The potential benefit of allergen immunotherapy is largely predetermined by the appropriate selection of constituent allergens. The summary statements of the Practice Parameters of Allergen Immunotherapy stated: “In choosing the components for a clinically relevant extract, the physician should know the local and regional aerobiology of pollens, fungi, and dust mites and should be aware of potential allergens in the patient's environment.”<sup>32 Joint Task Force on Practice Parameters Practice parameters for allergen immunotherapy J Allergy Clin Immunol 1996 ;  98 : 1001-1011

Cliquez ici pour aller à la section Références</sup> One must assess not only the patient's reactivity to a variety of aeroallergens, but also know the relevance of those sensitivities in light of the patient's exposure. The formulation of the allergen vaccine should reflect those exposures likely to be responsible for the patient's symptoms, and contain allergens in optimal concentrations to facilitate treatment response. An attempt to include all vaccines with skin test positivity will usually lead to diminishing the amounts of individual allergens, which may result in a particular component being subtherapeutic. Therefore, one should eliminate items that are either irrelevant owing to lack of exposure or are suitably covered through cross-reactivity with other constituents. For this reason, it behooves the physician to have a firm grasp of geographic distribution of allergenic plants, to know which types are relevant to the area of his or her practice, and have a practical knowledge of allergen cross-reactivity.