A 5-year retrospective review of children with peanut allergy in the largest paediatric hospital in Singapore

BACKGROUND: The prevalence of peanut allergy (PA) among children has increased significantly over the past decade. Even though the prevalence of PA in Singapore is considered low, peanut is the top trigger for food-induced anaphylaxis in Singaporean children.OBJECTIVE: To describe the demographic characteristics and clinical features of children with PA.METHODS: This is a 5-year retrospective review of children diagnosed with PA based on clinical history coupled with a positive skin prick test to peanut or positive oral food challenge results.RESULTS: There were 269 patients (53.9% males) with a clinical diagnosis of PA. The median age at first allergic presentation for the PA group was 24 months old, with interquartile range of 13–39 months. The most common form of peanut introduced was roasted peanut. The rate of peanut anaphylaxis was 7.1%. Concomitant tree nut sensitization was found in 32.3% of this cohort, predominantly to cashew nut. Majority of them have a personal history of atopy – 75.8% with eczema, 63.6% with allergic rhinitis, and 19.7% with asthma.CONCLUSION: This is the first large review of peanut-allergic children in Singapore. Prospective population-based studies are needed to establish the true prevalence and risk factors associated with the development of this potentially life-threatening condition.

A case report of mono-sensitization to peanut component Ara h6

Peanut is the most common food allergen in the US, affecting 1-2 % of the population and studies show that it is still on the rise.' Component testing has offered better insight into the likelihood of reactivity with exposure. Extensive literature shows Arachis hypogea (Ara h) 2 as being the most clinically significant component identified to correlate with reactivity with exposure to the peanut protein, however there is minimal research on the reactivity of Ara h6. This case report describes a patient with a clinical reaction to peanut as a toddler and subsequent positivity on annual skin testing with commercial peanut extract, likely confounded by positive birch with advancing age. Immuno CAP testing revealed a negative Ara h2 and positive Ara h6, describing mono-sensitization to Ara h 6 and high probability of clinical reactivity. The importance of this case is to raise awareness of other highly allergenic components in patients with peanut allergy.

Predictive value of peanut skin prick test, specific IgE in peanut-sensitized children in Singapore

BACKGROUND: The predictive decision points for both peanut skin prick test (SPT) wheal size and serum IgE concentrations, in peanut-sensitized children, have not been evaluated in Singapore. OBJECTIVE: We aim to derive clinically useful predictive decision points to be used for risk stratification of oral food challenge (OFC) in peanut-sensitized patients. METHODS: Patients with a positive SPT to peanut, performed during a 4-year period between 2012 and 2016, were included in a retrospective chart review. The patients were assessed for their peanut allergy status based on a convincing clinical history. Their first SPT and serum IgE results done at presentation to our centre were used. RESULTS: There were 269 patients with a clinical diagnosis of peanut allergy based on recent immediate reaction to peanut and 59 patients whom were tolerating peanuts regularly. There were 251 patients sensitized to peanut, without prior known peanut exposure. A wheal size of ≥8 mm and a peanut-specific IgE of ≥6 kU/L each provided for a 95% positive predictive value of clinical reaction to peanuts; the larger the wheal size on SPT, the higher the probability. CONCLUSION: The cutoff values derived in this study can help clinicians in the risk assessment of OFC in peanut-sensitized patients. Prospective studies using OFCs for the diagnosis of peanut allergy are needed to confirm the diagnostic performance of these tests in predicting OFC outcomes.

Diagnostic Value of Specific IgE to Peanut and Ara h 2 in Korean Children with Peanut Allergy

