ABSTRACT
I. INTRODUCTION Allergen injection immunotherapy is highly effective in carefully selected patients with IgE-mediated disease (1--4). Patient selection is important, and the risklbenefit ratio must be assessed in the individual patient. The underlying mechanisms of immunotherapy are important since they may provide insight into the mechanism of allergic (and immunological) disorders in general. For example, allergen injection immunotherapy is allergen specific. This enables one to observe the effects of specific modulation of the immune response in a patient in whom the provoking factor(s) (common aeroallergen or venom) is known. The effects of the allergen exposure may be observed either during experimental provocation in a clinical laboratory or during natural environmental conditions. Similarly, the influence of immunotherapy on clinical, immunological, and pathological changes may be observed under controlled conditions. This is in contrast to other immunological diseases where the antigen is unknown and no specific treatment is available.
