Emerging therapies and respiratory infections: Focus on the impact of immunosuppressants and immunotherapies.

Host defences to infection are based upon an integrated system of physical and biochemical barriers, innate and adaptive immunity. Weakness in any of these defensive elements leads to increased susceptibility to specific pathogens. Understanding how medical therapies disrupt host defences is key to the successful prevention, diagnosis and management of respiratory infection in the immunocompromised host.