Overview

• Karolinska Institutet awarded the 2025 Physiology or Medicine prize to the trio for discoveries explaining peripheral immune tolerance that prevents self-attack.
• Committee chair Olle Kämpe said the findings were decisive for understanding why most people avoid severe autoimmune disease.
• Key milestones: Sakaguchi identified regulatory T cells in 1995; Brunkow and Ramsdell tied Foxp3 mutations to autoimmunity in 2001; Sakaguchi linked Foxp3 to those cells two years later.
• Two U.S. laureates missed the initial call from Stockholm; Ramsdell was reached the next day after a hike and Brunkow later returned the call after dismissing it as spam.
• The laureates will share SEK 11 million, therapies informed by their work are in clinical trials without broad approval to date, and the Nobel ceremony is set for December 10.