Blood collection
Serum sIgE and IgG4 to peanut and peanut components (rAra h 1, rAra h 2,
rAra h 3, rAra h 8) were determined by ImmunoCAP (Thermofisher, Uppsala,
Sweden). Peanut component sIgE was assayed for participants with a
peanut IgE ≥0.1 kUA/L; for subjects with levels <0.1KU/L, an
imputation was performed. A ratio of Ara h 1, h2 and h3 to peanut sIgE
was calculated to examine the distribution of each component in relation
to sIgE to peanut. The median of this ratio was used to determine the
imputed value for each Ara h component for patients who had peanut
sIgE<0.1kUA/L. The ratio of peanut-specific
IgG4:IgE was calculated after peanut-specific
IgG4 levels were converted from µg/L to ng/mL and peanut
sIgE levels were converted from kU/L to ng/mL using the formula
(IgG4 ÷(IgE x 2.4)). (12) Plasma or serum was also used
for MAT.