PURPOSE: The purpose of this study was to establish the diagnostic decision point (DDP) of peanut specific IgE (sIgE) for predicting the outcome of oral food challenge (OFC). We also evaluated the usefulness of sIgE to peanut components (Ara h 1, 2, 3, 8, and 9) in diagnosing peanut allergy. METHODS: Korean children aged over 12 months with a suspected peanut allergy were enrolled. Diagnosis of peanut allergy was confirmed by an open OFC or through the convincing history of anaphylaxis. Cutoff levels of sIgE to peanut and peanut components were determined by analyzing receiver operating characteristic curves. RESULTS: Forty-eight children (22 boys and 26 girls) with a suspected peanut allergy were enrolled. The previously established DDP for peanut-sIgE antibodies (14 kU/L) showed a sensitivity of 22.7%, specificity of 100%, positive predictive value (PPV) of 100%, and negative predictive value of 60.4% in our study population. The median levels of peanut-sIgE (5.4 kU/L vs 1.1 kU/L, P<0.001) and Ara h 2-sIgE (0.8 kU/L vs 0 kU/L, P<0.001) were significantly higher in the peanut allergy group than in the peanut tolerance group. The peanut-sIgE concentration indicating a PPV of 100% was 10.3 kU/L. The Ara h 2-sIgE level of 4.0 kU/L had a PPV of 100%. CONCLUSIONS: Our results showed that the cutoff levels for peanut (10.3 kU/L) and Ara h 2 (4.0 kU/L) established in this study is useful for the diagnosis of peanut allergy in Korean children.

Sensibilización al maní en pacientes venezolanos con enfermedades atópicas y/o urticaria / Sensitization to peanut in Venezuelan patients with atopic diseases and / or uticaria

La sensibilización y las manifestaciones alérgicas al maní se han incrementado últimamente a nivel mundial, constituyendo el mismo la causa principal de anafilaxia por alimentos. Como la prevalencia de alergia al maní varía de acuerdo a las regiones nos propusimos evaluar, en una etapa preliminar, la sensibilización al maní por pruebas cutáneas (“skin prick test”) en pacientes venezolanos atópicos y/o con urticarias que acudieron a la Consulta ambulatoria de Alergía del Instituto de Inmunología. El 5,4 % de los pacientes manifestó algún tipo de manifestación cutánea o respiratoria al ingerir maní. Se demostró sensibilización al maní por pruebas cutánea en el 6,5 % de los pacientes. Sin embargo, un porcentaje pequeño (2 %) de ellos mostró, en conjunto, pruebas cutáneas positivas y síntomas a la ingesta del maní. Ningún paciente refirió síntomas severos tras la ingestión de maní. La mayoría de los pacientes con pruebas positivas al maní, también mostraron pruebas positivas a otros alimentos. Estos resultados concuerdan con la percepción de los médicos venezolanos de una baja frecuencia de reacciones adversas, especialmente graves, a la ingesta de maní en nuestro país

Peanut allergy and sensitization incidence has increased world wide to become the first cause of food anaphylaxis. Since the prevalence of peanut allergy changes according to geographical areas, the aim of the study was to assess, in a preliminary report, peanut allergy incidence by skin prick test in atopic Venezuelan patients with atopy and or urticaria from the outpatient allergy clinic of the Institute of Immunology. Cutaneous or respiratory manifestations after peanut ingestion was observed in 5.4 % of the patients studied. Cutaneous test was positive in 6.5 % of patients. In the other hand, a small group (2 %), showed positive skin test along with symptoms after peanut ingestion. None of the patients had severe reactions. Most of the patients with peanut positive skin test were positive to other food allergens. These results are in accordance with the general clinical perception of small frequency of adverse reaction, specially the most serious ones, to peanut ingestion in our country

Parameters Needed to Estimate the Global Burden of Peanut Allergy: Systematic Literature Review.

