Regulatory T Cells in <i>Mycobacterium tuberculosis</i> Infection

Anti-inflammatory regulatory T cells have lately attracted attention as part of the immune response to Mycobacterium tuberculosis infection, where they counterbalance the protective but pro-inflammatory immune response mediated by Th17 cells and especially by the better-known Th1 cells. In chronic infectious diseases there is a delicate balance between pro- and anti-inflammatory responses. While Th1 and Th17 are needed in order to control infection by Mycobacterium tuberculosis , the inflammatory onset can ultimately become detrimental for the host. In this review, we assess current information on the controversy over whether counterbalancing regulatory T cells are promoting pathogen growth or protecting the host.