Beer‐induced anaphylaxis: identification of allergens

BACKGROUND: We report on a 21-year-old atopic woman who developed urticaria, angioedema of the face, and wheezy dyspnea shortly after drinking beer and after eating a corn-made snack. METHODS: Skin prick tests and specific IgE determinations to beer ingredients and cereal extracts were performed. Immunoblotting inhibition assays were carried out to investigate possible common allergens shared by barley and malt with corn. RESULTS: Skin prick tests and specific IgE measurements with beer, barley, malt, wheat, corn, rye, rice, and oat flour were positive. Ten pollen-allergic patients showed negative skin tests to beer. Double-blind, placebo-controlled, oral challenge tests with sodium metabisulfite and wheat flour were negative. Immunoblotting demonstrated several IgE-binding bands at 31-56 kDa in malt and barley extracts, and a major band at 38 kDa in the beer extract. Immunoblot inhibition assays showed that malt extract was able to inhibit most of the IgE-binding bands in wheat and corn extracts, whereas corn did not produce significant inhibition to barley and malt extracts. CONCLUSIONS: This patient developed type I hypersensitivity to barley/malt and corn. Although she also showed IgE reactivity to wheat and other cereals, no symptoms were elicited upon ingestion of these cereals, probably indicating latent sensitization to them.     

Urticaria from beer: an immediate hypersensitivity reaction due to a 10-kDa protein derived from barley

BACKGROUND: Urticaria from beer has been reported in atopic patients. In these subjects, the skin-prick test positivity to and presence of specific serum immunoglobulin (Ig)E for barley malt, the basic ingredient used in brewing, suggested a type I hypersensitivity to barley component(s). OBJECTIVE: To identify the beer allergen(s) and to investigate the presence of related proteins in barley. METHODS: Three patients with urticaria from beer and other atopic people, some of them suffering from baker's asthma, were examined for both prick test sensitivity to and the occurrence of serum-specific IgE for partially purified proteins from beer. Allergen identification in beer, malt and barley was performed by immunoblotting. RESULTS: Skin-prick tests and detection of specific IgE by both solid-phase (RAST) and liquid-phase (AlaSTAT) assays demonstrated that the 5-20-kDa beer protein fraction contained the allergen. Immunoblot analysis with sera of patients with urticaria from beer showed that IgE bound only the 10-kDa protein band in beer and malt, whereas a main 16-kDa protein was revealed in barley in addition to a very faint 10-kDa band. With the serum of a patient suffering from baker's asthma no IgE binding bands were observed in beer, whereas specific IgE binding to several proteins, including a major 16-kDa component, were detected for both malt and barley. CONCLUSIONS: Urticaria from beer is an IgE-mediated hypersensitivity reaction induced by a protein component of approximately 10 kDa deriving from barley. This allergen does not seem to be related to the major barley 16-kDa allergen responsible for baker's asthma. Because of the severity of the allergic manifestations to beer we recommend testing atopic patients positive to malt/barley and/or who exhibit urticarial reactions after drinking beer for their sensitivity to this beverage.     

Buckwheat-induced anaphylaxis: a case report.

Buckwheat (Fagopyrum schulentum) is not taxonomically related to wheat and other cereal grains. Buckwheat flour is used as a wheat substitute in breads, biscuits, pancakes, and crepes. Occupational exposure to buckwheat flour has been associated with rhinitis, conjunctivitis, contact urticaria, and occupational asthma. We present a patient who developed urticaria and hypotension after ingestion of buckwheat crepes. Skin testing by the prick technique revealed 3+ positive reaction to buckwheat with negative reactions to other foods including wheat, egg white, and milk. RAST for anti-buckwheat IgE was strongly positive. Buckwheat ingestion is a potential cause of food-related anaphylaxis. There does not appear to be cross-reactivity between buckwheat and wheat allergy.     

Buckwheat-induced anaphylaxis: a case report.

