These data suggest, on the one hand, an enhancement of the proapoptotic effect of TRAIL on auto-reactive T cells as one of the mechanisms of action of IFN beta in MS, but, on the other hand, the induction of TRAIL on monocytes and granulocytes in response to IFN beta may contribute to the induction of apoptosis in these cells. This evidence concerns the gene TNFSF10 and myeloid sarcoma.