The reasons for the detrimental effect of atacicept include decrease of non-specific Fc blockade by immunoglobulins (in contrast, IVIg that upregulates FcRIIb is minimally, if any, effective in MS), elimination of B regulatory cells in the naïve B cell fraction (although these are also eliminated by CD20 depletion), disruption of BAFF-mediated Breg induction, and a stimulated increase of pathogenic memory B cells [41, 109, 110]. Here, TNFSF13B is linked to myeloid sarcoma.