Abstract

Specific allergen immunotherapy, consisting in the administration of increasing amounts of offending allergens into sensitive patients was first used nearly one hundred years ago and remains in use worldwide for treatment of allergic rhinitis and asthma. It has been recognised as the only effective treatment for type I allergic diseases when the appropriate quantities of allergens are used. The immunological mechanisms by which specific immunotherapy is effective include the modulation of T cells and the response of B-cells and is accompanied by significant decreases of specific IgE and increases in allergen specific IgG antibodies, mainly IgG4. While specific allergen injection immunotherapy is highly effective and the most common way of administration other routes such as oral or intranasal ways have been considered as and alternative to subcutaneous injections. During the last century, allergenic vaccines have been prepared using individual allergens adsorbed to different adjuvant substances. These vaccines have demonstrated efficacy and good results in different clinical trials. However, many novel approaches to allergen immunotherapy have been developed in the last years in order to increase the safety and efficacy of allergenic vaccines. In that way, different and modern vaccines have been prepared including more purified products such as depigmented allergen extracts; allergoids, consisting on big molecules of thousands of kDa, which contain all the individual allergens and show a significant decrease in severe adverse reactions; peptides or small aminoacid sequences; recombinant allergens; hypoallergenic vaccines where the IgE binding sites have been modified; or allergen-CpG fusion molecules. New presentations are under study and new treatments will be developed in the near future with the objective that the prevention of allergic disease may become a reality. The review article also discuss recent patent related to the field.

Keywords: Allergen immunotherapy, allergoids, depigmented allergen extracts, sublingual immunotherapy, MPL, recombinant allergens, peptides, anti-IgE, allergen-CpG fusion, allergen-fusion proteins