IL17A and myeloid sarcoma: NK cells secrete IL-17A and IL-17F that promote the permeability of the BBB in MS (Jadidi-Niaragh and Mirshafiey, 2011) and induce the cytotoxicity of autologous oligodendrocytes, inducing the inflammatory process; however, in the acute phase, NK cells can reduce damages and inflammations through the control of autoreactive T cells and microglia.