Background: The Foodborne Disease Burden Epidemiology Reference Group (FERG) established by the World Health Organization (WHO) is dedicated at estimating the global burden of a selection of foodborne diseases. Peanut allergy has been included in this initiative because of the severe and potentially fatal symptoms that can be induced. Peanuts are highly nutritious and consumed all over the world. In a small proportion of the population, consumption of peanuts can lead to peanut allergy, which is an overreaction of the immune system caused by otherwise harmless peanut proteins. Peanut allergy develops at an early age, in the majority of patients between 14 and 24 months and it is in almost all cases a life-long problem. Peanut allergy has a large impact on the quality of life of the allergic individuals and their families, since peanuts together with tree nuts, are the most common causes of fatal or near fatal food allergic reactions in children and adolescents. Aims: To define parameters which are essential to estimate the burden of peanut allergy and to make an inventory of the available data for these parameters. Approach: Systematic literature search focused on prevalence and incidence data, duration and severity of the disease, numbers of cases that recover, case fatalities and impact on quality of life. Prevalence data of studies assessing self-reported peanut allergy (questionnaires or interviews), peanut sensitization (positive skin prick tests or peanutspecific IgE antibodies) or clinically confirmed peanut allergy (oral peanut challenges) were all included in this report. Results: Prevalence data were predominantly available from developed countries (UK, Western Europe, Scandinavia, USA, Canada and Australia). There were no data from Africa and New-Zealand and limited data from East and South Europe, Asia, and South America. In Western countries the prevalence of peanut allergy ranges from 0.5%-1.5%. In some countries the prevalence was low or even zero, as has been shown for Israel and Turkey, respectively. This suggests that geographical differences do exist, but it is unclear which genetic, environmental or dietary factors can explain these differences. The symptoms that are elicited when patients accidentally eat peanuts can vary from mild to severe and occur very rapidly after exposure and have a short duration. Due to this short duration, severity of disease is considered to be irrelevant in the burden calculation. Several studies have shown that living with a peanut allergy has a considerably impact on quality of life. One study showed that quality of life was significantly poorer in peanut allergic children compared to children with diabetes mellitus. Compared to allergic asthma, the quality of life score was higher. Quality of life is an important parameter to consider when estimating the burden of peanut allergy. There are limited data on the mortality rate of peanut-induced anaphylaxis and studies report a case-fatality rate between 0.00125 to 0.017 deaths per 100,000 subjects per year. Hence, peanut allergy can be fatal but this occurs rarely. Conclusions: This systematic review has found relevant data that can be used to calculate the burden of disease of peanut allergens in developed countries. The most important parameters were found to be the prevalence and the impact of peanut allergy on quality of life. The mortality rate for peanut allergens is low and probably has a limited impact on the disease burden. Co-morbidities, such as other allergies, might have an impact as well. In the future it should be explored how quality of life and co-morbidities can be included in the calculation of the burden of peanut allergy. The complete RIVM report can be downloaded for free from http://www.rivm.nl/en/Library/Scientific/Reports/2012/april/Parameters_needed_to_estimat e_the_global_burden_of_peanut_allergy_Systematic_literature_review. Full report is also available as ‘Supplementary File’.

Use of Specific IgE and Skin Prick Test to Determine Clinical Reaction Severity.

Aims: To determine whether specific IgE and skin prick test correlate better in predicting reaction severity during a double-blinded placebo controlled food challenge (DBPCFC) for egg, milk, and multiple tree nut allergens. Study design: Prospective study. Place and Duration of Study: Department of Pediatrics, Stanford University School of Medicine, August 2009 and ongoing. Methodology: We examined the reaction severity of twenty-four subjects to nine possible food allergens: milk, egg, almond, cashew, hazelnut, peanut, sesame, pecan and walnut. Specific IgE and SPT were performed before each DBPCFC. DBPCFC results were classified into mild (1), moderate (2), or severe (3) reactions using a modified Bock’s criteria. Results: Twenty four subjects underwent a total of 80 DBPCFC. Eighty percent of all DBPCFCs resulted in a positive reaction. A majority, 71%, were classified as mild. No reactions occurred with a SPT of zero mm while three reactions occurred with a negative specific IgE. All reactions were reversible with medication. Conclusion: These data suggest that SPT and specific IgE levels are not associated with reaction severity (p<0.64 and 0.27, respectively). We also found that combining specific IgE and SPT improved specificity but did not help to achieve clinically useful sensitivity. For instance, an SPT > 5mm had a sensitivity of 91% and specificity of 50%. Combining SPT > 5mm and IgE > 7 resulted in a reduced sensitivity of 64%. Unexpectedly, a history of anaphylaxis 70% (n=17) was not predictive of anaphylaxis on challenge 4% (n=2).

