In the current study, we aimed to examine the involvement of the placenta in the production and release of the soluble decoy receptor osteoprotegerin (OPG), a member of the TNF receptor superfamily [17], able to control the binding between receptor activator of nuclear factor-kB (RANK) and its ligand (RANKL), never investigated before in the context of MS, pregnancy, and placenta. Here, TNFRSF11B is linked to myeloid sarcoma.