IL2 and plasma cell myeloma: Several mechanisms may contribute to myeloma cell ‘tolerance’, including myeloma-derived cytokines such as transforming growth factor (TGF)-β (which suppresses B cells and T cells via inhibition of IL-2 autocrine pathway [3]), inadequate antigen presentation [4], resistance to NK cell lysis, and defective T, B, natural killer (NK) and NK-T cells [5,6].