In DLBCL, IL-10, PDL-1, and S100A12 are involved in M-MDSC suppressive activity. DLBCL patients were classified into groups: without (Gr.1, n = 5) or with (Gr.2, n = 4) suppressive monocytes based on suppressive assay or a number of M-MDSCs at more than threefold the median count. The percentage of increase or decrease in T-cell proliferation (proliferating index) between cells treated by blocking antibodies (anti–IL-10, –PD-1, and -S100A12) and an irrelevant antibody is shown for CD4^pos and CD8^pos cells. *P < .05.