Allergen specific immunotherapy has been introduced in the clinic more than 100
years ago showing effectiveness and, so far, it represents the only curative approach to treat allergic
disorders ameliorating the symptoms, reducing the medication costs and blocking the onset of
new sensitizations. However, some questions are still open regarding to the safety of the treatment
and the need to reduce the dose and time of administration to improve the compliance of the
patients. All preparations that are currently available may trigger side effects. For these reasons,
new formulations and route of administration have been exploited demonstrating that such products
presented improved efficacy and safety. Nanotechnology for biomedical applications offers
many advantages, such as improved stability and bioavailability, favourable biodistribution profiles and targeting to specific cell populations
whose impact on the immune system has been evaluated in animal systems. Nanoparticles interact with the immune system, and the
final outcome of this interaction depends on their physico-chemical characteristics. Concerns can be raised when immunotoxic effect are
induced, resulting in inflammatory dangerous responses or in the reduction of the normal defensive activity of the immune system.
In this paper, we will review the most relevant data about the synthesis of allergen/nanoparticles systems and will discuss their impact on
the immune system in terms of immunomodulatory activity and immunotoxicity risk assessment.