Birinapant had modest effects on circulating immune cell subsets or cytokines. (A) Most patients showed decreases in circulating T cells, as measured by CD3+ cells on flow cytometry. CD4+ T cells appeared to decrease more than CD8+ T cells. (B) B cells, as measured by CD19, also showed mild decrease after birinapant exposure. There was no significant change in circulating NK cells, as measured by CD3neg, CD45+ and CD16+ cells. (D) Cytokine TNF was measured by multiplex ELISA (Mesoscale), and showed a trend towards increasing in patients’ plasma. Plasma levels of TRAIL did not significantly change with birinapant administration, nor did IL-6 and IL-8 levels.