Atopic disorders: a vaccine around the corner?

The incidence and severity of atopic disorders, in particular asthma, is steadily increasing at an alarming rate. Furthermore, no primary prevention measure exists to date. However, recent results obtained from numerous animal studies suggest that primary prevention in humans might be possible in the near future. The most promising approaches include the induction of systemic or local allergen-dependent or -independent T helper 1 (Th1) immune responses, through the use of killed bacteria (or components derived from them), CpG oligodeoxynucleotides or plasmid DNA, and the induction of allergen-specific T-cell tolerance. Here, we review the data showing that animals can be protected from developing allergic Th2 responses by vaccination. Possible future use in humans and potential side-effects of the described vaccination strategies are discussed also.