This article gives an overview about the current state of preclinical and clinical studies using different kinds of adjuvants and their effect on allergen-specific immunotherapy (SIT).
Recently, vectors such as liposomes and microspheres and adjuvants such as Toll-like-receptor agonists [e.g. nonmethylated cytosine–guanine dinucleotide (CpG) motifs derived from bacterial DNA or monophosphoryl lipid A (MPL A)] have been used in clinical phase II and III trials demonstrating encouraging clinical effects.
SIT has been optimized for more than 100 years with different approaches. Among these, adjuvants have been shown to amplify the effect of SIT by modulating the immune response to this therapy. In the first part, this article reviews the immunological mechanisms underlying the use of adjuvants targeting key cells of the innate immune system such as dendritic cells. In the second part, it overviews first clinical trials which have been reported so far in both subcutaneous and sublingual allergen-specific immunotherapy investigating the therapeutic potential of adjuvanted extracts. Most of these clinical trials revealed both clinical efficacy and immunological effects. However, more studies are warranted to further focus the specific role of adjuvants in the process of tolerance induction in allergic patients.
aDepartment of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, Germany
bCentre for Rhinology and Allergology, Wiesbaden, Germany
cHospital Médica Sur, México, Distrito Federal, México
dSection of Allergy and Clinical Immunology, Imperial College, National Heart and Lung Institute, Royal Brompton Hospital, London, UK
Correspondence to Oliver Pfaar, MD, Center for Rhinology and Allergology, An den Quellen 10, D-65183 Wiesbaden, Germany. Tel: +49 611 308 608 250; fax: +49 611 308 608 255; e-mail: email@example.com