The pathogenesis of multiple sclerosis (MS) has been tied to ineffective immune control of Epstein-Barr virus-driven autoimmune responses. Patients with MS are deficient in protective adaptive natural killer cells (pNK cells) in contrast to healthy individuals. These pNK cells are positive for NKG2A, NKG2C and NKG2D and recognize and kill autoreactive B cells in a selective and efficient manner.