Buckwheat (Fagopyrum schulentum) is not taxonomically related to wheat and other cereal grains. Buckwheat flour is used as a wheat substitute in breads, biscuits, pancakes, and crepes. Occupational exposure to buckwheat flour has been associated with rhinitis, conjunctivitis, contact urticaria, and occupational asthma. We present a patient who developed urticaria and hypotension after ingestion of buckwheat crepes. Skin testing by the prick technique revealed 3+ positive reaction to buckwheat with negative reactions to other foods including wheat, egg white, and milk. RAST for anti-buckwheat IgE was strongly positive. Buckwheat ingestion is a potential cause of food-related anaphylaxis. There does not appear to be cross-reactivity between buckwheat and wheat allergy.     

IgE binding to pepsin-digested water soluble and insoluble wheat proteins

BACKGROUND: Positive skin prick tests to wheat are a common finding among atopic patients, but only a minor fraction of these patients show immediate clinical symptoms after wheat ingestion. The aim of this study was to evaluate the allergenicity of wheat proteins after pepsin treatments. METHODS: Six patients with positive specific IgE and/or skin prick test to soluble wheat proteins and to gluten were studied. Five of them had no symptoms after wheat ingestion and showed a negative oral challenge test. All sera were analysed with extracts obtained after pepsin hydrolysis during different time periods of water-soluble and insoluble wheat proteins by IgE immunoblotting. RESULTS: A pepsin-sensitive allergen of around 35 kDa was recognized by the five atopic negative wheat oral challenge patients in the undigested water-insoluble extract. A patient showing immediate urticaria after wheat ingestion detected a pepsin-resistant allergen with similar molecular weight. Finally, an inhalation-induced asthma patient recognized water-soluble proteins (of around 14 kDa) that could correspond to the alpha-amylase inhibitors. CONCLUSIONS: Our immunoblotting method shows better correlation with the clinical symptoms than skin prick test and CAP results. Pepsin resistance of the acetic acid-soluble wheat proteins may be responsible for the immediate symptoms of the patient who presented immediate urticaria.     

IgE binding to soluble and insoluble wheat flour proteins in atopic and non-atopic patients suffering from gastrointestinal symptoms after wheat ingestion

BACKGROUND: The involvement of IgE-mediated hypersensitivity reactions in the genesis of gastrointestinal symptoms after ingestion of foods containing wheat has been rarely reported. OBJECTIVE: To detect IgE specifically binding to wheat proteins in the sera of atopic and non-atopic patients suffering from gastrointestinal symptoms after ingestion of wheat and to evaluate the reliability of skin prick test and CAP in the diagnosis of food allergy to wheat. METHODS: The sera of patients (10 atopic and 10 non-atopic) previously diagnosed as suffering from irritable bowel syndrome and complaining of symptoms after wheat ingestion were analysed by immunoblotting for IgE binding to water/salt-soluble and insoluble wheat flour proteins. RESULTS: All the atopic patients and only one of the non-atopic patients were positive to wheat CAP. For the patients tested, skin prick test was positive for all the atopic patients and for only one of the non-atopic patients. However, immunoblotting experiments showed the presence of specific IgE to wheat proteins in all the patients. Ten out of 11 of the wheat CAP-positive patients had IgE binding to a soluble 16-kDa band, but the same band was recognized, in a slighter way, by only two out of nine of the wheat CAP-negative patients. Moreover, although almost all of the patients were negative in CAP testing with gluten, 19 out of 20 recognized protein bands belonging to the prolamin fraction. CONCLUSIONS: For the atopic patients the positivity to skin prick test and CAP to wheat was in accordance with the immunoblotting results and a food allergy to wheat could be diagnosed. In these patients a major allergen was a 16-kDa band corresponding to members of the cereal alpha-amylase/trypsin inhibitors protein family, the major allergens involved in baker's asthma. In the non-atopic patients the positive immunoblotting results contrasted with the responses of the allergologic tests, indicating that the allergenic wheat protein preparations currently used are of limited value in detecting specific IgE to wheat and that the fraction of irritable bowel syndrome (IBS) patients with food allergy may be larger than believed.     

