Reasoning for a Defective Lymphocyte

There is a possibility that there is a defective lymphocyte that is responsible for the autoimmune destruction of beta cells. The abnormal white blood cell may see a crucial domestic substance located on the beta cell as a foreign antigen and therefore destroy the beta cell. Antigens are substances that attract an immune reaction. One possibility for the killer white blood cell is the Cytotoxic T cell. Above: Cytotoxic T cell (left) attaches to somatic cell

Cytotoxic T cells that are both CD4+ and CD8+ (CD4 & CD8 are glycoproteins on the surface of T cells.) are known as double positive (DP) T cells. These cells undergo two selections: positive selection and negative selection. These make sure that any defective lymphocytes are destroyed in order to ensure that no autoimmunity occurs. The cells that survive the selection mature to become mature cytotoxic T lymphocytes.

The glitch here, I believe, is that there may be a mistake (possibly genetic) that occurs during negative selection of DP T lymphocytes. These cells, though they should be destroyed by apoptosis, survive the selection but are still at the risk of causing autoimmunity. Therefore, they are loose in the body, including the pancreas. They may mistake a self antigen on a beta cell to a be a harmful foreign antigen. This may be the reason that they are destroying pancreatic beta cells