Tr1 cells in the neat sighting-pole

Many cell subsets with regulatory function have been described, including natural CD4+CD25+Foxp3+ T cells and acquired regulatory T cells such as regulatory type I cells (Tr1) or Th3 cells. They are generated from different precursors and have different mechanisms of action. Tr1 cells are induced in the presence of high levels of IL-10 and they exert their immunomodulatory activity through the production of large amounts of IL-10 and TGF-β. Tr1 cell function is impaired in several immunological diseases such as autoimmune diseases (multiple sclerosis, rheumatic disease, psoriasis, or type I diabetes), allergic diseases, or graft rejection. The impairment of Tr1 function can be related to the decrease of IL-10 production by Tr1 cells or by an alteration in the IL-10 signalling pathway. In this work, the characteristics of Tr1 cell are reviewed, highlighting the potential of these regulatory T cells for immunotherapy.