Search

Background: Sesame seed allergy, a potentially very severe food allergy, seems on the rise worldwide but is still uncommon in Italy. The aim of the present study was to investigate the allergenic profile of Italian sesame seed-allergic patients., Methods: Patients with genuine sesame seed allergy diagnosed over one year in a large number of allergy centers scattered through Italy were considered for the study. Their IgE reactivity to sesame seed allergens was characterized by immunoblot analysis., Results: Eleven sesame seed allergic patients were detected and studied. 10/10 patients showed IgE reactivity against a sesame allergen at about 20 kDa, and 7/10 showed an extremely strong reactivity at about 32 kDa. The same 7 sera reacted also against a 28 kDa allergen, although such reactivity was significantly weaker in 6/7 cases. Eight patients showed IgE reactivity at about 48 kDa, and 5 sera reacted against higher m.w. proteins at about 67 kDa. Two sera showed IgE reactivity at about 43 kDa as well. Only one serum appeared to react to 2S-albumin., Conclusions: Italian sesame seed-allergic patients react mostly against allergens other than those described so far as major ones. A large number of recombinant sesame allergens will be needed for a comprehensive component- resolved diagnosis of allergy to this food.

Background: Shrimp is a frequent cause of food allergy worldwide. Besides tropomyosin, several allergens have been described recently., Objective: We investigated which allergens are involved in Italian shrimp-allergic adults., Methods: Sera from 116 shrimp-allergic patients selected in 14 Italian allergy centers were studied. Skin prick tests with house dust mite (HDM) as well as measurements of IgE to Pen a 1 (shrimp tropomyosin) and whole shrimp extract were performed. All sera underwent shrimp immunoblot analysis, and inhibition experiments using HDM extract as inhibitor were carried out on some Pen a 1-negative sera., Results: Immunoblots showed much variability. IgE reactivity at about 30 kDa (tropomyosin) was found in <50% of cases, and reactivity at about 67 kDa and >90 kDa was frequent. Further reactivities at 14-18, 25, 43-50, about 60 and about 80 kDa were detected. Most subjects had a history of shrimp-induced systemic symptoms irrespective of the relevant allergen protein. IgE to Pen a 1 were detected in sera from 46 (41%) patients. Skin reactivity to HDM was found in 43/61 (70%) Pen 1-negative subjects and inhibition studies showed that pre-adsorption of sera with HDM extract induced a marked weakening of the signal at >67 kDa., Conclusions: Several allergens other than tropomyosin are involved in shrimp allergy in adult Italian patients. Some hitherto not described high molecular weight allergens seem particularly relevant in this population and their cross-reactivity with HDM allergens makes them novel potential panallergens of invertebrates., (Copyright © 2011 S. Karger AG, Basel.)

Background: Lipid transfer protein (LTP), the most frequent cause of primary food allergy in Italy, is a cross-reacting plant pan-allergen. Markers able to predict whether a patient sensitized to a certain food but not yet clinically allergic will develop allergy would be extremely helpful., Objective: It was the aim of this study to investigate the relevance of IgE levels to some plant foods other than Rosaceae as predictors of either local or systemic allergic reaction in LTP-allergic subjects., Methods: One hundred (40 males, 60 females , mean age 29 years) peach-allergic patients monosensitized to LTP seen at 14 Italian centres in 2009 were studied. Walnut, hazelnut, peanut, tomato, rice and/or maize allergy was ascertained by interview and confirmed by positive skin prick test. IgE levels to these foods and to rPru p 3 were measured., Results: Higher levels of IgE to Pru p 3 were associated with a higher prevalence of allergy to hazelnut, peanut and walnut. For all study foods, except rice, median IgE levels in allergic subjects significantly exceeded those in tolerant subjects, though within single allergic groups, the differences between patients reporting systemic or local (oral) symptoms were not significant. Ninety-five percent cut-off IgE levels predictive of clinical allergy were established for study foods although the marked overlaps between allergic and tolerant subjects made them of limited usefulness., Conclusion: Specific IgE levels are only partially predictive of clinical allergy. The reasons why some individuals showing low specific IgE levels develop clinical allergy whereas others showing high IgE levels do not, despite similar exposure to the allergen, remain unclear., (Copyright © 2010 S. Karger AG, Basel.)

