Le sarrasin

La farine de sarrasin est un trophallergène puissant. La sensibilisation survient habituellement par ingestion, mais aussi par inhalation au cours d'expositions professionnelles ou domestiques. Les oreillers contenant des cosses de sarrasin peuvent être contaminés par la farine de sarrasin au cours de leur fabrication et représenter une cause d'asthme nocturne chez les individus sensibilisés au sarrasin.

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[3] - Fritz FB, Gold BL. Buckwheat pillow-induced asthma and allergic rhinitis. Ann Allergy Asthma Immunol 2003;90:355-358

BACKGROUND: Immunoglobulin (Ig)E-mediated hypersensitivity is a mechanism suggested to explain adverse reactions to buckwheat. This is the first reported case in the United States of a person who developed asthma and worsening allergic rhinitis after exposure to a buckwheat pillow . OBJECTIVE: To describe a patient who developed asthma and worsening allergic rhinitis after exposure to a buckwheat pillow and to provide evidence that the adverse reaction was IgE-mediated . METHODS: The patient underwent skin prick and ImmunoCAP testing (Pharmacia Diagnostics, Kalamazoo, MI) to buckwheat as well as skin prick testing to several environmental allergens . RESULTS: The patient showed a 4+ skin prick test response to buckwheat. He also showed 4+ positive skin prick responses to multiple trees, grasses, and weeds, Alternaria, Helminthosporium, dog, and histamine control and was 3+ positive to house-dust mites, Penicillium, Aspergillus, cat, and feather mix. His negative control was negative. His ImmunoCAP test for buckwheat-specific IgE was class 4, or strongly positive. He had normal spirometry values. Performance of house-dust mite avoidance measures did not result in improvement of the patient's symptoms. Removal of the patient's two buckwheat pillows resulted in resolution of his asthma and improvement of rhinitis symptoms . CONCLUSIONS: The positive skin prick and ImmunoCAP test to buckwheat along with the positive clinical response to buckwheat pillow elimination support an IgE-mediated mechanism in explaining our patient's buckwheat pillow-induced asthma and allergic rhinitis.

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[4] - Park HS, Nahm DH. Buckwheat flour hypersensitivity: an occupational asthma in a noodle maker. Clin Exp Allergy 1996;26:423-427

BACKGROUND: There have been very few reports of occupational allergies caused by inhalation of buckwheat flour. In this paper, we present a case of occupational asthma and rhinitis caused by buckwheat flour inhalation. METHODS AND RESULTS: The patient had strong positive responses to grass and ragweed pollens as well. The bronchoprovocation test showed early asthmatic response to buckwheat flour extracts. Serum specific IgE antibody to buckwheat flour was detected by enzyme-linked immunosorbent assay (ELISA). In order to further identify the allergenic component of the extracts, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and electroblotting studies were performed. Eight IgE binding components (9-55 kDa) were detected within the buckwheat flour extracts. CONCLUSION: These results suggest that inhalation of buckwheat flour can caused IgE mediated bronchoconstriction.

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[5] - Stember RH. Buckwheat allergy. Allergy Asthma Proc 2006;27:393-395

Buckwheat, which has been abundantly consumed in Asian countries and has been increasingly popular in the United States, Canada, and Europe, can be a potent allergen when ingested or inhaled. A case is reported of a 36-year-old man who experienced nausea, vomiting, urticaria, a sensation of throat closing, inability to speak, dyspnea, and dizziness shortly after ingesting a large portion of buckwheat that required emergency room treatment. In the previous 2 years he had experienced asthma, contact urticaria, allergic conjunctivitis, and allergic rhinitis from sleeping with a buckwheat pillow. Six months after the first ingestion reaction, the patient again experienced anaphylaxis requiring emergency treatment when he accidentally ate crackers with a small amount of buckwheat. Skin-prick testing showed a strong positive response to buckwheat, and a radioallergosorbent assay test was highly positive to buckwheat. It is possible that inhaled buckwheat provoking asthma sensitized the patient before his two episodes of ingestion anaphylaxis. Buckwheat is a potent allergen that can induce various clinical manifestations in the same individual.

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[6] - van Ginkel CJ. [Sensitisation to 'poffertjes' as a result of sleeping on a pillow containing buckwheat]. Ned Tijdschr Geneeskd 2002;30:624-625

A 19-year-old man suffered an anaphylactic reaction after eating 'poffertjes' (small Dutch pancakes). This reaction appeared to be the result of an IgE-mediated allergy to buckwheat, a principal ingredient of 'poffertjes'. It is highly likely that the patient was sensitised by sleeping on a pillow stuffed with buckwheat husk.

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[7] - Imai T, Ebisawa M. Nationwide Survey of Immediate Type Food Allergy in Japan. AAAAI 60th Annual Meeting, San Francisco, 19-23 March 2004, Poster n°491

Rationale To understand the current condition of food allergy in Japan, we investigated the immediate type food allergy cases in the past two years in collaboration with more than 2000 doctors. Method s : We sent questionnaire to contributing doctors every three months from 2001 to 2002. Contributing doctors were asked to report immediate type food allergy cases seen by those doctors by mail. The details of questionnaire consisted of age, sex, cause of food allergy, symptoms, IgE CAPRAST, and type of treatment. To only focus on the immediate type food allergy, cases were restricted to the cases, of which symptoms occurred within one hour after ingestion of suspected food. Result s : The total number of reported cases reached 3882 cases. Although reported cases ranged from 0 to 80 years old, 50% of reported cases (1969) were below 2 years old. The most common cause was hen's egg (38.3%), followed by cow's milk (15.9%), wheat (8%), shellfish (6.2%), fruits (6%), buckwheat (4.6%), fish (4.4%) and peanuts (2.8%). Interestingly, the cause of food allergy was completely different from childhood to adulthood. Food-induced anaphylaxis was seen in 10.9% out of reported cases. Compared to our previous investigation, fruits allergy such as kiwi and banana seemed to be increasing trend in our society. Conclusions : Based on these data, countermeasures against food allergy are on going in collaboration with the Ministry of Health, Labor, and Welfare in Japan in order to improve quality of life of patients with food allergy.

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[8] - Beaudouin E, Sergeant P, Douillet C, Vidal G, Hassoun S, Jacson F, et al. Allergie alimentaire au sarrasin : analyse des 22 observations publiées par le réseau d'Allergo-Vigilance (2002-2006). Alim'Inter 2007;12:119-123

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[9] - Plaza T, Mahler V. [Anaphylactic shock due to French galette. Type I allergic reaction to buckwheat]. Hautarzt 2005;56:160-163

A 37-year-old woman twice developed a life-threatening anaphylactic reaction after eating galettes, a special French pancake from Brittany. She had tolerated ordinary pancakes and crepes for many years. The allergological work-up revealed a Type I allergic reaction to buckwheat contained in the galettes. A prick test to buckwheat was positive and specific IgE antibodies to buckwheat were found in her serum. In contrast to wheat, buckwheat is not a cereal but a gluten-free knot-grass, initially from Asia. Whenever a patient suffers from allergic reactions due to pastries, a buckwheat allergy should be considered.

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[10] - Bessot JC, Kopferschmitt MC, Pauli G, Pradalier A, Vincent D, Cohen-Jonathan C. Réactions anaphylactiques à la farine de sarrasin. Rev Fr Allergol Immunol Clin 1995;35:444-446

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[11] - Baruteau J, Sadani G, Jourdan C, Morelle K, Broué-Chabbert A, Rancé F. Allergie au sarrasin : à propos d'une observation chez l'enfant et revue de la littérature. Rev Fr Allergol Immunol Clin 2005;45:422-425

L'allergie au sarrasin est une allergie émergente en raison de son utilisation croissante dans l'industrie agroalimentaire. Le sarrasin est aussi fréquemment utilisé comme céréale de substitution chez les enfants atteints de maladie c˛liaque. Il faut évoquer une allergie au sarrasin devant les symptômes classiques de l'allergie alimentaire. Les signes sont parfois sévères. Il existe une allergie croisée démontrée entre sarrasin et latexˆfruits et légumes du groupe latex qui mérite d'être recherchée systématiquement en cas d'allergie prouvée au sarrasin. Les données de la littérature sont discutées à partir d'une observation pédiatrique.

