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