Development of subcutaneous allergen immunotherapy (part 2): preventive aspects and innovations

Background: Allergen immunotherapy with subcutaneous injection (SCIT) of the relevant allergen is the classic causal treatment method for IgE-mediated allergic respiratory disease and has already been successfully used for over 100 years. Methods: This publication is based on a selective literature search in PubMed and MEDLINE. Recent publications in German-language journals that are not available in literature databases were also analyzed. This literature search included original and review articles both in German and in English. Results: Primary, secondary and tertiary prevention characteristics have been demonstrated for SCIT; however, these require further evaluation. In combination with biologic agents, the safety, and in some cases the efficacy, of SCIT can be increased. Adjuvants seem to offer enormous development potential for SCIT. Aluminum salts, microcrystalline tyrosine (MCT), and monophosphoryl lipid A (MPL) are already used in commercial SCIT preparations. At the same time, other adjuvants are being researched, e.g., liposomes, microspheres, CpG motifs (C: nucleotide cytosine, p: phosphate, G: nucleotide guanine), or virus-like particles (VLPs). The therapeutic extracts themselves are also undergoing further development, for instance as recombinant allergens, hypoallergenic variants such as site-directed mutants (SDM), conformational variants, allergen fragmentation, allergen oligomers, deletion mutants, and hybrid allergens/mosaic antigens. Conclusion: SCIT preparations are among the most innovative treatment options in the immunotherapy of allergic diseases. Due to the numerous immunological approaches, they will make treatment safer and more effective in the future with reduced effort.