Peanut can be used as a reference allergen for hazard characterization in food allergen risk management: A rapid evidence assessment and meta-analysis.
Regional and national legislation mandates the disclosure of "priority" allergens when present as an ingredient in foods, but this does not extend to the unintended presence of allergens due to shared production facilities. This has resulted in a proliferation of precautionary allergen ("may contain") labels (PAL) which are frequently ignored by food-allergic consumers. Attempts have been made to improve allergen risk management to better inform the use of PAL, but a lack of consensus has led to variety of regulatory approaches and non-uniformity in the use of PAL by food businesses. One potential solution would be to establish internationally-agreed "reference doses", below which no PAL would be needed. However, if reference doses are to be used to inform the need for PAL, then it is essential to characterize the hazard associated with these low-level exposures. For peanut, there are now published data relating to over 3000 double-blind, placebo-controlled challenges in allergic individuals, but a similar level of evidence is lacking for other priority allergens. We present the results of a rapid evidence assessment and meta-analysis for the risk of anaphylaxis to low-level allergen exposure for priority allergens. On the basis of this analysis, we propose that peanut can and should be considered an exemplar allergen for the hazard characterization at low-level allergen exposure. https://doi.org/10.1016/j.jaip.2021.08.008
Effect of Sample Preparation on the Detection and Quantification of Selected Nuts Allergenic Proteins by LC-MS/MS.
The detection and quantification of nut allergens remains a major challenge. The liquid chroma-tography tandem mass spectrometry (LC-MS/MS) is emerging as one of the most widely used methods, but sample preparation prior to the analysis is still a key issue. The objective of this work was to establish optimized protocols for extraction, tryptic digestion and LC-MS analysis of almond, cashew, hazelnut, peanut, pistachio and walnut samples. Ammonium bicar-bonate/urea extraction (Ambi/urea), SDS buffer extraction (SDS), polyvinylpolypyrroli-done (PVPP) extraction, trichloroacetic acid/acetone extraction (TCA/acetone) and chloro-form/methanol/sodium chloride precipitation (CM/NaCl) as well as the performances of con-ventional tryptic digestion and microwave-assisted breakdown were investigated. Overall, the protein extraction yields ranged from 14.9 ± 0.5 (almond extract from CM/NaCl) to 76.5 ± 1.3% (hazelnut extract from Ambi/urea). Electrophoretic profiling showed that the SDS extraction method clearly presented a high amount of extracted proteins in the range of 0-15 kDa, 15-35 kDa, 35-70 kDa and 70-250 kDa compared to the other methods. The linearity of the LC-MS methods in the range of 0 to 0.4 µg equivalent defatted nut flour was assessed and recovery of internal standards GWGG and DPLNV(d8)LKPR ranged from 80 to 120%. The identified bi-omarkers peptides were used to relatively quantifier selected allergenic protein form the inves-tigated nut samples. Considering the overall results, it can be concluded that SDS buffer allows a better protein extraction from almond, peanut and walnut samples while PVPP buffer is more appropriate for cashew, pistachio and hazelnut samples. It was also found that conventional overnight digestion is indicated for cashew, pistachio and hazelnut samples, while microwave assisted tryptic digestion is recommended for almond, hazelnut and peanut extracts. https://doi.org/10.3390/molecules26154698
Open‐label follow‐on study evaluating the efficacy, safety, and quality of life with extended daily oral immunotherapy in children with peanut allergy.
Background: The benefit of daily administration of Peanut (Arachis hypogaea) Allergen Powder-dnfp (PTAH)-formerly AR101-has been established in clinical trials, but limited data past the first year of treatment are available. This longitudinal analysis aimed to explore the impact of continued PTAH therapeutic maintenance dosing (300 mg/day) on efficacy, safety/tolerability, and food allergy-related quality of life. Methods: We present a subset analysis of PALISADE-ARC004 participants (aged 4-17 years) who received 300 mg PTAH daily for a total of ~1.5 (Group A, n=110) or ~2 years (Group B, n=32). Safety assessments included monitoring the incidence of adverse events (AEs), accidental exposures to food allergens, and adrenaline use. Efficacy was assessed by double-blind, placebo-controlled food challenge (DBPCFC); skin prick testing; peanut-specific antibody assays; and Food Allergy Quality of Life Questionnaire (FAQLQ) and Food Allergy Independent Measure (FAIM) scores. Results: Continued maintenance with PTAH increased participants' ability to tolerate peanut protein: 48.1% of completers in Group A (n=50/104) and 80.8% in Group B (n=21/26) tolerated 2000 mg peanut protein at exit DBPCFC without dose-limiting symptoms. Immune biomarkers showed a pattern consistent with treatment-induced desensitisation. Among PTAH-continuing participants, the overall and treatment related exposure-adjusted AE rate decreased throughout the intervention period in both groups. Clinically meaningful improvements in FAQLQ and FAIM scores over time suggest a potential link between increased desensitisation as determined by the DBPCFC and improved quality of life. Conclusions: These results demonstrate that daily PTAH treatment for peanut allergy beyond 1 year leads to an improved safety/tolerability profile and continued clinical and immunological response. https://doi.org/10.1111/all.15027
An Updated Overview of Almond Allergens.
