title: Effect of Avoidance on Peanut Allergy after Early Peanut Consumption.
abstract: BACKGROUND
  In a randomized trial, the early introduction of peanuts in infants at high risk for allergy was shown to prevent peanut allergy. In this follow-up study, we investigated whether the rate of peanut allergy remained low after 12 months of peanut avoidance among participants who had consumed peanuts during the primary trial (peanut-consumption group), as compared with those who had avoided peanuts (peanut-avoidance group).
  
  
  METHODS
  At the end of the primary trial, we instructed all the participants to avoid peanuts for 12 months. The primary outcome was the percentage of participants with peanut allergy at the end of the 12-month period, when the participants were 72 months of age.
  
  
  RESULTS
  We enrolled 556 of 628 eligible participants (88.5%) from the primary trial; 550 participants (98.9%) had complete primary-outcome data. The rate of adherence to avoidance in the follow-up study was high (90.4% in the peanut-avoidance group and 69.3% in the peanut-consumption group). Peanut allergy at 72 months was significantly more prevalent among participants in the peanut-avoidance group than among those in the peanut-consumption group (18.6% [52 of 280 participants] vs. 4.8% [13 of 270], P<0.001). Three new cases of allergy developed in each group, but after 12 months of avoidance there was no significant increase in the prevalence of allergy among participants in the consumption group (3.6% [10 of 274 participants] at 60 months and 4.8% [13 of 270] at 72 months, P=0.25). Fewer participants in the peanut-consumption group than in the peanut-avoidance group had high levels of Ara h2 (a component of peanut protein)-specific IgE and peanut-specific IgE; in addition, participants in the peanut-consumption group continued to have a higher level of peanut-specific IgG4 and a higher peanut-specific IgG4:IgE ratio.
  
  
  CONCLUSIONS
  Among children at high risk for allergy in whom peanuts had been introduced in the first year of life and continued until 5 years of age, a 12-month period of peanut avoidance was not associated with an increase in the prevalence of peanut allergy. Longer-term effects are not known. (Funded by the National Institute of Allergy and Infectious Diseases and others; LEAP-On ClinicalTrials.gov number, NCT01366846.).
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: George
authors.initials: G
authors.lastname: Du Toit
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Sayre
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Graham
authors.initials: G
authors.lastname: Roberts
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Sever
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Kaitie
authors.initials: K
authors.lastname: Lawson
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Henry T
authors.initials: HT
authors.lastname: Bahnson
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Helen A
authors.initials: HA
authors.lastname: Brough
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Alexandra F
authors.initials: AF
authors.lastname: Santos
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Kristina M
authors.initials: KM
authors.lastname: Harris
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Suzana
authors.initials: S
authors.lastname: Radulovic
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Monica
authors.initials: M
authors.lastname: Basting
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Victor
authors.initials: V
authors.lastname: Turcanu
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Marshall
authors.initials: M
authors.lastname: Plaut
authors.affiliation: From the Department of Pediatric Allergy, Division of Asthma, Allergy and Lung Biology, King's College London and Guy's and St. Thomas' NHS Foundation Trust, London (G.D.T., H.A.B., A.F.S., S.R., M.B., V.T., G.L.), and the University of Southampton and National Institute for Health Research Respiratory Biomedical Research Unit, Southampton and David Hide Centre, Newport, Isle of Wight (G.R.) - both in the United Kingdom; the Division of Hematology-Oncology, Department of Medicine, University of California, San Francisco, San Francisco (P.H.S.); Rho Federal Systems Division, Chapel Hill, NC (M.L.S., K.L., H.T.B.); and the Immune Tolerance Network (K.M.H.) and the National Institute of Allergy and Infectious Diseases (M.P.), Bethesda, MD.
authors.forename: Gideon
authors.initials: G
authors.lastname: Lack
mesh_terms: D010367:Arachis / Q000276:immunology; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D057194:Intention to Treat Analysis; D008297:Male; D010349:Patient Compliance; D021183:Peanut Hypersensitivity / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control
chemical_list: D007074:Immunoglobulin G; D007073:Immunoglobulin E