Background Results from several studies indicate that the magnitude of immediate symptoms of type I allergy caused by allergen-induced cross-linking of high-affinity Fcɛ receptors on effector cells (mast cells and basophils) is not always associated with allergen-specific IgE levels.
Objective To investigate the association of results from intradermal skin testing, basophil histamine release and allergen-specific IgE, IgG1–4, IgA and IgM antibody levels in a clinical study performed in birch pollen-allergic patients (n=18).
Methods rBet v 1-specific IgEs were measured by quantitative CAP measurements and by using purified FcɛRI-derived α-chain to quantify IgE capable of binding to effector cells. Bet v 1-specific IgG subclasses, IgA and IgM levels were measured by ELISA, and basophil histamine release was determined in whole blood samples. Intradermal skin testing was performed with the end-point titration method.
Results Our study demonstrates on the molecular level that the concentrations of allergen-specific IgE antibodies capable of binding to FcɛRI and biological sensitivities are not necessarily associated. A moderate association was found between cutaneous and basophil sensitivity.
Conclusion Our results highlight the quantitative discrepancies and limitations of the present diagnostic tools in allergy, even when using a single allergenic molecule. The quantity of allergen-specific serum IgE is only one component of far more complex cellular systems (i.e. basophil-based tests, skin tests) used as indirect diagnostic tests for IgE-mediated allergic sensitivity.