ABSTRACT
Allergy immunotherapy, much as it is practiced today, was introduced in 1911 by the reports of Leonard Noon1 and John Freeman2 on their injection of increasing doses of Timothy pollen extract to patients with a history of hay fever. In an era when effective symptomatic treatment for allergic rhinitis and asthma was lacking the use of immunotherapy became quite widespread, despite only anecdotal evidence for its effectiveness. Indeed, controlled studies confi rming the effectiveness of immunotherapy in allergic rhinitis3,4,5 and bronchial asthma6 were not conducted until some 40 yr after its introduction. An understanding of the mechanism behind the improvement was even later in coming7,8,9 and even now, the relative contribution of the observed immunological changes in producing the improvement in symptoms and the persisting benefi t after discontinuation is completely understood. With an appreciation of the immunological response and demonstration that immunotherapy is the only truly disease modifying treatment for the allergic diseases there is currently a high level of enthusiasm among allergy/immunology specialists for immunotherapy, but this has not translated into increased use in suitable patients. There are two main reasons, one is the availability of reasonably effective symptomatic treatment, the other, the investment in time, the expense and the risks of adverse reactions that are associated with immunotherapy by the current subcutaneous route. For this reason, alternative routes of administration or modifi cations in the allergen extracts are being explored to enhance the safety and reduce the inconvenience of this form of treatment.
