Regulatory T cells in the control of transplantation tolerance and autoimmunity.

A role for immunoregulatory T cells in the maintenance of self-tolerance and in transplantation tolerance has long been suggested, but the identification of such cells has not been achieved until recently. With the characterisation of spontaneously occurring CD4+CD25+ and NK1.1+ T subpopulations of T cells as regulatory cells in rodents and in humans, together with several in vitro generated regulatory T-cell populations, it seems possible that 'customised' regulatory cells possessing antidonor specificity may become therapeutic tools in clinical transplantation tolerance.