Clinical use of adjuvants in allergen-immunotherapy.

INTRODUCTION: Allergen-specific Immunotherapy (AIT) is the only available treatment aimed to tackle the underlying causes of allergy. The active components of subcutaneous vaccines traditionally consist of natural or modified allergen extracts which can be combined with adjuvant platforms. In recent years new targets have been further developed in an attempt to raise the safety and efficacy profile of AIT. Areas covered: In this review, we discuss the desirable attributes of adjuvants and delivery systems from empiricism to rational design, for current and future clinical applications in AIT. Expert commentary: The introduction of novel adjuvants, in combination with active targets, has been demonstrated to reduce symptoms of AIT, increase clinical efficacy of allergy treatment and reduce the number of doses. The evolution of vaccine development for AIT is entering a phase of scientific progress that challenges dogmas. Over the past century the traditional concept of immunotherapy, entailing long-course administration of native extract preparations and first generation adjuvants, has seen evolution in the past decade from proof-of-concept to clinical development pipelines encompassing the advent of second generation adjuvants and delivery systems forming essential components of modern AIT development.