Background: Epinephrine is the treatment of choice for acute food-allergic reactions but existing guidelines state that it should be prescribed uniquely to patients who already experienced at least one food-induced anaphylactic episode., Objective: We investigated whether in Italy epinephrine auto-injector is prescribed uniquely following the existing guidelines only, or is allergen-informed as well (i.e., based on the potential risk associated with sensitization to certain food allergens), and hence preventive., Methods: 1110 adult patients (mean age 31 years; M/F 391/719) with food allergy seen at 19 allergy outpatient clinics were studied. Patients with a history of probable anaphylaxis were identified. Subjects were classified as having primary (type 1) and/or secondary (type 2) food allergy and were divided into several subgroups based on the offending allergen/food. Epinephrine prescriptions were recorded and analyzed both as a whole and by sensitizing allergen., Results: Epinephrine was prescribed to 138/1100 (13%) patients with a significant difference between subjects with type-1 and type-2 food allergy (132/522 [25%] vs. 6/629 [1%]; p < 0.001). The epinephrine group included most patients with a history of anaphylaxis (55/62 [89%]) or emergency department visits 106/138 (77%). In some specific subsets, namely fish-, tree nuts-, and lipid trasfer protein (LTP)-allergic patients, epinephrine was prescribed to patients without a history of systemic allergic reactions., Conclusions: Italian allergy specialists prescribe epinephrine auto-injectors both on the basis of clinical history of severe reactions and on a critical analysis of the hazard associated with the relevant protein allergens, which suggests a good knowledge of allergens as well as acquaintance with the guidelines for prescription of emergency medication.

Background: Studies of the prevalence of different types of food allergy in adults are lacking., Objective: To define the prevalence of IgE-mediated food allergies in Italian adults attending allergy clinics and to assess possible differences associated with geographical position and/or dietary habits., Methods: Seventeen allergy outpatient clinics scattered throughout Italy participated to a multi-centre study in 2007. The number of atopic subjects and of food allergic patients along with clinical features were recorded by pre-defined criteria. Patients with unequivocal history of food allergy confirmed by positive skin prick test were included as cases., Results: Twenty five thousand six hundred and one subjects were screened; 12,739 (50%) were atopic, and 1079 (8,5%) had IgE-mediated food allergy. Sixty four percent of patients were females. Overall, the most frequent food allergy was the pollen-food allergy syndrome (55%), which was associated with oral allergy syndrome in 95% of cases and whose frequency decreased southbound. Forty-five percent of patients had a type 1 food allergy, in most cases (72%) caused by fruits and vegetables, and generally associated with a history of systemic symptoms. Type 1 food allergies represented 96% of food allergies in the South. Lipid transfer protein (LTP) accounted for 60% of sensitizations and caused most primary food allergies in all areas., Conclusion: Plant-derived foods cause most food allergies in Italian adults. The pollen-food allergy syndrome is the most frequent type of food allergy followed by allergy to LTP whose frequency increases southbound. The pattern of allergy to certain foods is clearly influenced by specific geographic features such as pollen exposure and dietary habits.

Background: Data about food-induced anaphylaxis in Italy are missing., Objective: It was the aim of this study to detect the main foods/food allergens causing anaphylaxis in Italy., Methods: The frequency of anaphylaxis and the relative importance of many offending foods were assessed in 1,110 adult patients with food allergy diagnosed by common criteria at 19 allergy centres scattered throughout Italy from 1 January to 31 December 2007., Results: Fifty-eight of 1,110 (5%) food-allergic patients experienced at least 1 episode of anaphylaxis. On average, they were older than other food-allergic patients (34 vs. 31 years; p < 0.05). The majority of anaphylactic episodes occurred in patients sensitized to lipid transfer protein (LTP; n = 19), followed by shrimp (n = 10), tree nuts (n = 9), legumes other than peanut (n = 4), and seeds (n = 2); peanut, spinach, celery, buckwheat, wheat, avocado, tomato, fish, meat, and Anisakis caused an anaphylactic reaction in single patients. Among LTP-hypersensitive patients, peach caused 13/19 anaphylactic episodes. Shrimp-allergic patients were significantly older than other patients with food-induced anaphylaxis (p < 0.05), whereas patients allergic to LTP experienced their anaphylactic episodes at a younger age (p < 0.001). The frequency of anaphylaxis among patients sensitized to LTP, shrimp or tree nuts did not differ between northern and central/southern Italy., Conclusion: LTP is the most important allergen causing food-induced anaphylaxis in Italy, peach being the most frequently offending food. Peanut-induced anaphylaxis seems very uncommon. Geographic and environmental differences both between Italy and other countries and within Italy seem to play a relevant role in the pattern of sensitization to foods., (Copyright 2009 S. Karger AG, Basel.)

Carrot is frequently involved in food allergies and oral allergy syndromes, usually in association with other foods. Nevertheless, carrot alone is rarely responsible for severe systemic reactions. We report a case of anaphylactic shock due to the inadvertent ingestion of carrot as a hidden allergen contained in an ice-cream. The etiological role of carrot in provoking the symptoms was thoroughly ascertained through appropriate in vivo and in vitro assays and by excluding, through double-blind placebo-controlled challenge, the involvement of other ingredients of the food. We highlight once again the harm and risks due to hidden food allergens contained in commercial preparations and the importance of thorough patient education and information.

We describe a case of severe systemic reactions caused from poppy seed ingestion. Poppy seeds were suspected to be responsible for the symptoms on the basis of the clinical history. This suspicion was confirmed by skin testing and the prick-prick test. Moreover, a RAST assay was conducted with an extract of fresh food, confirming the presence of specific IgE to poppy seed. Although poppy seeds are not commonly used, we highlight the possible importance of such rare and often hidden sources of allergens.