The link between IFN-γ–producing CD4 T cells and excessive neutrophilia during clinical manifestations of TB has been clearly established (40), and we observed high recruitment of IL-1β–producing inflammatory neutrophils in IFN-γR−/− mice that correlated with elevated levels of CD4 T cells and IFN-γ and highly lesioned lungs. This evidence concerns the gene CD4 and tuberculosis.