Rye flour allergens associated with baker's asthma. Correlation between in vivo and in vitro activities and comparison with their wheat and barley homologues

Background A number of wheat and barley flour proteins that belong to the cereal α-amylase/trypsin inhibitor family have been identified as major allergens associated with baker's asthma. However, the allergenic role of this protein family had not been investigated in rye. Objective To study the allergenicity of flve purified proteins from rye flour which belong to the same inhibitor family, as well as to compare their properties with those of their wheat and barley homologues. Methods In vivo skin-prick tests were carried out in 21 patients with radioallergo-sorbent test (RAST) 2–3 to rye and allergic sensitization mainly to this cereal flour. In addition, sera from all these patients were used to assay the IgE binding capacity of dot blotted purified proteins. Results Three of the rye proteins tested, namely Sec c 1, RDAI-1 and RDAI-3, provoked positive skin-prick tests in more than 50% of patients, although their in vitro reactivity was lower. Different reactivities were found for the rye components compared with their wheat and barley homologues. Statistical analyses showed a significant correlation between the results of in vivo and in vitro tests for seven out of the nine purified proteins considered in this study. Conclusion Members of the rye α-amylase inhibitor family are main allergens involved in allergic reactions to cereal flours. However, different allergenic behaviours were found between homologous allergens from rye, barley, and wheat.     

Asthma induced by inhalation of flour in adults with food allergy to wheat

Background Wheat is one of the major food allergens and it is also an inhalant allergen in workers exposed to flour dusts. Food allergy to wheat in adulthood seems to be rare and has never been reported to be associated with asthma induced by flour inhalation.
Objective The study aimed at detecting adults with food allergy to wheat and screening them for the presence of specific bronchial reactivity to inhaled wheat proteins.
Methods Adults with a history of adverse reactions to ingestion of wheat underwent skin prick test with commercial wheat extract and were assessed for the presence of specific wheat IgE in the sera. Food sensitivity to wheat was confirmed by double-blind, placebo-controlled food challenge (DBPCFC). Specific bronchial reactivity was investigated through a specific bronchial challenge with wheat proteins.
Results In nine patients with evidence of specific IgE response to wheat, a diagnosis of food allergy was made by DBPCFC. Only two subjects had asthma as disease induced by ingestion of wheat. Seven subjects reported a history of respiratory symptoms when exposed to flour dusts. A significant reduction of forced expiratory volume in 1 s (FEV₁) was detected in these seven patients when a specific bronchial challenge with flour proteins was performed. Only three out of seven subjects with asthma induced by flour could be considered occupationally exposed to flour dusts.
Conclusion For the first time, it has been shown that specific bronchial reactivity to wheat proteins can be detected in patients with different disorders associated with food allergy to wheat. The presence of asthma induced by inhaled flour is not strictly related to occupational exposure and it may also occur in subjects not displaying asthma among symptoms induced by wheat ingestion.     

EAACI position paper: Comparing insect hypersensitivity induced by bite,sting, inhalation or ingestion in human beings and animals

Adverse reactions to insects occur in both human and veterinary patients. Systematic comparison may lead to improved recommendations for prevention and treatment in all species. In this position paper, we summarize the current knowledge on insect allergy induced via stings, bites, inhalation or ingestion, and compare reactions in companion animals to those in people. With few exceptions, the situation in human insect allergy is better documented than in animals. We focus on a review of recent literature and give overviews of the epidemiology and clinical signs. We discuss allergen sources and allergenic molecules to the extent described, and aspects of diagnosis, prophylaxis, management and therapy.