Severe Reactions to a Soy Containing Beverage in Peanut Allergic Individuals Not Avoiding Soy

Abstract

S U N D A Y 351 Differentiating Cause and Severity of Allergic Reaction to Soy Based On Component Testing to PR-10 and Storage Proteins Rabia Q. Chaudhry, MD, Stephen Bigelsen, MD, Alan H. Wolff, MD, Danyoul Yamin; UMDNJ, Newark, NJ. RATIONALE: The heat sensitive PR-10 soy protein is a BetV1 homologue and associated with oral allergy syndrome (OAS). OAS is seen in soy allergic patients with IgE to GlyM4 (PR-10 protein). The soy storage proteins GlyM5 and GlyM6 are storage proteins that are heat stable and associated with systemic/more severe reactions. In the case of soy allergy, we wanted to see if differentiating between IgE sensitivity to PR10 and storage proteins correlated with the severity of the reaction. METHODS: We report seven patients with a history of birch pollen allergy who were betv1 positive and reacted to soy drinks, but tolerated other soy products. All experienced oropharyngeal pruritus, but five developed systemic symptoms including hives, angioedema, respiratory distress and nasal congestion. RESULTS: All patients were positive to BetV1. Six patients were positive to the GlyM4 component of soy (individual results5 0.4, 0.8, 1.5, 1.8, 2.4, 48 by ImmunoCAP-ISAC). All were negative to storage proteins GlyM5 and GlyM6. One patient who was BetV1 positive was not found to be positive to any of the tested soy components. CONCLUSIONS: Reactions to soy protein drinks have been reported in patients with birch tree pollinosis. The GlyM4 component of soy protein is cross-reactive with PR-10 allergens. Patients may have a reaction to GlyM4 protein that is more severe than OAS. GlyM5 and GlyM6 allergies are less often identified and may risk an even graver reaction. A better understanding of component testing and its relevance on individual foods is needed.