Next steps in regulatory T cells: Biology and clinical application.

Recent advances in regulatory T cell (Treg) biology and clinical application of Treg-based treatments show promise as a new generation of transforming therapeutics for immune-related disorders, positioning Tregs as a "living drug" to rebuild immune tolerance and repair damaged tissues simultaneously. This perspective summarizes the key knowledge on Treg biology and highlights the recent important discoveries in the development of clinical applications based on Treg biology, from low-dose interleukin-2 therapy showing promising results in trials for ALS and adoptive Treg transfer demonstrating efficacy in preventing GVHD to early pilot studies of CAR Tregs. Drawing on these advances, we provide perspectives on key research priorities and translational challenges and set forth a roadmap that integrates basic and clinical insights into developing next-generation therapies focusing on precision tolerance strategies.