As shown in Figure 5, 4–15% of IFN-γ producing CD4+ T cells specific for Ag85B in TB patients exhibited the TCNP phenotype, and a similar fraction (12–25%) of IFN-γ-producing CD4+ TCNP cells was found in response to Acr. These results indicate that CD4+ TCNP cells are a common feature of the global immune response to M. tuberculosis. Here, CD4 is linked to tuberculosis.