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[12] - Tanaka K, Matsumoto K, Akasawa A, Nakajima T, Nagasu T, Iikura Y, et al. Pepsin-Resistant 16-kD Buckwheat Protein Is Associated with Immediate Hypersensitivity Reaction in Patients with Buckwheat Allergy. Int Arch Allergy Immunol 2002;129:49-56

Background: Buckwheat is becoming popular in many countries as a health food and the incidence of buckwheat allergy is increasing in Asia. The ingestion of small amounts sometimes provokes an anaphylactic reaction. However, it remains controversial which is the major allergen responsible for such reactions. Methods: The patients whose sera are positive for buckwheat-specific IgE antibody measured by the CAP system fluorescein-enzyme immunoassay (CAP-FEIA) were classified into two subgroups depending on the history of immediate hypersensitivity reactions (IHR). Major buckwheat allergens were identified with immunoblotting, ELISA and N-terminal amino acid sequencing. Various treatments such as pepsin digestion were added to characterize the proteins. Results: We found that the 24-kD protein that had previously been reported to be a major allergen reacted to IgE antibodies present in sera from almost all subjects (19/20) regardless of symptoms. On the other hand, 16- and 19-kD proteins were bound with IgE antibodies present in sera from 9 of the 10 patients with IHR including 8 patients with anaphylaxis but not in sera from buckwheat-specific IgE-positive subjects without IHR. After pepsin treatment, the 16-kD protein but not the 19- and 24-kD proteins remained undigested and preserved the capacity of IgE binding. This pepsin-resistant 16-kD protein had no homology with the 24-kD protein by the N-terminal amino acid sequencing. Conclusions: The 16-kD buckwheat protein was resistant to pepsin digestion and appeared to be responsible for IHR including anaphylaxis, while the pepsin-sensitive 24-kD protein was responsible for CAP-FEIA but not IHR.

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[13] - Beaudouin E, Sergeant P, Douillet C, Vidal G, Hassoun S, Jacson F, et al. Allergie alimentaire au sarrasin : analyse des 22 observations publiées par le réseau d'Allergo-Vigilance (2002-2006). Alim'Inter 2007;12:119-123

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[14] - Baruteau J, Sadani G, Jourdan C, Morelle K, Broué-Chabbert A, Rancé F. Allergie au sarrasin : à propos d'une observation chez l'enfant et revue de la littérature. Rev Fr Allergol Immunol Clin 2005;45:422-425

L'allergie au sarrasin est une allergie émergente en raison de son utilisation croissante dans l'industrie agroalimentaire. Le sarrasin est aussi fréquemment utilisé comme céréale de substitution chez les enfants atteints de maladie c˛liaque. Il faut évoquer une allergie au sarrasin devant les symptômes classiques de l'allergie alimentaire. Les signes sont parfois sévères. Il existe une allergie croisée démontrée entre sarrasin et latexˆfruits et légumes du groupe latex qui mérite d'être recherchée systématiquement en cas d'allergie prouvée au sarrasin. Les données de la littérature sont discutées à partir d'une observation pédiatrique.

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[15] - Bessot JC, Kopferschmitt MC, Pauli G, Pradalier A, Vincent D, Cohen-Jonathan C. Réactions anaphylactiques à la farine de sarrasin. Rev Fr Allergol Immunol Clin 1995;35:444-446

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[16] - Bourrier T, Noormahomed T, Coache M, Albertini M, Boutte P. Un cas d'allergie au sarrasin chez l'enfant. Rev Fr Allergol Immunol Clin 2003;43:530-532

Utilisé sous forme de farine, le sarrasin souvent responsable d'allergies respiratoire et alimentaire en Asie, est encore rarement rapporté en Europe. Voici un nouveau cas pédiatrique.

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[17] - Noma T, Yoshizawa I, Ogawa N, Ito M, Aoki K, Kawano Y. Fatal buckwheat dependent on exercise-induced anaphylaxis. Asian Pac J Allergy Immunol 2001;19:283-286

Cases of food-dependent exercise-induced anaphylaxis (FEA) caused by buckwheat have been rare. Clinical, laboratory, and autopsy findings are present on an 8-year old girl with FEA caused by Japanese buckwheat. The patient consumed buckwheat noodles called "zaru soba" and immediately thereafter swam vigorously. Approximately 30 minutes later, she complained of abdominal pain, vomiting, coughing, and chest discomfort. Another ten minutes later her consciousness level deteriorated and she experienced cardiorespiratory arrest. The heart beat was restored and she was admitted to the hospital. She never regained consciousness and expired after another arrest 13 days later. Her IgE level was high (2,840 IU/ml) and the IgE-radioallergosorbent test (RAST) score was 2 for soybeans, 3 for buckwheat, 2 for rice, and 3 for wheat. An exaggerated hematemesis that occurred immediately after hospital admission indicated an inflammatory condition of the digestive tract that was caused by buckwheat. Marked ulceration accompanied with hemorrhage and necrosis was noted at the ileum. Extensive hemorrhage involving the endotracheal pulmonary field and lymphocyte infiltration of the alveolar space likely appeared after the inflammation. The analysis of buckwheat-specific IgE antibody by immunoblotting showed 7 bands that reacted with the IgE of the patient's serum, 4 bands: 16, 20, 24, and 58 kDa, were specific to the patient as compared to subjects not allergic to buckwheat. A first case of fatal FEA by buckwheat is reported with reference to specific IgE.

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[18] - Mittaine M, Sordet C, Culerrier R, Barre A, Rougé P, Didier A. Anaphylaxie au sarrasin par voie inhalée. Rev Fr Allergol Immunol Clin 2008;48:106-108

Une jeune fille présente un tableau de choc anaphylactique, après être entrée dans une crêperie, mais... avant toute consommation alimentaire ! Le bilan allergologique montre une sensibilisation aux acariens et au sarrasin. L'histoire clinique et le bilan allergologique font suspecter les allergènes de sarrasin aéroportés dans la genèse de cette réaction anaphylactique. En immuno-empreinte, le sérum de la patiente réagit contre une albumine 2S, allergène majeur du sarrasin, mais aussi contre une globuline 13S, dont le rôle dans la réaction par voie aéroportée reste à déterminer. Le sarrasin est répandu en Asie dans l'alimentation et pour usages domestiques. En Occident, sa consommation revient à la mode. Notre cas clinique est un nouvel exemple de réaction sévère à cet allergène, déjà décrit comme responsable de réactions graves par voie inhalée comme par voie ingérée.

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[19] - Yang MS, Lee SH, Kim TW, Kwon JW, Lee SM, Kim SH, et al. Epidemiologic and clinical features of anaphylaxis in Korea. Ann Allergy Asthma Immunol 2008;100:31-36

BACKGROUND: Little is known about the characteristics of anaphylaxis in Korea or even in Asia. OBJECTIVE: To evaluate the incidence of anaphylaxis and the clinical features of patients with anaphylaxis in a Korean tertiary care hospital. METHODS: We performed a retrospective review from January 1, 2000, through July 31, 2006, of 138 patients with anaphylaxis, including inpatients, outpatients, and emergency department visitors, in the Seoul National University Hospital. RESULTS: Among 978,146 patients, 138 (0.014%) had anaphylaxis. Two cardiopulmonary resuscitations were performed and 1 death occurred. The total mortality rate of anaphylactic patients was 0.0001%. The causes of anaphylaxes were drug (35.3%), food (21.3%), food-dependent exercise-induced (13.2%), idiopathic (13.2%), insect stings (11.8%), exercise induced (2.9%), blood products (1.5%), and latex (0.7%). Radiocontrast media and buckwheat were the leading causes of drug and food anaphylaxis, respectively. The organs most frequently involved in the anaphylaxis were cutaneous (95.7%), cardiovascular (76.8%), and respiratory (74.6%). The most common manifestations were dyspnea (71.3%), urticaria (81.9%), and angioedema (69.4%). Three of 138 patients (2.2%) had biphasic reactions. CONCLUSIONS: The incidence, mortality rate, and clinical features of Korean patients with anaphylaxis were similar to rates for patients from other countries, despite some differences in causative agents.

