IFNB1 and myeloid sarcoma: Importantly, we have reported that IFN-β therapy mediates a marked and specific reduction of memory B cells in peripheral blood of treated MS patients via a mechanism requiring a FAS-R-mediated caspase-3-dependent apoptosis, and this memory B-cell decrease is associated with reduced expression of the latent EBV gene LMP2A in PBMC of MS patients under IFN-β treatment (19).