Genetic engineering of pollen allergens for hayfever immunotherapy.

Type I allergy is an immunoglobulin E-mediated disease, representing a major health problem affecting more than 25% of the world's population. Grass, birch and ragweed pollen are a major source of environmental allergen. Specific immunotherapy is clinically proven to be an effective treatment for allergic conditions that involve the administration of crude extracts prepared from natural sources with potential life-threatening anaphylactic side effects. Recent developments in the molecular biology of pollen allergens have made it possible to design novel therapeutic approaches for improved and safer forms of specific immunotherapy. Hypoallergenic forms of major allergens with reduced immunoglobulin E epitopes have been produced using genetic engineering, whilst preserving other characteristics of the molecule that are able to induce a protective response. These modified forms are expected to make allergen-specific immunotherapy more widely used.