Effects of Cooking Methods on Peanut Allergenicity / 소아알레르기및호흡기학회지

PURPOSE: Peanut allergy is a major cause of fatal food-induced anaphylaxis. Cooking methods can affect the allergic properties of peanut proteins. The aim of this study was to determine the allergenicity of peanut according to cooking methods. METHODS: Eight kinds of peanut were included in the study: raw peanut, boiled peanut, roasted peanut (10 min, 20 min and 30 min), peanut butter, fried peanut and vinegarish peanut. The proteins were extracted with PBS and analyzed using the SDS-PAGE IgE immunoblot assay with pooled sera from 8 patients with atopic dermatitis. These patients had peanut- specific IgE levels greater than 15 kU/L, which were measured by the CAP-FEIA. RESULTS: The SDS-PAGE IgE immunoblot assay revealed more intense protein bands of Ara h 2 in roasted peanut and peanut butter than in raw, boiled, fried and vinegarish peanut. The protein band of Ara h 1 was not undetected in fried and vinegarish peanut. Ara h 3 had a stable band pattern in all samples, but there was the most prominent band at 37-40 kDa in vinegarish peanut. The IgE immunoblot assay revealed that 10 min roasted peanut had more IgE binding to Ara h 2, and there was no IgE binding to Ara h 1 in fried and vinegarish peanut. In vinegarish peanut, there was almost no IgE binding to it. CONCLUSION: The results of this study suggest that the roasted peanut may increase the allergenicity of Ara h 2 as compared to Ara h 1. Fried and vinegarish peanut may reduce the allergenicity of peanut.

Selection of Anti-Allergic Lactobacillus in Murine Model of Peanut Allergy / 소아알레르기및호흡기학회지

PURPOSE: To evaluate the anti-allergic effects of intragastric treatment with various strains of lactobacillus, we undertook this study in the murine model of peanut allergy. METHODS: Ten groups of mice were sensitized and boosted with 1 mg/dose of crude peanut intragastricly at day 1, 2, 3, 7 and 21. Also, each groups of mice was treated with various strains of lactobacillus or PBS starting on the 1st day of sensitization, for 3 weeks daily. During the experiment, peanut specific serum IgE, IgG1, IgG2a were measured at weekly intervals, and compared at week four which is one week after the end of lactobacillus treatment. RESULTS: By treatment with various strains of lactobacillus, peanut specific IgE levels were decreased in all treated groups of mice compared to sham-treated mice. And at least six of the 10 groups of mice treated with various strains of L. casei or L. acidophilus showed remarkable down-regulatory effects on the production of peanut specific IgE antibodies, while the regulatory effects on specific IgG1, and IgG2a antibodies were variable. Especially, L. casei IBS041 showed harmonized regulatory effect on the productions of peanut specific IgE, IgG1 and IgG2a. CONCLUSION: We selected and partly confirmed several strains of lactobacillus which showed anti-allergic effects in the production of antigen specific IgE in the murine model of peanut allergy.

Peanut Allergy / 소아알레르기및호흡기학회지

Recently, the peanut allergy has been of great concern because its prevalence and life-threatening events are increasing in North America and Europe. Peanut is the most common food to cause fatal and near-fatal food allergy. The threshold of clinical reactivity can be very low. Approximately 50% of young children with egg allergy develop oral tolerance to egg by age 5 years, while about 80% of young children will react to peanuts after this age. Current treatment is strict avoidance of all peanut products and timely treatment of accidental ingestions with antihistamines and self-injectable epinephrine. Several factors of processing and cooking methods of peanut can explain the differences of the rate of peanut allergy among the countries. However, it is expected that the prevalence of peanut allergy will increase in Korea because westernized dietary pattern are getting popular. This review focuses on current understandings of peanut allergy including immunologic characteristics of peanut, diagnosis, recommendation, and recent researches for new treatment of peanut allergy.

Peanut Allergy / 소아알레르기및호흡기학회지

Recently, the peanut allergy has been of great concern because its prevalence and life-threatening events are increasing in North America and Europe. Peanut is the most common food to cause fatal and near-fatal food allergy. The threshold of clinical reactivity can be very low. Approximately 50% of young children with egg allergy develop oral tolerance to egg by age 5 years, while about 80% of young children will react to peanuts after this age. Current treatment is strict avoidance of all peanut products and timely treatment of accidental ingestions with antihistamines and self-injectable epinephrine. Several factors of processing and cooking methods of peanut can explain the differences of the rate of peanut allergy among the countries. However, it is expected that the prevalence of peanut allergy will increase in Korea because westernized dietary pattern are getting popular. This review focuses on current understandings of peanut allergy including immunologic characteristics of peanut, diagnosis, recommendation, and recent researches for new treatment of peanut allergy.

