Diagnosis of Peanut Allergy in Preschool Children: The Impact of Skin Testing With a Novel Composition of Peanuts

Peanut allergy is an increasing concern in younger children. Available bedside diagnostic tools, i.e., prick tests with commercial extracts or peanut-containing foods have only limited predictive values. In a cohort of preschoolers with both a history of allergic reactions and sensitization to peanut proteins, we aimed to characterize the impact of skin tests with a novel composition of peanuts LPP-MH. Almost one quarter (27/110) of preschool children, with a history of allergic reactions to peanuts and positive standard IgE-mediated tests for peanut allergy, can tolerate the reintroduction of peanut proteins into their diet after resolving their allergy and, thus, can avoid adverse health outcomes associated with the false diagnosis. In the younger age group, a quarter of peanut allergic children, display a relatively high threshold, potentially enabling an easier and safer oral immunotherapy protocol in this window of opportunity in childhood. The use of the novel diagnostic skin test, LPP-MH, significantly improves the predictive value of outpatient evaluation for the outcomes of peanut challenge as well as the expected threshold at which the PA child will react, thus, making for a better informed decision of how, when, and where to challenge.

Peanut Component Ara h 1 and 2 Sensitization in Patients with Food Allergy in Kuwait

<b><i>Introduction:</i></b> There is limited knowledge on the sensitization patterns to peanut proteins and food allergy in the Middle East. The objective of this study is to analyze the relationship between sensitization patterns to peanut proteins and clinical symptoms in a group of patients with physician-diagnosed peanut allergy (PA) in Kuwait. <b><i>Methods:</i></b> PA patients were evaluated by the skin prick test (SPT), serum total IgE, peanut-specific IgE (sIgE), and sIgE against Ara h 1–3, 8, and 9, and clinical data were collected. <b><i>Results:</i></b> Sixty-nine patients were included. A positive correlation between peanut SPT and sIgE was detected for all 3 storage proteins (Ara h 1–3) in patients &#x3c;6 years old and for Ara h 1 and 2 in older patients. ROC analysis of positive correlations showed that oral food challenge should be considered for definite diagnosis of PA only if the level of Ara h 2 is &#x3c;22.25 KUA/L, with level of Ara h 2 ≥15.4 allowing the detection of systemic reactions with a sensitivity of 55.56%. Patients presenting with systemic reactions more frequently had positive Ara h 1 (88.9%) and Ara h 2 (83.3%), compared with 44.1% and 52.9% in those with local reaction (<i>p</i> = 0.0046 and <i>p</i> = 0.0378). The levels of Ara h 1 and 2 were also significantly higher in patients with systemic reactions compared to those with a local reaction, with those differences being especially relevant for Ara h 2 (15.9 vs. 0.4) (<i>p</i> = 0.0005). <b><i>Conclusions:</i></b> The pattern of sensitization to peanut proteins in the Middle East is similar to that of the Western world. Measurement of sIgE antibodies to Ara h 1, 2, and 3 is useful in the diagnosis of PA and in the investigation of reactions to raw and roasted peanuts.

Increased intestinal permeability in an orally-reactive peanut allergy model identifies Angiopoietin like-4 as a biomarker

Peanut allergy reaction severity correlates with increased intestinal epithelial cell (IEC) barrier permeability. CC027/GeniUnc mice develop peanut allergy by intragastric administration of peanut proteins without adjuvant. We report that peanut-allergic CC027/GeniUnc mice showed increased IEC barrier permeability and systemic peanut allergen Ara h 2 after challenge. Jejunal epithelial cell transcriptomics showed effects of peanut allergy on IEC proliferation, survival, and metabolism, and revealed IEC-predominant angiopoietin like-4 (Angptl4) as a unique feature of CC027/GeniUnc peanut allergy. CC027/GeniUnc mice and peanut-allergic pediatric patients demonstrated significantly higher serum Angptl4 and ANGPTL4 compared to control C3H/HeJ mice and non-peanut-allergic but atopic patients, respectively, highlighting its potential as a biomarker of peanut allergy.

Functional Uses of Peanut (Arachis hypogaea L.) Seed Storage Proteins

Peanut (Arachis hypogaea L.) is an important grain legume crop of tropics and subtropics. It is increasingly being accepted as a functional food and protein extender in developing countries. The seed contains 36% to 54% oil, 16% to 36% protein, and 10% to 20% carbohydrates with high amounts of P, Mg, Ca, riboflavin, niacin, folic acid, vitamin E, resveratrol and amino acids. Seed contains 32 different proteins comprised of albumins and globulins. The two-globulin fractions, arachin and non-arachin, comprise approximately 87% of the peanut seed proteins. Peanut worldwide is mainly used for oil production, consumption as raw, roasted, baked products, peanut butter, peanut flour, extender in meat product formulations, confectionary and soups. Peanut proteins have many properties such as good solubility, foaming, water/oil binding, emulsification that make them useful in various food products. Very limited studies have been carried out in peanut functional properties, which has been reviewed in the present article. Adequate modifications can be done in protein functionality that are influenced by pH, temperature, pressure etc. However, some individuals develop severe IgE-mediated allergies to peanut seed proteins. Thus, methods to improve nutrition and reduce allergenicity have also been discussed. Within the last decade, manipulations have been done to alter peanut chemistry and improve nutritional quality of peanuts and peanut products. Hence, improved comprehensive understanding of functional properties and nutritional chemistry of peanut proteins can generate better source of food grain to meet nutritional requirement of growing population. In the present review, composition of peanut seed proteins, functional properties, nutritional components and nutraceutical value have been discussed with respect to beneficial aspects to health, reducing hunger and usage in food end products.

Thermal Processing of Peanut Grains Impairs Their Mimicked Gastrointestinal Digestion While Downstream Defatting Treatments Affect Digestomic Profiles

Resistance to digestion by digestive proteases represents a critical property of many food allergens. Recently, a harmonized INFOGEST protocol was proposed for solid food digestion. The protocol proposes digestion conditions suitable for all kinds of solid and liquid foods. However, peanuts, as a lipid-rich food, represent a challenge for downstream analyses of the digestome. This is particularly reflected in the methodological difficulties in analyzing proteins and peptides in the presence of lipids. Therefore, the removal of the lipids seems to be a prerequisite for the downstream analysis of digestomes of lipid-rich foods. Here, we aimed to compare the digestomes of raw and thermally treated (boiled and roasted) peanuts, resulting from the INFOGEST digestion protocol for solid food, upon defatting the digests in two different manners. The most reproducible results of peanut digests were obtained in downstream analyses on TCA/acetone defatting. Unfortunately, defatting, even with an optimized TCA/acetone procedure, leads to the loss of proteins and peptides. The results of our study reveal that different thermal treatments of peanuts affect protein extraction and gastric/gastrointestinal digestion. Roasting of peanuts seems to enhance the extraction of proteins during intestinal digestion to a notable extent. The increased intestinal digestion is a consequence of the delayed extraction of thermally treated peanut proteins, which are poorly soluble in acidic gastric digestion juice but are easily extracted when the pH of the media is raised as in the subsequent intestinal phase of the digestion. Thermal processing of peanuts impaired the gastrointestinal digestion of the peanut proteins, especially in the case of roasted samples.