Changes in Allergic Inflammation Associated with Successful Immunotherapy

Allergen injection immunotherapy in selected patients is effective and has wide ranging anti-inflammatory effects. These include modulation of serum (and presumably local) IgE and IgG antibody responses, a reduction in mast cell numbers in the target organ and inhibition of mast cell mediator release. Tissue eosinophilia and eosinophil activation are also reduced. We have compared and contrasted the effects of immunotherapy and topical corticosteroids on allergen-induced late nasal responses. Both treatments inhibit allergen-induced late nasal symptoms and associated CD4+ T cell and eosinophil recruitment, possibly by distinct mechanisms. Whereas topical corticosteroids may act by suppressing cytokine mRNA expression for Th2-type cytokines, particularly interleukin-4, immunotherapy induces a local Th1 response with an increase in interferon-gamma.