Systemic anaphylaxis after the ingestion of pancake contaminated with the storage mite Blomia freemani.

BACKGROUND: Systemic anaphylaxis after the ingestion of mite-contaminated food has rarely been reported. OBJECTIVE: To describe an 8-year-old boy in whom systemic anaphylaxis developed shortly after the ingestion of pancakes prepared with commercial pancake flour. METHODS: The patient underwent skin prick testing for house dust mites and with uncontaminated and mite-contaminated pancake flour. Specific IgE for mites and the main ingredients of the pancake flour were also evaluated, with titers for Der p 1, Der f 1, and Blo t 5 quantitated using immunochemical methods. A sample of pancake flour was examined microscopically for mites. RESULTS: The patient had positive skin prick test results to contaminated pancake flour extract (1 g/5 mL), Dermatophagoides pteronyssinus, and Dermatophagoides farinae but a negative skin test response to uncontaminated pancake flour. The patient's serum specific IgE analysis was positive for antibodies to dust and storage mite allergens. There was no response, however, to the main ingredients of the pancake mix. Microscopic examination of the pancake flour revealed the storage mite Blomia freemani. Using an immunochemical assay, we found that the contaminated flour contained 5.4 microg/g of the allergen Blo t 5 but no Der p 1 or Der f 1. CONCLUSIONS: This patient's anaphylactic episode was the result of ingestion of the storage mite B. freemani. To our knowledge, this is the first reported systemic hypersensitivity reaction caused by this mite anywhere in the world.     

Antigliadin IgE--indicator of wheat allergy in atopic dermatitis

BACKGROUND: Cereal grains are recognized as the cause of adverse reactions in some patients exposed to grain or flour by either inhalation or ingestion. Cereal-related diseases, such as celiac disease and baker's asthma, have been well studied and the causative cereal proteins have been characterized. Although cereals form an essential part of daily nutrition, the allergenic proteins causing symptoms on ingestion in atopic dermatitis (AD) have remained obscure. In this study, we have investigated the allergenic fraction of wheat in AD. METHODS: Skin prick tests (SPT) with a NaCl wheat suspension and the ethanol-soluble wheat gliadin were performed on 18 wheat-challenge-positive or -negative children with AD, six adult AD patients with suspected cereal allergy, and one adult with wheat-dependent exercise-induced urticaria/anaphylaxis. Serum total IgE and specific IgE-antibody levels to wheat and gluten were measured with the radioallergosorbent test (RAST) simultaneously. In addition serum samples of all 25 patients were analyzed by IgE immunoblotting with the ethanol-soluble wheat-protein extract. RESULTS: Thirteen of the AD children were wheat-challenge-positive, 11/12 of them appeared to be positive with gliadin SPT, and all had an elevated gluten RAST value. Those challenge-negative were negative with both gliadin SPT and gluten RAST. Positive wheat SPT and RAST alone were not associated with positive challenges. Four of the adult patients responded to a cereal-free diet, although only two of them appeared to be positive with gliadin SPT and gluten RAST. A broad and intensive staining of gliadin peptides in IgE-immunoblotting studies was seen in challenge-positive children with positive gliadin SPT and/ or gluten RAST. Besides staining of peptides in the main gliadin area of 30-46 kDa, a characteristic finding was the staining of small, <14-kDa proteins with sera of challenge- and gliadin-SPT-positive patients. CONCLUSIONS: We found that wheat-allergic AD patients have IgE antibodies against gliadin that can be detected by both SPT and the sensitive immunoblotting method. This suggests that gliadin peptides are important allergens, and ingestion of wheat causes symptoms of AD. A broad and intensive IgE staining was seen of gliadin peptides against both the previously characterized peptides in the main gliadin area and small, previously uncharacterized peptides of less than 14 kDa. The gliadin SPT and gluten RAST are good screening methods. Further characterization of the IgE-stained gliadin proteins is needed.     

