ALLERGEN IMMUNOTHERAPY - THERAPEUTIC VACCINES FOR ALLERGIC DISEASES

Allergen immunotherapy is the administration of gradually increasing q uantities of an allergen vaccine to an allergic subject, reaching a do se which is effective in ameliorating the symptoms associated with sub sequent exposure to the causative allergen. Controlled studies have sh own that allergen immunotherapy is an effective treatment for patients with allergic rhinitis/conjunctivitis, allergic asthma, and allergic reactions from stinging insects. The treatment of allergic diseases is based on allergen avoidance, pharmacotherapy, allergen immunotherapy, and education of the patient. Immunotherapy, where appropriate, shoul d be used in combination with all forms of therapy with the goal that the allergic patient will become as symptom-free as medically possible . Allergen immunotherapy is indicated for patients who have demonstrat ed evidence of specific IgE antibodies to clinically relevant allergen s. The rationale for prescribing allergen immunotherapy depends on the degree to which symptoms can be reduced by medication, the amount and type of medication required to control symptoms, and whether effectiv e allergen avoidance is possible. The response to immunotherapy is spe cific for the antigen administered. Mixtures of allergens unrelated to the patient's sensitivity should not be utilized.Physicians should kn ow of local and regional aerobiology and the exposure of the patient i n the home and work environments. Only physicians with training in all ergology (allergy/immunology) should prescribe the clinically relevant vaccine for allergen immunotherapy. The quality of the allergen vacci ne is critical for both diagnosis and treatment. Where possible, stand ardized vaccines of known potency and shelf life should be utilized fo r allergen immunotherapy. The use of well-characterized and standardiz ed vaccines makes it possible to define an optimal maintenance dose in the range of 5-20 mu g of major allergen per injection for a number o f primary allergens. Therapeutic efficacy correlates with such doses. The major risk of allergen immunotherapy is anaphylaxis. Therefore, al lergen immunotherapy should be administered by or under the close supe rvision of a trained physician who can recognize early symptoms and si gns of anaphylaxis and administer appropriate emergency treatment. The optimal duration of immunotherapy is still unknown. Many clinicians a dvise 3-5 years of therapy for patients who have had a good therapeuti c response. However, the decision to discontinue allergen immunotherap y should be individualized. Several studies suggest that venom immunot herapy may be discontinued after 3-5 years in most patients. However, the decision to discontinue venom immunotherapy should be individualiz ed.