TNF and plasma cell myeloma: •Inhibit TNF synthesis•Inhibit the surface expression of TNFR2 on T cells (in vitro assay)•Reduce the number and function of Tregs and TNFR2 expression on Tregs in patients with leukemia (in vivo assay)•Increase the number of Tregs in patients with multiple myeloma (MM) (in vivo assay)