title: Multiple sclerosis and regulatory T cells.
abstract: BACKGROUND
  Multiple sclerosis (MS) is a complex genetic disease characterized by chronic inflammation of the central nervous system (CNS). The pathology of MS is largely attributed to autoreactive effector T cells that penetrate the blood-brain barrier and become activated within the CNS. As autoreactive T cells are present in the blood of both patients with MS and healthy individuals, other regulatory mechanisms exist to prevent autoreactive T cells from causing immune disorders. Active suppression by regulatory T (Treg) cells plays a key role in the control of self-antigen-reactive T cells and the induction of peripheral tolerance in vivo. In particular, the importance of antigen-specific Treg cells in conferring genetic resistance to organ-specific autoimmunity and in limiting autoimmune tissue damage has been documented in many disease models including MS.
  
  
  RESULTS
  We have found that the frequency of Tregs in MS patients is unchanged from controls, but their function measured in vitro may be diminished, correlating with impaired inhibitory activity in vivo. This review discusses the immunopathology of MS with particular focus given to regulatory T cells and their potential for the development of new therapies to treat this disease.
authors.affiliation: Division of Molecular Immunology, Center for Neurologic Diseases, Harvard Medical School/Brigham and Women's Hospital, 77 Ave Louis Pasteur, Boston, MA 02115, USA. ccostantino@rics.bwh.harvard.edu
authors.forename: Cristina Maria
authors.initials: CM
authors.lastname: Costantino
authors.forename: Clare
authors.initials: C
authors.lastname: Baecher-Allan
authors.forename: David A
authors.initials: DA
authors.lastname: Hafler