On October 6, 2025, the Nobel Prize in Medicine was awarded to three scientists for pioneering work on a crucial regulatory mechanism of the immune system. Professor Stephan Ehl (A01), Director of the Institute for Immunodeficiency at the Medical Center of the University of Freiburg and spokesperson of CRC 1160, provides insight into the impact of these discoveries for patients.
“The outstanding research by Mary Brunkow, Fred Ramsdell, and Shimon Sakaguchi on peripheral immune tolerance has been instrumental in understanding how the immune system regulates its activity and avoids self-destruction,” says Stephan Ehl.
“These scientists identified and characterized regulatory T cells (Tregs), establishing the concept of specialized immune cells that actively suppress immune responses. They demonstrated that a congenital deficiency of Tregs leads to severe autoimmune diseases, which underscores their central role in maintaining immunological balance.
These findings have paved the way for new therapeutic approaches aiming to prevent or modulate autoimmune reactions—such as in type 1 diabetes, multiple sclerosis, or rheumatoid arthritis—and prevent rejection of organ transplants. At the same time, tumors exploit immune tolerance mechanisms to evade immune surveillance. Deepening our understanding of peripheral immune tolerance will thus also help develop cancer therapies that precisely reactivate the immune system without compromising its natural protective functions.”
About Prof. Stephan Ehl:
Prof. Dr. Stephan Ehl is a pediatrician and Director of the Institute for Immunodeficiency at the Medical Center – University of Freiburg, Professor of Pediatric Immunology at the Faculty of Medicine, spokesperson of the Collaborative Research Center 1160 “Impath,” and member of the Cluster of Excellence CIBSS at the University of Freiburg. Prof. Ehl is also a member of the German National Academy of Sciences – Leopoldina.
