Functional and dysfunctional T regulatory cell states in human tissues in RA and other autoimmune arthritic diseases

Nature Immunology, Published online: 16 June 2026; doi:10.1038/s41590-026-02540-4 Brenner and colleagues identify two predominant tissue-resident Treg cell subsets (suppressive CD25hiCXCR6pos and dysfunctional CD25loAREGpos) in synovial joints from patients with rheumatoid arthritis. These functionally divergent Treg cell subsets are shaped by local microenvironmental cues supplied by macrophages or fibroblasts.