Enzymatic hydrolysis: a method in alleviating legume allergenicity.

Legumes are involved in IgE mediated food allergy in many countries. Avoidance of allergenic food is the only way to avoid symptomatic reaction. The present study investigated the effect of enzymatic hydrolysis on the allergenicity of three legumes - kidney bean (Phaseolus vulgaris), black gram (Vigna mungo) and peanut (Arachis hypogaea). Soluble protein extracts of the study legumes were sequentially treated by Alcalase(®) and Flavourzyme(®). Allergenicity of hydrolysates was then determined by ELISA, immunoblot, stripped basophil histamine release and skin prick test (SPT). Hydrolysis resulted in the loss of all IgE binding fractions determined by immunoblot in the three legumes. Specific IgE binding in ELISA was reduced by 62.2 ± 7.7%, 87.1 ± 9.6% and 91.8 ± 7.2% in the hydrolysates of kidney bean, black gram and peanut, respectively (p < 0.01). The release of histamine was decreased significantly when sensitized basophils were challenged with hydrolysates as compared to raw extracts. Significant reduction in the biopotency of hydrolysates was also observed in SPT where only 1/10 kidney bean-sensitive individuals, 2/6 black gram-sensitive individuals and 1/7 peanut-sensitive individuals were found positive to their respective hydrolysates. In conclusion, enzymatic hydrolysis is effective in attenuating allergenicity of legume proteins and may be employed for preparing hypoallergenic food extracts.

Wheat threshing dust--a "new allergen" in April-May nasobronchial allergy.

OBJECTIVE: To identify the allergen(s) responsible for mid April-mid May nasobronchial allergy seen in North India. DESIGN: Case control study. SETTING: Children living in and around Chandigarh (urban, rural). SUBJECTS: 39 children suffering from wheat harvest period (mid April-mid May) respiratory allergy along with randomly selected controls. METHODS: Aerobiological surveys were done from March to June for identification of prevailing allergens for performing allergy tests. Patients were subjected to skin tests (ST), nasal provocation tests (NPT) and bronchial provocation tests (BPT) with extracts prepared from identified pollens and fungal spores. Specific IgE (SIgE) was assayed by ELISA and comparison between pre-season, season and post-season values made. RESULTS: 81% patients had ST positive to antigen of wheat threshing dust (WTD), 30% to fungal antigens, 14% to wheat dust antigens and none to the wheat plant (WP) antigens. Nasal provocation test and bronchial provocation tests were also positive to WTD in 80% and 66% patients, respectively. WTD SIgE was demonstrated in 77% of ST positive patients. CONCLUSIONS: These in vivo and in vitro tests confirm wheat threshing dust as a major causative inhalant allergen for the April-May nasobronchial allergy; in addition, fungal allergens also play a role in 1/3rd of these patients.