Thus, both TNF-α+IL-2+, IFN-γ+TNF-α+IL-2+ and IFN-γ+TNF-α+ CD4 T cells showed significant correlation, and it could be speculated that all T cell subsets arise from one pre infection subset, the TNF-α+IL-2+ subset, which is able to both provide post infection effector T cell subsets as well as maintaining a central memory pool of T cells. This evidence concerns the gene IFNG and infection.