Several modes of action by Daratumumab have been demonstrated including inhibition of production of immunosuppressive adenosine, inhibition of adhesion of myeloma cells to bone marrow stroma, inhibition of formation of nanotubes that transfer mitochondria from stroma cells to myeloma cells and invigorate the myeloma cells, direct stimulation of T-cell mediated cytotoxicity, inhibition of expression of immunosuppressive PD-L1 by antigen-presenting cells and elimination of regulatory cells of the T-, B- and monocyte/macrophage system that inhibit cytotoxic T-cells. Here, CD274 is linked to plasma cell myeloma.