High-risk children who consumed peanut products from infancy until they were 5 years old were significantly less likely to develop a peanut allergy than those who avoided peanuts, according to the LEAP randomized trial (Du Toit G et al. N Engl J Med. 2015;372:803-813).
The 640 infants in the trial were aged 4 to 11 months at enrollment, and all had severe eczema, egg allergy, or both. Results of a skin-prick test to peanut protein separated the participants into 2 cohorts: one with no measurable wheal after testing (nonsensitized) and the other with a wheal 1 to 4 mm in diameter (mildly sensitized). Participants in each cohort were randomly assigned to consume a peanut protein–containing bar or to avoid peanuts. Infants in the group that consumed peanuts ate at least 6 g of peanut protein per week until age 5 years.
Among the 530 infants in the non-sensitized cohort that could be evaluated for the primary outcome, the prevalence of peanut allergy at 60 months was 13.7% in the avoidance group and 1.9% in the consumption group. The absolute difference in risk of 11.8% represents an 86.1% relative reduction in the prevalence of peanut allergy.
In the mildly sensitized cohort (98 infants), the prevalence of peanut allergy was 35.3% in the avoidance group and 10.6% in the consumption group.
The LEAP-ON study is currently investigating whether immune tolerance will persist after children stop eating peanuts.