Allergen Immunotherapy: Novel Approaches in the Management of Allergic Diseases and Asthma

Currently available pharmacotherapies for allergic diseases and asthma, which are serious public health problems, are aimed primarily at neutralizing effector molecules and inflammatory mediators such as histamine and leukotrienes or at inhibiting the function of inflammatory cells such as eosinophils and Th2 lymphocytes. While this approach is effective in controlling symptoms, these therapies have a limited capacity to alter the natural course of allergic diseases and asthma, and discontinuation of medications results in the redevelopment of symptoms on reexposure to the offending allergens. In contrast, immune-based allergen immunotherapies modify and correct the underlying pathological immune responses in allergy and asthma in an antigen-specific manner. These immunotherapies replicate the regulatory processes that occur in nonallergic individuals and allow patients to tolerate exposure to allergens. Current and future methodologies for immunotherapy involve immunization with allergen, modified allergen, peptides of allergen, cDNA of allergen, with adjuvants, including immunostimulatory DNA sequences, cytokines, and bacterial products such as Listeria monocytogenes. This form of therapy can provide a long-lasting cure for allergic diseases without the need for continous therapeutic intervention and without causing generalized immunosuppression or immune augmentation.