On occassion, a medical transplant will confer more than the intended primary benefit from donor to recipient. That's what happened when a 10-year-old boy lost his peanut allergy after receiving bone marrow to treat his acute lymphocytic leukemia.

"It has been reported that bone marrow and liver transplants can transfer peanut allergy from donor to recipient," allergist Yong Luo, told reporters. "But our research found a rare case in which a transplant seems to have cured the recipient of their allergy.”
Boy Cured Of Peanut Allergy
One of the most common food allergies, peanut allergy affects some 400,000 Americans. Unlike allergies to soy or milk, however, peanut allergy cannot be "outgrown." CC By 2.0

Luo presented his findings on Friday in Baltimore to the American College of Allergy, Asthma, and Immunology’s annual meeting, sharing the boy’s history as a case study. The research team noted the boy had been diagnosed at 15 months of age with a peanut allergy after vomiting and erupting in whole-body hives after eating peanuts.

Later, the boy received a diagnosis for leukemia and, at age 10, underwent the transplant from a donor with no known allergies. Intrigued, allergists confirmed the loss of the peanut allergy by conducting an “oral food challenge,” which should not be undertaken at home doctors warn. Under close watch, the boy ingested a small amount of peanut and showed no reaction.

Medical researcher Steven Weiss, a co-author of the study, told attendees at the meeting that food allergy is associated with the body’s abnormal production of high specific IgE levels. This case adds to previous reports indicating that “genetic modification during the early stages of immune cell development in bone marrow may play a large role in causing allergy.”

One of the most common food allergies in the United States, peanut allergy affects some 400,000 Americans. Among schoolchildren, peanut allergy is the leading type of food allergy. But unlike other types of allergies, such as reactions to milk or soy, peanut allergy lasts a lifetime. Should any parent insist their child has “outgrown” his or her peanut allergy, experts advise a visit to a board-certified allergist for proper testing for allergens.

Any child with a peanut allergy should carry a prescribed epinephrine pen, at all times. "Food allergies are serious and can cause a severe, life-threatening reaction known as anaphylaxis," Weiss said. "It's important to be under the regular care of an allergist who can perform proper tests and administer treatment."

Although minor reactions to peanut allergens are common, the more severe anaphylaxis causes a rush of symptoms including an itchy rash, throat swelling, and lowered blood pressure, which could progress to fatal shock.

There is no known cure for peanut allergy.