Anaphylaxis due to green beans (Phaseolus vulgaris): a new phenotype?

Background: Anaphylaxis is a severe allergic reaction with increasing incidence in Europe. It is often caused by food, insect venom, and drugs. White, red, and green beans (Phaseolus vulgaris) are legumes of the Fabaceae family consumed worldwide. In Spain, beans are the third most consumed legume species after chickpeas and lentils. Allergy to different legumes is very frequent in children and represents the fifth cause of food allergy.

Objective: Demonstrate a new phenotype in patients with green bean anaphylaxis.

Material and methods: We report a 20-year-old woman who experienced anaphylaxis after consuming cooked green beans and required emergency treatment. There were no associated cofactors such as medications, alcohol, or physical exercise. After the episode, she tolerated well nuts, garlic, chickpeas, peas, and soy. Prick-prick with raw and cooked green bean, ISAC, SDS-PAGE and IgE-Western blot were performed.

Results: The prick+prick test with raw and cooked green beans was positive. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis-immunoglobulin E (SDS-PAGE/IgE)-western blot analysis with white and red beans as well as cooked and raw green beans showed identification of several proteins with a molecular weight of 25-75 kDa in the extract of raw beans. Only one protein with a molecular weight of approximately 10 kDa was recognized in cooked beans.

Conclusion: We present a case of anaphylaxis induced by green beans (Phaseolus vulgaris) because of a 10-kDa protein and tolerance to other legumes, which suggests a new phenotype.