Lupine-induced anaphylaxis

Background: Legumes are one of the most common foods causing allergic react ions in children and adults. Cross-reacting antibodies are frequently demon strated in this family but the real clinical cross-reactivity is uncommon. Objective: To report a case of lupine-induced anaphylaxis and to elucidate in vivo and in vitro cross-reactivity with some legumes. Methods: Skin prick test (SPT) with some legumes were performed. Cap-IgE, E LISA-IgE, and immunoblotting were carried out. Open oral challenges with so me legumes were performed. Cross-reactivity was studied by ELISA and immuno blotting inhibition. Results: The results demonstrated type-I hypersensitivity reactions with lu pine and some other legumes. Cap-IgE with peanut was positive but the SPT a nd ELISA-IgE were negative and the patient tolerated a peanut challenge. EL ISA inhibition revealed a partial inhibition (62%) using lupine as the soli d phase. Partial inhibition was demonstrated by immunoblotting inhibition. Open oral challenge with peanut and green bean were negative but positive w ith pea. Conclusion: We present a lupine sensitized patient with positive SPT and in vitro cross-reactivity with other legumes. Clinical cross-reactivity progr essively developed over a 5-year period. Discrepancies were found between t he clinical aspect and in vitro study of peanut allergy. Factors determinin g the wide variability in crossreactivity among individuals are still obscu re.