2018 Section 5 - Rhinology and Allergic Disorders

Avoidance after Early Peanut Consumption

avoidance group at month 72 (P<0.001) (Fig. 2A, and Fig. S5B in the Supplementary Appendix). After the yearlong period of peanut avoidance, the peanut-specific IgG4 levels continued to be higher in the peanut-consumption group than in the peanut-avoidance group (P<0.001) (Fig. 2B, and Fig. S5C in the Supplementary Appendix), despite a decline that started before the partici- pants in the peanut-consumption group stopped eating peanuts. The ratio of peanut-specific IgG4:IgE also continued to be significantly higher in participants in the peanut-consumption group than in those in the peanut-avoidance group (Fig. 2B). New allergy developed in three participants in the peanut-consumption group (1.1%) and in three in the peanut-avoidance group (1.1%) between month 60 and month 72 (Fig. 3). The ratio of peanut-specific IgG4:IgE declined between month 60 and month 72 in all six participants (Table S6A in the Supplementary Appendix). In addition, four participants in the peanut- Figure 1. Primary Outcome. The prevalence of peanut allergy at 72 months of age is shown among participants who had a negative result on the skin-prick test (SPT) at the baseline visit in the primary trial, among those who had a positive result at the baseline visit, and in both groups combined. In the primary trial, participants at high risk for allergy had been randomly assigned to consume peanuts begin- ning in the first 11 months of life (peanut-consump- tion group) or avoid peanuts (peanut-avoidance group). Panel A shows the prevalence of peanut allergy at 60 months of age among only the participants in the pri- mary trial who enrolled in the follow-up study. Panel B shows the prevalence of peanut allergy at 72 months of age among participants in the follow-up study who were included in the intention-to-treat analysis (i.e., all enrolled participants in the follow-up study who had a peanut-allergy outcome that could be evaluated). Panel C shows the prevalence of peanut allergy at 72 months of age among participants who met the per-protocol criteria in both the primary trial and the follow-up study. The main per-protocol criterion in the primary trial was adequate adherence to the randomized assignment to consume or avoid peanuts; the main per-protocol cri­ terion in the follow-up study was adequate adherence to avoidance of peanut protein over a period of 12 months. Immunologic Changes in Participants Whose Allergy Outcome Changed

Peanut-avoidance group Peanut-consumption group

A Intention-to-Treat Population in Primary Trial

P=0.002

38.3

40

30

P<0.001

P<0.001

18.8

20

14.9

10.9

10

3.6

2.2

Prevalence of Peanut Allergy (%)

0

SPT-Negative Cohort (N=463)

SPT-Positive Cohort (N=93)

Both Cohorts (N=556)

B Intention-to-Treat Population in Follow-up Study

P=0.004

39.1

40

30

P<0.001

P<0.001

18.6

20

14.5

13.0

10

4.8

3.1

Prevalence of Peanut Allergy (%)

0

SPT-Negative Cohort (N=458)

SPT-Positive Cohort (N=92)

Both Cohorts (N=550)

C Per-Protocol Population in Both the Primary Trial and Follow-up Study

P=0.001

40

37.8

30

P<0.001

P<0.001

19.2

20

15.2

10

3.6

2.1

1.9

Prevalence of Peanut Allergy (%)

0

SPT-Negative Cohort (N=372)

SPT-Positive Cohort (N=73)

Both Cohorts (N=445)

avoidance group who had peanut allergy at month 60 did not have an allergic status by month 72. Their wheal size on skin-prick testing

n engl j med 374;15  nejm.org  April 14, 2016

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