Real World Experience With Peanut Oral Immunotherapy: Lessons Learned From 270 Patients.
BACKGROUND: Peanut allergy (PA) is a significant and increasing problem, interfering with psychological development and family life. The standard recommendation to avoid peanut products and have access to injectable epinephrine is often inadequate. Oral immunotherapy for PA has been formally studied. Clinical observations of allergen immunotherapy have repeatedly enhanced patient care. OBJECTIVE: The purpose of this study was to report observations on the treatment of 270 patients with PA over 8.5 years. METHODS:
This is a retrospective record review of patients beginning peanut oral immunotherapy between January 1, 2009, and June 1, 2017, approved by the North Texas Institutional Review Board. RESULTS: A total of 270 patients aged 4 to 18 years comprising 107 girls and 163 boys were treated. A total of 214 of 270 patients (79%) completed immunotherapy escalation. Age (P < .001) and peanut IgE (P < .001) correlate inversely with completing dose escalation. Epinephrine-treated reactions in 63 and isolated gastrointestinal symptoms in 101 patients, respectively, were the most common adverse reactions to treatment but did not preclude success. Peanut IgE decreased by 65% after 3 years of maintenance treatment and 14 of 214 patients (6.5%) were able to achieve sustained unresponsiveness. CONCLUSIONS: In an allergy office practice setting, 79% of patients are able to complete a peanut desensitization protocol and maintain the desensitized state indefinitely with daily dosing. With appropriate planning and precautions, peanut oral immunotherapy may be performed in an allergy office. Careful observations of clinical treatment can contribute to the development of effective treatment strategies.
Differences in the Uptake of Ara h 3 from Raw and Roasted Peanut by Monocyte-Derived Dendritic Cells.
Roasting has been implicated in the increase of peanut allergenicity due to the chemical reactions that occur during the process. However, this increase is not fully understood, and little information is available regarding the role of roasted peanut allergens in the initial phase of allergy, where dendritic cells (DCs) play a key role. We sought to analyze differences in the internalization of Ara h 3 from raw and roasted peanut by immature monocyte-derived DCs (MDDCs) and the implication of the mannose receptor in the uptake. Ara h 3 was purified from raw and roasted peanut (Ara h 3-raw and Ara h 3-roas) and labeled with a fluorescent dye. The labeled allergens were added to MDDCs obtained from 7 donors and internalization was analyzed after 10, 30, and 120 min by flow cytometry. In parallel, mannan, which blocks the mannose receptor, was added 30 min before adding the labeled allergens. Results showed that the internalization of Ara h 3-roas by MDDCs was significantly increased at every time point. However, the increase in the internalization of Ara h 3-raw was only significant after 2 h of incubation. Ara h 3-roas had an enhanced capacity to be internalized by MDDCs in comparison with Ara h 3-raw at every time point. Blocking the mannose receptor decreased the internalization of Ara h 3-roas but not Ara h 3-raw. In conclusion, the internalization of Ara h 3-roas by the MDDCs is enhanced when compared to Ara h 3-raw, and the mannose receptor might be implicated in this enhancement.
Detection of Peanut Allergen Ara h 6 in Commercially Processed Foods using a Single-Walled Carbon Nanotube-Based Biosensor.
Background: The peanut protein Arachis hypogaea (Ara h) 6 is one ofthe most serious food allergens that contributes to food-related, life-threatening problems worldwide. The extremely low allergic dose demands for more selective and rapid methods for detecting Ara h 6. Objective: The goal of this study was to develop a single-walled carbon nanotube (SWCNT)-based biosensor for the rapid detection of Ara h 6 in commercial food products. Methods: The detection principle of this biosensor was based on the binding of Ara h 6 to the anti-Ara h 6 antibody (pAb) through 1-pyrenibutanoic acid succinimidyl ester. The resistance difference (ΔR) was calculated via linear sweep voltammetry using a potentiostat. Results: The ∆R increased as the Ara h 6 concentrations increased above the range of 100-107 pg/L. A specificity analysis showed that the anti-Ara h 6 pAb selectively interacted with Ara h 6 molecules in the buffer solution (pH 7.4). Conclusions: This research proposes that an SWCNT-based biosensor in self-assembly with antibodies could be an effective tool for the rapid detection of allergen proteins in food. Highlights: The developed biosensor exhibited higher sensitivity and selectivity. Application studies resulted in precise Ara h 6 detection in peanut-containing processed food.
Accidental food allergy reactions: products and undeclared ingredients.
BACKGROUND: Accidental allergic reactions to food are frequent, can be severe and even fatal. OBJECTIVE: To analyze the culprit food products and levels of unexpected allergens in accidental reactions.