Tree nuts are considered an important food in healthy diets. However, for part of the world’s population, they are one of the most common sources of food allergens causing acute allergic reactions that can become life-threatening. They are part of the Big Eight food groups which are responsible for more than 90% of food allergy cases in the United States, and within this group, almond allergies are persistent and normally severe and life-threatening. Almond is generally consumed raw, toasted or as an integral part of other foods. Its dietary consumption is generally associated with a reduced risk of cardiovascular diseases. Several almond proteins have been recognized as allergens. Six of them, namely Pru du 3, Pru du 4, Pru du 5, Pru du 6, Pru du 8 and Pru du 10, have been included in the WHO-IUIS list of allergens. Nevertheless, further studies are needed in relation to the accurate characterization of the already known almond allergens or putative ones and in relation to the IgE-binding properties of these allergens to avoid misidentifications. In this context, this work aims to critically review the almond allergy problematic and, specifically, to perform an extensive overview regarding known and novel putative almond allergens. https://doi.org/10.3390/nu13082578
Effect of processing on polyphenol profile, aflatoxin concentration and allergenicity of peanuts.
Worldwide peanuts are often thermally processed before consumption, which might alter its bioactive composition and toxicity. The presented work explores the effect of processing methods such as roasting, frying, and pressure cooking on the bioactive composition, polyphenol profiles, aflatoxin concentration and, allergenicity response of peanuts. Effect of processing methods was assessed by monitoring total polyphenol content (TPC), total flavonoid content (TFC), antioxidant activity by DPPH & ABTS radicals, sensory analysis and, indirect ELISA. Compared to raw peanuts, all processing methods caused significant differences in TPC, TFC, DPPH & ABTS radical scavenging activities. Comparison of polyphenol profiles of raw to processed peanuts by LC-ESI-Q-TOF-MS chromatograms revealed different effects on concentrations of individual bioactive polyphenols. Indirect ELISA showed a significant decrease in the assay response on pressure cooking as compared to other samples. Total aflatoxin concentration was significantly reduced after processing in roasted (97.7%) and fried (98.3%) peanuts. Optimum processing conditions based on bioactive concentration and sensory analysis were found to be, roasting: 150 °C for 10 min, frying: 170 °C for 2 min and, pressure cooking: 15 min. Polyphenol profiles and bioactive constituents of peanuts were influenced by processing and may alter health benefits associated with them hence, vital for research and food industry applications. https://doi.org/10.1007/s13197-020-04779-7
Microfluidic origami nano-aptasensor for peanut allergen ara h1 detection.
In this study, an origami microfluidic electrochemical nano-aptasensor was developed for the rapid detection of the peanut allergen Ara h1. Specifically, the microfluidic aptasensor was fabricated through sequential folding of a piece of chromatography paper substrate patterned with microchannel and screen-printed electrodes. Aptamer-decorated black phosphorus nanosheets (BPNSs) were electrodeposited onto the paper-based electrode surface as sensing probes for enhanced electrochemical detection and high specificity and selectivity. Critical design parameters (the concentration of probe, time for self-assembly of aptamer and reaction time) were investigated to optimize the aptasensor performance. The prepared aptasensor was able to complete detection within 20 min and demonstrated a linear range from 50 ~ 1000 ng/mL with a detection limit of 21.6 ng/mL. The aptasensor was successfully used to detect the Ara h1 spiked cookie dough sample. The proposed method reduces the gap between complex lab testing and food allergen analysis at the point of need. https://doi.org/10.1016/j.foodchem.2021.130511
The Risk Reduction of Accidental Exposure-Related Systemic Allergic Reactions Extrapolated Based on Food Challenge Data After 1 Year of Peanut Oral Immunotherapy.
Introduction: The phase 3 trial PALISADE, comparing peanut (Arachis hypogaea) allergen powder-dnfp (PTAH) oral immunotherapy versus placebo in peanut-allergic children, reported that a significantly higher percentage of PTAH-treated participants tolerated higher doses of peanut protein after 1 year of treatment. This study used PALISADE data to estimate the reduction in the risk of systemic allergic reaction (SAR) after accidental exposure following 1 year of PTAH treatment. Methods: Participants (aged 4-17 years) enrolled in PALISADE were included. Parametric interval-censoring survival analysis with the maximum likelihood estimation was used to construct a real-world distribution of peanut protein exposure using lifetime SAR history and highest tolerated dose (HTD) from a double-blind, placebo-controlled food challenge conducted at baseline. The SAR risk reduction was extrapolated using the exposure distribution and the HTD were collected at baseline and trial exit for PTAH- and placebo-treated participants. Results: Assuming a maximum peanut protein intake of 1500 mg, participants were estimated to have < 1% probability of ingesting > 0.01 mg during daily life. The mean annual SAR risk at trial entry was 9.25-9.98%. At trial exit, the relative SAR risk reduction following accidental exposure was 94.9% for PTAH versus 6.4% for placebo. For PTAH-treated participants with exit HTD of 600 or 1000 mg without dose-limiting symptoms, the SAR risk reduction increased to 97.2%. The result was consistent in the sensitivity analysis across different parametric distributions. Conclusion: Oral immunotherapy with PTAH is expected to result in a substantially greater reduction in risk of SAR following accidental exposure compared to placebo among children with peanut allergy. https://doi.org/10.1007/s12325-021-01843-2
Research on the Structure of Peanut Allergen Protein Ara h1 Based on Aquaphotomics.
