCT03211247.).
https://doi.org/10.1056/NEJMoa2212895
Immune signatures predicting the clinical outcome of peanut oral immunotherapy: where we stand
Peanut allergy is a growing health concern that can cause mild to severe anaphylaxis as well as reduced quality of life in patients and their families. Oral immunotherapy is an important therapeutic intervention that aims to reshape the immune system toward a higher threshold dose reactivity and sustained unresponsiveness in some patients. From an immunological point of view, young patients, especially those under 3 years old, seem to have the best chance for therapy success. To date, surrogate markers for therapy duration and response are evasive. We provide a comprehensive overview of the current literature state regarding immune signatures evolving over the course of oral immunotherapy as well as baseline immune conditions prior to the initiation of treatment. Although research comparing clinical and immune traits in the first years of life vs. later stages across different age groups is limited, promising insights are available on immunological endotypes among peanut-allergic patients. The available data call for continued research to fill in gaps in knowledge, possibly in an integrated manner, to design novel precision health approaches for advanced therapeutic interventions in peanut allergy.
https://doi.org/10.3389/falgy.2023.1270344
Early Peanut Introduction in Infants: Improving Guideline Adherence With EMR Standardization
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.
https://doi.org/10.1542/peds.2023-062371
Fast impedimetric immunosensing of IgGs associated with peanut and hazelnut allergens
Food allergies trigger a variety of clinical adverse symptoms and clinical evidence suggests that the presence of food allergy-related IgG can be helpful in the diagnosis when analyzed at the peptide-epitope level. To validate and select the peptides based on their specificity toward hazelnut or peanut epitopes, the authors of this study developed a silicon-based microchip coupled with click-chemistry bound peptides identified by the Fraunhofer Institute for Cell Therapy and Immunology. Peptides related to hazelnut and peanut allergies were identified and used to develop a silicon-based microchip. Peptides were coupled with click-chemistry to the sensor surface. The immunosensor was developed by electrografting diazotized amino phenylacetic acid and subsequently, dibenzocyclooctyne-amine (DBCO-NH2) was used as click-chemistry to allow coupling of the peptides with a C-terminal linker and azide structure. Energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy (EIS), and fluorescence microscopy techniques have been used to analyze the bio-functionalization of the developed electrode. The peptide-epitope recognition was studied for seven allergen-derived peptides. The electrochemical responses were studied with sera from rabbits immunized with hazelnut and peanut powder. The microchips functionalized with the chosen peptides (peanut peptides T12 and EO13 and hazelnut peptides S4 and EO14 with an RSD of 4%, 3%, 9%, and 1% respectively) demonstrated their ability to specifically detect prevalent anti-nut related IgGs in rabbit sera in a range of dilutions from 1:500000 (0.0002%) until 1:50000 (0.002%). In addition, the other peptides showed promising differentiation abilities which can be further studied to perform multivariable detection fingerprint of anti-allergens in blood sera.
https://doi.org/10.1016/j.bios.2023.115612
EAACI guidelines on the diagnosis of IgE-mediated food allergy
This European Academy of Allergy and Clinical Immunology guideline provides recommendations for diagnosing IgE-mediated food allergy and was developed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. Food allergy diagnosis starts with an allergy-focused clinical history followed by tests to determine IgE sensitization, such as serum allergen-specific IgE (sIgE) and skin prick test (SPT), and the basophil activation test (BAT), if available. Evidence for IgE sensitization should be sought for any suspected foods. The diagnosis of allergy to some foods, such as peanut and cashew nut, is well supported by SPT and serum sIgE, whereas there are less data and the performance of these tests is poorer for other foods, such as wheat and soya. The measurement of sIgE to allergen components such as Ara h 2 from peanut, Cor a 14 from hazelnut and Ana o 3 from cashew can be useful to further support the diagnosis, especially in pollen-sensitized individuals. BAT to peanut and sesame can be used additionally. The reference standard for food allergy diagnosis is the oral food challenge (OFC). OFC should be performed in equivocal cases. For practical reasons, open challenges are suitable in most cases. Reassessment of food allergic children with allergy tests and/or OFCs periodically over time will enable reintroduction of food into the diet in the case of spontaneous acquisition of oral tolerance.
https://doi.org/10.1111/all.15902
Prevalence of tree nut allergy in Europe: A systematic review and meta-analysis
In 2014, the European Academy of Allergy and Clinical Immunology (EAACI) published the first systematic review that summarized the prevalence of food allergy (FA) and food sensitization in Europe for studies published 2000-2012. However, only summary estimates for tree nut allergy (TNA) were feasible in that work. In the current update of that systematic review, we summarized the prevalence of tree nut allergy/sensitization to individual tree nuts. Six databases were searched for relevant papers published 2012-2021 and 17 eligible studies were added to the 15 studies already identified between 2000 and 2012, giving a total of 32 studies. Of the investigated tree nuts, meta-analysis was possible for hazelnut, walnut, almond, and in few cases, for cashew, and Brazil nut. The lifetime self-reported prevalence was 0.8% (95% CI 0.5-1.1) for hazelnut and 0.4% (0.2-0.9) for walnut. The point self-reported prevalence was 4.0% (2.9-5.2) for hazelnut, 3.4% (2.0-4.9) for Brazil nut, 2.0% (1.1-2.9) for almond, and 1.8% (1.1-2.5) for walnut. Point prevalence of food challenge-confirmed TNA was 0.04% (0.0-0.1) for hazelnut and 0.02% (0.01-0.1) for walnut. Due to paucity of data, we could not identify any meaningful and consistent differences across age groups and European regions.
https://doi.org/10.1111/all.15905
Revised Swedish infant feeding guidelines are associated with earlier introduction of allergenic foods.
Background: Randomized controlled trials have demonstrated that early introduction of allergenic foods, such as peanut and egg, can reduce food allergy in high-risk children. Many international guidelines recommend introduction in the first year of life and accordingly, the Swedish National Food agency released updated guidelines in June 2019. Objective: To examine if the age at introduction and consumption frequency of allergenic foods have changed since the release of revised national guidelines on the introduction of solid foods in Sweden. Methods: Children born between June 2016 and December 2018 (n=1925) were compared to children born between June 2019 and April 2021 (n=1761) using data from the NorthPop Birth Cohort study. Data on food introduction, eczema and food allergy were prospectively collected until age 18 months using web-based questionnaires. IgE sensitization was assessed at 18 months of age. Results: The proportion who had introduced egg, legume, soy protein, peanut, almond and cashew nut during the first year of life increased after the implementation of revised national guidelines. The most significant change was seen for legume (55.2% to 69.8% aOR 1.90 (95% CI: 1.62-2.24) and peanut (29.2% to 43.2% aOR 1.87 (95% CI: 1.55-2.24) and the consumption frequency had also increased. No differences in the prevalence of eczema, food allergy or sensitization to the foods of interest were found. Conclusion: Since the release of revised guidelines, infants in the general population introduce and consume a variety of allergenic foods earlier and more frequently, while early manifestations of allergic disease remained unchanged.
https://doi.org/10.1016/j.jaci.2023.08.037