" To Screen or not to Screen": Comparing the Health and Economic Benefits of Early Peanut Introduction Strategies in Five Countries.
BACKGROUND: Early peanut introduction (EPI) in the first year of life is associated with reduced risk of developing peanut allergy in children with either severe eczema and/or egg allergy. However, EPI recommendations differ among countries with formal guidelines. METHODS: Using simulation and Markov modeling over a 20-year horizon to attempt to explore optimal EPI strategies applied to the US population, we compared high-risk infant specific IgE peanut screening (US/Canadian) with the Australiasian Society for Clinical Immunology and Allergy (Australia/New Zealand) (ASCIA) and the United Kingdom Department of Health (UKDOH) published EPI approaches. RESULTS: Screening peanut skin testing of all children with early onset eczema and/or egg allergy before in-office peanut introduction was dominated by a no-screen approach, in terms of number of cases of peanut allergy prevented, QALY's, and healthcare costs, though screening resulted in a slightly lower rate of allergic reactions to peanut per-patient in high-risk children. Considering costs of peanut allergy in high-risk children, the per-patient cost of early introduction without screening over the model horizon was $6,556.69 (95%CI, $6,512.76-$6,600.62), compared with a cost of $7,576.32 (95%CI, $7,531.38-$7,621.26) for skin test screening prior to introduction. From a US societal perspective, screening prior to introduction cost $654,115,322 and resulted in 3,208 additional peanut allergy diagnoses. Both screening and non-screening approaches dominated deliberately delayed peanut introduction. CONCLUSIONS: A no-screening approach for EPI has superior health and economic benefits in terms of number of peanut allergy cases prevented, QALY's, and total health care costs compared to screening and in-office peanut introduction.
Changes in immunoreactivity of allergen-reduced peanuts due to post-enzyme treatment roasting.
The objective of this study was to evaluate the effect of enzyme treatment and post-enzyme treatment roasting on allergenicity of raw peanut kernels. Raw peanuts were treated by single- and two-enzyme treatments, respectively. Enzyme-treated raw peanuts were dry roasted. Reductions of four major allergens (Ara h 1, 2, 3, and 6) and in vitro allergenicity of peanuts were evaluated. Quantitative measurements show that enzyme treatment of raw peanuts reduced Ara h 1, 2, 3 and 6 in raw peanuts by 99-100%, 95-99%, 35-46% and 85-88%, respectively. Roasting of enzyme-treated peanuts significantly reduced the total soluble protein (P < 0.05), Ara h 3 and 6 (P < 0.0001), slightly increased Ara h 1 in the extracts (P < 0.05), but did not significantly affect Ara h 2. Immunoblot shows that the IgE-bindings of both soluble and insoluble proteins of enzyme-treated peanuts were slightly enhanced by roasting but still tremendously lower than that of untreated peanuts.
Food Allergy.
PURPOSE OF REVIEW: The goal of this review is to present an updated summary of the natural history of major childhood and adult food allergies and report recent advances in potential treatments for food allergy. RECENT FINDINGS: The most common childhood food allergies are typically outgrown by adolescence or adulthood. However, peanut/tree nut allergies appear to more commonly persist into adulthood. Adults can develop new IgE-mediated food allergies; the most common is oral allergy syndrome. There are multiple different approaches being tried as possible treatments for food allergy. The prevalence of food allergy appears to be increasing but the varied approaches to treatment are being actively pursued such that an approved modality may not be too far in the future.
Clinical presentation of cashew nut allergy in a paediatric cohort attending an allergy clinic in the West of Ireland.
