C. Elduque (1), B. Navarro (1), M. Morales (1), A. Claver (1), E. Botey (1), M. Castillo (2), F. Pineda (2), A. Cisteró-Bahíma (1)

1. Al.lèrgia Dexeus. Institut Universitari Quirón-Dexeus. Universitat Autònoma de Barcelona.
2. Application Department. DIATER Laboratorios. Madrid

Prevalence in legume allergy in different countries is highly influenced by eating habits. It is well known that food processing can induce changes in protein structure, resulting in differences in its allergenicity. Legumes are widely used in Mediterranean diet, specially prepared in a stew.

Case Report:
A 44-year-old woman with personal history of persistent rhinoconjunctivitis due to house dust mite consulted to Allergy department explaining various episodes of facial angioedema and dyspnoea with bronchospasm after the ingestion of white beans cooked in a stew. She tolerated lentils, green beans and chickpeas with no reactions.

Skin prick test with commercial extracts to different legumes were positive only to white bean (Leti, 10 mg/ml) with negative results to soy, chickpea, lentil and peanut. Prick-by-prick to different types of white beans was also performed and showed positive results to all of them. Skin prick test and specific IgE to rPru p3 were also negative. Specific IgE to white bean (UniCAP Thermofisher) was < 0,1 KU/L.

Proteins from white beans were extracted with a phosphate saline buffer for two hours and after several consecutive steps of centrifugation, filtration and dialysis, were stabilized by freeze-drying.

A raw white bean extract showed a concentration of protein of 9,35 mg/ml, while cooked white bean extract showed only 0,38 mg/ml.

SDS-PAGE and Western Blot with chickpea, broad bean, soy flour, raw white bean, cooked white bean, green bean and lentil extracts showed IgE-binding bands for raw white bean of 50 kDa and 36 KDa; no bands were detected in the other extracts assayed.

Clinical implications:
We present a case of white bean induced anaphylaxis with good tolerance to other legumes. Spite of its frequency in the Mediterranean area, in this specific case there’s no implication of LTPs. The laboratory results suggest that the white bean protein responsible for the allergic reactions could be found in the broth, thus the patient could tolerate beans alone.