Peptide-Mediated Immune Responses in Specific Immunotherapy

Conventional immunotherapy using whole allergen extracts has been shown to be an effective, disease-modifying treatment in carefully selected patients with allergic conjunctivo-rhinitis, asthma and bee and wasp venom hypersensitivity. However, this form of therapy is associated with the risk of systemic anaphylaxis, which, when severe, can be life threatening. A potentially significant reduction in the incidence of IgE-mediated events during immunotherapy may be achieved by the use of short peptides corresponding to T cell epitopes which, by virtue of their size, are incapable of cross-linking allergen-specific IgE bound to the surface of mast cells and basophils. Initial clinical studies have demonstrated degrees of efficacy which have, in some cases, been associated with adverse events occurring immediately or several hours after peptide administration. Preliminary data from studies employing shorter peptides (20 amino acids or less) suggest that improved efficacy may be achieved by using peptides of defined major histocompatibility complex-binding specificity administered in an incremental dose fashion comparable to conventional immunotherapy. This review will discuss the concept of peptide immunotherapy and the implications of recent studies.