Essentials of allergen immunotherapy: A primer for the practitioner.

It has been more than a decade since the most recent allergen immunotherapy (AIT) practice parameter was published and 5 years since a focused practice parameter on sublingual immunotherapy (SLIT) was issued. There is an unmet need, therefore, for a more up-to-date, concise summary of AIT to be published to provide allergy/immunology practitioners, allergy/immunology fellows-in-training, medical students, residents, and other health-care practitioners with the most current information available on AIT. The Allergen Immunotherapy Primer (AITP) is not intended to define a standard of care or to be inclusive of all proper methods of care, nor is it intended to replace or supplant established AIT practice parameters; rather, the goal of this AITP is to supplement the established practice parameters and to serve primarily as an updated tool for the practicing allergist/immunologist, allergy/immunology trainees, and health-care professionals seeking practical and concise information with regard to AIT. Primer topics include the history of AIT; descriptions of the mechanisms and biomarkers of subcutaneous immunotherapy (SCIT) and SLIT; the efficacy and safety of SCIT; the efficacy and safety of SLIT, pediatric SLIT, and SCIT; the long-term efficacy of SLIT and SCIT; long-term adherence strategies for AIT; the implications of real-world data for AIT; the role of AIT for asthma; patterns of cross-allergenicity among pollens; a practical implementation guide for optimized construction of AIT vaccines; standardization of allergen extracts; updated information on federal regulations about the United States Pharmacopeia and the compounding of allergenic extracts; an update on AIT venom immunotherapy; the advantages and disadvantages of accelerated immunotherapy regimens; the important role of shared decision-making in AIT and how it can be incorporated into the informed consent process; and a forecast of future directions in allergen immunotherapy.