01494nas a2200241   4500000000100000008004100001260001300042653002300055653003800078653003100116653001100147653002100158653001200179653001800191653002900209653002500238100001600263245007800279300001100357490000700368520086300375022001401238       2012                            d  c2012 Sep10aDisease resistance10aGenetic Predisposition to Disease10aHost-Pathogen Interactions10aHumans10aImmunity, Innate10aleprosy10aMycobacterium10aMycobacterium Infections10aT-Lymphocyte Subsets1 aOttenhoff T00aNew pathways of protective and pathological host defense to mycobacteria.  a419-280 v203 a<p>Recent studies have uncovered new mechanisms by which the human immune system attempts to control infection and how pathogens elude these mechanisms. Mycobacterial infections are prime examples of chronic battle fields between host and pathogens. The study of tuberculosis and related mycobacterial infectious diseases such as leprosy have greatly aided in deciphering mechanisms of immune mediated protection and pathology in humans. Here we review recent insights into the role of newly discovered T cell subsets including Th17, Tregs and nonclassically restricted T cells in adaptive immunity to mycobacteria. The role of newly discovered innate immune mechanisms in tuberculosis and leprosy along with recent results from 'unbiased' genome-wide and functional genetic approaches, are deciphering critical host pathways in human infectious disease.</p>  a1878-4380