Evaluation of Anti-allergic Effect of Bifidobacteria in Murine Model of Peanut Allergy / 소아알레르기및호흡기학회지

PURPOSE: We underwent this study to evaluate the immunomodulating effects of intragastric administration of bifidobacterium(BGN4) using murine model of peanut allergy. METHODS: C3H/HeJ mice were sensitized with 1 mg/dose of crude peanut(PN) extract with cholera toxin, intragastricly. Group I mice were pretreated with BGN4 for 14 days before PN snesitization, Group II were treated 14-days each before and during sensitization, Group III were sham treated PN sensitized mice, and Group IV were naive. PN-specific serum IgE levels and PN stimulated cytokine productions from splenocyte were measured in study groups. RESULTS: PN-specific IgE levels were significantly lowered in Group II mice compare to Group I or Group III. PN-stimulated IL-4 productions were also remarkably depressed in Group II mice. The ratio of IFN-gamma/IL-4 in Group II was the highest among experimental Groups, furthermore, PN-stimulated IL-12 production was only measured in Group II mice. The decreased levels of PN-specific IgE in Group II consist with decreased production of IL-4 and increased ratio of IFN-gamma/IL-4 in this experiment. CONCLUSION: BGN4 treatment, especially pre-and-during PN sensitization, seemed to have anti-allergic effect by suppressing PN-specific IgE production. And lowered production of IL-4, increased production of IL-12, and the increased ratio of IFN-gamma/IL-4 could be suggested as a part of immunomodulating mechanism of BGN4 treatment in this experiment.

Development and Expression of Recombinant Ara h 1 Fragment Proteins

No abstract available.

A Case of Atopic Dermatitis due to Peanut Allergy / 대한피부과학회지

Peanut allergy is common and potentially severe. This hypersensitivity reaction starts early in childhood and continues throughout life. Dietary elimination of peanuts is mandatory when atopic dermatitis is accompanied with peanut allergy. We experienced a case of a 9-year-old female atopic dermatitis patient showing positive CAP RAST and oral food challenge test with peanuts. Her skin lesions were cleared after dietary elimination of peanuts.

A Case of Anaphylaxis Induced by Peanut / 대한피부과학회지

Peanut allergy is a significant health problem because of the potential severity of the allergic reaction, the life-long nature of the allergic hypersensitivity, and the ubiquitous use of peanut products. Peanut is one of the most common foods causing serious anaphylactic reactions. Three major peanut allergens, Ara h 1, Ara h 2, and Ara h 3 are 64.5, 17.5, 14 kd glycoproteins belong to the vicillin, conglutin, and glycinin families of seed storage proteins, respectively. We report a case of anaphylaxis induced by peanut with generalized edema, skin rash, dyspnea, hypotension, syncope after accidental peanut ingestion of a 33-year-old man. The diagnosis could be confirmed as peanut-induced anaphylaxis on the basis of prick test, open patch test, MAST, and T cell proliferation assay in addition to history.

A comparison study on allergen components between Korean (Arachis fastigiata Shinpung) and American peanut (Arachis hypogaea Runner)

The prevalence of peanut allergy in Korea is lower than in America. Peanut extract allergens between the two countries have not been standardized. This study was performed to compare the allergenicity of raw Korean and American peanuts with that of roasted peanuts. We prepared the peanut extracts in Korean raw (KP) and roasted peanuts (KRP), and also in American raw (AP) and roasted (ARP) peanuts. We compared the peanut extract allergens of KP, KRP, AP and ARP in vitro with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting, T-cell proliferation assay and skin prick test with sera from peanut-allergic patients. SDS-PAGE and Western blotting demonstrated four allergenic extracts, numerous bands that displayed a high prevalence of IgE binding. IgE-binding bands were at 64, 36 and 17 kDa. Western blot inhibition revealed that either KP or AP could almost completely inhibit the reactivity of the other extract. There were no differences between T-cell proliferation assay and skin prick test. In conclusion, this investigation showed no different allergic components in both raw and roast extracts of Korean and American peanuts.