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[20] - Imamura T, Kanagawa Y, Ebisawa M. A survey of patients with self-reported severe food allergies in Japan. Pediatr Allergy Immunol 2008;19:270-274

Food allergies have increased in recent years in Japan. Details of causative foods, places where anaphylaxis developed, and other allergic factors remain unknown, and we investigated them. A'questionnaire survey for the prevention of food allergies' was conducted using a nationwide group of patients with food allergies. A total of 1383 patients from 878 families (including 319 patients who experienced anaphylaxis) provided valid answers to the questionnaire. The average age of the first anaphylactic attack was 3.20 +/- 6.327 yr. The most common allergens causing anaphylaxis were in order milk, eggs, wheat, peanuts, and soybeans, followed by sesame and buckwheat. The most common place where anaphylaxis developed was the patient's own home, followed by fast food restaurants, places visited, restaurants, and schools. In patients' own homes, fast food restaurants (buffet), places visited and schools, the most common allergens were milk, eggs, and wheat. In restaurants and accommodation facilities, eggs were the most common allergen followed by milk. As possible food allergies can cause anaphylaxis, it is necessary to provide precise information for consumers regarding packaged and processed foods.

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[21] - Heffler E, Guida G, Badiu I, Nebiolo F, Rolla G. Anaphylaxis After Eating Italian Pizza Containing Buckwheat as the Hidden Food Allergen. J Investig Allergol Clin Immunol 2007;17:261-263

A 20-year-old woman developed anaphylaxis after eating pizza on 4 different occasions in 2 restaurants. Both restaurants made their pizza dough with a mixture of wheat and buckwheat flours. A prick-to-prick test with buckwheat flour was positive. Skin prick tests and specific immunoglobulin E responses to soybean and peanut were weakly positive while the response to buckwheat was negative. We ruled out a pathogenic role for peanut and soybean because the patient usually eats both with no signs of allergic reaction. Double-blind, placebo-controlled food challenges with buckwheat flour were positive after the administration of a cumulative dose of 2.3 g of the culprit flour. To our knowledge, our report describes the first case of anaphylaxis after intake of buckwheat flour as the hidden allergen in pizza dough.

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[22] - Wüthrich B, Trojan A. Wheatburger anaphylaxis due to hidden buckwheat. Clin Exp Allergy 1995;25:1263

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[23] - Beaudouin E, Sergeant P, Douillet C, Vidal G, Hassoun S, Jacson F, et al. Allergie alimentaire au sarrasin : analyse des 22 observations publiées par le réseau d'Allergo-Vigilance (2002-2006). Alim'Inter 2007;12:119-123

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[24] - Sergeant P, Beaudouin E. Régime d'éviction du sarrasin. Alim'Inter 2007;12:125

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[25] - Tanaka K, Matsumoto K, Akasawa A, Nakajima T, Nagasu T, Iikura Y, et al. Pepsin-Resistant 16-kD Buckwheat Protein Is Associated with Immediate Hypersensitivity Reaction in Patients with Buckwheat Allergy. Int Arch Allergy Immunol 2002;129:49-56

Background: Buckwheat is becoming popular in many countries as a health food and the incidence of buckwheat allergy is increasing in Asia. The ingestion of small amounts sometimes provokes an anaphylactic reaction. However, it remains controversial which is the major allergen responsible for such reactions. Methods: The patients whose sera are positive for buckwheat-specific IgE antibody measured by the CAP system fluorescein-enzyme immunoassay (CAP-FEIA) were classified into two subgroups depending on the history of immediate hypersensitivity reactions (IHR). Major buckwheat allergens were identified with immunoblotting, ELISA and N-terminal amino acid sequencing. Various treatments such as pepsin digestion were added to characterize the proteins. Results: We found that the 24-kD protein that had previously been reported to be a major allergen reacted to IgE antibodies present in sera from almost all subjects (19/20) regardless of symptoms. On the other hand, 16- and 19-kD proteins were bound with IgE antibodies present in sera from 9 of the 10 patients with IHR including 8 patients with anaphylaxis but not in sera from buckwheat-specific IgE-positive subjects without IHR. After pepsin treatment, the 16-kD protein but not the 19- and 24-kD proteins remained undigested and preserved the capacity of IgE binding. This pepsin-resistant 16-kD protein had no homology with the 24-kD protein by the N-terminal amino acid sequencing. Conclusions: The 16-kD buckwheat protein was resistant to pepsin digestion and appeared to be responsible for IHR including anaphylaxis, while the pepsin-sensitive 24-kD protein was responsible for CAP-FEIA but not IHR.

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[26] - Choi SY, Sohn JH, Lee YW, Lee EK, Hong CS, Park JW. Characterization of Buckwheat 19-kD Allergen and Its Application for Diagnosing Clinical Reactivity. Int Arch Allergy Immunol 2007;144:267-274

BACKGROUND: The 19-kD protein of buckwheat (BW) has been suggested to be a major allergen, but its characteristics and clinical significance are poorly defined . METHODS: cDNA of the 19-kD BW allergen was cloned and expressed in Escherichia coli. Allergenicity and cross-allergenicity were confirmed by inhibition immunoblotting or by ELISA inhibition. The recombinant (r19-kD) protein was assessed for clinical utility in the diagnosis of BW reactivity in 18 BW-allergic and 19 BW-asymptomatic sensitized subjects using receiver operating characteristic analysis . RESULTS: The 19-kD BW allergen, which is composed of 135 amino acids, has a weak homology to the vicilin-like allergens of cashew (Ana o 1), English walnut (Jug r 2) and 7 S globulin from Sesamum indicum. The r19-kD protein can inhibit sIgE binding to native 19-kD BW allergen. The maximum percentage inhibition of sIgE binding to crude BW extract was 56%. About 83.3% of the BW allergy patients had sIgE bound to r19-kD protein, compared to only 1 of the 19 BW-asymptomatic sensitized subjects. The areas under the receiver operating characteristic curves for the skin prick tests [0.925 (95% confidence interval: 0.839-1.012), p < 0.001] as well as r19-kD protein sIgE ELISAs [0.860 (95% confidence interval: 0.725-0.995), p <0.001] were higher than that of BW sIgE coated allergen particle test results [0.803 (95% confidence interval: 0.661-0.945), p = 0.002] . CONCLUSIONS: The 19-kD BW allergen may be the major allergen from BW. For the diagnosis of clinical reactivity to BW, the r19-kD protein sIgE ELISA test was more discriminative than the coated allergen particle sIgE measurement using whole BW extract.

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[27] - Park JW, Kang DB, Kim CW, Ko SH, Yum HY, Kim KE, et al. Identification and characterization of the major allergens of buckwheat. Allergy 2000;55:1035-1041

BACKGROUND: Buckwheat (BW) has been recognized as a common food allergen in Korea, Japan, and other countries. Until now, serologic findings of BW food-allergic patients and its major allergenic components have not been clarified. In this study, we analyzed the serologic findings of BW food allergy and characterized its major allergenic components. METHODS: Nineteen BW-allergic subjects with symptoms after BW ingestion and 15 asymptomatic control subjects with positive skin prick test to BW were recruited. BW-specific IgE was measured with the Pharmacia CAP kit. Allergenic components of BW were analyzed by IgE immunoblotting, periodate oxidation, two-dimensonal PAGE, and sequencing of N-terminal amino acids. RESULTS: From the BW-allergic patients and asymptomatic controls, the sensitivity (100%), specificity (53%), and negative (100%) and positive predictive values (73%) of Pharmacia CAP specific IgE for diagnosis were estimated. The prevalence of IgE binding to 24-kDa (pI 8.3), 16-kDa (pI 5.6), and 9-kDa (pI 5.0/ 6.0) allergens was higher than 50% in BW-allergic and asymptomatic subjects. However, the specific IgE to split 19-kDa (pI 6.5/7.0) allergens were more specifically found in BW-allergic patients than in asymptomatic subjects (78% vs 7%). N-terminal amino-acid sequences of 19-kDa and 16-kDa allergens showed moderate and weak homology to the 19-kDa globulin protein of rice and alpha-amylase/trypsin inhibitor of millet, respectively. The N-terminus of the 9-kDa isoallergens were not different from each other and were identified as the reported trypsin inhibitors of BW. Attenuation of the IgE binding to the 9-kDa allergen was found with periodate oxidation. CONCLUSIONS: The allergens of 24, 19, 16, and 9 kDa are strong candidates to be major allergens, and the 19-kDa allergen was relatively specific for BW-allergic patients. Moreover, measurement of BW-specific IgE and the features of immunoblotting should be very useful tools in the diagnosis of BW allergy.

