Multiple sclerosis (MS) is a Th1-mediated autoimmune disease characterised by relapses followed by clinically stable remissions. A new hypothesis suggests that regulatory immune cells may play an active part not only in relapses but also in maintaining the remission of MS. In the
Kazuya Takahashi and colleagues examined NK cells in the peripheral blood of 22 patients with MS and found that during remissions these cells were characterized by an elevation of IL-5 mRNA and a decreased expression of IL-12Rβ2 mRNA. Moreover, the NK cells produced larger amounts of IL- 5 than controls after non-specific stimulation.
These features resemble those of NK type 2 cells, which can favour functional deviation of T cells toward Th2 and prohibit autoimmune effector T cells. The NK cells lost the NK2-like property when relapse of MS occurred but regained it after recovery. Targeting NK cells with immunological interventions such as NK bias may benefit patients with MS.