On Monday, 6 October 2025, at 11:30 a.m., it was announced that the 2025 Nobel Prize in Physiology or Medicine would be awarded to three scientists working on an important control mechanism of the immune system. Prof. Dr. Stephan Ehl, Director of the Institute for Immunodeficiency at the University Medical Centre Freiburg, explains what the findings mean for patients:
· Press Release
Classification of the 2025 Nobel Prize in Medicine
Freiburg immunologist explains the significance of the research honoured with the 2025 Nobel Prize in Medicine
Prof. Dr. Stephan Ehl
“The outstanding research work of Mary Brunkow, Fred Ramsdell and Shimon Sakaguchi on peripheral immune tolerance has made a decisive contribution to understanding how the immune system controls its activity and avoids self-destruction.”
"The researchers identified and characterised regulatory T cells (Tregs), thereby establishing a concept of specialised immune cells that actively suppress immune responses. They demonstrated that a congenital deficiency of Tregs leads to severe autoimmune diseases, highlighting their central role in maintaining immunological balance.
These findings have led to concrete approaches for new therapies aimed at preventing or modulating autoimmune reactions – for example, in type 1 diabetes, multiple sclerosis or rheumatoid arthritis – as well as preventing the rejection of organ transplants. At the same time, tumours use immune tolerance mechanisms to evade immune surveillance. A deeper understanding of peripheral immune tolerance will therefore also help oncology to develop future therapies that specifically reactivate the immune system without compromising its natural protective function."
About the person:
Prof. Dr. Stephan Ehl is a paediatrician, Director of the Institute for Immunodeficiency at the University Medical Centre Freiburg, Professor of Paediatric Immunology at the Medical Faculty of the University of Freiburg, spokesperson for the Collaborative Research Centre 1160 ‘Impath’ and member of the Centre for Integrative Biological Signalling Studies (CIBSS) Cluster of Excellence at the University of Freiburg. Ehl is also a member of the German National Academy of Sciences Leopoldina.