title: Regulatory T cells: prospective for clinical application in hematopoietic stem cell transplantation.
abstract: OBJECTIVE
  Regulatory T cells exert a dominant effect in controlling autoimmunity and maintaining peripheral tolerance. Regulatory T cells are also involved in preventing allograft rejection and graft versus host disease. Cellular therapy with expanded regulatory T cells represents a promising approach to control T-cell mediated pathology. In this review we will summarize the efforts to design new methods for expanding regulatory T cells and exploit their regulatory function as cellular therapy for the treatment of graft versus host disease after hematopoietic stem cell transplantation.
  
  
  RESULTS
  Among CD4+ T cells, the best described are the naturally occurring CD4+CD25+ regulatory T cells and type 1 regulatory T cells. Recent progress has been made in the characterization of both subsets in terms of isolation and induction, respectively. However, a clear definition of their mechanisms of action has still to be achieved.
  
  
  CONCLUSIONS
  Better understanding of the mechanisms of suppression mediated by regulatory T cells might enable their use to modulate specific immune responses. Moreover, the recent development of methods allowing the ex-vivo expansion of regulatory T cells, to provide sufficient number of cells for in-vivo infusion, represents the first step toward the use of these cells as cellular therapy for the treatment of immunologic and hematological diseases.
authors.affiliation: San Raffaele Telethon Institute for Gene Therapy (HSR-TIGET), Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Gregori
authors.forename: Rosa
authors.initials: R
authors.lastname: Bacchetta
authors.forename: Ehud
authors.initials: E
authors.lastname: Hauben
authors.forename: Manuela
authors.initials: M
authors.lastname: Battaglia
authors.forename: Maria-Grazia
authors.initials: MG
authors.lastname: Roncarolo
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D006086:Graft vs Host Disease / Q000276:immunology / Q000628:therapy; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D051379:Mice