A small but carefully designed double-blind, placebo-controlled study published in The Journal of Allergy and Clinical Immunology (March 2011;127(3):640–646.e1) explored whether sublingual immunotherapy (SLIT) could safely increase peanut tolerance in children with peanut allergies.
The study involved 18 children between the ages of 1 and 11 with confirmed peanut allergy. Participants were randomly assigned to receive either a placebo or very small doses of peanut protein extract placed under the tongue. In the treatment group, doses were gradually increased every two weeks over six months, followed by daily maintenance dosing. Once a maximum dose of 2,000 micrograms (2 mg) of peanut protein was reached, that dose was continued for an additional six months.
After one year of treatment, participants underwent an oral peanut challenge using peanut flour mixed into food. Skin prick testing and blood markers of allergy were also assessed throughout the study.
Children receiving sublingual peanut extract were able to tolerate, on average, 20 times more peanut protein than those in the placebo group. The treatment group tolerated a median of 1,710 mg of peanut protein, compared with 85 mg in the placebo group. For context, a single peanut weighs roughly 100 mg, suggesting that the level of desensitization achieved may be sufficient to protect against accidental exposure, rather than allowing unrestricted peanut consumption. Skin testing also demonstrated reduced allergic reactivity in the treatment group.
This was a small pilot study, and the findings do not establish a cure for peanut allergy. However, they do suggest that controlled, medically supervised immunotherapy may meaningfully reduce the risk of severe reactions from accidental ingestion. Larger and longer-term studies are needed to confirm safety, durability of tolerance, and real-world applicability.
