Molecular sIgE profile in infants and young children with peanut sensitization and eczema

Many children develop a sensitization to peanut in early infancy, even before peanut is introduced in their diet. Sensitization is particularly common in young children with eczema. There have been scant data available to date on the sensitization pattern for specific peanut allergens in this patient group. The aim of this study was to investigate the allergen profile of infants and young children with peanut sensitization and eczema.

Sera from 53 children aged ≤ 20 months with eczema and sensitization to peanut but who had not yet consumed products containing peanuts were included in the analysis. Sera were analyzed using microarray immunoassay (ImmunoCAP ISAC).

In total, 63 % of peanut-sensitized children showed specific immunoglobulin E (sIgE) against at least one peanut allergen on the microarray. Specific IgE to the 7S globulin Ara h 1 was detected in 40 % of the children, to the 2S albumin Ara h 2 in 30 % and to the 11S globulin Ara h 3 in 23 %. Only one child had sIgE to Arah 8, the homologoue of Bet-v-1. Data on clinical relevance were available for 24 of 53 children: 14 of 24 patients had objective allergic reactions to peanut, while 10 children were peanut-tolerant. The seed storage protein Ara h 2 was not detected on microarray in 43 % (6 of 14) of children with peanut allergy. Two of these six children were mono-sensitized to Ara h 1 and two to Ara h 3, while in three children none of these seed storage proteins was detected.

It could be shown that infants and young children with eczema and sensitization to peanut recognize predominantly seed storage proteins from peanut, even before the introduction of peanut into their diet. Sensitization to pollen-related food allergens seems to be rare at this age. At this age not only Ara h 2, but also Ara h 1 seems to be related to clinical relevance.