From discovery to precision tolerance: Re-imagining patient-matched regulatory T cells in shaping of a roadmap for personalized immune re-balancing.

The recognition of FOXP3 as the master regulator of regulatory T cells (Tregs) established the genetic and functional basis for peripheral immune tolerance. Contemporary advances in single-cell genomics and epigenetic mapping have further refined this landscape, revealing distinct, tissue-adapted Treg subsets and identifying the Treg-specific demethylated region (TSDR) as the critical molecular marker for durable lineage stability. The transition toward personalized Treg medicine has become feasible through an integrated pipeline that maps individual cellular signatures and employs precision engineering. Transitioning to personalized Treg medicine requires an integrated pipeline combining antigen-specific CAR-Treg design, CRISPR-mediated epigenetic stabilization, and metabolic reprogramming. However, durable success hinges on navigating biological and translational hurdles, including lineage plasticity, receptor-driven exhaustion, and manufacturing bottlenecks. By integrating real-time TSDR monitoring and inducible safety switches like iCasp9, this framework translates mechanistic insights into context-matched, precision interventions. This roadmap provides a definitive strategy for restoring immune balance in autoimmunity and transplantation while addressing the complex constraints of modern living-cell therapies.