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 food s 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 l arge quantities in India. This study reports for the first time chickpea hy persensitivity reactions diagnosed with in vivo and in vitro tests. Methods: One thousand four hundred patients visiting allergy clinics were r andomly selected for the study. Those patients reporting an allergic reacti on on every occasion after eating chickpea were considered history-positive . Modified prick tests were performed with chickpea and other members of th e legume family on all these patients. The claims of the history-positive p atients 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 nitrocellulos e paper. Serum specimens from history-positive patients were analyzed by im munoblot 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 predomina nt symptoms after chickpea ingestion were respiratory. The ELISA results di d not correlate well with the DBPCFC results; however, the skin test result s correlated with DBPCFC in 75% of patients. Immunoblot analysis showed tha t 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.