Introduction:
The progressive advance in the knowledge and characterization of allergenic molecules responsible for allergic sensitization to most sources have had a profound impact in the etiological management of allergic disease. This impact can be summarized in three main aspects. Firstly, it has profoundly transformed the way allergenic extracts are characterized and standardized which is legally reflected in the regulatory framework for allergens, especially on the Note for Guidance on Allergenic Extracts, issued by the European Medicine Agency (EMA) and on the allergen monograph of the European Pharmacopoeia, issued by EDQM (Council of Europe), that is adopted by European Directives for Medicinal products 1-3. Secondly, it improved the accuracy of allergy diagnosis. Single or multiplexed, allergenic molecules are routinely used and have changed the way we diagnose 4. Lastly, but not least, some sensitization profiles are linked to different clinical phenotypes, and can be used to stratify allergic patients, to predict intervention outcomes, and to perform system biology studies that open new avenues for allergy disease management5-11.
The implementation of a new regulatory framework led to the commercialization of allergy vaccines with registration clinical trials performed during five years. Based on these studies, a better understanding of AIT mechanisms is now possible. From allergen-specific effector cell desensitization5,12-14to a progressive onset of T and B cell-mediated regulatory mechanisms15-19 responsible for the disease-modifying effect, their temporal alignment is critical to establish best AIT practices. In this context, the quality of the extract used − and its standardization −, the knowledge of patient’s sensitization profiles, and the link to the AIT product used are pivotal to maximize the odds of AIT success. In this review, we discuss the different aspects of molecular allergology, from an overview of allergenic molecules and diagnostic methods to the quality of allergen preparation and the clinical approaches to AIT. We aim to offer a practical document to support the allergy specialist in the daily clinical management of allergic patients.