We choose to examine the effects of pFTY720 on the levels of IFNγ in MOG-reactive cells given that this cytokine regulates Th1 cell differentiation, CD8+ cell-induced cell death and microglial recruitment in MS [35], [36], [52]–[55], that S1P attenuates the production of IFNγ by splenic CD4 T cells [40] and that effect of pFTY720 on IFNγ was not examined in these reports [35], [40]. This evidence concerns the gene CD4 and myeloid sarcoma.