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[28] - Koyano S, Takagi K, Teshima R, Sawada J. Molecular Cloning of cDNA, Recombinant Protein Expression and Characterization of a Buckwheat 16-kDa Major Allergen. Int Arch Allergy Immunol 2006;140:73-81

BACKGROUND: Buckwheat is a common food in Japan, Korea and other countries. A candidate major buckwheat allergen, a 16-kDa protein (BWp16), was previously characterized as a pepsin-resistant protein associated with immediate-type allergies to buckwheat. However, whether recombinant BWp16 can react with a patient's IgE remains uncertain . METHODS: The cDNA encoding BWp16 from Japanese buckwheat seeds was cloned based on the sequences obtained by the 5'-rapid amplification of cDNA ends (RACE) and 3'-RACE PCR. Recombinant BWp16 protein expressed in Escherichia coli was purified using affinity chromatography. Western blotting, ELISA and cross inhibition tests of the purified recombinant BWp16 were performed using sera from patients with positive IgE binding to buckwheat and controls. Pepsin digestion experiments were also performed . RESULTS: The full-length cDNA encodes 149 amino acid residues with a calculated molecular mass of 16.9 kDa. The deduced amino acid sequence included a putative signal peptide sequence. BWp16 showed significant homologies to the buckwheat 8-kDa allergen and Ricinus communis (castor bean) 2S albumin. Sera from patients with positive IgE binding to buckwheat reacted with the purified BWp16. Cross inhibition tests revealed immunological equivalence of the purified recombinant and natural BWp16. The recombinant and natural BWp16 were comparably resistant to pepsin digestion . CONCLUSIONS: BWp16 belongs to the 2S albumin family and is a buckwheat allergen. This purified recombinant BWp16 could be used in the diagnosis of buckwheat allergy.

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[29] - Matsumoto R, Fujino K, Nagata Y, Hashiguchi S, Ito Y, Aihara Y, et al. Molecular characterization of a 10-kDa buckwheat molecule reactive to allergic patients' IgE. Allergy 2004;59:533-538

BACKGROUND: Using the sera from buckwheat (BW)-allergic patients, several putative causative molecules were reported. However, few molecules were determined on the molecular structure. We demonstrated in 2000 that the major allergen with 24 kDa (BW24KD) is a legumin-like storage protein . OBJECTIVE: The aim of this study was to isolate and characterize further a major allergen with 10 kDa by molecular cloning. METHODS AND RESULTS: Buckwheat allergens were identified by immunoblotting analysis using sera from 14 allergic and two nonallergic individuals. We identified a protein with 10 kDa (BW10KD) that reacted with immunoglobulin E (IgE) more strongly than with IgG and IgA in 57% of the allergic patients but not with IgE in nonallergic individuals. Analyses were performed by N-terminal amino acid sequencing and molecular cloning. Physiological significance was assessed by an immunoblotting experiment showing that the reactivity of an allergic patient's serum IgE to BW10KD was competitively inhibited by natural BW extracts . CONCLUSION: Molecular cloning experiments indicated that BW10KD as a BW allergen was a member of the 2S-albumin multigene family.

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[30] - Wang Z, Wang L, Chang W, Li Y, Zhang Z, Wieslander G, et al. Cloning, expression, and identification of immunological activity of an allergenic protein in tartary buckwheat. Biosci Biotechnol Biochem 2006;70:1195-1199

A cDNA fragment encoding a 24 kDa allergenic protein in tartary buckwheat was obtained using reverse transcription PCR, 3'-rapid amplification of cDNA ends (RACE), and nest PCR. The cDNA clone contained 768 nucleotides, including 588 nucleotides in the open reading frame (ORF) and 180 nucleotides in the 3'-terminal sequence. The ORF encoded a functional protein of 195 amino acids. It shared 95% and 93% nucleotide homology with the allergenic storage protein and a legumin-like protein from common buckwheat respectively. The encoding region was expressed in host strain Escherichia coli BL21 (DE3) induced by IPTG at 28 degrees C. The inclusion bodies of recombinant protein obtained were analyzed by western blot and purified by affinity chromatography. The purity of target protein reached above 95%. After they were refolded by step-wise dialysis, 68% of the inclusion bodies reached soluble state. An analysis of immunological activity showed that the recombinant protein had a specific IgE binding activity. This is the first report of the molecular cloning and expression of the major allergen from tartary buckwheat.

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[31] - Nair A, Adachi T. Screening and selection of hypoallergenic buckwheat species. ScientificWorldJournal 2002;2:818-826

Both common buckwheat (Fagopyrum esculentum) flour and meal cause an allergy in sensitive patients, and if unnoticed, it can be fatal. It has become a potential occupational hazard for some mill workers. The development of hypoallergenic buckwheat would be more efficient if natural mutants for allergenic protein are detected. A screening and selection method was developed using SDS-PAGE coupled with PCR techniques. SDS-PAGE analysis of 14 different species of buckwheat revealed that F. lineare and F. urophyllum lack the 22-kDa major allergenic protein. PCR-based screening with specific primers for sequences encoding the allergenic protein was also effective in distinguishing the allergen-deficient species.

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[32] - Choi SY, Sohn JH, Lee YW, Lee EK, Hong CS, Park JW. Characterization of Buckwheat 19-kD Allergen and Its Application for Diagnosing Clinical Reactivity. Int Arch Allergy Immunol 2007;144:267-274

BACKGROUND: The 19-kD protein of buckwheat (BW) has been suggested to be a major allergen, but its characteristics and clinical significance are poorly defined . METHODS: cDNA of the 19-kD BW allergen was cloned and expressed in Escherichia coli. Allergenicity and cross-allergenicity were confirmed by inhibition immunoblotting or by ELISA inhibition. The recombinant (r19-kD) protein was assessed for clinical utility in the diagnosis of BW reactivity in 18 BW-allergic and 19 BW-asymptomatic sensitized subjects using receiver operating characteristic analysis . RESULTS: The 19-kD BW allergen, which is composed of 135 amino acids, has a weak homology to the vicilin-like allergens of cashew (Ana o 1), English walnut (Jug r 2) and 7 S globulin from Sesamum indicum. The r19-kD protein can inhibit sIgE binding to native 19-kD BW allergen. The maximum percentage inhibition of sIgE binding to crude BW extract was 56%. About 83.3% of the BW allergy patients had sIgE bound to r19-kD protein, compared to only 1 of the 19 BW-asymptomatic sensitized subjects. The areas under the receiver operating characteristic curves for the skin prick tests [0.925 (95% confidence interval: 0.839-1.012), p < 0.001] as well as r19-kD protein sIgE ELISAs [0.860 (95% confidence interval: 0.725-0.995), p <0.001] were higher than that of BW sIgE coated allergen particle test results [0.803 (95% confidence interval: 0.661-0.945), p = 0.002] . CONCLUSIONS: The 19-kD BW allergen may be the major allergen from BW. For the diagnosis of clinical reactivity to BW, the r19-kD protein sIgE ELISA test was more discriminative than the coated allergen particle sIgE measurement using whole BW extract.

