Functional profiles of immune cells in MGUS/MM. (A) Cytokine secretion (GM-CSF, IL-2, IFN-γ, TNF-α, and IL-17) by CD4 T cells in bone marrow (BM) mononuclear cells from MGUS (n = 12) and MM (n = 17), after stimulation with anti-CD2/3/28. (B) Cytokine secretion (IL-2, IFN-γ, TNF-α, and IL-17) by CD4 T cells in BM mononuclear cells from MGUS (n = 12) and MM (n = 17), after stimulation with anti-CD2/3/28. Flow cytometry self-organizing map clustering of mass cytometry data on BM CD4⁺ T cells (C-D) and CD8⁺ T cells (E-F) from MGUS (n = 12) and MM (n = 17). Panels C,E show proportions of MC in patients with MGUS/MM. Panels D,F are heat maps showing phenotypes of MC. (G-H) T-cell proliferation after stimulation with anti-CD2/3/28. In panel G, representative plot shows proliferation of carboxyfluorescein succinimidyl ester-labeled peripheral blood T cells. In panel H, bar graph shows proliferating CD4 and CD8 T cells in blood (right image; healthy controls, n = 10; MGUS, n = 7; MM, n = 7) and BM (left image; MGUS, n = 5; MM, n = 5). In panels A-C and E, box plots represent median with Q1 to Q3 and error bars as minimum-maximum. P values were calculated using a 2-tailed Mann-Whitney. In panel H, bar graph shows proliferating CD4 and CD8 T cells in blood (left image; HC, n = 10; MGUS, n = 7; MM, n = 7) and BM (right image; MGUS, n = 5; MM, n = 5). P values were calculated using a 2-tailed Mann-Whitney. ns, not significant.