Serum immunoglobulin IgE in a pediatric population: A retrospective analysis

Allergic sensitization is mediated by immunoglobulin E (IgE) and an increase of their total value is frequently used to complete a correct diagnosis of atopy. Serum IgE may be considered a typical biomarker for the allergic phenotype. The aim of this study was to evaluate total serum IgE, according to sensitizations, and to find a cut off to discriminate between atopic and non-atopic subjects. Seven hundred and ninety-five patients were enrolled in this study. Serum levels of total IgE were measured by a fluorescence immunoassay (ImmunoCAP; ThermoFisher, Uppsala, Sweden) while specific IgE levels were measured by immunofluorometric assay (ImmunoCAP; ThermoFisher, Uppsala, Sweden). Both tests were expressed in kU/L, according to manufacturer's instructions. Results: A difference for total IgE, according to the gender, has been found (p = 0, 0012 ) with higher values for males than for females. A correlation has been found between total IgE and specific IgE, even distinguishing the population in sensitized and non-sensitized. A statistically significant difference has been found according to the presence or the absence of sensitization (p < 0, 0001) and also considering mono-sensitized and poly-sensitized patients (p < 0, 0001). ROC analysis has been performed to define a cut off for total serum IgE, according to sensitization and to the type of sensitization (mono-sensitization or poly-sensitization). Finally multiple regression models have been performed to describe total IgE response (positive or negative) and to predict total IgE values. Since clinical limitations are well known, total IgE provide a useful aid to define atopy, allowing the clinician to carry out further investigations in patients with total IgE values beyond normal limits.