Prediction of challenge test results by flour-specific IgE and skin prick test in symptomatic bakers

Background:  Wheat and rye flours are among the most important allergens causing occupational asthma. Usually, the diagnosis of baker's asthma is based on inhalation challenge tests with flours.
Aims of the study:  To evaluate the relevance of flour-specific serum immunoglobulin E (IgE) and skin prick test (SPT) in the diagnosis of baker's asthma and to define flour-specific IgE concentrations and wheal sizes that allow a prediction of the outcome of challenge testing.
Methods:  Bronchial and nasal challenge tests with wheat (rye) flour were performed in 71 (95) symptomatic bakers. Determinations of flour-specific IgE as well as SPTs were performed in all subjects. Analyses included the calculation of sensitivity, specificity, positive (PPV) and negative predictive values (NPV) at different IgE concentrations and different wheal sizes, and receiver-operating characteristics (ROC) plots with the challenge result as gold standard.
Results:  Thirty-seven bakers were positive in the challenge with wheat flour, while 63 were positive with rye flour. Depending on the flour-specific IgE concentrations (wheal size), PPV was 74–100% (74–100%) for wheat and 82–100% (91–100%) for rye flour, respectively. The minimal cut-off values with a PPV of 100% were 2.32 kU/l (5.0 mm) for wheat flour and 9.64 kU/l (4.5 mm) for rye flour. The shapes of the ROC plots were similar for wheat and rye flour.
Conclusion:  High concentrations of flour-specific IgE and clear SPT results in symptomatic bakers are good predictors for a positive challenge test. Challenge tests with flours may be avoided in strongly sensitized bakers.     

Occupational IgE-mediated allergy to Tribolium confusum (confused flour beetle)

BACKGROUND: We report on IgE-mediated allergy in a worker caused by Tribolium confusum (confused flour beetle). These beetles lived in the "old" flour to which he was exposed in his work. CASE REPORT: A 35-year-old, nonatopic mechanic in a rye crispbread factory developed rhinitis, conjunctivitis, and asthmatic symptoms, as well as urticaria on his wrists, lower arms, hands, neck, and face, during the maintenance and repair of machines contaminated by flour. This flour had been in and on the machines for a long time, and it contained small beetles. The patient did not suffer any symptoms when handling fresh, clean flour. RESULTS: Skin prick tests with standard environmental allergens, storage mites, enzymes, flours, and molds were negative. A prick test with flour from the machines gave a 10-mm reaction. An open application of the same flour caused urticarial whealing on the exposed skin. Prick tests with fresh flour from the factory were negative. A prick test with minced T. confusum from the flour in the machines gave a 7-mm reaction. Histamine hydrochloride 10 mg/ml gave a 7-mm reaction. Specific serum IgE antibodies to T. confusum were elevated at 17.2 kU/l. Prick tests with the flour from the machines were negative in five control patients. CONCLUSIONS: The patient had occupational contact urticaria, rhinitis, conjunctivitis, and asthmatic symptoms from exposure to flour. His symptoms were caused by immediate allergy to the beetle T. confusum. Immediate allergy to this beetle has rarely been reported in connection with respiratory symptoms, but it may be more common. Contact urticaria from this source has not been reported before.     

