Influenza is responsible for significant morbidity after transplantation. We evaluated Th1/Th2 cytokines and IL-10 levels during influenza infection in the post-transplant setting. Sera from 277 transplant recipients were analyzed at influenza diagnosis and 28 days later for IFN-γ, IL-4, IL-13 and IL-10. IL-13 levels were associated with protection against pneumonia and ICU admission, whereas the IFN-γ/IL-13 ratio and IL-10 levels were associated with an increased risk of pneumonia and ICU admission. This association was independent of viral load. A skewing of immune responses towards Th2 in transplant patients appears to confer protection from severe influenza infection, independently of viral load.