IGHE and Allergy: Additionally, further parameters such as results of the determination of the half-maximal concentration (EC50, CD-sens, basophil sensitivity), the calculation of a ratio (CD63 ratio), of allergen-induced CD63 activation in comparison to an IgE-dependent positive control (anti-IgE of anti-FcεRI), or of the area under the curve (AUC) in dose-response curves turned out to be of value for the assessment of clinically relevant allergies and therapy outcomes (1–4).