The target tissue in autoimmunity--an influential niche.

Central and peripheral tolerance mechanisms were for a long time the only regulatory circuits known in autoimmunity. It is now becoming clear that the target tissue itself may have the capacity to control its own destiny. Here we review mechanisms by which the target tissue regulates local inflammation, and the way this could influence progression to overt autoimmunity. Moreover, we discuss recent data showing that physiological properties of the target tissue can determine the organ specificity of autoimmune disease. These recent discoveries and ideas concerning the regulatory potential of the target tissue may, in the future, add a new dimension to our concept of regulatory circuits in autoimmunity.