Allergen Immunotherapy: Past, Present, and Future

Abstract

Allergen-specific immunotherapy (AIT), although in clinical use for more than a century, is still the only causal treatment of allergic diseases. The safety and efficacy of AIT has been demonstrated in a large number of clinical trials. In addition to allergy symptom reduction AIT plays an essential role in preventing new allergies and asthma and shows long-term effects after discontinuation of treatment. Ideally, it is capable of curing allergy. However, AIT is not effective in all allergic individuals and is not equally effective in the treatment of various hypersensitivities to different allergens. For many years, the route of administration and the vaccine compositions have been evolving. Still there is a strong need for research in the field of new AIT modalities to increase its effectiveness and safety. Growing evidence on immunological effects of AIT, especially new T cell subsets involved in antigen/allergen tolerance, provides novel concepts for safer and more effective vaccination. Pharmacoeconomic studies have demonstrated a clear advantage of AIT over pharmacologic therapies.

Keywords: Allergen immunotherapy; allergen vaccines.

Fig. 1. First administration of AIT vaccine causes decrease in degranulation of mast cells and basophils by blocking effect of Th2 and Treg cytokines. This decreases amounts of secreted histamine and other mediators by effector cells. IgE production is impaired as well by IL-10 and TGF-β cytokines produced by activated Treg cells.

Fig. 2. Novel vaccine development for AIT.