Modified forms of allergen immunotherapy

There have been many attempts to modify allergens and thus to improve upon conventional immunotherapy, which has been proved effective but has several drawbacks. These include the risk of systemic reactions and the time and cost involved. The modifications have taken three major approaches. One approach, to impede allergen release from the site of deposition, has met with limited success. An example is alum precipitation, which has modestly reduced the number of injections and incidence of systemic reactions. A second approach, to suppress specific IgE production and to induce specific tolerance, has not been successful in man. The third approach, to reduce allergenicity while retaining immunogenicity of allergens, has been the most successful and appears to have the most promise. One example is polymerized allergens, which have been shown to be safe, efficacious, and immunogenic in multiple clinical trials. Other examples include allergoids and glutaraldehyde-treated, tyrosine-adsorbed allergens.