Wheat anaphylaxis in children

Food anaphylaxis is now the leading known cause of anaphylactic reactions treated in emergency departments, and wheat is one of the most common causes of anaphylaxis. Wheat is an important source of food worldwide. Wheat anaphylaxis is increasingly observed in our clinic. The purpose of this study was to describe the clinical features of wheat-induced anaphylaxis in 19 children for better elucidation of this disease. Children with severe reactions after ingestion of small amounts of wheat were referred to our clinic during a 4-year period. A detailed clinical history was recorded for each of the patients and a skin prick test was performed with wheat allergen extracts. The wheat-specific IgE and total IgE were measured. Grading of anaphylaxis episodes was performed according to a specific grading system. We identified 36 episodes of wheat anaphylaxis in 19 patients. All of the first attacks of wheat anaphylaxis occurred in the first-time ingestion. The most frequent manifestations of the reactions were skin and respiratory symptoms. In this study 78.9% of reactions were moderate and 21.1% of them were severe. All of our patients had positive skin prick tests to wheat. Mean total IgE level was 853.4 ± 455.27 IU/ml, and mean wheat-specific IgE was 70 ± 14.61 Ucs/ml. We conclude that wheat-induced anaphylaxis is a disease that is sufficiently severe, and. prevention of first wheat-induced anaphylaxis episodes is almost impossible. It would, however, probably be good practice to educate physicians to recognize the common clinical manifestations of this disease for early management.     

Wheat Anaphylaxis in Children

Food anaphylaxis is now the leading known cause of anaphylactic reactions treated in emergency departments, and wheat is one of the most common causes of anaphylaxis. Wheat is an important source of food worldwide. Wheat anaphylaxis is increasingly observed in our clinic. The purpose of this study was to describe the clinical features of wheat-induced anaphylaxis in 19 children for better elucidation of this disease. Children with severe reactions after ingestion of small amounts of wheat were referred to our clinic during a 4-year period. A detailed clinical history was recorded for each of the patients and a skin prick test was performed with wheat allergen extracts. The wheat-specific IgE and total IgE were measured. Grading of anaphylaxis episodes was performed according to a specific grading system. We identified 36 episodes of wheat anaphylaxis in 19 patients. All of the first attacks of wheat anaphylaxis occurred in the first-time ingestion. The most frequent manifestations of the reactions were skin and respiratory symptoms. In this study 78.9% of reactions were moderate and 21.1% of them were severe. All of our patients had positive skin prick tests to wheat. Mean total IgE level was 853.4 ± 455.27 IU/ml, and mean wheat-specific IgE was 70 ± 14.61 Ucs/ml. We conclude that wheat-induced anaphylaxis is a disease that is sufficiently severe, and. prevention of first wheat-induced anaphylaxis episodes is almost impossible. It would, however, probably be good practice to educate physicians to recognize the common clinical manifestations of this disease for early management.     

Occupational Rhinoconjunctivitis due to Maize in a Snack Processor: A Cross-Reactivity Study Between Lipid Transfer Proteins From Different Cereals and Peach

We report the case of a snack processor who developed occupational rhinoconjunctivitis due to maize brand exposure during the extrusion process, and who experienced abdominal pain upon drinking beer. The allergens implicated and the cross-reactivity between non-specific lipid transfer proteins (LTPs) from different cereals and peach were investigated. Skin prick tests and specific IgE to cereal flours, pulmonary functions tests and specific conjunctival and inhalation challenges to maize extract were performed. In vitro studies included IgE immunoblotting and ELISA inhibition assays. Skin prick tests with maize flour, maize brand and wheat flour extracts were positive, whereas serum specific IgE was positive only to maize flour. Specific inhalation challenge (SIC) to maize flour did not elicit an asthmatic reaction; however, conjunctival challenge test with the same extract was positive. Patient''s serum recognized IgE-binding bands in the maize and beer extracts corresponding to LTPs. In the ELISA inhibition assays, a significant degree of allergenic cross-reactivity was found between maize and beer LTPs, whereas no cross-reactivity was observed between maize LTP and wheat and peach LTPs.     

Beef-Induced Anaphylaxis Confirmed by the Basophil Activation Test

Beef allergies are relatively rare, especially in adults. However, clinical manifestations can vary from urticaria, angioedema, anaphylaxis to gastrointestinal symptoms. Currently available tests, such as skin testing or in vitro determination of beef-specific immunoglobulin E (IgE), do not provide an accurate diagnosis of beef allergy. The recent development of the basophil activation test (BAT) presents a new opportunity for the diagnosis of food allergies. Here, we report a 37-year-old woman with a history of recurrent generalised urticaria, nausea, vomiting and hypotension after ingestion of beef, suggesting a beef allergy. Although the skin prick test and serum specific IgE to beef, pork and milk allergens showed negative results using commercial kits, the BAT showed significant upregulation of CD203c in a dose-dependent manner compared to both non-atopic and atopic controls. To our knowledge, this is the first case study of beef allergy consisting of a non-IgE-mediated reaction. The detection of food allergies using direct basophil activation is suggested to complement conventional diagnostic tests.     

