 Allergic vaccination AV, also referred to as immunotherapy or allergen-specific immunotherapy SIT, is a curative approach that is available for allergic diseases, which directly treats the underlying disease. AV is the practice of administering gradually increasing quantities of an allergen extract to an allergic patient to ameliorate the symptoms associated with the subsequent exposure to the causative allergen. AV is believed to exert its beneficial effects on the immune system, at least in part, by modifying the T-lymphocyte response to subsequent natural allergen exposure. AV has been shown to inhibit both early and late responses to allergen exposure. AV acts on T cells to modify peripheral and mucosal TH2 responses to an allergen in favor of helper T cell type 1 TH1 responses. One of the hallmarks of successful AV is the redressing of a healthy TH1TH2-balance. 