Multiple Tree Nut Research Articles

Electrochemical immunosensing of walnut and hazelnut allergenic proteins in processed foods

Nuts are a well-known cause of food allergy and, once this has been diagnosed, due to the likelihood of cross-sensitization to multiple tree nut allergens, their strict avoidance from the diet is advisable. In this context, we present electrochemical bioplatforms to detect traces of hazelnut and walnut in processed foods through the determination of their respective allergenic proteins Cor a 9 and Jug r 1 in a fast and sensitive assay. First, the evaluation of the single determination of both proteins was performed by building sandwich immunoconjugates on the surface of magnetic microbeads relying on specific antibodies unmodified or conjugated to horseradish peroxidase. Amperometric transduction was made upon trapping the magnetic bioconjugates on the surface of disposable carbon electrodes, using the hydroquinone/hydrogen peroxide system. The great analytical performance achieved with the individual platforms (detection limits of 0.12 and 0.56 ng mL−1 for Jug r 1 and Cor a 9, respectively), led us to the individual and dual quantification of both proteins in raw dough and baked cookies incurred with ground nuts. The developed method allowed detecting baked cookies incurred with 0.0025% ground walnut and 0.00002% ground hazelnut with results comparable to those provided by ELISA techniques. The feasibility of performing the dual determination of both allergens in a single run was demonstrated.

Pomegranate seed allergy in a child with multiple tree nut allergies

Pomegranate (Punica granatum) is a fruit-bearing plant of the Lythraceae family that consists of pulp surrounding fleshy seeds. Pomegranate juice and seeds are widely consumed, and rare cases of hypersensitivity reactions to pomegranate have been described elsewhere in the world. In this study, we report what we believe is the first case of immunoglobulin (Ig) E-mediated pomegranate seed allergy in a girl with multiple tree nut allergies in the United States.

The Safety of Multiple Tree Nut Oral Food Challenges Completed on a Single Day

The Safety of Multiple Tree Nut Oral Food Challenges Completed on a Single Day

Tree nut allergies: Allergen homology, cross-reactivity, and implications for therapy.

Tree nut allergy is a potentially life-threatening disease that is increasing in prevalence, now affecting 1% of the general population in the United States. While other food allergies often resolve spontaneously, tree nut allergies are outgrown in less than 10% of cases. Due to the likelihood of cross-sensitization to multiple tree nut allergens, the current treatment guideline is strict avoidance of all nuts once one tree nut allergy has been diagnosed. For example, walnut and pecan are highly cross-reactive, along with cashew and pistachio, but the extent of clinical, IgE-mediated cross-reactivity among other tree nuts remains unclear, therefore making avoidance of all tree nuts a safe approach. There have been recent advances in immunotherapy for food allergies. For instance, there are investigational immunotherapies for milk, egg and peanut allergies, specifically oral immunotherapy, sublingual immunotherapy and epicutaneous immunotherapy. However, there are no large randomized controlled clinical trials for tree nut allergies. Even though there has been less research into tree nut allergy immunotherapies, the evidence of T-cell cross-reactivity among tree nuts exists in animal models and in T cells from allergic patients indicates that immunotherapeutic interventions may be possible. Here, we review the literature regarding epidemiology, allergen homology and cross-reactivity among tree nuts, and explore how current findings can be employed for effective therapy.

Feasibility of mixed nut challenges in children with suspicion of multiple tree nut allergies

Background In children without any previous ingestion of nuts multiple sensitization to tree nuts is common. To minimize the risk of accidental reactions, those children are advised to exclude all nuts from their diets. Multiple food challenges would be needed to determine the presence of clinical relevant tree nut allergies, which is practically impossible. A pilot study to determine the feasibility of a mixed nut challenge in children with suspicion of multiple tree nut allergies was performed.

Usefulness of open mixed nut challenges to exclude tree nut allergy in children.