A case of food-dependent exercise-induced anaphylaxis caused by various foods which contained flour for thirty years]

The patient was a 65-year-old man with chief complaints of flare, swelling, itching and loss of consciousness. He had a history of diabetes diagnosed at the age of 34 years and was receiving medication from a local doctor. He had experienced systemic flare, swelling and loss of consciousness 20 minutes after drinking beer at a party at the age of 34 years. Since that time, he had frequently experienced urticaria and loss of consciousness while taking a walk after eating various foods (all of which contained flour). In February 2001, he experienced systemic flare, swelling and loss of consciousness when he returned home from a walk after eating a meal that included meat dumplings. Laboratory tests on admission showed a serum IgE level of 253 IU/ml, and the IgE level for flour in a RAST was 2.13 UA/ml (class 2). The results of exercise tolerance tests were normal during fasting, after ingestion of food that did not include allergens (wheat, shrimps and crab) and after ingestion of half of a thick slice of white bread, but systemic wheal and flare reactions appeared during an exercise tolerance test after ingestion of one thick slice of white bread. A diagnosis of food-dependent exercise-induced anaphylaxis caused by flour was made on the basis of the results.     

Clinical presentation,allergens, and management of wheat allergy

IgE-mediated allergy to wheat proteins can be caused by exposure through ingestion, inhalation, or skin/mucosal contact, and can affect various populations and age groups. Respiratory allergy to wheat proteins is commonly observed in adult patients occupationally exposed to flour, whereas wheat food allergy is more common in children. Wheat allergy is of growing importance for patients with recurrent anaphylaxis, especially when exercise related. The diagnosis of wheat allergy relies on a consistent clinical history, skin prick testing with well-characterized extracts and specific IgE tests. The accuracy of wheat allergy diagnosis may be improved by measuring IgE responses to several wheat components. However, a high degree of heterogeneity has been found in the recognition pattern of allergens among patient groups with different clinical profiles, as well as within each group. Thus, oral provocation with wheat or the implicated cereal is the reference test for the definitive diagnosis of ingested wheat/cereal allergy.     

Late-onset anaphylaxis to fermented soybeans: the first confirmation of food-induced, late-onset anaphylaxis by provocation test.

BACKGROUND: Late-onset anaphylactic reactions without early-phase reactions are rarely reported. The hypothesized mechanism of late-onset anaphylaxis to fermented soybeans is delayed absorption or release into the bowel rather than an immunologic phenomenon. OBJECTIVES: To investigate the mechanisms of late-onset anaphylaxis to fermented soybeans in 2 patients and to characterize the allergens involved in anaphylaxis caused by fermented soybeans. METHODS: Two patients underwent skin prick-by-prick tests with fermented soybeans as is. We used an open challenge for the provocation test of anaphylaxis and measured changes in plasma histamine, plasma tryptase, serum eosinophil cationic protein, and plasma leukotriene B4 levels in 1 patient. In addition, specific IgE against fermented soybeans and the allergens of fermented soybeans were detected by enzyme-linked immunosorbent assay and immunoblotting, respectively. RESULTS: The results of the prick-by-prick tests with fermented soybeans as is were positive in both patients and negative in control subjects. The challenge with 50 g of fermented soybeans caused generalized urticaria and dyspnea 13 hours after ingestion of fermented soybeans in 1 patient. In addition, his plasma histamine and tryptase levels transiently elevated during the anaphylactic event. In enzyme-linked immunosorbent assay, the patients showed elevated IgE levels to the proteins of fermented soybeans. Serum IgE antibodies of patients 1 and 2 were bound to approximately 5- and 26-kDa proteins in immunoblotting of fermented soybeans, respectively. CONCLUSION: To our knowledge, this is the first report of late-onset anaphylaxis provoked by the challenge test half a day after ingestion of fermented soybeans.     

