In 1995, Japanese researcher Shimon Sakaguchi made a key discovery in immunology. He identified a previously unknown class of immune cells that could protect the body against autoimmune diseases, cells that later became known as regulatory T cells, or Tregs.
Six years later, in 2001, American scientists Mary Brunkow and Fred Ramsdell published results explaining why a particular strain of mice was especially vulnerable to autoimmune disease. They found that the mice carried a mutation in a gene they named Foxp3. When the same mutation was later found in humans, it turned out to cause the severe condition known as IPEX.