METHODS: A prospective cohort study was conducted in adults (n=157) with a physician-confirmed diagnosed food allergy. During a 1-year follow up, 73 patients reported accidental allergic reactions and the culprit food products. Food samples received (51) were analyzed for a wide range of suspected non-ingredient allergens and the risk was quantified. RESULTS: A very diverse range of food products was responsible for the unexpected allergic reactions. Thirty-seven percent (19/51) of products analyzed had 1 to 4 culprit allergens identified that were not supposed to be present according to the ingredient declaration. Concentrations varied from 1 to 5000 mg protein of the allergenic food per kg food product, and were highest for peanut, milk and sesame. Milk proteins posed the highest estimated risk for objective allergic reactions. The intake of culprit allergens by patients varied considerably. For these cases in which culprit allergens were detected, the intake of at least one allergen exceeded the reference dose or a culprit allergen with a yet unknown reference dose was present. Both patient neglect of PAL statements and omission of using a PAL statement by food manufacturers seem to contribute to accidental reactions. CONCLUSION: A wide range of food products are causing accidental reactions in food allergic patients. Eight different allergens not declared on the ingredient lists were detected in the culprit food products, all representatives of the allergens regulated in the EU.
A Mouse Model of Peanut Allergy Induced by Sensitization Through the Gastrointestinal Tract. In Type 2 Immunity.
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.
A subset of walnut allergic adults is sensitized to walnut 11S globulin Jug r 4.
BACKGROUND: The role of sensitization to commercially available allergens of English walnut (Juglans regia) Jug r 1, 2 and 3 in walnut allergy has been previously investigated in walnut allergic adults and was unable to explain allcases of walnut allergy. OBJECTIVES: Identify recognized walnut allergens, other than the ones previously investigated (Jug r 1-3), in walnut allergic adults and determine the sensitization frequency and diagnostic value. METHODS: Three different in-house walnut extracts were prepared and analysed on SDS-PAGE blots to identify allergenic walnut proteins. Immunoblots and immunoprecipitation, followed by LC-MS analysis, were performed to screen for, and confirm, IgE binding to walnut allergens in selected walnut allergic adults. In a cohort of 55 walnut challenged adults, including 33 allergic and 22 tolerant, sensitization to native and recombinant walnut allergen Jug r 4 was assessed using immunoblotting and immuno-line blot (EUROLINE), respectively. RESULTS: Screening of sera of eight walnut allergic adults identified Jug r 4 as an allergen in our population. In the total cohort of 55 subjects, five were positive for Jug r 4 on immunoblot and 10 on EUROLINE. All but one EUROLINE positive subject had a positive food challenge (sensitivity 27%, specificity 95%, PPV 90%, NPV 47%). All five subjects positive on immunoblot were also positive on EUROLINE. LC-MS analysis showed a lack of Jug r 4 in the ImmunoCAP extract. Co-sensitization to other 11S albumins (e.g. hazelnut Cor a 9) was common in Jug r 4 sensitized subjects, potentially due to cross-reactivity. CONCLUSIONS: Walnut 11S globulin Jug r 4 is a relevant minor allergen, recognized by 27% of walnut allergic adults. It has a high positive predictive value of 90% for walnut allergy. Specific IgE against Jug r 4 occurred mostly with concomitant sensitization to other walnut components, mainly Jug r 1.
Immunoglobulin E-binding Proteins of Cooked Walnuts in Korean Children
PURPOSE: The immunological characteristics of young Korean children with walnut (WN) allergy and the influence of different cooking methods on WN proteins have not been evaluated to date. This study aimed to evaluate the major WN allergens identified among Korean children, together with changes in WN antigenicity caused by common cooking methods. METHODS: We enrolled children under the age of 13 years with WN serum-specific immunoglobulin (Ig) E concentrations. The protein fractions of dry-fried and boiled WN extracts were compared with those of raw WNs using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), 2-dimentional gel electrophoresis (2DE) and a proteomic analysis using electrospray ionization (liquid chromatography-mass spectrometry [LC-MS]). An immunoblotting analysis was conducted to examine IgE reactivity toward raw WNs using serum samples from 6 children with a clinical WN allergy. To determine the processed WN proteins with IgE-binding capacity, a 2D-immunoblotting analysis was performed using the pooled sera of 20 WN-sensitized children. RESULTS: Protein bands from raw WNs were identified at 9, 16, 28, 52, 58, and 64 kDa via SDS-PAGE. The 9- and 16-kDa protein bands were enhanced by boiling, whereas the 52- and 64-kDa bands were considerably diminished. On LC-MS analysis, of the 66 IgE-binding proteins present in raw WNs, 57 were found in dry-fried WNs, but only 4 in boiled WNs. The sera of 5 out of 6 participants reacted with the 52-kDa protein bands and those of 4 out of 6 participants reacted with the 16- and 28-kDa protein bands, respectively. Meanwhile, a 2D-immunoblotting result confirmed the presence of different binding patterns among children who consumed cooked WNs. CONCLUSIONS: The protein profile of boiled WNs is substantially different from that of raw WNs. However, 4 proteins including prolamins remained stable after dry-frying or boiling. Further studies are needed to evaluate the clinical relevance of these findings.
