One possible mechanism of autoimmunity concerns the integrity of the cellular and nuclear membranes. When these membranes begin to lose their integrity leaking minute amounts of nuclear genetic material directly into the bloodstream, these nuclear proteins are perceived by the liver as an indication that upstream tissue damage has occurred. In response, the liver develops what are called natural tissue antibodies that are put into circulation designed to target the upstream tissue break down and degrade the perceived damage before infection by an external agent can occur.