The Role of Synthetic Peptide Immuno-Regulatory Epitope (SPIRE) in the Treatment of Allergic Disease

Abstract

Immunotherapy has been used for over a century for the treatment of allergic rhinitis, starting with the administration of whole allergens which are still in use today. Up-titration of allergen concentrations is thought to induce immune-tolerance, reducing symptoms upon exposure of the same allergen in the natural environment. More recently, peptide immunotherapy research aims to reduce sensitization to the allergen while utilizing a much shorter treatment schedule and avoiding the risk of anaphylactic reactions associated with whole allergen administration. Other immunotherapies undergoing clinical trials utilize linear joined peptides of the natural antigen, which are thought to avoid triggering anaphylaxis by selectively joining non-IgE binding allergen proteins. These novel therapies have been investigated using a variety of methods, including at controlled allergen challenge facilities (CACF) and in phase 3 trials in the “real world” setting. Experimental phase 2 trial designs were also used, the nasal allergen challenge (NAC) protocols, involving the direct exposure of the nasal mucosa to the allergen. The mechanism of action of peptide immunotherapies is thought to vary from that of conventional immunotherapies, though more research is needed to understand how desensitization occurs in each case. A shift from CD4+ to CD8+ Th cells is thought to be one way to explain this and is backed by change in cytokine expression in various experimental models.