Learning Early About Peanut Allergy (LEAP) study

Last edited 06/2022 and last reviewed 10/2022

The Learning Early About Peanut Allergy (LEAP) (2015) study triggered a paradigm shift in the field of food allergy prevention from an understanding that, in infants at high risk of developing a peanut allergy, prevention was best achieved by peanut avoidance to active early peanut consumption:

• LEAP showed that in infants at high risk of peanut allergy aged 4-10 months with either severe eczema or egg allergy, or both, peanut consumption three times a week achieved an 81% reduction in the prevalence of peanut allergy at 5 years of age
• among infants with high-risk atopic disease, sustained peanut consumption beginning in the first 11 months of life, as compared with peanut avoidance, resulted in a significantly smaller proportion of children with peanut allergy at the age of 60 months
  • intervention was safe, tolerated, and highly efficacious
  • in the intention-totreat analysis, peanut consumption was associated with an 86% reduction in peanut allergy at 60 months of age among participants who had had negative results on a peanut-based skin-prick test at study entry and with a 70% reduction among those who had had positive test results at study entry
• at 60 months
  • the mean diameter of wheals and the number of participants with markedly elevated levels of peanut-specific IgE titers were higher in the peanut-avoidance group than in the consumption group
  • in the peanut-consumption group showed a significantly greater and earlier increase in levels of peanutspecific IgG and IgG4
    • effect mirrors the immunologic changes seen in successful allergen immunotherapy
      • in the avoidance group, unless peanut-specific IgE levels were very high, elevated IgG4 levels were associated with the absence of an allergic reaction to peanuts
    • both observations indicate that IgG4 is associated with a protective role against the development of allergy

Study authors concluded that early introduction of peanuts significantly decreased the frequency of the development of peanut allergy among children at high risk for this allergy and modulated immune responses to peanuts (1)

Reference:

• Du Toit G, Roberts G, Sayre PH, Bahnson HT, Radulovic S, Santos AF, Brough HA, Phippard D, Basting M, Feeney M, Turcanu V, Sever ML, Gomez Lorenzo M, Plaut M, Lack G; LEAP Study Team. Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 2015 Feb 26;372(9):803-13. doi: 10.1056/NEJMoa1414850. Epub 2015 Feb 23. Erratum in: N Engl J Med. 2016 Jul 28;375(4):398. PMID: 25705822; PMCID: PMC4416404