The first molecular structures of allergens were identified more than 30 years ago, and characterised recombinant allergens became available. We evaluate the current state of the art in molecular AIT with the purpose of understanding why progress in this field has been modest, despite the fact that there is enormous promise for treatment and allergen-specific prevention. Several AIT techniques have been developed and are being tested in clinical trials based on allergen structures. In clinical AIT trials, promising results were obtained with recombinant and synthetic allergen derivatives inducing allergen-specific IgG antibodies, which interfered with allergen recognition by IgE, whereas clinical efficacy for approaches targeting only allergen-specific T-cell responses could not yet be demonstrated. According to the available research, molecular AIT techniques have significant advantages over allergen extract-based AIT.

Clinical trials show that recombinant allergen-based AIT vaccines that outperform existing allergen extract-based AIT vaccines for respiratory, food, and venom allergy can be created. Allergen-specific preventative techniques based on recombinant allergen-based vaccine methods and T-cell tolerance induction are on the horizon and hold the promise of allergy prevention. However, progress is hampered by a shortage of resources for clinical trials, which are required for the development of these novel therapies.