Phenotypical characterization of peanut allergic children with differences in cross‐allergy to tree nuts and other legumes.
BACKGROUND: Peanut allergy in children is often associated with allergies to tree nuts and/or legumes. The aim of the present study was to analyze in cluster a cohort of children allergic to peanuts and assessed for cross-reactivity to nuts and legumes and to identify different phenotypes. METHODS: We included retrospectively 317 children with peanut allergy evaluated at the Allergy Unit of the Saint Vincent Hospital of Lille in the last 12 years. A complete work-up for peanut allergy and nuts and legumes was carried out for each patient. A hierarchical agglomerative clustering method was used to search for clusters of individuals in the evaluated cohort. RESULTS: Cross-allergy to TN and/or other legumes was identified in 137 patients (43.2%), atopic dermatitis being a major risk factor (adjusted OR = 16 [95%CI: 7.4-37]; p<0.001). Three phenotypes emerged from cluster analysis. Cluster 1 (72 patients) is characterized by high level of rAra h 2, low threshold reactive doses for peanut and high proportion of asthma; Cluster 2 (93 patients) is characterized by high threshold reactive doses for peanut and the lowest proportion of cross-allergy to TN and/or legumes; Cluster 3 (152 patients) has a high risk of cross-allergy to TN and/or legumes and most patients suffer from eczema. CONCLUSIONS: The three phenotypes highlighted by the present study could be useful to identify children with high risk of cross-allergic reaction to TNs and legumes early after PA diagnosis.
Role of Commodity Boards in Advancing the Understanding of the Health Benefits of Whole Foods: California Dried Plums.
Food and agriculture commodity boards have become important funders of nutrition research. There are benefits and cautions (biases toward health benefits, failure to publish negative results, and aggressive promotion of single studies) for this activity. The California Dried Plum Board, along with other commodity boards, have developed independent Scientific Nutrition Advisory Panels to guide and evaluate the research they fund. In the case of the California Dried Plum Board, this has resulted in research that has distinguished the nature and dose of dried plum and juice to maintain bowel health and opened up a surprising new function for dried plum in the prevention of age-related bone loss.
Can pan-allergens affect the sensitization pattern?
The present study tested the hypothesis that a pan-allergen sensitization may affect the sensitization pattern. For this reason, 22 sensitization pattern allergens (SPA), common in Genoa (Italy), were selected for analyses. Successively, five of them, such as Pru p 3 as representative for LTP family, Bet v 1 and Pru p 1 for PR-10, and Bet v 2 and Pru p 4 for Profilin, were used as target allergens (TA). This retrospective study included 1059 subjects, (396 males and 663 females, mean age 42.8 years). The current study showed that sensitization to a pan-allergen entails higher odds to have other sensitizations. In addition, the co-sensitization pattern depends on the basis of the sensitizing pan-allergen family. LTP-sensitization is strongly associated with peanut sensitization, PR10 and profiling sensitization with hazelnut positivity. This study shows that a pan-allergen sensitization is frequently associated with co-sensitizations and the sensitization pattern depends on the sensitizing pan-allergen.
A Multi‐Center Study on Anaphylaxis caused by Peanut, Tree Nuts and Seeds in Children and Adolescents.
Peanut (PN) and tree nuts (TNs) are common causes of anaphylaxis in Western countries, but no information is available in Korea. To feature clinical characteristics of anaphylaxis caused by PN, TNs, and seeds, a retrospective medical record review was performed in 14 university hospitals in Korea (2009-2013). One hundred and twenty-six cases were identified, with the mean age of 4.9 years. PN, walnut (WN), and pine nut accounted for 32.5%, 41.3%, and 7.1%, respectively. The median values of specific IgE (sIgE) to PN, WN, and pine nut were 10.50, 8.74, and 4.61 kUA /l, respectively. Among 50 cases managed in the emergency department, 52.0% were treated with epinephrine, 66.0% with steroid, 94.0% with antihistamines, 36.0% with oxygen, and 48.0% with bronchodilator. In conclusion, WN, PN, and pine nut were the three most common triggers of anaphylaxis in Korean children, and anaphylaxis could occur at remarkably low levels of sIgE.
Review suggests that the immunoregulatory and anti‐inflammatory properties of allergenic foods can provoke oral tolerance if introduced early to infants’ diets.
For years, the advice was to postpone introducing allergenic foods, in order to prevent food allergies. However, food allergies have escalated rather than declined and our review of the latest epidemiological, immunological and nutritional research suggests that early weaning practices may be beneficial. The most allergenic foods, such as fish, eggs and peanuts, have proved to be inherently rich in tolerogenic substances that can play a significant role in preventing allergies. CONCLUSION: We found evidence that the immunoregulatory and anti-inflammatory properties of allergenic foods can provoke oral tolerance if introduced early to both low-risk and high-risk infants.
Identifying Epithelial Endocytotic Mechanisms of the Peanut Allergens Ara h 1 and Ara h 2.
BACKGROUND: Peanuts are still one of the highest contributors to anaphylactic deaths after ingestion of a food allergen. At the molecular level, interactions between peanut allergens and the intestinal epithelium are largely unexplored. Previous findings by our research group demonstrated that the major peanut allergens, i.e., Ara h 1, Ara h 2, Ara h 3, and Ara h 6, were able to cross the Caco-2 human cell culture model of the intestinal epithelium. This research broadened our investigation to identify the mechanisms by which the Caco-2 monolayers uptake peanut allergens, specifically by endocytosis. Here, we aim to increase our understanding of allergen-epithelial interactions and, more broadly, the pathway from allergen to allergy. METHODS: The human Caco-2 cell culture model was exposed to peanut extract and a combination of confocal microscopy and inhibition studies were used to identify the endocytotic mechanisms of peanut allergens in intestinal epithelia. RESULTS: Our findings demonstrate that the peanut allergens Ara h 1 and Ara h 2 are transported through intestinal epithelia initially via early endosomes using multiple endocytotic mechanisms. From there, they are then transported to late endosomes and ultimately to lysosomes. CONCLUSIONS: These novel findings provide insight into the allergen-epithelial interactions of peanut allergens with the intestinal epithelium. Consequently, this opens the possibility of the use of these endocytotic pathways as targets for inhibitors in therapeutic development and preventative measures for peanut allergy in the future.
