Crypticity of self antigenic determinants is the cornerstone of a theory of autoimmunity

Extract: The immune system is designed to keep in check, to kill, and to clear from the body any invading disease-causing microbial agents such as bacteria and viruses. This immunity against foreign pathogens is mediated primarily through T lymphocytes and antibodies. Furthermore, there are in-built regulatory mechanisms that monitor the activity of these immune effector components. However, under certain constellations of genetic predisposition and environmental triggers, the same immune system can turn against the host and cause damage to the body's own ("self") cells and tissues (autoimmunity). Diseases like multiple sclerosis (MS), insulin-dependent diabetes mellitus (IDDM), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and thyroiditis represent a spectrum of autoimmune diseases caused by a dysregulated immune system. Although the autoimmune nature of many of these disorders is clear, their precise etiology is far from evident. Both the genetic composition of an individual [represented, for example, by the major histocompatibility complex (MHC), which in humans is termed HLA (human leukocyte antigens)] and environmental influences (e.g., microbial agents, stress, etc.) are believed to be the major factors that determine outcome of an immune response against self components.