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[33] - Choi SY, Sohn JH, Lee YW, Lee EK, Hong CS, Park JW. Characterization of Buckwheat 19-kD Allergen and Its Application for Diagnosing Clinical Reactivity. Int Arch Allergy Immunol 2007;144:267-274

BACKGROUND: The 19-kD protein of buckwheat (BW) has been suggested to be a major allergen, but its characteristics and clinical significance are poorly defined . METHODS: cDNA of the 19-kD BW allergen was cloned and expressed in Escherichia coli. Allergenicity and cross-allergenicity were confirmed by inhibition immunoblotting or by ELISA inhibition. The recombinant (r19-kD) protein was assessed for clinical utility in the diagnosis of BW reactivity in 18 BW-allergic and 19 BW-asymptomatic sensitized subjects using receiver operating characteristic analysis . RESULTS: The 19-kD BW allergen, which is composed of 135 amino acids, has a weak homology to the vicilin-like allergens of cashew (Ana o 1), English walnut (Jug r 2) and 7 S globulin from Sesamum indicum. The r19-kD protein can inhibit sIgE binding to native 19-kD BW allergen. The maximum percentage inhibition of sIgE binding to crude BW extract was 56%. About 83.3% of the BW allergy patients had sIgE bound to r19-kD protein, compared to only 1 of the 19 BW-asymptomatic sensitized subjects. The areas under the receiver operating characteristic curves for the skin prick tests [0.925 (95% confidence interval: 0.839-1.012), p < 0.001] as well as r19-kD protein sIgE ELISAs [0.860 (95% confidence interval: 0.725-0.995), p <0.001] were higher than that of BW sIgE coated allergen particle test results [0.803 (95% confidence interval: 0.661-0.945), p = 0.002] . CONCLUSIONS: The 19-kD BW allergen may be the major allergen from BW. For the diagnosis of clinical reactivity to BW, the r19-kD protein sIgE ELISA test was more discriminative than the coated allergen particle sIgE measurement using whole BW extract.

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[34] - Park JW, Kang DB, Kim CW, Ko SH, Yum HY, Kim KE, et al. Identification and characterization of the major allergens of buckwheat. Allergy 2000;55:1035-1041

BACKGROUND: Buckwheat (BW) has been recognized as a common food allergen in Korea, Japan, and other countries. Until now, serologic findings of BW food-allergic patients and its major allergenic components have not been clarified. In this study, we analyzed the serologic findings of BW food allergy and characterized its major allergenic components. METHODS: Nineteen BW-allergic subjects with symptoms after BW ingestion and 15 asymptomatic control subjects with positive skin prick test to BW were recruited. BW-specific IgE was measured with the Pharmacia CAP kit. Allergenic components of BW were analyzed by IgE immunoblotting, periodate oxidation, two-dimensonal PAGE, and sequencing of N-terminal amino acids. RESULTS: From the BW-allergic patients and asymptomatic controls, the sensitivity (100%), specificity (53%), and negative (100%) and positive predictive values (73%) of Pharmacia CAP specific IgE for diagnosis were estimated. The prevalence of IgE binding to 24-kDa (pI 8.3), 16-kDa (pI 5.6), and 9-kDa (pI 5.0/ 6.0) allergens was higher than 50% in BW-allergic and asymptomatic subjects. However, the specific IgE to split 19-kDa (pI 6.5/7.0) allergens were more specifically found in BW-allergic patients than in asymptomatic subjects (78% vs 7%). N-terminal amino-acid sequences of 19-kDa and 16-kDa allergens showed moderate and weak homology to the 19-kDa globulin protein of rice and alpha-amylase/trypsin inhibitor of millet, respectively. The N-terminus of the 9-kDa isoallergens were not different from each other and were identified as the reported trypsin inhibitors of BW. Attenuation of the IgE binding to the 9-kDa allergen was found with periodate oxidation. CONCLUSIONS: The allergens of 24, 19, 16, and 9 kDa are strong candidates to be major allergens, and the 19-kDa allergen was relatively specific for BW-allergic patients. Moreover, measurement of BW-specific IgE and the features of immunoblotting should be very useful tools in the diagnosis of BW allergy.

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[35] - Tanaka K, Matsumoto K, Akasawa A, Nakajima T, Nagasu T, Iikura Y, et al. Pepsin-Resistant 16-kD Buckwheat Protein Is Associated with Immediate Hypersensitivity Reaction in Patients with Buckwheat Allergy. Int Arch Allergy Immunol 2002;129:49-56

Background: Buckwheat is becoming popular in many countries as a health food and the incidence of buckwheat allergy is increasing in Asia. The ingestion of small amounts sometimes provokes an anaphylactic reaction. However, it remains controversial which is the major allergen responsible for such reactions. Methods: The patients whose sera are positive for buckwheat-specific IgE antibody measured by the CAP system fluorescein-enzyme immunoassay (CAP-FEIA) were classified into two subgroups depending on the history of immediate hypersensitivity reactions (IHR). Major buckwheat allergens were identified with immunoblotting, ELISA and N-terminal amino acid sequencing. Various treatments such as pepsin digestion were added to characterize the proteins. Results: We found that the 24-kD protein that had previously been reported to be a major allergen reacted to IgE antibodies present in sera from almost all subjects (19/20) regardless of symptoms. On the other hand, 16- and 19-kD proteins were bound with IgE antibodies present in sera from 9 of the 10 patients with IHR including 8 patients with anaphylaxis but not in sera from buckwheat-specific IgE-positive subjects without IHR. After pepsin treatment, the 16-kD protein but not the 19- and 24-kD proteins remained undigested and preserved the capacity of IgE binding. This pepsin-resistant 16-kD protein had no homology with the 24-kD protein by the N-terminal amino acid sequencing. Conclusions: The 16-kD buckwheat protein was resistant to pepsin digestion and appeared to be responsible for IHR including anaphylaxis, while the pepsin-sensitive 24-kD protein was responsible for CAP-FEIA but not IHR.

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[36] - Koyano S, Takagi K, Teshima R, Sawada J. Molecular Cloning of cDNA, Recombinant Protein Expression and Characterization of a Buckwheat 16-kDa Major Allergen. Int Arch Allergy Immunol 2006;140:73-81

BACKGROUND: Buckwheat is a common food in Japan, Korea and other countries. A candidate major buckwheat allergen, a 16-kDa protein (BWp16), was previously characterized as a pepsin-resistant protein associated with immediate-type allergies to buckwheat. However, whether recombinant BWp16 can react with a patient's IgE remains uncertain . METHODS: The cDNA encoding BWp16 from Japanese buckwheat seeds was cloned based on the sequences obtained by the 5'-rapid amplification of cDNA ends (RACE) and 3'-RACE PCR. Recombinant BWp16 protein expressed in Escherichia coli was purified using affinity chromatography. Western blotting, ELISA and cross inhibition tests of the purified recombinant BWp16 were performed using sera from patients with positive IgE binding to buckwheat and controls. Pepsin digestion experiments were also performed . RESULTS: The full-length cDNA encodes 149 amino acid residues with a calculated molecular mass of 16.9 kDa. The deduced amino acid sequence included a putative signal peptide sequence. BWp16 showed significant homologies to the buckwheat 8-kDa allergen and Ricinus communis (castor bean) 2S albumin. Sera from patients with positive IgE binding to buckwheat reacted with the purified BWp16. Cross inhibition tests revealed immunological equivalence of the purified recombinant and natural BWp16. The recombinant and natural BWp16 were comparably resistant to pepsin digestion . CONCLUSIONS: BWp16 belongs to the 2S albumin family and is a buckwheat allergen. This purified recombinant BWp16 could be used in the diagnosis of buckwheat allergy.

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[37] - Koyano S, Takagi K, Teshima R, Sawada J. Molecular Cloning of cDNA, Recombinant Protein Expression and Characterization of a Buckwheat 16-kDa Major Allergen. Int Arch Allergy Immunol 2006;140:73-81

BACKGROUND: Buckwheat is a common food in Japan, Korea and other countries. A candidate major buckwheat allergen, a 16-kDa protein (BWp16), was previously characterized as a pepsin-resistant protein associated with immediate-type allergies to buckwheat. However, whether recombinant BWp16 can react with a patient's IgE remains uncertain . METHODS: The cDNA encoding BWp16 from Japanese buckwheat seeds was cloned based on the sequences obtained by the 5'-rapid amplification of cDNA ends (RACE) and 3'-RACE PCR. Recombinant BWp16 protein expressed in Escherichia coli was purified using affinity chromatography. Western blotting, ELISA and cross inhibition tests of the purified recombinant BWp16 were performed using sera from patients with positive IgE binding to buckwheat and controls. Pepsin digestion experiments were also performed . RESULTS: The full-length cDNA encodes 149 amino acid residues with a calculated molecular mass of 16.9 kDa. The deduced amino acid sequence included a putative signal peptide sequence. BWp16 showed significant homologies to the buckwheat 8-kDa allergen and Ricinus communis (castor bean) 2S albumin. Sera from patients with positive IgE binding to buckwheat reacted with the purified BWp16. Cross inhibition tests revealed immunological equivalence of the purified recombinant and natural BWp16. The recombinant and natural BWp16 were comparably resistant to pepsin digestion . CONCLUSIONS: BWp16 belongs to the 2S albumin family and is a buckwheat allergen. This purified recombinant BWp16 could be used in the diagnosis of buckwheat allergy.