Wheat omega-5 gliadin is a major allergen in children with immediate allergy to ingested wheat

BACKGROUND: Sensitization to wheat by ingestion can lead to food allergy symptoms and wheat-dependent, exercise-induced anaphylaxis. Sensitization by inhalation causes bakers' asthma and rhinitis. Wheat allergens have been characterized at the molecular level in bakers' asthma and in wheat-dependent, exercise-induced anaphylaxis, in which omega-5 gliadin (Tri a 19) is a major allergen. However, little information is available regarding allergens responsible for hypersensitivity reactions to ingested wheat in children. OBJECTIVE: The aim of this study was to examine whether children with allergy to ingested wheat have IgE antibodies to omega-5 gliadin. METHODS: Sera were obtained from 40 children (mean age, 2.5 years; range, 0.7-8.2 years) with suspected wheat allergy who presented with atopic dermatitis and/or gastrointestinal and/or respiratory symptoms. Wheat allergy was diagnosed with open or double-blinded, placebo-controlled oral wheat challenge. Wheat omega-5 gliadin was purified by reversed-phase chromatography, and serum IgE antibodies to omega-5 gliadin were measured by means of ELISA. In vivo reactivity was studied by skin prick testing. Control sera were obtained from 22 children with no evidence of food allergies. RESULTS: In oral wheat challenge, 19 children (48%) reacted with immediate and 8 children (20%) with delayed hypersensitivity symptoms. Sixteen (84%) of the children with immediate symptoms had IgE antibodies to purified omega-5 gliadin in ELISA. In contrast, IgE antibodies to omega-5 gliadin were not detected in any of the children with delayed or negative challenge test results or in the control children. The diagnostic specificity and positive predictive value of omega-5 gliadin ELISA were each 100% for immediate challenge reactions. Skin prick testing with omega-5 gliadin was positive in 6 of 7 children with immediate challenge symptoms and negative in 2 children with delayed challenge symptoms. CONCLUSION: The results of this study show that omega-5 gliadin is a significant allergen in young children with immediate allergic reactions to ingested wheat. IgE testing with omega-5 gliadin could be used to reduce the need for oral wheat challenges in children.     

Allergy to kiwi in patients with baker's asthma: identification of potential cross-reactive allergens

BACKGROUND: Baker's asthma is a frequent IgE-mediated occupational disorder mainly provoked by inhalation of cereal flour. Allergy to kiwifruit has being increasingly reported in the past few years. No association between both allergic disorders has been described so far. METHODS: Twenty patients with occupational asthma caused by wheat flour inhalation were studied. Kiwi allergens Act d 1 and Act d 2 were purified by cation-exchange chromatography. Wheat, rye, and kiwi extracts, purified kiwi allergens, and model plant glycoproteins were analyzed by IgE immunodetection, enzyme-linked immunosorbent assay (ELISA), and inhibition ELISAs. RESULTS: Kiwifruit ingestion elicited oral allergy syndrome in 7 of the 20 patients (35%) with baker's asthma. Positive specific IgE and skin prick test responses to this fruit were found in all these kiwi allergic patients, and IgE to Act d 1 and Act d 2 was detected in 57% and 43%, respectively, of the corresponding sera. Actinidin Act d 1 and bromelain (harboring cross-reactive carbohydrate determinants) reached above 50% inhibition of the IgE binding to wheat and/or kiwi extracts. CONCLUSIONS: A potential association between respiratory allergy to cereal flour and allergy to kiwifruit has been disclosed. Cross-reactive carbohydrate determinants and thiol-proteaseshomologous to Act d 1 are responsible for wheat-kiwi crossreactivity in some patients.