IFNG and infection: IFN-γ is produced by Th1 cells, CD8+T (cytotoxic T) cells, natural killer (NK) cells, and NKT cells27, 28, and in our study, IFN-γ levels were elevated against the high virus load in the asthmatic/A(H1N1)pdm09 group at 3 days post-infection, but were not sufficiently augmented at 7 days post-infection.