Abstract
Allergen-specific immunotherapy (SIT) has been used for almost a century as a desensitising therapy for allergic diseases. Administration of appropriate concentrations of allergen extracts has been shown to be reproducibly effective when patients are carefully selected. The disadvantage with allergen extracts is that they consist of nonallergenic or even toxic proteins, and can induce severe side effects including anaphylaxis and death. Several strategies have been developed to tackle this issue. With the introduction of recombinant DNA technology and peptide chemistry, it became possible to produce SIT vaccines with reduced allergenic activity. In addition, current understanding of immunological mechanisms of SIT, particularly the role of regulatory Tcells in allergen-specific peripheral tolerance, may enable novel treatment strategies.