Targeting allergic airway diseases by siRNA: an option for the future?

Allergic diseases emerge as a substantial health problem of the 21(st) century. Current therapies including combination therapies of corticosteroids and beta(2)-agonists are highly effective, inexpensive and relatively safe. However, these medicaments only relieve symptoms but are not curing disease. So the challenge has to be to develop new therapeutics which are as effective as present medicaments without any side effects and hopefully even heal the disease. It has become clear over the past years that Th2-cells and their cytokines have an outstanding role in the development of airway hyperresponsiveness, airway inflammation, airway remodelling and reversible airway obstruction, the cardinal symptoms of allergic asthma. There is legitimate hope that down regulation of these factors could result in a susceptible damage of pathologic mechanisms. Out of different gene silencing techniques RNAi seems to be the most promising method to achieve long-lasting and effective abrogation of key elements in allergic diseases. In particular, this review will highlight the potential of small interfering RNAs to specifically inhibit the function of transcription factors and tyrosine kinases which are involved in orchestrating an allergic immune response.