Although the treatment was too dangerous to try on children with the most severe and life-threatening peanut allergies, the findings offer a ray to hope to some people with the allergy, which is at best inconvenient and at worst deadly.

The teams at Duke University Medical Center in North Carolina and Arkansas Children's Hospital gave a group of children almost microscopic doses of peanut daily and watched not only their symptoms but their blood for signs of allergic reaction.

Nine of the 33 children in the study have been able to tolerate the treatment for more than two years and four appear to be allergy-free, the researchers told reporters.

"At the start of the study, these participants couldn't tolerate one-sixth of a peanut," said Dr. Wesley Burks of Duke, who helped lead the study. "Six months into it, they were ingesting 13 to 15 peanuts before they had a reaction."

Reporting at a meeting in Washington of the American Academy of Asthma and Immunology, the researchers said it was the first time the method had been shown to help someone with a food allergy become tolerant to the food.

"This gives other parents and children hope that we'll soon have a safe, effective treatment that will halt allergies to certain foods," Burks said.