What is Autoimmunity?



The healthy person's body is equipped with a powerful set of tools in the form of "immune system" to resist the attack of invading microorganisms such as viruses, bacteria, and parasites.

Immune system responds in a regulated fashion towards microbes and eliminates them, but it does not respond to self-antigens.

Several regulatory mechanisms terminate immune response to foreign antigens to return the immune system in to the normal condition following clearance of the antigens.

Regulatory mechanisms also maintain immune unresponsiveness, or tolerance, to self-antigens.

Unfortunately, in spite of these regulatory mechanisms, immune system sometimes goes awry and attacks its own body. Failure of immune systems tolerance to self antigens ensues in pathological state.

The misdirected immune response results in debilitating illness and sometimes death is referred as "autoimmunity".

This can be demonstrated by the presence of auto antibodies or T lymphocytes reactive with self antigens.

Generally immune system tolerates its own potentially antigenic substances, and failure of self tolerance is the fundamental cause for autoimmunity.

To some extent autoimmune response (sometimes termed as natural autoimmunity) is an integral part of vertebrate immune systems.

Auto antibodies are believed to be a product of natural selection and have been suggested to play an important role in "housekeeping" functions. They serve as physiological regulators of the immune system and act as components of body's homeostasis.

Indeed, natural autoimmunity performs several functions that include the scavenging of metabolic waste and senescent cells, a first line of protection against viral and bacterial infection.