Auto-immune disease.

Auto-immune disease may result from the interaction of the genetic load of the individual, modification of self-tissue antigens by environmental agents such as virus or drugs and abnormalities of the immunological system itself such as the loss of controlling or suppressor T cells with age. In the majority of people the outcome is tolerance, maintenance of normal tissue architecture and function. In the unfortunate few the outcome is auto-immune disease, that is, failure to recognize "self".