Rare Blood Transfusion Reaction Linked to Peanut Allergy

A Rare Transfusion Crisis

A 6-year-old boy undergoing treatment for lymphoblastic leukemia in the Netherlands suffered a severe anaphylactic reaction during a blood transfusion, highlighting a dangerous and often overlooked risk: the passive transfer of food allergens from donor to recipient. The case, documented in the New England Journal of Medicine, illustrates how common food proteins can circulate in a donor’s bloodstream and trigger a life-threatening immune response in a sensitized patient.

Anaphylaxis in the Clinical Setting

The young patient’s reaction was immediate and frightening. As the transfusion progressed, the boy experienced a sudden drop in blood pressure, respiratory distress, and visible swelling of his lips, tongue, and eyelids, accompanied by a skin rash. Medical staff acted quickly, administering epinephrine to stabilize the child. Within 30 minutes, the symptoms subsided. Laboratory analysis later confirmed the severity of the event, revealing significantly elevated levels of mast-cell tryptase—a definitive biomarker for immune cells activated during anaphylaxis.

The Persistence of Peanut Proteins

The boy had lived with a peanut allergy since age one. Investigators traced the source of the reaction back to the blood bank: three of the five donors who provided the transfusion had eaten peanuts the night before their donation. Researchers identified the protein Ara h2 as the primary offender. Specifically, a fragment known as DRP-Ara h2 proved to be remarkably stable, capable of circulating in the bloodstream for over 24 hours while retaining the potency to trigger an immune response. Diagnostic testing of the boy’s blood confirmed the presence of antibodies against both Ara h2 and DRP-Ara h2, proving the allergen had traveled directly from the donors into the child’s system.

Rethinking Transfusion Safety Protocols

While allergic reactions to blood transfusions are rare, occurring in just 0.001% to 0.1% of cases, the authors of the report believe this phenomenon may be underreported. Current safety protocols prioritize screening for infectious diseases, often leaving the causes of non-infectious reactions unexplained. The report suggests that clinicians should now consider food allergen transfer when faced with unexpected anaphylaxis during a transfusion. Reviewing the recent dietary history of donors may be a necessary safeguard for protecting highly sensitive recipients from these hidden triggers.

Clinical Summary of Passive Allergen Transfer

• Mechanism: Anaphylaxis can occur when food allergens in a donor’s plasma are transferred to a recipient who is already sensitized to that specific allergen.
• Stability: Certain proteins, such as the peanut allergen DRP-Ara h2, are resistant to digestion and can persist in the bloodstream long enough to cause reactions in recipients.
• Diagnosis: Elevated mast-cell tryptase levels and specific antibody testing can help confirm a reaction caused by passive allergen transfer.
• Management: Epinephrine remains the standard, first-line treatment for reversing the life-threatening symptoms of transfusion-associated anaphylaxis.