Chickpea: a major food allergen in the Indian subcontinent and its clinical and immunochemical correlation.

BACKGROUND: The food allergy pattern of a country is influenced by the foods most commonly consumed. In India, the majority of the population consumes a vegetarian diet made up of pulse (legumes), cereals, and vegetables. In contrast to many western countries, chickpea preparations are consumed in large quantities in India. This study reports for the first time chickpea hypersensitivity reactions diagnosed with in vivo and in vitro tests.
METHODS: One thousand four hundred patients visiting allergy clinics were randomly selected for the study. Those patients reporting an allergic reaction on every occasion after eating chickpea were considered history-positive. Modified prick tests were performed with chickpea and other members of the legume family on all these patients. The claims of the history-positive patients were verified with double-blind, placebo-controlled food challenges (DBPCFCs). Proteins in chickpea extracts were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred on nitrocellulose paper. Serum specimens from history-positive patients were analyzed by immunoblot and ELISA. To verify the IgE specificity, an immunoblot inhibition assay was also performed.
RESULTS: Of the 1,400 patients screened, 142 patients were history-positive to some food and 59 of these implicated chickpeas. Forty-one patients were skin test-positive and 31 were DBPCFC-positive for chickpea. The predominant symptoms after chickpea ingestion were respiratory. The ELISA results did not correlate well with the DBPCFC results; however, the skin test results correlated with DBPCFC in 75% of patients. Immunoblot analysis showed that 70, 64, 35, and 26 kD proteins were major allergens.
CONCLUSIONS: Chickpea is an important source of allergen that can cause IgE-mediated hypersensitivity reactions ranging from rhinitis to anaphylaxis.