Cell-mediated immunity after influenza vaccination. Recently, specific cellular responses have also been implicated in protection against influenza, independently of the humoral response. Cellular mediated immunity has been evaluated measuring IL-2 and IFN-(for T-helper type 1 response), IL-10 (for T-helper type 2 response), and granzyme B expression (which correlates with lytic activation). The cell-mediated immune response has been mainly used to evaluate the response to influenza vaccine in the elderly. In a study with 90 persons >60 year-old, the IFN-/IL-10 ratio and granzyme B levels were significantly higher in persons who did not develop influenza during the follow-up, compared to persons who developed influenza. There was no correlation between the antibody levels and the risk of developing influenza infection. In a previous study, granzyme B levels were found to be higher in young people than in old people. Taken together, these data suggest that cell-mediated immune response may correlate better with the risk of influenza after vaccination.