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[38] - Park JW, Kang DB, Kim CW, Ko SH, Yum HY, Kim KE, et al. Identification and characterization of the major allergens of buckwheat. Allergy 2000;55:1035-1041

BACKGROUND: Buckwheat (BW) has been recognized as a common food allergen in Korea, Japan, and other countries. Until now, serologic findings of BW food-allergic patients and its major allergenic components have not been clarified. In this study, we analyzed the serologic findings of BW food allergy and characterized its major allergenic components. METHODS: Nineteen BW-allergic subjects with symptoms after BW ingestion and 15 asymptomatic control subjects with positive skin prick test to BW were recruited. BW-specific IgE was measured with the Pharmacia CAP kit. Allergenic components of BW were analyzed by IgE immunoblotting, periodate oxidation, two-dimensonal PAGE, and sequencing of N-terminal amino acids. RESULTS: From the BW-allergic patients and asymptomatic controls, the sensitivity (100%), specificity (53%), and negative (100%) and positive predictive values (73%) of Pharmacia CAP specific IgE for diagnosis were estimated. The prevalence of IgE binding to 24-kDa (pI 8.3), 16-kDa (pI 5.6), and 9-kDa (pI 5.0/ 6.0) allergens was higher than 50% in BW-allergic and asymptomatic subjects. However, the specific IgE to split 19-kDa (pI 6.5/7.0) allergens were more specifically found in BW-allergic patients than in asymptomatic subjects (78% vs 7%). N-terminal amino-acid sequences of 19-kDa and 16-kDa allergens showed moderate and weak homology to the 19-kDa globulin protein of rice and alpha-amylase/trypsin inhibitor of millet, respectively. The N-terminus of the 9-kDa isoallergens were not different from each other and were identified as the reported trypsin inhibitors of BW. Attenuation of the IgE binding to the 9-kDa allergen was found with periodate oxidation. CONCLUSIONS: The allergens of 24, 19, 16, and 9 kDa are strong candidates to be major allergens, and the 19-kDa allergen was relatively specific for BW-allergic patients. Moreover, measurement of BW-specific IgE and the features of immunoblotting should be very useful tools in the diagnosis of BW allergy.

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[39] - Matsumoto R, Fujino K, Nagata Y, Hashiguchi S, Ito Y, Aihara Y, et al. Molecular characterization of a 10-kDa buckwheat molecule reactive to allergic patients' IgE. Allergy 2004;59:533-538

BACKGROUND: Using the sera from buckwheat (BW)-allergic patients, several putative causative molecules were reported. However, few molecules were determined on the molecular structure. We demonstrated in 2000 that the major allergen with 24 kDa (BW24KD) is a legumin-like storage protein . OBJECTIVE: The aim of this study was to isolate and characterize further a major allergen with 10 kDa by molecular cloning. METHODS AND RESULTS: Buckwheat allergens were identified by immunoblotting analysis using sera from 14 allergic and two nonallergic individuals. We identified a protein with 10 kDa (BW10KD) that reacted with immunoglobulin E (IgE) more strongly than with IgG and IgA in 57% of the allergic patients but not with IgE in nonallergic individuals. Analyses were performed by N-terminal amino acid sequencing and molecular cloning. Physiological significance was assessed by an immunoblotting experiment showing that the reactivity of an allergic patient's serum IgE to BW10KD was competitively inhibited by natural BW extracts . CONCLUSION: Molecular cloning experiments indicated that BW10KD as a BW allergen was a member of the 2S-albumin multigene family.

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[40] - Park JW, Kang DB, Kim CW, Ko SH, Yum HY, Kim KE, et al. Identification and characterization of the major allergens of buckwheat. Allergy 2000;55:1035-1041

BACKGROUND: Buckwheat (BW) has been recognized as a common food allergen in Korea, Japan, and other countries. Until now, serologic findings of BW food-allergic patients and its major allergenic components have not been clarified. In this study, we analyzed the serologic findings of BW food allergy and characterized its major allergenic components. METHODS: Nineteen BW-allergic subjects with symptoms after BW ingestion and 15 asymptomatic control subjects with positive skin prick test to BW were recruited. BW-specific IgE was measured with the Pharmacia CAP kit. Allergenic components of BW were analyzed by IgE immunoblotting, periodate oxidation, two-dimensonal PAGE, and sequencing of N-terminal amino acids. RESULTS: From the BW-allergic patients and asymptomatic controls, the sensitivity (100%), specificity (53%), and negative (100%) and positive predictive values (73%) of Pharmacia CAP specific IgE for diagnosis were estimated. The prevalence of IgE binding to 24-kDa (pI 8.3), 16-kDa (pI 5.6), and 9-kDa (pI 5.0/ 6.0) allergens was higher than 50% in BW-allergic and asymptomatic subjects. However, the specific IgE to split 19-kDa (pI 6.5/7.0) allergens were more specifically found in BW-allergic patients than in asymptomatic subjects (78% vs 7%). N-terminal amino-acid sequences of 19-kDa and 16-kDa allergens showed moderate and weak homology to the 19-kDa globulin protein of rice and alpha-amylase/trypsin inhibitor of millet, respectively. The N-terminus of the 9-kDa isoallergens were not different from each other and were identified as the reported trypsin inhibitors of BW. Attenuation of the IgE binding to the 9-kDa allergen was found with periodate oxidation. CONCLUSIONS: The allergens of 24, 19, 16, and 9 kDa are strong candidates to be major allergens, and the 19-kDa allergen was relatively specific for BW-allergic patients. Moreover, measurement of BW-specific IgE and the features of immunoblotting should be very useful tools in the diagnosis of BW allergy.

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[41] - Choi SY, Sohn JH, Lee YW, Lee EK, Hong CS, Park JW. Application of the 16-kDa buckwheat 2S storage albumin protein for diagnosis of clinical reactivity. Ann Allergy Asthma Immunol 2007;99:254-260

BACKGROUND: The 16-kDa protein of buckwheat (BW) has been implicated as a major allergen in BW allergy. OBJECTIVE: To characterize the 16-kDa allergen and evaluate its clinical significance as an indicator of BW allergy. METHODS: Complementary DNA from the 16-kDa allergen was cloned and expressed in Escherichia coli. Allergenicity was confirmed with IgE immunoblotting or with an enzyme-linked immunosorbent assay. The clinical utility of the recombinant protein (r16 kDa) for diagnosis of BW reactivity was evaluated in 18 BW-allergic and in 20 asymptomatic BW-sensitized subjects. RESULTS: The 16-kDa allergen, composed of 127 amino acids, has 50% homology to the reported 8-kDa BW allergen, which belongs to the 2 S storage albumin. The r16-kDa protein can inhibit specific IgE (sIgE) antibody binding to the native BW 16-kDa allergen but minimally inhibited sIgE binding to crude BW extract. Approximately 77.8% of patients with the BW allergy produced sIgE antibodies to the r16-kDa protein, compared with a complete lack of reactivity in the 20 asymptomatic BW-sensitized subjects. The areas of the receiver operating characteristic curves for the skin prick test (mean, 0.93; 95% confidence interval, 0.85 to approximately 1.01; P < .001) and the rl6-kDa enzyme-linked immunosorbent assay (mean, 0.93; 95% confidence interval, 0.84 to approximately 1.01; P < .001) were higher than the area of the BW IgE measurement curve determined by ImmunoCAP (a system for assaying serum IgE) (mean, 0.80; 95% confidence interval, 0.66 to approximately 0.94; P = .002). CONCLUSIONS: The 16-kDa allergen belongs to the 2 S storage albumin. Measurement of rl6-kDa sIgE was more discriminating than measurement of ImmunoCAP sIgE in whole BW extracts for the diagnosis of clinical reactivity to BW.

