Novel Allergen Immunotherapy Routes

Abstract

Allergic diseases are among the most common human diseases of humans. Approximately 33 % of the total population in industrialized countries may be affected. The immune response towards allergens is regulated by T lymphocytes and characterized by an interleukin (IL)-4, IL-5 and IL-13 dominated Th2 cytokine profile. Allergen-specific immunotherapy (AIT) is the only causative treatment option and able to change the natural course of disease, e.g., to prevent the development of asthma and new sensitizations. Classically, the allergen extract has been applied subcutaneously to the patient. New application methods for delivering the allergen to the patient have been developed in recent years. The intralymphatic delivery of allergens named intralymphatic immunotherapy (ILIT) has been evaluated in clinical trials and was demonstrated to be a highly potent application route with low effort and side effects while having equal efficacy if compared with current standard AIT forms. However, large studies that verify important questions like optimal dose, injection intervals, new allergen forms, use of adjuvants, etc. are still missing. Moreover, it has to be evaluated, whether different indications like rhinitis, asthma, or atopic dermatitis are suitable for ILIT and whether it is useful in children. Epicutaneous immunotherapy (EPIT) is a possible alternative application form. EPIT is minimally invasive and basically consists of the affixation of allergen containing patches to the epidermis over 6 weeks. From the studies performed so far, the authors concluded, that EPIT is safe and efficacious in a dose-dependent manner after six patches only. EPIT is increasingly attracting attention because of its capacity to offer a safe, needle-free, and potentially self-administrable treatment option for IgE-mediated allergic diseases. AIT is accepted to be the only causative treatment option for allergies. New application routes in ILIT and EPIT may become more important and allow for different delivery methods in the future, however further clinical studies are required and in preparation.