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The immune system has very powerful effector mechanisms that can eliminate a wide variety of pathogens. Early in the study of immunity, it was realized that these could, if turned against the host, cause severe tissue damage. Autoimmune responses resemble normal immune responses to pathogens as specifically activated by antigens, in this case self-antigens or auto-antigens, and give rise to auto-reactive effector cells and to antibodies, called autoantibodies, against the self-antigen.
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Autoimmunity The immune system has very powerful effector mechanisms that can eliminate a wide variety of pathogens. Early in the study of immunity, it was realized that these could, if turned against the host, cause severe tissue damage. Autoimmune responses resemble normal immune responses to pathogens as specifically activated by antigens, in this case self-antigens or auto-antigens, and give rise to auto-reactive effector cells and to antibodies, called autoantibodies, against the self-antigen. When reactions to self-tissues do occur and are then improperly regulated, they cause a variety of chronic syndromes called autoimmune diseases. Immune Tolerance Although individual autoimmune diseases are uncommon, collectively they affect approximately 5% of the populations in United States, and their incidence is on the rise. Nevertheless, their relative rarity indicates that the immune system has evolved multiple mechanisms to prevent damage to self-tissues. The most fundamental principle underlying these mechanisms is the discrimination of self from non self, but this discrimination is not easy to achieve.
