The ambivalent nature of T-cell infiltration in the central nervous system of patients with multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) of presumed autoimmune origin. On the basis of the pathophysiology of MS, inflammatory reactions in the CNS are considered detrimental. Recent evidence suggests that the injured CNS can also benefit from immune activity. In this review, we will first provide an overview of the mechanisms by which immune cells contribute to CNS injury in MS. We will further review evidence supporting a neuroprotective role of CNS inflammation with special focus on the protective properties of autoimmune reactions. Finally, we discuss the proposed mechanisms by which autoreactive T cells exert protection in the CNS and how this protection is regulated.