Peanut Allergy in Spanish Children: Comparative Profile of Peanut Allergy versus Tolerance

Abstract

Background: Peanut storage proteins (Ara h 1, Ara h 2, and Ara h 3) have been described as the major peanut allergens in children, although not all peanut-sensitized individuals have clinical reactivity after exposure. Objectives: We studied the sensitization profile of peanut-allergic and peanut-tolerant children in a pediatric cohort. Methods: The clinical features and sensitization profile to the peanut storage proteins Ara h 9 and Pru p 3 were compared between peanut-allergic and peanut-tolerant children using component-resolved diagnostics. Results: Thirty-three peanut-sensitized children were included: 22 allergic and 11 tolerant patients. Seventy-two percent of the peanut-allergic children were sensitized to at least one peanut storage protein. The rates of sensitization to Ara h 1, Ara h 2, and Ara h 3 were 63.6, 68.1, and 68.1%, respectively, among the peanut-allergic children and 27.2, 18.1, and 45.4% among the peanut-tolerant children. IgE from the sera of 18% of the peanut-allergic patients recognized Ara h 9, whereas no sensitization to Ara h 9 was detected in the peanut-tolerant children. A total of 59% of the peanut-allergic and 27% of the peanut-tolerant children were sensitized to Pru p 3. Sensitization to Ara h 1 and Ara h 2 was more frequent among the peanut-allergic children (p < 0.05). Although the levels of specific IgE against peanut storage proteins were higher in peanut allergy, there were not statistically significantly different from the levels in peanut tolerance, probably due to the small number of patients included. Conclusions: In our population, the peanut-allergic children were mainly sensitized to peanut storage proteins, and Ara h 2 sensitization allows a more accurate diagnosis of clinical reactivity to peanuts. More than half of the peanut-allergic patients were sensitized to peach Pru p 3, and 50% of them had fruit allergy at the time of the study.

Diagnostic accuracy of Ara h 2 for detecting peanut allergy in children

“…However, it should be kept in mind that rare cases of (severe) peanut allergy have been described in literature in children who are not sensitized to Ara h 2. 20 , 21 , 22 , 23 , 24 These children might be sensitized to other peanut components than Ara h 2, for example Ara h 6 or Ara h 7. 25 , 26 Furthermore, the adherence to the diagnostic flow chart for children with an Ara h 2 level ≤0.1 kU A /L was low.…”

“…We believe our diagnostic flow chart is safe to use as the probability of an allergic reaction in children with an Ara h 2 level ≤0.1 kU A /L is very low (0% in this and in our previous study) and children are instructed to introduce peanut according to an introduction schedule starting at a very small amount of peanut. However, it should be kept in mind that rare cases of (severe) peanut allergy have been described in literature in children who are not sensitized to Ara h 2 20‐24 25,26 .…”