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[42] - Park JW, Kang DB, Kim CW, Ko SH, Yum HY, Kim KE, et al. Identification and characterization of the major allergens of buckwheat. Allergy 2000;55:1035-1041

BACKGROUND: Buckwheat (BW) has been recognized as a common food allergen in Korea, Japan, and other countries. Until now, serologic findings of BW food-allergic patients and its major allergenic components have not been clarified. In this study, we analyzed the serologic findings of BW food allergy and characterized its major allergenic components. METHODS: Nineteen BW-allergic subjects with symptoms after BW ingestion and 15 asymptomatic control subjects with positive skin prick test to BW were recruited. BW-specific IgE was measured with the Pharmacia CAP kit. Allergenic components of BW were analyzed by IgE immunoblotting, periodate oxidation, two-dimensonal PAGE, and sequencing of N-terminal amino acids. RESULTS: From the BW-allergic patients and asymptomatic controls, the sensitivity (100%), specificity (53%), and negative (100%) and positive predictive values (73%) of Pharmacia CAP specific IgE for diagnosis were estimated. The prevalence of IgE binding to 24-kDa (pI 8.3), 16-kDa (pI 5.6), and 9-kDa (pI 5.0/ 6.0) allergens was higher than 50% in BW-allergic and asymptomatic subjects. However, the specific IgE to split 19-kDa (pI 6.5/7.0) allergens were more specifically found in BW-allergic patients than in asymptomatic subjects (78% vs 7%). N-terminal amino-acid sequences of 19-kDa and 16-kDa allergens showed moderate and weak homology to the 19-kDa globulin protein of rice and alpha-amylase/trypsin inhibitor of millet, respectively. The N-terminus of the 9-kDa isoallergens were not different from each other and were identified as the reported trypsin inhibitors of BW. Attenuation of the IgE binding to the 9-kDa allergen was found with periodate oxidation. CONCLUSIONS: The allergens of 24, 19, 16, and 9 kDa are strong candidates to be major allergens, and the 19-kDa allergen was relatively specific for BW-allergic patients. Moreover, measurement of BW-specific IgE and the features of immunoblotting should be very useful tools in the diagnosis of BW allergy.

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[43] - Rougé P, Sordet C, Culerrier R, Granier C, Didier A. Caractérisation des allergènes du sarrasin (Fagopyrum esculentum). Rev Fr Allergol Immunol Clin 2008;48:274-275

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[44] - Choi SY, Sohn JH, Lee YW, Lee EK, Hong CS, Park JW. Application of the 16-kDa buckwheat 2S storage albumin protein for diagnosis of clinical reactivity. Ann Allergy Asthma Immunol 2007;99:254-260

BACKGROUND: The 16-kDa protein of buckwheat (BW) has been implicated as a major allergen in BW allergy. OBJECTIVE: To characterize the 16-kDa allergen and evaluate its clinical significance as an indicator of BW allergy. METHODS: Complementary DNA from the 16-kDa allergen was cloned and expressed in Escherichia coli. Allergenicity was confirmed with IgE immunoblotting or with an enzyme-linked immunosorbent assay. The clinical utility of the recombinant protein (r16 kDa) for diagnosis of BW reactivity was evaluated in 18 BW-allergic and in 20 asymptomatic BW-sensitized subjects. RESULTS: The 16-kDa allergen, composed of 127 amino acids, has 50% homology to the reported 8-kDa BW allergen, which belongs to the 2 S storage albumin. The r16-kDa protein can inhibit specific IgE (sIgE) antibody binding to the native BW 16-kDa allergen but minimally inhibited sIgE binding to crude BW extract. Approximately 77.8% of patients with the BW allergy produced sIgE antibodies to the r16-kDa protein, compared with a complete lack of reactivity in the 20 asymptomatic BW-sensitized subjects. The areas of the receiver operating characteristic curves for the skin prick test (mean, 0.93; 95% confidence interval, 0.85 to approximately 1.01; P < .001) and the rl6-kDa enzyme-linked immunosorbent assay (mean, 0.93; 95% confidence interval, 0.84 to approximately 1.01; P < .001) were higher than the area of the BW IgE measurement curve determined by ImmunoCAP (a system for assaying serum IgE) (mean, 0.80; 95% confidence interval, 0.66 to approximately 0.94; P = .002). CONCLUSIONS: The 16-kDa allergen belongs to the 2 S storage albumin. Measurement of rl6-kDa sIgE was more discriminating than measurement of ImmunoCAP sIgE in whole BW extracts for the diagnosis of clinical reactivity to BW.

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[45] - Yamada K, Urisu A, Morita Y, Kondo Y, Wada E, Komada H, et al. Immediate hypersensitive reactions to buckwheat ingestion and cross allergenicity between buckwheat and rice antigens in subjects with high levels of IgE antibodies to buckwheat. Ann Allergy Asthma Immunol 1995;75:56-61

Immediate hypersensitive reactions induced by buckwheat ingestion are considered to be IgE-mediated. Some subjects, however, develop no immediate adverse reactions after buckwheat ingestion despite high levels of buckwheat-specific antigens IgE. The mechanism is unknown. OBJECTIVE: To investigate the mechanisms. METHODS: RAST for buckwheat and rice and RAST inhibition between these antigens were performed using sera from 23 buckwheat-sensitive subjects and 30 buckwheat-tolerant subjects who had IgE antibodies for both buckwheat and rice. RESULTS: RAST values for buckwheat and rice were significantly correlated with each other (P < .01) in the buckwheat-tolerant group, but not in the buckwheat-sensitive group. This suggests the IgE antibodies from the subjects without any overt symptoms after buckwheat ingestion recognize the cross-reactive epitope between buckwheat and rice, whereas the IgE antibodies from those with immediate reactions to buckwheat ingestion do not. RAST inhibition assays were performed to evaluate this. RAST inhibition of heterogeneous combination of inhibitor and disc antigen such as rice and buckwheat was significantly smaller than that of homologous combination of rice and rice or buckwheat and buckwheat in the group with immediate symptoms after buckwheat ingestion. There was no significant difference in RAST inhibition between homologous and heterogeneous combinations in the group without the symptoms. CONCLUSIONS: There was cross-reactivity with IgE antibodies between buckwheat and rice and IgE antibodies from the buckwheat-tolerant subjects with high levels of IgE antibodies from the buckwheat might recognize the epitopes on buckwheat antigens which cross-react with rice antigens, whereas IgE antibodies from the buckwheat-sensitive subjects might bind to buckwheat-specific epitopes.

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[46] - Lee SY, Lee K, Jeon K, Chun WS. Cross-allergenicity between buckwheat and rice flour using Western-blot and ELISA inhibition assay. AAAAI 57th Annual Meeting, New Orleans, 16-21 March, 2001, Poster n°622

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[47] - Wada E, Urisu A, Kondo Y, Horiba F, Tsuruta M, Yasaki T, et al. [Relationship between immediate hypersensitive reactions by buckwheat ingestion and specific IgE for rice in subject with positive IgE-RAST for buckwheat]. Arerugi 1991;40:1493-1499

IgE-mediated mechanisms are important in immediate hypersensitive reactions (IHR) to buckwheat. However, a part of subjects with high IgE for buckwheat show no IHR to buckwheat ingestion. Inspite of cross-allergenicity between buckwheat and rice, rice ingestion rarely induces IHR even in subjects with high IgE for rice unlike buckwheat-induced IHR. We speculated that there were some relationships between the presence of IHR to buckwheat and recognition of cross-allergenic determinants on buckwheat components with rice components. We examined IgE-RAST for rice in 58 subjects with positive IgE-RAST for buckwheat. IgE-RAST for Dermatophagoides pteronyssinus (Dp), egg white and cow's milk as unrelated antigens with rice were also assessed for a comparison. Subjects (n = 33) without IHR to buckwheat showed higher IgE-RAST values for rice than those (n = 25) with IHR, whereas there were no differences in IgE-RAST values for Dp, egg white and cow's milk between two groups with and without IHR. IgE-RAST values for buckwheat showed significant close correlations to those for rice in subjects without IHR to buckwheat but not in those with IHR. There were no significant correlations between IgE-RAST values for buckwheat and for Dp, egg white or cow's milk in both groups with and without IHR. These results suggested that the IgE from subjects without IHR to buckwheat recognized cross-allergenic determinants with rice on the buckwheat components.

