IMMUNE DYSREGULATION POLYENDOCRINOPATHY AND ENTEROPATHY, X-LINKED SYNDROME
The product of the FOXP3 gene (belonging to the forkhead family) is required for the generation and the function of CD4 CD25 T-regulatory cells. Mice that are FOXP3-/- lack these cells and develop a syndrome characterized by lymphoproliferation and autoimmunity. Expression of ectopic FOXP3 confers suppressive function on CD4 and CD25 T cells. Human males with mutations of the FOXP3 gene (which is located on the X chromosome) develop a syndrome characterized by neonatal endocrinopathies (including type 1 diabetes) enteropathy, eczema, immune thrombocytopenia, and cachexia. In these patients, pancreatic islet cell and intestinal mucosal damage are secondary to infiltration of the tissues with mononuclear cells and plasma cells, signifying an autoimmune pathogenesis. This condition is called the immune dysregulation polyendocinopathy and enteropathy, X-linked (IPEX) syndrome. This condition provides evidence supporting current concepts on the role of T-regulatory cells in preventing autoimmunity.