Peanut allergy is becoming a life-threatening disease that could induce severe allergic reactions in modern society, especially for children. The most promising method applied for deallergization is heating pretreatment. However, the mechanism from the view of spectroscopy has not been illustrated. In this study, near-infrared spectroscopy (NIRS) combined with aquaphotomics was introduced to help us understand the detailed structural changes information during the heating process. First, near-infrared (NIR) spectra of Ara h1 were acquired from 25 to 80°C. Then, aquaphotomics processing tools including principal component analysis (PCA), continuous wavelet transform (CWT), and two-dimensional correlation spectroscopy (2D-COS) were utilized for better understanding the thermodynamic changes, secondary structure, and the hydrogen bond network of Ara h1. The results indicated that about 55°C could be a key temperature, which was the structural change point. During the heating process, the hydrogen bond network was destroyed, free water was increased, and the content of protein secondary structure was changed. Moreover, it could reveal the interaction between the water structure and Ara h1 from the perspective of water molecules, and explain the effect of temperature on the Ara h1 structure and hydrogen-bonding system. Thus, this study described a new way to explore the thermodynamic properties of Ara h1 from the perspective of spectroscopy and laid a theoretical foundation for the application of temperature-desensitized protein products. https://doi.org/10.3389/fnut.2021.696355
Oleosin Cor a 15 is a novel allergen for Italian hazelnut allergic children.
Background. Hazelnut allergy, which is characterized by symptoms that range from mild to severe, is one of the most common allergies in children throughout Europe, and an accurate diagnosis of this allergy is therefore essential. However, lipophilic allergens, such as oleosins, are generally underrepresented in diagnostic tests. We therefore sought to characterize the IgE reactivity of raw and roasted hazelnut oleosins, using the sera of hazelnut-allergic pediatric patients. Methods. Raw and roasted hazelnut oil body–associated proteins were analyzed by means of 1D and 2D electrophoresis and MS. Oleosin IgE reactivity was assessed by immunoblotting with the sera of 27 children who have confirmed hazelnut allergies and from 10 tolerant subjects. A molecular characterization of the oleosins was performed by interrogating the C. avellana cv. Jefferson and cv. TGL genomes, and through expression and purification of the recombinant new allergen. Results. A proteomic and genomic investigation allowed two new oleosins to be identified, in addition to Cor a 12 and Cor a 13, in hazelnut oil bodies. One of the new oleosins was registered as a new allergen, according to the WHO/IUIS Allergen Nomenclature Subcommittee criteria, and termed Cor a 15. Cor a 15 was the most frequently immunorecognized oleosin in our cohort. Oleosins resulted to be the only immunorecognized allergens in a subgroup of allergic patients who showed low ImmunoCAP assay IgE values and positive OFC and PbP. Hazelnut roasting resulted in an increase in oleosin immunoreactivity. Conclusion. A novel hazelnut oleosin, named Cor a 15, has been discovered. Cor a 15 could play a role in eliciting an allergic reaction in a subgroup of pediatric patients that exclusively immunorecognize oleosins. The high prevalence of hazelnut oleosin sensitization here reported further confirms the need to include oleosins in routine diagnostic procedures. https://doi.org/10.1111/pai.13579
Clinical predictors and outcomes of oral food challenges illustrate differences among individual tree nuts.
Background. Although allergy to tree nuts is often considered a single entity, there is heterogeneity in patient reactivity and immune response to different tree nuts. Objective. We sought to characterize tree nut oral food challenges (OFC) in a pediatric population performed at a single center over a 12-year period and determine differences in OFC outcome to different tree nuts. Methods. A retrospective chart review was conducted in patients (0- 20 years) who completed an unblinded OFC to any tree nut from 2007-2019 at Lurie Chlildren’s Hospital of Chicago. Differences among almond, cashew, hazelnut, and walnut challenges were compared and probability curves were used to estimate positive predictive values (PPV) of specific IgE (sIgE) at OFC. Results. 531 tree nut OFCs were included. The mean age at OFC was 7.77 years (SD 4.33). Overall, 74.0% of children passed clinically indicated OFCs. Of the four most commonly challenged tree nuts, almost all patients passed OFC to almond (97.3%) and hazelnut (87.9%). Pass rates were lower for cashew (65.3%) and walnut (57.0%), p<0.0001. The odds of failure were 0.83 times lower for patients who were avoiding without a previous reaction compared to those who had previously reacted (p=0.0025). Conclusions. The majority of patients pass low risk almond and hazelnut OFCs. PPV at the 50th percentile for walnut (2.84 kU/L) and cashew (3.35 kU/L) were lower than previous studies have suggested. https://doi.org/10.1016/j.jaip.2021.05.035