BackgroundTo minimize the risk of accidental reactions, atopic children with multiple sensitizations to tree nuts are advised to avoid all nuts. Multiple food challenges would be needed to confirm the clinical relevance, but are too burdensome to be practical.The usefulness of open mixed nut challenges in terms of safety, reactions during challenge, tolerance of the challenge material, effect on the elimination diet and satisfaction of the parents was evaluated.FindingsOpen mixed nut challenges were performed in 19 children with a previous negative hazelnut challenge and long term elimination diet for tree nuts. Challenges were negative in 13 (68 %) children, in four (21 %) children (non-severe) allergic symptoms were observed. The challenges were well accepted, safe and efficient. We were able to avoid multiple nut challenges in 15 (79 %) children.ConclusionsOpen mixed nut challenge can efficiently exclude multiple tree nut allergies in children with a lifelong nut free diet and low suspicion of clinical allergy.

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).

The Pattern and Progression of Multiple Tree Nut Allergy in Preschool Children

The Pattern and Progression of Multiple Tree Nut Allergy in Preschool Children

Cross-reactivity of walnut, cashew, and hazelnut legumin proteins in tree nut allergic patients

Rationale Walnut, cashew, and hazelnut contain similar legumin proteins identified as allergens. The aim of this study was to determine if cross-reactivity of IgE specific for the legumin proteins from walnut (Jug r 4), cashew (Ana o 2), and hazelnut (Cor a 9) in sera of tree nut allergic patients could be responsible for multiple tree nut allergies. Methods IgE immunoblotting was performed using sera from three adult subjects with a history of systemic allergic reactions to walnut, cashew and hazelnut to assess IgE reactivity to both recombinant legumin proteins and tree nut extracts. Inhibition blots were conducted to assess the presence ofIgE cross-reactivity between the recombinants and extracts. Results Immunoblot results showed IgE reactivity to both the recombinant legumins and extracts. Inhibition blots revealed pre-incubation of sera with walnut, cashew, or hazelnut extracts resulted in a significant decrease in IgE binding to the recombinant proteins, indicating allergenic cross-reactivity. Pre-incubation of sera with the recombinant legumin proteins was not as effective as the extracts in absorbing out IgE in sera, which completely abolished IgE binding to Ana o 2 and Jug r 4 recombinants in crossed inhibitions for two of the three sera used. Conclusions These results support the hypothesis that multiple tree nut sensitivities observed in allergic subjects may be due to cross-reactive IgE epitopes present in homologous tree nut allergens.

Cross-reactivity between coconut and hazelnut proteins in a patient with coconut anaphylaxis

The medical literature reports few cases of severe allergic reactions to coconut. We encountered a patient with anaphylaxis to coconut and oral symptoms to tree nuts. To identify cross-reactive antibodies between coconut and other tree nuts. We performed commercial radioallergosorbent tests to coconut and various tree nuts using the patient's serum. Skin prick testing was performed to fresh coconut and commercial extracts of coconut, almond, Brazil nut, cashew, pecan, walnut, and hazelnut. Proteins from fresh coconut, commercial coconut extract, and tree nuts were extracted. Immunoblot and inhibition assays were performed to evaluate for cross-reacting IgE antibodies between similar-sized allergens in coconut and hazelnut. Positive skin test results occurred to the coconut and multiple tree nut extracts. In vitro serum specific IgE was present for coconut, hazelnut, Brazil nut, and cashew. Immunoblots demonstrated IgE binding to 35- and 50-kDa protein bands in the coconut and hazelnut extracts. Inhibition assays using coconut demonstrated complete inhibition of hazelnut specific IgE, but inhibition assays using hazelnut showed only partial inhibition of coconut specific IgE. Our study demonstrates the presence of cross-reactive allergens between hazelnut (a tree nut) and coconut (a distantly related palm family member). Because there are many potentially cross-reactive allergens among the tree nuts, we recommend patients with coconut hypersensitivity be investigated for further tree nut allergies.