Reacción a "Nobel Prize in Medicine or Physiology awarded to Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi for understanding how the immune system is kept under control without attacking organs"

The discoveries of Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi led to the establishment of the concept of peripheral tolerance, an immune control mechanism that prevents the immune response from attacking our own body (autoimmunity). Until the 1990s, it was thought that immune tolerance depended almost exclusively on central mechanisms in the thymus, where autoreactive lymphocytes are eliminated by negative selection. However, Sakaguchi demonstrated the existence of an additional peripheral control system based on CD4+ CD25+ regulatory T cells (Tregs) that inhibited the immune response, preventing autoimmunity. Subsequent research by Brunkow and Ramsdell identified the FoxP3 gene as an essential regulator of Treg development and function. They demonstrated that mutations in FoxP3, which eliminated Tregs, resulted in autoimmune diseases in mice and also in humans (X-linked immunodysregulation-polyendocrinopathy-enteropathy syndrome, IPEX).

Increasing Tregs helps combat autoimmunity and transplant rejection, while reducing Tregs improves cancer immunotherapy. The discoveries of Sakaguchi, Brunkow and Ramsdell have resolved a fundamental question in basic immunology: how the immune system maintains the delicate balance between defending the body against infection and avoiding attack on its own tissues. Their findings opened up a new field of research in immunoregulation and paved the way for therapeutic strategies aimed at modulating the immune response.