BACKGROUND: Cashew nut (CN) allergy appears to be increasing. Reactions are variable and may include anaphylaxis. AIM: To describe the clinical features of CN allergy in a group of children attending an allergy clinic with suspected peanut allergy and confirmed sensitisation to CN. METHODS: Patients were identified retrospectively by reviewing the Immunology Database at University Hospital Galway over a 5-year period, Oct. 2010 to Sept. 2015. Patients confirmed sensitised to CN (specific IgE > 0.35 kUa/L, ImmunoCAP Assay) were selected and contacted. RESULTS: Over the 5-year period, 115 children were identified; 102/115 were individually contacted. Of the 102 children, 55 had a history of prior CN exposure with confirmed clinical reaction, 43 had no prior CN exposure, and 4 were sensitised and tolerating CN. For those with clinical CN allergy (N = 55), 30 (55%) were male and median age of onset was 2 years (lower quartile 1.5, upper quartile 4.8). Severity of reaction was graded as mild for 13 children, moderate in 13 additional children, and severe in 29 children. Median CN serum IgE level was 3.2 kUa/L (range 0.36 to > 100) in the clinical reaction group, 2.91 kUa/L (range 0.36 to > 100) in the sensitised group, and 3.4 kUa/L (range 0.94 to 5.21) in those tolerating CN. IgE values were not significantly different between those with mild, moderate, or severe reaction to CN (p = 0.346). CONCLUSION: Children are ingesting CN at a young age with more than half of allergic reactions reportedly severe in nature. The specific CN IgE value was not helpful in predicting severity of reactions.
Microbead-based simultaneous fluorometric detection of three nut allergens.
A microbead-based method is developed for the detection of three nut allergens that can occur in food. The bead array constitutes of a suspension of spectrally distinct fluorescent polystyrene microbeads and has been applied for the simultaneous detection of three main and serious allergens (hazelnut, peanut and walnut). The method is based on the simultaneous identification of specific DNA sequences after PCR. The PCR products are biotinylated and hybridized to nut-specific oligonucleotide probes attached to the microbeads. The hybrids are finally detected by a streptavidin-phycoerythrin conjugate and flow cytometric analysis. As low as 0.01% content of the three nuts in processed food (cookies) can be detected by this method. Graphical abstract Schematic of a method for simultaneous fluorometric detection of three nut allergens in processed food (cookies) based on the use of fluorescent microbeads and flow cytometric analysis. B: Biotin; SA-PE: Streptavidin conjugated to phycoerythrin.
Application of Multiantigen Profiling To Detect Pecan.
A problem often encountered in the detection and identification of undeclared tree nut food allergens is the lack of analytical methods. This problem is accentuated by the current trend, whereby the primary methods used to detect food allergens are antibody-based enzyme-linked immunosorbent assays (ELISAs) and the development of analyte-specific antibodies takes months. The recently developed xMAP food allergen detection assay (xMAP FADA) has the ability to generate multiantigen profiles with tree nuts, thereby providing a potential solution to this problem. The xMAP FADA includes 22 antibodies targeting peanut, soy, and nine tree nuts. The high number of antibodies to a diverse group of tree nuts and legumes and the propensity of tree nuts to cross-react have enabled the development of multiantigen profiling, whereby an analyte reacts with the various antibodies to generate a profile. Recently, a question arose regarding the possible presence of pecan dust at a manufacturer of pecan products that also stored fresh produce. The lack of suitable pecan ELISAs created an analytical challenge that was resolved using multiantigen profiling with the xMAP FADA. Pecan was detected on swab samples by using multiantigen profiling and confirmed by DNA analysis. The use of multiantigen profiling provided an analytical capability beyond what was possible with an analyte-specific analytical method.
Assessment of peanut allergen Ara h1 in processed foods using a SWCNTs-based nanobiosensor.
The goals of this research were to develop a rapid single-walled carbon nanotube (SWCNT)-based biosensor and to employ it to commercial food products for Ara h1 detection. The SWCNT-based biosensor was fabricated with SWCNTs immobilized with antibody (pAb) through hybridization of 1-pyrenebutanoic acid succinimidyl ester (1-PBASE) as a linker. The resistance difference (ΔR) was calculated by measuring linear sweep voltammetry (LSV) using a potentiostat. Resistance values increased as the concentration of Ara h1 increased over the range of 1 to 105 ng/L. The specific binding of anti-Ara h1 pAb to antigen including Ara h1 was confirmed by both indirect ELISA kit and biosensor assay. The biosensor was exposed to extracts prepared from commercial processed food containing peanuts, or no peanuts, and could successfully distinguish the peanut containing foods. In addition, the application of present biosensor approach documented the precise detection of Ara h1 concentrations in commercially available peanut containing foods.