Conjunctival provocation test in diagnosis of peanut allergy in children.
BACKGROUND: Peanut allergy frequently cause severe allergic reactions. Diagnosis include detection of IgE to peanuts in serum or by skin prick tests. While children may have allergic sensitisation without having clinical peanut allergy, oral peanut challenge is often required for accurate diagnosis. The conjunctival provocation test is used for diagnosis and evaluation of treatment effect in inhalant allergies, but it has not been evaluated as a tool for diagnosing peanut allergy. OBJECTIVE: To investigate if the conjunctival provocation tests may be feasible, accurate and safe in diagnosing clinically relevant peanut allergy in patients with suspected peanut allergy. METHODS: This cross-sectional case-control study in children with clinical or laboratory suspected peanut allergy included 102 children recruited from the regional paediatric departments and specialist practices during one year from April 2011. A peanut tolerant control group of 28 children of similar age was recruited locally. A double-blind placebo-controlled conjunctival provocation test with peanut extract was performed in all children, while oral peanut provocation was performed as double-blind placebo-controlled challenge in children with suspected peanut allergy and as an open challenge in the control children. RESULTS: All 81 children with a positive double-blind placebo-controlled oral food challenge also had a positive conjunctival provocation test. None of the children with negative conjunctival provocation test had a positive oral food challenge. The sensitivity and the specificity of the conjunctival provocation test was 0.96 and 0.83 respectively. No children had severe adverse reaction caused by the conjunctival provocation test, whereas 23 children suffered an anaphylactic reaction to the oral food challenge. CONCLUSION & CLINICAL RELEVANCE: Conjunctival allergen challenge appears to be a feasible, accurate and safe in diagnosing children referred for suspected peanut allergy.
Low percentage of clinically relevant pistachio nut and mango co-sensitisation in cashew nut sensitised children.
BACKGROUND: Cashew nut, pistachio nut and mango belong to the Anacardiaceae family and are botanically related. Therefore, cashew nut sensitised children are frequently advised to eliminate cashew nuts and pistachio nuts from their diet. The 'Improvement of Diagnostic mEthods for ALlergy assessment (IDEAL trial number NTR3572) study showed that cashew nut sensitised children were co-sensitised to pistachio nut in 98% of cases and to mango in 21% of cases. The aim of this follow-up study to IDEAL is to assess the clinical relevance of co-sensitisation to pistachio nut and mango in cashew nut sensitised children. METHODS: Children were recruited from the study: 'Improvement of Diagnostic mEthods for ALlergy assessment (IDEAL trial number NTR3572). Inclusion criterion for the IDEAL study was sensitization to cashew nut as demonstrated by either SPT or sIgE, and a clinical history of reactions to cashew nuts or no previous (known) exposure. Sensitized children who were tolerant to cashew nuts were excluded. Inclusion criterion for this IDEAL follow-up study was co-sensitization to pistachio nut, regardless the result of the DBPCFC with cashew nut. In this follow-up study a double-blind placebo-controlled food challenge with pistachio nut and an open food challenge with mango were performed. RESULTS: Twenty-nine children (mean age of 11.6 years, 62% male) were included. Pistachio nut sensitisation was clinically relevant in only 34% of cashew-sensitised children and only 31% of cashew challenge positive children. None of the children was challenge positive to mango. CONCLUSION: Although co-sensitisation between cashew nut and pistachio nut was observed in 98%, pistachio nut sensitisation was only clinically relevant in 34% of the children. Therefore, a challenge test with pistachio nut is recommended in children with cashew nut and pistachio nut sensitisation. Trial registration The study was registered in the Dutch trial register (registration number 3572) on 10 August 2012 (retrospectively registered).
Early introduction of peanuts.
Peanut allergy is the most common food allergy and the leading cause of anaphylaxis and death due to food allergy. Despite previous guidelines created by the American Academy of Pediatrics in 2003, peanut allergy has continued to significantly increase over the past decade. Therefore, further research has been done to help clinicians provide more evidence-based recommendations about the timing of introduction of peanuts. The LEAP study, published in February 2015, demonstrated the value of much earlier introduction of peanuts to nonallergic patients than previously suggested. These findings have altered current practice, and recommendations supported by the American Academy of Pediatrics now allow the introduction of peanuts as early as age 4 months to reduce the likelihood of developing peanut allergy.
Detection of Food Allergens by Taqman Real-Time PCR Methodology.
Real-time PCR (polymerase chain reaction) has shown to be a very effective technology for the detection of food allergens. The protocol described herein consists on a real-time PCR assay targeting the plant ITS (Internal Transcribed Spacer) region, using species-specific primers and hydrolysis probes (Taqman) dual labeled with a reporter fluorophore at the 5' end (6-carboxyfluorescein, FAM) and a quencher fluorophore at the 3' end (Blackberry, BBQ). The species-specific real-time PCR systems (primers/probe) described in this work allowed the detection of different nuts (peanut, hazelnut, pistachio, almond, cashew, macadamia, walnut and pecan), common allergens present in commercial food products, with a detection limit of 0.1 mg/kg.