Case reports of peanut-fenugreek and cashew-sumac cross-reactivity

Relevance of sensitization to legumes in peanut-allergic children

BACKGROUND

Legume consumption has increased during the two past decades. In France, legumes are responsible for 14.6% of food-related anaphylaxis in children, with peanut as the main allergen (77.5%). Few studies have demonstrated cross-reactivities between peanut and other legumes. The aim of this study was to determine prevalence and relevance of sensitization to legumes in peanut-allergic children.

METHODS

All children, aged of 1-17 years, admitted to the Pediatric Allergy Department of the University Hospital of Nancy between January 1, 2017 and February 29, 2020 with a confirmed peanut allergy (PA) and a documented consumption or sensitization to at least one other legume were included. Data were retrospectively collected regarding history of consumption, skin prick tests, specific immunoglobulin E (IgE), prior allergic reactions, and oral food challenges for each legume.

RESULTS

Among the 195 included children with PA, 122 were sensitized to at least one other legume (63.9%). Main sensitizations were for fenugreek (N = 61, 66.3%), lentil (N = 38, 42.2%), soy (N = 61, 39.9%), and lupine (N = 63, 34.2%). Among the 122 sensitized children, allergy to at least one legume was confirmed for 34 children (27.9%), including six children who had multiple legume allergies (4.9%). Lentil, lupine, and pea were the main responsible allergens. Half of allergic reactions to legumes other than peanut were severe.

CONCLUSION

The high prevalence of legume sensitization and the frequent severe reactions reported in children with PA highlight that tolerated legume consumption should be explored for each legume in the case of PA, and sensitization should be investigated if not.

Food-Induced Anaphylaxis: Role of Hidden Allergens and Cofactors

Food anaphylaxis is on the increase, with those who have an allergy to peanuts, tree nuts, milk, and seafood at the highest risk of developing such a reaction. However, the diet in many societies is increasingly varied, much of the food consumed is prepared outside the home, and meals are often composed of many different ingredients. Anaphylaxis may occur to a composite food, and it may be unclear whether the reaction is due to contamination or to a culprit allergen present in an added ingredient. Composite foods can contain many allergic proteins present in small amounts, which do not always have to be labeled, unless they feature in European or US labeling regulations. These “hidden” allergens include mustard, celery, spices, lupine, pea, natural food colourings, and preservatives, but can occasionally include allergenic material from contaminants such as cereal mites. Hidden allergens can provoke severe reactions to seemingly unconnected foods which might then lead to a diagnosis of idiopathic anaphylaxis. The same problem can arise with two well-known types of food allergy; wheat-dependant exercise induced anaphylaxis and allergy to non-specific Lipid Transfer Protein allergens, both of which might only manifest when linked to a cofactor such as exercise. Many of these risk factors for food anaphylaxis have a common link; the public's engagement with popular concepts of health and fitness. This includes the development of a food and exercise culture involving the promotion and marketing of foods for their health-giving properties i.e., meat substitutes, wheat substitutes, supplements and alternative, or “natural” remedies for common ailments. Some of these foods have been reported as the cause of severe allergic reactions, but because they are often viewed as benign unlikely causes of severe allergic reactions, could be considered to be hidden allergens. The best resource to elicit the likelihood of a hidden allergen provoking an allergic reaction is to take a detailed history of the allergic reaction, presence of co-factors, foods suspected, type of food and where it was consumed. A good knowledge of commonly used ingredients, and list of potential hidden allergen suspects are essential tools for the food allergy detective.

IgE Cross-Reactivity of Cashew Nut Allergens

BACKGROUND

Allergic sensitisation towards cashew nut often happens without a clear history of eating cashew nut. IgE cross-reactivity between cashew and pistachio nut is well described; however, the ability of cashew nut-specific IgE to cross-react to common tree nut species and other Anacardiaceae, like mango, pink peppercorn, or sumac is largely unknown.

OBJECTIVES

Cashew nut allergic individuals may cross-react to foods that are phylogenetically related to cashew. We aimed to determine IgE cross-sensitisation and cross-reactivity profiles in cashew nut-sensitised subjects, towards botanically related proteins of other Anacardiaceae family members and related tree nut species.

METHOD

Sera from children with a suspected cashew nut allergy (n = 56) were assessed for IgE sensitisation to common tree nuts, mango, pink peppercorn, and sumac using dot blot technique. Allergen cross-reactivity patterns between Anacardiaceae species were subsequently examined by SDS-PAGE and immunoblot inhibition, and IgE-reactive allergens were identified by LC-MS/MS.

RESULTS

From the 56 subjects analysed, 36 were positive on dot blot for cashew nut (63%). Of these, 50% were mono-sensitised to cashew nuts, 19% were co-sensitised to Anacardiaceae species, and 31% were co-sensitised to tree nuts. Subjects co-sensitised to Anacardiaceae species displayed a different allergen recognition pattern than subjects sensitised to common tree nuts. In pink peppercorn, putative albumin- and legumin-type seed storage proteins were found to cross-react with serum of cashew nut-sensitised subjects in vitro. In addition, a putative luminal binding protein was identified, which, among others, may be involved in cross-reactivity between several Anacardiaceae species.

CONCLUSIONS

Results demonstrate the in vitro presence of IgE cross-sensitisation in children towards multiple Anacardiaceae species. In this study, putative novel allergens were identified in cashew, pistachio, and pink peppercorn, which may pose factors that underlie the observed cross-sensitivity to these species. The clinical relevance of this widespread cross-sensitisation is unknown.

Fenugreek Anaphylaxis in a Pediatric Patient

Fenugreek (Trigonella foenum-graecum) is a food product that belongs to the Leguminosae family along with other legumes. It has been used in India, Greece, and Egypt for culinary and medical purposes since ancient times, and today, fenugreek is used for flavoring foods, dyes, and drugs throughout the world. Many members of the Leguminosae family have been associated with allergies including soybean, green pea, and peanut. Fenugreek is also included in this family and may result in allergic reactions. Two cases of anaphylaxis have been described in children after ingestion of curry and pastes that contain fenugreek, although the true nature of the causative agent was unclear. We report the first case of fenugreek anaphylaxis in a pediatric patient defined by skin testing, immunoglobulin E ImmunoCAP assays, and clear ingestion.

The Journal of Allergy and Clinical Immunology: In Practice 2017 Year in Review

An impressive number of clinically impactful studies and reviews were published in The Journal of Allergy and Clinical Immunology: In Practice in 2017. As a service to our readers, the editors provide this Year in Review article to highlight and contextualize the advances published over the past year. We include information from articles on asthma, allergic rhinitis, rhinosinusitis, immunotherapy, atopic dermatitis, contact dermatitis, food allergy, anaphylaxis, drug hypersensitivity, urticarial/angioedema, eosinophilic disorders, and immunodeficiency. Within each topic, epidemiologic findings are presented, relevant aspects of prevention are described, and diagnostic and therapeutic advances are enumerated. Treatments discussed include behavioral therapy, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We hope this review will help readers consolidate and use this extensive and practical knowledge for the benefit of patients.