MTOR and metabolic syndrome: Biological processes altered in T cell aging are not only those typically associated with immune cells (T cell receptor signalling, cytokine-cytokine receptor interactions, etc.)but also some not specific of immune cells, such as peroxisome proliferator-activated receptors and mTOR signalling, as well as glucose and glutathione metabolism, suggesting that T cell aging may be representative of a more generalized aging phenomenon [25], with features characteristic also of the MetS.