[Immunological tolerance and autoimmune disease]

The immune system must remain tolerant to self-antigens so as not to destroy what it has evolved to protect. There appears several mechanism for this purpose; deletion, anergy, sequestration of autoantigen and active suppression. These mechanism cooperate, constituting a fail-safe system, although the strategy against each autoantigen is determined by the nature of the autoantigen, i.e., the amount, timing and location of the expression. Here, we review and discuss on the pathogenesis of autoimmune disease as a consequence of the breakdown of the surveillance network, based on the recent advances in immunology.