Utility of Specific IgE to Ara h 2 in Italian Allergic and Tolerant Children Sensitized to Peanut

Emerging data suggest that measurement of serum IgE to peanut components can be clinically helpful and more
accurate than IgE to whole peanut to predict peanut allergy. Not all studies have used prospective samples,
multiple components and oral challenges. Currently, there are no data on this topic involving Italian children. 32
patients (23 males; median age 9 years) with reported history for peanut allergy and evidence of peanut
sensitization (skin prick test to peanut extract ≥ 3mm) have been analyzed for serum IgE to whole peanut and
recombinant allergen components Ara h 1, 2, 3, 8, and 9 with Immuno CAP and completed an open oral food
challenge with peanut. 12 (37.5%) children had a positive challenge to peanut and were considered allergic. No
differences were seen between the median values of IgE to peanut, Ara h 1, 3, 8 and 9 in allergic and tolerant
children to peanut challenge. Noteworthy, 5 of 20 tolerant children had IgE to peanut> 15 kUA/l which is
commonly considered a predictive value of peanut allergy. Conversely, a significant difference was seen when
comparing the median value of IgE to Ara h 2 in the two groups: 0.75 kUA/l (IQR: 0.22-4.34 kUA/l) in allergic
children versus 0.1 kUA/l (IQR: 0.1-0.12 kUA/l) in tolerant ones (P< 0.001). IgE levels to Ara h 2 are
significantly higher in children that react to oral peanut challenge. Our findings in Italian children have been in
line with recent reports in various populations of Northern Europe, the US and Australia and add confirmatory
evidence that analysis of IgE to Ara h 2 could reduce the need for peanut challenge in suspected allergic patients.