WEDNESDAY, May 18 (HealthDay News) -- A boy with a peanut allergy had a severe reaction after receiving a blood platelet transfusion that may have contained bits of undigested peanut protein, according to a new case report published in a major medical journal.
Though the findings suggest that people with nut allergies may be susceptible to an allergic reaction from blood products, experts stressed there is no cause for alarm.
Not only does the report document only a single case, the boy received a platelet transfusion, which contain lots of blood serum (the liquid components of blood that don't contain red or white blood cells), explained Dr. Scott Sicherer, chair of the American Academy of Pediatrics' section on allergy and immunology.
That's different from a typical blood transfusion, in which the blood is "washed" and only red blood cells are transfused, said Sicherer, also a researcher at Jaffe Food Allergy Institute at Mount Sinai School of Medicine in New York City.
"A blood transfusion would have a lot less of the liquid from the bloodstream, and that would presumably mean if there was any peanut in the blood it would have been washed away," Sicherer noted.
The case report was published in the May 18 issue of the New England Journal of Medicine.
After a person eats nuts, some of the proteins circulate in the blood, Sicherer said. That's led experts to speculate whether or not someone with a nut allergy who receive donated blood products could react to peanut proteins in the blood.
For people with severe peanut allergies, ingesting even tiny amounts of peanut protein can set off a life-threatening allergic reaction called anaphylaxis.
But it's premature to encourage blood donors not to eat peanuts before giving blood or for questions about diet to become part of the screening process, said the report authors.
"Our case report will not change any of the current protocols surrounding blood donations," said Dr. Johannes F.M. Jacobs, of Radboud University Nijmegen Medical Center in the Netherlands. "Further research is needed before evidence-based decisions on this point can be taken. In our case report, we only wanted to create awareness for this phenomenon among clinicians."
Sicherer agreed that the possibility that peanuts in blood products -- or other tree nuts or other foods, for that matter -- could cause an allergic reaction is worth further study.
The 6-year-old boy in the case report was being treated for leukemia and received a platelet transfusion, which helps with clotting. The boy experienced swelling, low blood pressure and difficulty breathing, all signs of anaphylaxis. The boys' mother said he'd had a similar reaction after eating peanuts as a 1-year-old.
He was given adrenalin and recovered, according to the report.
Three of the five platelet donors reported eating several handfuls of peanuts less than 24 hours before donating blood. Researchers never actually tested the blood product that the boy received, but they did test the boy's blood for peanut-specific IgE antibodies, the results of which indicated the boy had a peanut allergy. In addition, the boy had other prior platelet transfusions and had no reaction, Jacobs said.
Peanut proteins are more resistant to digestion that other foods, according to the authors.
"One percent of the population has peanut allergy and people get blood transfusions all the time," Sicherer said. "Allergic reactions seem to be exceedingly rare if it happens."
The Nemours Foundation has more on nut and peanut allergies.
SOURCES: Johannes F.M. Jacobs, Ph.D., M.D., Radboud University, Nijmegen Medical Center, the Netherlands; Scott Sicherer, M.D., chair, American Academy of Pediatrics, section on allergy and immunology; associate professor, pediatrics, and researcher, Jaffe Food Allergy Institute, Mount Sinai School of Medicine, New York City; May 18, 2011, New England Journal of Medicine
All rights reserved