Anaphylaxis is a severe allergic response characterized by the development of hives, swelling, and dramatic drops in blood pressure. It is estimated that 1,500 people in the United States die yearly from anaphylaxis. A plethora of substances can elicit allergic reactions, and the exact allergen is often unknown. What is known is that an allergen binds to IgE found on mast cells, and this leads to the release of inflammatory mediators such as histamine, the substances responsible for the allergic response. Mast cells are found in tissue, yet can respond to allergens in the blood via a mechanism that is not well understood.
He may have loved to eat kiwifruit. He may have been indifferent towards the fuzzy green egg-shaped things. He may not have liked them at all. But, whatever his attitude towards the innocent-looking berries was, he was not allergic to them. That is, until, at age 26, he needed a bone marrow transplant to battle acute lymphocytic leukemia. His sister turned out to be a matching donor, and the transplantation was a success. It kept the leukemia in check.