Despite the little role played by inactivation of natural CD4+CD25+ Treg cells in improving protective BCG immunity [18], several reports indicate that pathogen-specific Treg cells, mainly IL-10-secreting CD4+CD25+ Tr1, are generated following MTB infection and suppress IFN-γ cell responses in anergic TB patients [19]–[23]. This evidence concerns the gene IL10 and tuberculosis.