If a patient with a peanut allergy receives a blood transfusion from a donor who recently ate peanuts, which consequence follows due to passive sensitization?

💡 Explanation

Mast cells become passively sensitized by donor IgE already bound to peanut allergens from the donor meal. Upon encountering remaining peanut allergens in the transfusion recipient, localized mast cell degranulation occurs, releasing histamine and causing a local reaction, because the IgE is already bound. Therefore, localized degranulation results, rather than systemic activation, which requires more widespread allergen exposure.

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