Is There Any Necessity to Prescribe Consumption of Walnuts Cooked by Different Processing Techniques to Patients With Walnut Allergy?
The present study focused on identifying the usual methods of cooking walnuts in order to investigate changes in walnut allergen activity caused by cooking and evaluated the allergenic changes in walnut proteins within raw, dry-fried and boiled walnuts. Previous studies have reported a decrease in the allergen activity of walnut by thermal processing methods, which are not used in Korean kitchens, such as dry-frying and boiling. In Korea, Walnuts are consumed with rice and usually boiled and stir-fried with seasoning. Thus, the present study clarified the protein bands corresponding to raw walnuts and confirmed that the patterns of each walnut protein differ depending on cooking methods. This concern may be a very crucial point to understand the other tree nuts allergy as well as walnut allergy. The results of the present study differ from those of previous studies performed in Europe, although further studies with older participants are needed in order to draw more definite conclusions on lipid transfer protein (LTP). The other crucial point is that the findings of the present study support existing findings that the allergenic components of walnut have varying antigenicity depending on cooking methods. The allergenic components of walnut identified using diagnostic tests for walnut allergic patients could be reduced in walnuts cooked by different processing techniques. The allergenic components of walnut have varying allergen activity depending on cooking methods. Therefore, the allergenic components of walnuts identified using diagnostic tests for walnut allergic patients could allow physicians to prescribe consumption of walnuts cooked by different processing techniques to patients with walnut allergy.
Comparison of Real-Time Polymerase Chain Reaction and Enzyme-Linked Immunosorbent Assay for Sensitive and Quantitative Detection of Hazelnuts in Nut Pastes.
Background: Hazelnuts, being a frequent agent of allergenic reactions, need to be detected in food products. Thus, it is necessary to develop and further investigate appropriate methods for detection. Objective: The aim of the study was to compare the analysis of nut pastes (peanut paste spiked with different amounts of hazelnut paste) as a model of contamination of confectionery. Methods: Real-time PCR and sandwich ELISA (RidaScreen Hazelnut Fast Kit) were used. Results: For real-time PCR, LOQ of 2 mg/kg and a quantification range from 2 to 10 000 mg/kg were determined. For ELISA, LOQ of 1 mg/kg and a quantification range from 1 to 100 mg/kg were determined. Conclusions: The comparison shows that the methods had comparable sensitivity with LOQs in the same order of magnitude. Although ELISA was slightly more sensitive, it required dilution of samples at higher concentrations of the analyte because of its narrow quantification range. Results of this study suggest that real-time PCR and ELISA are both suitable methods for the analysis of nut pastes over a wide range of concentrations. Achieved results could be useful for control as well as for technological purposes. Highlights: Real-time PCR analysis of peanut paste spiked with different amounts of hazelnut paste as a model is proposed. Sandwich ELISA analysis of peanut paste spiked with different amounts of hazelnut paste as a model is proposed. The analytical parameters of real-time PCR and ELISA methods are compared.
Effect of thermal/pressure processing and simulated human digestion on the immunoreactivity of extractable peanut allergens.
Peanut allergy is one of the most widespread types of food allergies especially affecting developed countries. To reduce the risk of triggering allergic reactions, several technological strategies have been devised to modify or remove allergens from foods. Herein we investigated the combination of high temperature and pressure on the modulation of peanuts immunoreactivity after simulated gastro-duodenal digestion. Extractable proteins of raw and autoclaved peanuts were separated on SDS-PAGE and immunogenicity was assessed by ELISA and Western Blot analyses. Proteins surviving the heat treatment and reacting towards allergic patients' sera were analysed and attributed to Ara h 3 and Ara h 1 proteins by untargeted LC-high resolution-MS/MS. A progressive reduction in the intensity of the major allergen proteins was also highlighted in the protein fraction extracted from autoclaved peanuts, with a total disappearance of the high molecular allergens when samples were preliminary exposed to 2 h hydration although the lower molecular weight fraction was not investigated in the present work. Furthermore, raw and processed peanuts underwent simulated digestion experiments and the IgE binding was assessed by using allergic patients' sera. The persistence of an immunoreactive band was displayed around 20 kDa. In conclusion, the synergistic effects of heat and pressure played a pivotal role in the disappearance of the major peanut allergens also contributing to the significant alteration of the final immunoreactivity. In addition, the surviving of allergenic determinants in peanuts after gastrointestinal breakdown provides more insights on the fate of allergenic proteins after autoclaving treatments.