Allergens are natural components of the environment. The identification of sources of allergens responsible for symptoms is a required precondition for introducing advice and specific treatment. 

Allergens are antigens that react with specific IgE antibodies. Allergens are extremely numerous. Among the different types, there are allergens inhaled via the respiratory tract (called airborne allergens). The airborne allergens most commonly involved in rhinitis and asthma are mites, plants (pollens, latex), animal dander, cockroaches and molds, depending on the geographic area.

The ability to produce allergenic proteins using recombinant DNA technology has provided enormous amounts of information on the structure of allergens and their common antigen, which is the basis of cross reactivity.

Genes for more than 150 allergens have been cloned and can be produced using different vectors (bacteria, plants, yeasts). Some recombinant allergens - those of birch and grass pollens, and house dust mites - have been tested in vitro and in vivo (skin tests and allergenic provocation tests).

 
These results of such studies suggest that recombinant allergens could be used, not only for diagnostic purposes but also for treatment in the form of desensitisation.[1] The first therapeutic trials are ongoing. Finally, work is being carried out on using recombinant products for the standardisation of allergens in the context of the European research program CREATE (Certified REferences for Allergens and Test Evaluation).[2]

[1] Chapman M. et al. J Allergy Clin Immunol 2002; 109: 440-45.
[2] Van Ree R. Allergy 2004; 59: 571-74.