ABSTRACT Legumes are dicotyledonous plants belonging to the Fabales order. The main distinctive characteristic of which is their fruit (legumen, seeds contained in pods). This botanical order is formed by three families: Mimosaceae, Caesalpiniaceae and Papilionaceae or Fabacea. The Papilionaceae family includes the most important allergenic species: Lens culinaris (lentil), Cicer arietinum (chick-pea), Pisum sátivum (pea), Arachis hipogea (peanut), Phaseolus vulgaris (bean) y Glycine max (soy). Legumes are an important ingredient in the Mediterranean diet. Among Spanish children, sensitivity to legumes is the fifth most prevalent food allergy. Lentil and chick-pea are the most frequent cause of allergic reactions to legumes in Spanish children. Legumes could be involved in severe allergic symptoms. The different legumes have structurally homologous proteins, but they are not all equally allergenic, thus making it difficult to distinguish in vitro and in vivo cross-reactivity. We have demonstrated by skin tests and CAP that most of the patients are sensitised to more than one species. We have demonstrated a great degree of cross-reactivity among lentil, chick-pea, pea and peanut by ELISA inhibition (> 50 % max. inhibition). Unlike the Anglo-Saxons population, this phenomenon implies clinical sensitisation for many Spanish children. The majority of our patients have had symptoms with more than one legume (median 3 legumes). Thirty-nine patients were challenged (open or simple blind) with two or more legumes and 32 (82 %) reacted to two or more legumes: 43,5 % to 3, 25,6 % to 2, 13 % to 4 legumes. Seventy three per cent of the patients challenged with lentil and pea had positive challenge to both, 69,4 % to lentil and chick-pea, 60 % to chick-pea and 64,3 % to lentil, chick-pea and pea simultaneously. Peanut allergy peanut can be associated to allergy to lentil, chick-pea and pea but less frequently. Contrarily, white bean and overall green bean and soy are well tolerated by children allergic to other legumes. In our study, 82 % of the children allergic to legumes had a sensitisation to pollen. Pea and bean are the legumes with more in vitro cross-reactivity with Lolium perenne, Olea europea and Betula alba. This cross-reactivity could be because of common antigenic determinants or due to the coexistence of pollen and legume allergy. Panallergens implication seems to be less probable. It is important to emphasize that in spite of an evident clinical and immunological cross-reactivity, the diagnosis of legume allergy should not be based only on specific IgE tests. The decision to eliminate one legume from the diet should be based on a positive oral food challenge.
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ABSTRACT: In the past few decades, the prevalence of allergic diseases has deeply increased, with a key role played by food allergies. Legumes seem to play a major role towards the overall increase in the scenario of food allergy, since they are an appreciated source, consumed worldwide, due to their high protein content, variable amounts of lipids and for the presence of vitamins. In literature there are numerous descriptions of adverse reactions after ingestion of uncooked and cooked legumes. Nevertheless, cases of allergic reactions induced by inhaling vapours from cooking legumes have rarely been described. Herein the authors report an update of the literature data on allergic reactions caused by legume steam inhalation, underlying the possible pathogenic mechanism of these atopic events and the knowledge of literature data in paediatric age. The importance of this review is the focus on the clinical aspects concerning legume vapour allergy, referring to literature data in childhood.Allergologia et Immunopathologia 01/2014; DOI:10.1016/j.aller.2013.09.009 · 1.23 Impact Factor
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ABSTRACT: The occurrence of homologous proteins in foods, pollen and latex is the molecular basis of the plant sources' allergenic cross-reactivity. However, there is not a generic cross-reactivity. Each allergic patient is sensitized to particular allergens and even to particular IgE-binding epitopes. Molecular studies on the main panallergens may explain the major plant-food, pollen and latex syndromes. Some examples of the best- characterized plant panallergens are presented. Novel technologies on recombinant proteins and microarrayed allergens will provide allergen-sensitization profiles, associated to food allergies and cross-reactivity, that will enable the diagnosis and prediction of cross-reactions as well as individual treatment of these pathologies.
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ABSTRACT: Legumes are a rich source of proteins but are also potential elicitors of IgE-mediated food allergy. This study aimed to isolate and characterize a major allergen of Phaseolus vulgaris (kidney bean) and determine its allergenicity. Kidney bean allergen was purified using Q Sepharose column (anion exchanger) and eluates with high intensity were pooled to purify protein using Superdex 75 (gel filtration) and C18 column (RP-HPLC). Patients with history of kidney bean allergy were skin prick tested (SPT) with crude kidney bean extract and the purified protein. Specific IgE was estimated in sera by enzyme-linked immunosorbent assay (ELISA). Characterization of purified protein and its cross-reactivity was investigated by immunobiochemical methods. Identification of purified protein was carried out by tandem mass spectrometry. Purified protein appeared as a single band at 31 kDa on SDS-PAGE and showed IgE binding to 88% patients' sera by ELISA and immunoblotting. SPT with purified protein identified 78% hypersensitive patients of kidney bean. Significant release of histamine from sensitized basophils was observed after challenge with purified protein. PAS staining suggested it to be a glycoprotein, but no change in IgE binding was observed after periodate oxidation. The 31 kDa protein remained stable for 60 min on incubation with pepsin. The purified protein had high allergenic potential since it required only 102 ng of self protein for 50% IgE inhibition. Mass spectrometric analysis identified it as Phytohemagglutinin. It also showed hemagglutination with human RBCs. Cross-reactivity was observed with peanut and black gram with IC50 of 185 and 228 ng respectively. CONCLUSIONSIGNIFICANCE: A 31 kDa major allergen of kidney bean was purified and identified as phytohemagglutinin with cross-reactivity to peanut and black gram.PLoS ONE 05/2013; 8(5):e63063. DOI:10.1371/journal.pone.0063063 · 3.53 Impact Factor