Origin and Processing Methods Slightly Affect Allergenic Characteristics of Cashew Nuts (Anacardium occidentale).
The protein content and allergen composition was studied of cashews from 8 different origins (Benin, Brazil, Ghana, India, Ivory Coast, Mozambique, Tanzania, Vietnam), subjected to different in-shell heat treatments (steamed, fried, drum-roasted). On 2D electrophoresis, 9 isoforms of Ana o 1, 29 isoforms of Ana o 2 (11 of the acidic subunit, 18 of the basic subunit), and 8 isoforms of the large subunit of Ana o 3 were tentatively identified. Based on 1D and 2D electrophoresis, no difference in allergen content (Ana o 1, 2, 3) was detected between the cashews of different origins (P > 0.5), some small but significant differences were detected in allergen solubility between differently heated cashews. No major differences in N- and C-terminal microheterogeneity of Ana o 3 were detected between cashews of different origins. Between the different heat treatments, no difference was detected in glycation, pepsin digestibility, or IgE binding of the cashew proteins.
Caregiver and expecting caregiver support for early peanut introduction guidelines.
BACKGROUND: Recent guidelines recommend early peanut introduction (EPI) beginning around 4-6 months in infants with either severe eczema and/or egg allergy, and around 6 months for all other infants. Caregiver preferences for such practices are unkown. METHODS: We explored preferences for EPI and in-office allergy risk assessment (IRA) through a nationally-representative survey of expecting (n=1000) and new caregivers of infants < 1 year (n=1000). RESULTS: Among a primarily female (99.7%), married (80.3%), and white (74.4%) sample, 29% had no/vague awareness of the new guidelines, 61% had no/minimal concern for their child developing food allergy, but 54% felt timing of introduction has moderate/strong importance for developing food allergy. Only 31% expressed willingness for EPI before/around 6 months of life, with 40% reporting willingness to introduce peanut after 11 months of life, similar to tree nuts and seafood. However, 60% reported willingness to introduce egg before 8 months. 51% and 56.8% were unwilling to allow IRA methods such as skin testing and oral challenge before 11 months of life, respectively. Odds of willingness to both delay peanut introduction and undergo challenge after 6 months of life were lower among expecting caregivers (OR 0.79, CI 0.65-0.96; OR 0.67, CI 0.54-0.82, respectively). CONCLUSIONS: Among new and expecting caregivers, there is poor current willingness and questionable support for early allergenic solid food recommendations, including IRA before introduction. Willingness was better among expecting versus current caregivers. These trends underscore a need for broader formal implementation planning to facilitate early allergen introduction and maximize its preventive benefits.
Anaphylaxis to packaged foods in Australasia.
AIMS: To examine reports of anaphylaxis in Australasia from consumption of packaged food products with or without precautionary allergen labelling (PAL), where the known allergen triggers were not a listed ingredient. METHODS: A questionnaire was sent to all members of the Australasian Society of Clinical Immunology and Allergy (n = 548). Participants were asked to complete a survey reporting whether they have had seen any patients over the last 3 months reporting anaphylaxis following ingestion of a packaged food where the suspected food allergen was not a listed ingredient. RESULTS: Of the n = 548 members approached, n = 198 responded (response rate 36.1%).There were 14 reports of anaphylaxis to packaged foods (where the suspected allergen was not a listed ingredient), which met the case definition from a total of 198 respondents over the 9-month period. Of those reactions, 50.0% (confidence interval 95% 21-78) were reported from foods that did not have a PAL statement, and 50.0% (confidence interval 95% 21-78) were due to peanuts. CONCLUSION: Anaphylaxis to undeclared allergens was not rare and did not appear to depend on whether the product was labelled with precautionary advice. There is currently no reliable labelling system that can inform food-allergic consumers of safer food choices. Improvements in the regulation of food labelling with PAL are required.