The role of regulatory T cells in nervous system pathologies

Regulatory T (Treg) cells are a special subpopulation of immunosuppressive T cells that are essential for sustaining immune homeostasis. They maintain self-tolerance, inhibit autoimmunity, and act as critical negative regulators of inflammation in various pathological states including autoimmunity, injury, and degeneration of the nervous system. Treg cells are known to convey both beneficial and detrimental influences in certain disease contexts, and accumulating research suggests that their action may be altered in a range of peripheral and central nervous system pathologies. In this review, we discuss emerging evidence for the dichotomous role of Treg cells in various neurological pathologies including multiple sclerosis, Guillain-Barré syndrome, neuropathic pain, traumatic central nervous system injury, stroke, and neurodegenerative diseases such as amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease. We are in the early stages of uncovering the role of Treg cells in these conditions, and a better understanding of the ways in which these cells operate in the nervous system will enable us to develop novel therapeutic interventions.