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[48] - Choi SY, Sohn JH, Lee YW, Lee EK, Hong CS, Park JW. Application of the 16-kDa buckwheat 2S storage albumin protein for diagnosis of clinical reactivity. Ann Allergy Asthma Immunol 2007;99:254-260

BACKGROUND: The 16-kDa protein of buckwheat (BW) has been implicated as a major allergen in BW allergy. OBJECTIVE: To characterize the 16-kDa allergen and evaluate its clinical significance as an indicator of BW allergy. METHODS: Complementary DNA from the 16-kDa allergen was cloned and expressed in Escherichia coli. Allergenicity was confirmed with IgE immunoblotting or with an enzyme-linked immunosorbent assay. The clinical utility of the recombinant protein (r16 kDa) for diagnosis of BW reactivity was evaluated in 18 BW-allergic and in 20 asymptomatic BW-sensitized subjects. RESULTS: The 16-kDa allergen, composed of 127 amino acids, has 50% homology to the reported 8-kDa BW allergen, which belongs to the 2 S storage albumin. The r16-kDa protein can inhibit specific IgE (sIgE) antibody binding to the native BW 16-kDa allergen but minimally inhibited sIgE binding to crude BW extract. Approximately 77.8% of patients with the BW allergy produced sIgE antibodies to the r16-kDa protein, compared with a complete lack of reactivity in the 20 asymptomatic BW-sensitized subjects. The areas of the receiver operating characteristic curves for the skin prick test (mean, 0.93; 95% confidence interval, 0.85 to approximately 1.01; P < .001) and the rl6-kDa enzyme-linked immunosorbent assay (mean, 0.93; 95% confidence interval, 0.84 to approximately 1.01; P < .001) were higher than the area of the BW IgE measurement curve determined by ImmunoCAP (a system for assaying serum IgE) (mean, 0.80; 95% confidence interval, 0.66 to approximately 0.94; P = .002). CONCLUSIONS: The 16-kDa allergen belongs to the 2 S storage albumin. Measurement of rl6-kDa sIgE was more discriminating than measurement of ImmunoCAP sIgE in whole BW extracts for the diagnosis of clinical reactivity to BW.

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[49] - Oppel T, Thomas P, Wollenberg A. Cross-Sensitization between Poppy Seed and Buckwheat in a Food-Allergic Patient with Poppy Seed Anaphylaxis. Int Arch Allergy Immunol 2006;140:170-173

The opium poppy, Papaver somniferum L., is the source of both poppy seeds and opium. The commercially available seeds are widely used as ingredients for various kinds of food. IgE-mediated sensitization to poppy seeds is rare, but, if present, clinical symptoms are usually severe. Cross-sensitizations between poppy seeds and other food allergens have been described with sesame, hazelnut, rye grain and kiwi fruit. We report the case of a 17-year-old female with an apparently food-allergic reaction after ingestion of a poppy seed cake. Allergological workup revealed a poppy seed anaphylaxis and led to the identification of a novel cross-sensitization with buckwheat.

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[50] - Rougé P, Sordet C, Culerrier R, Granier C, Didier A. Caractérisation des allergènes du sarrasin (Fagopyrum esculentum). Rev Fr Allergol Immunol Clin 2008;48:274-275

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[51] - Maria Y, Guilloux L. Allergy to natural rubber latex and cross-sensitization to food allergens: is buckwheat a new candidate? Rev Fr Allergol Immunol Clin 1997;37:1218

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[52] - Guinnepain MT, Guilloux L, Laurent J. Cross-reactivity between latex and buckwheat. EAACI 22th Congress, Paris, 7-11 June, 2003, Poster n°30

Background: Allergy to natural latex is frequently associated with hypersensitivity to fruits (banana, avocado, chestnut and kiwi). Few patients who have developed anaphylactic reaction when eating buckwheat Brittany pancakes were also allergic to latex, leading us to suspect a cross-reactivity between these two allergens. Method: A series of such patients (n=35) were investigated. Skin prick-tests were positive to buckwheat in 30/31 and to latex in 25/29. CAP-RASTs were positive to buckwheat (0,49 to 33,4 kU/l) in 16/25 and to latex (1,1 to >100 kU/l) in 17/23. A cross-reactivity was assessed by CAP-RAST-inhibition assay in 10. Results: There was clinical evidence for an association of these two allergies in this series. CAP-RAST-inhibition assay showed reciprocal inhibitions in 3 , and only unilateral in 7 others (only 1 by B). CAP-RAST inhibition of buckwheat by latex was demonstrative as dose-dependent and up to 87%. These results are consistent with a cross-reactivity between buckwheat and latex. Conclusion: Some of the patients allergic to latex are prone to react when eating food containing buckwheat flour. We propose to test buckwheat in patients with latex allergy in order to propose specific avoidance in case of clinical allergy. Similarly, patients with buckwheat allergy must be investigated for latex allergy. These data are suggestive of common epitopes in these two allergens.

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[53] - Schiffner R, Przybilla B, Burgdorff T, Landthaler M, Stolz W. Anaphylaxis to buckwheat. Allergy 2001;56:1020-1021

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[54] - de Maat Bleeker F, Stapel SO. Cross-reactivity between buckwheat and latex. Allergy 1998;53:538-539

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[55] - Abeck D, Börries M, Kuwert C, Steinkraus V, Vieluf D, Ring J. [Food-induced anaphylaxis in latex allergy]. Hautarzt 1994;45:364-367

Contact uticaria and anaphylactic reactions to latex-containing rubber products are being recognized with increasing frequency in all kinds of medical disciplines. Recently a number of reports have been published describing anaphylactic reactions to food items in patients with latex allergy. The cases of three patients who developed anaphylactic reactions to both latex and food items are presented, and the importance of the association of latex and cross-reactivity with food items is stressed. The food items that led to anaphylactic reactions were banana and avocado; banana, avocado and buckwheat; and banana, avocado and tomato. The cross-reactivity of latex to buckwheat and tomato has not been reported before.

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[56] - Sohn MH, Lee SY, Kim KE. Prediction of buckwheat allergy using specific IgE concentrations in children. Allergy 2003;58:1308-1310

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[57] - Satoh R, Koyano S, Takagi K, Nakamura R, Teshima R, Sawada J. Immunological Characterization and Mutational Analysis of the Recombinant Protein BWp16, a Major Allergen in Buckwheat. Biol Pharm Bull 2008;31:1079-1085

Buckwheat allergy is one of the most critical diseases manifested by severe and dangerous symptoms in Japan and other countries. We previously isolated the cDNA encoding protein BWp16, a member of the 2S albumin family with a conserved motif of 8 cysteine (Cys) residues. Comparison of the deduced amino acid sequences of BWp16 and related proteins in the 2S albumin family showed similarities between BWp16 and BW 8-kDa from buckwheat, Ara h 6 from peanuts and Ric c 1 from castor bean. Purified recombinant BWp16 (rBWp16) expressed in Escherichia coli was recognized by >80% of sera from patients with positive for IgE binding to buckwheat. Mutational analysis of rBWp16 revealed that 7 out of 10 mutants in the Cys residues showed weaker IgE binding to patient's serum than wild-type rBWp16 (rBWp16 WT). Mutations of Cys65 and Cys66 in rBWp16 decreased the pepsin digestibility of the protein, and an ELISA inhibition assay revealed a weaker inhibitory effect of rBWp16 C65S than that of rBWp16 WT. These results suggest that the Cys residues, especially Cys65, are involved in the allergenicity of rBWp16. Our findings provide new evidence for the role of Cys residues in 2S albumin family proteins and open the door to the production of hypoallergens and application to safe diagnostic methods and allergen-specific immunotherapy of buckwheat allergy.

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Les allergènes du sarrasin

Réactivités croisées du sarrasin

Diagnostic in vitro d’une allergie au sarrasin

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