IgE to Bet v 1 and profilin: cross-reactivity patterns and clinical relevance

BACKGROUND: Individuals with pollen allergy often have IgE against plant-derived foods. This can be due to cross-reactive IgE against Bet v 1 and homologues, profilins, and/or cross-reactive carbohydrate determinants.

OBJECTIVE: The aim of this study was to correlate sensitization to Bet v 1 and profilin with individual recognition patterns to plant foods and clinical relevance.

METHODS: Fifty-two patients with pollen allergy and IgE against at least one plant-derived food were included in the study. Adverse reactions to plant-derived foods were documented by using standardized interviews. Skin prick tests were performed for pollen (grass, birch, and mugwort) and 14 plant-derived foods. In addition, recombinant (r) Bet v 1 and rBet v 2 (profilin) were tested intracutaneously. Specific IgE against the abovementioned allergens were determined by means of RAST. Cross-reactivity was studied by means of RAST inhibition.

RESULTS: Eighty-five percent of patients were sensitized to Bet v 1, and 71% were sensitized to profilin. Profilin was associated with a higher number of positive RAST results to plant-derived foods than Bet v 1. In contrast, Bet v 1 was associated with more positive skin prick test responses and more food-related symptoms. Sensitization to Bet v 1 was associated with IgE against apple, hazelnut, and peach, whereas sensitization to profilin was associated with positive RAST results to all investigated plant-derived foods except apple, peach, and melon.

CONCLUSIONS: IgE antibodies against Bet v 1 have a more limited spectrum of cross-reactivity than those against profilin, but they frequently give rise to clinically relevant cross-reactivities to food. In analogy to anticarbohydrate IgE, cross-reactive IgE against food profilins have no or very limited clinical relevance.