Homeostatic mechanisms in the control of autoimmunity

The data in this article challenge the current paradigm that self tolerance among T cells can be fully accounted for in terms of intrathymic clonal deletion, anergy and T-cell 'indifference'. We show that autoreactive T cells are under the control of a dominant T-cell-mediated control mechanism and that the thymus is a particularly potent source of these protective cells. We further show that 'peripheral' self antigens implicated in autoimmune diseases are expressed intrathmically and we consider possible consequences of such expression. Finally we show that autoantigen-specific peripheral T cells can be programmed to prevent autoimmunity.