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Seed storage proteins are extremely stable allergens in nuts, seeds, and legumes and are responsible for the most severe allergic reactions to these foods. The cross-reactivity between seed storage proteins from different sources has not been studied at a molecular level so far. This study aimed to ascertain the cross-reactivity between walnut and hazelnut seed storage proteins using recombinant allergens. Sera from 13 consecutive patients with severe primary walnut and/or hazelnut allergy and hypersensitive to both nuts were studied. IgE specific for rCor a 9, rCor a 14, and rJug r 1 was measured, and inhibition experiments were carried out by measuring IgE reactivity after absorption of patients' sera with freshly prepared walnut extract. All 13 sera showed strong IgE reactivity against walnut 2S albumin, Jug r 1, 12 reacted to hazelnut 2S albumin, Cor a 14, and 8 to the hazelnut legumin, Cor a 9. In inhibition experiments, absorption of sera with whole walnut extract led to the complete disappearance of IgE reactivity to Jug r 1 in 12/13 cases, as expected, but also to the complete disappearance of specific IgE to Cor a 14 in 9/12 sera, and of IgE reactivity to Cor a 9 in 7/8. In the remaining cases a dramatic drop in IgE reactivity was observed. The study shows that patients primarily allergic to either walnut or hazelnut showing a skin or serological reactivity to the other nut also are potentially at risk of severe allergic reactions caused by cross-reactivity between 2S albumins and legumins. [ABSTRACT FROM AUTHOR]

Mosquito bite is usually followed by a local reaction, but severe or systemic reaction may, in rare cases, occur. Allergic reactions to Aedes communis (Ac) may be underestimated due to the lack of reliable diagnostic tools. In this multicenter study, 205 individuals reporting large local reactions to Ac were enrolled and studied for cutaneous or IgE reactivity to Ac, Blattella germanica, Penaeus monodon, and Dermatophagoides pteronyssinus. Extract and molecular IgE reactivity to bees, wasps, hornets, and yellow jacket venoms were also studied in 119 patients with a clinical history of adverse reaction to Hymenoptera. Immunoblot (IB) analysis and immunoCAP IgE inhibition experiments were carried out in selected sera. Ac sensitization was recorded in 96 (46.8%) patients on SPT. Strict relationship between Ac and D. pteronyssinus, B. germanica, P. monodon, or Apis mellifera reactivity on SPT was observed. Ac IgE recognition was seen in 60/131 (45.8%) patients, 49 (81.6%) of them SPT positive, and 5/14 IB reactors. Ac IgE sensitization was associated with Tabanus spp, A. mellifera, Vespula vulgaris, and Polistes dominula reactivity. A strict relationship between Ac IgE reactivity and Api m 1, Api m 2, Api m 3, Api m 5, and Api m 10 was recorded. IgE reactivity to AC was inhibited in 9/15 cases after serum absorption with the A. mellifera extract. Both SPT and IgE Ac reactivity is observed in about half of patients with a history of large local reactions to mosquito bites. The significant relationship between Ac sensitization and either extract or single bee venom components is suggestive of a “bee-mosquito syndrome” occurrence. [ABSTRACT FROM AUTHOR]

Background: Due to unclear reasons, allergy to lipid transfer protein (LTP) is frequent in Mediterranean countries but rare in Northern Europe. Objective: We report a paradigmatic case of primarily airborne sensitization to LTP that might explain the geographical distribution of this type of food allergy. Methods: A 21-year-old woman began having severe perennial rhinitis 6 months after she started working in a wholesale fruit storehouse in Southern Italy where large amounts of fruits, including peaches, were handled; symptoms subsided when she left the workplace for >5 days and relapsed as soon as she was back at work. Later on, she developed severe food allergies to peach, hazelnut, peanut, apricot, plum and tomato. The patient underwent a nasal challenge with peach peel extract, and IgE reactivity was assessed by immunoblot analysis. Results: In vivo and in vitro analyses showed sensitivity to LTP. The nasal challenge with peach peel extract (6 μg protein) induced acute, severe respiratory symptoms. On immunoblot with peach peel extract patient’s serum reacted uniquely against LTP, as demonstrated by inhibition assays with the recombinant peach protein. Conclusion: LTP may induce sensitization via the respiratory tract due to inhalation of air-dispersed food particles, and this may precede the onset of food allergy. If this way of sensitization were effective in the majority of LTP allergic patients (e.g. by exposure to peaches showing intact fuzz in areas where peaches are grown and directly sold on the market) our findings could explain the strange geographical distribution of this type of food allergy. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Lipid transfer protein (LTP) is a widely cross-reacting plant pan-allergen. Adverse reactions to Rosaceae, tree nuts, peanut, beer, maize, mustard, asparagus, grapes, mulberry, cabbage, dates, orange, fig, kiwi, lupine, fennel, celery, tomato, eggplant, lettuce, chestnut and pineapple have been recorded. Objective: To detect vegetable foods to be regarded as safe for LTP-allergic patients. Methods: Tolerance/intolerance to a large spectrum of vegetable foods other than Rosaceae, tree nuts and peanut was assessed by interview in 49 subjects monosensitized to LTP and in three distinct groups of controls monosensitized to Bet v 1 (n = 24) or Bet v 2 (n = 18), or sensitized to both LTP and birch pollen (n = 16), all with a history of vegetable food allergy. Patients and controls underwent skin prick test (SPT) with a large spectrum of vegetable foods. The absence of IgE reactivity to foods that were negative in both clinical history and SPT was confirmed by immunoblot analysis and their clinical tolerance was finally assessed by open oral challenge (50 g per food). Results: All patients reported tolerance and showed negative SPT to carrot, potato, banana and melon; these foods scored positive in SPT and elicited clinical symptoms in a significant proportion of patients from all three control groups. All patients tolerated these four foods on oral challenge. Immunoblot analysis confirmed the lack of IgE reactivity to these foods by LTP-allergic patients. Conclusion: Carrot, potato, banana and melon seem safe for LTP-allergic patients. This finding may be helpful for a better management of allergy to LTP. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Recent studies show that the lipid transfer protein (LTP), the major Rosaceae allergen in patients not sensitized to birch pollen, is a largely cross-reacting allergen. Moreover, it is a potentially hazardous allergen due to its stability upon thermal treatment and pepsin digestion. The present study reports 3 cases of rice-induced anaphylaxis in LTP-allergic patients. In vitro inhibition studies, carried out using LTP purified from both rice and apple as well as whole peach extract, show that LTP was the relevant allergen in these patients and demonstrate the cross-reactivity between rice LTP and peach/apple LTP. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

This case report describes a patient with bee moth-induced rhinoconjunctivitis, asthma and contact urticaria. Immunoblot analysis showed IgE reactivity to two distinct bee moth proteins at 23 and 70 kDa, respectively. ELISA inhibition studies excluded cross-reactivity to the other popular live bait, fly larva. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]