Increased frequency of induced T_h17 cells in myeloma. Purified naive CD4 cells from peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMMCs) were polarized with T_h17 cocktail for 12 days. After restimulation with PMA and ionomycin, IL-17–expressing cells were measured by intracellular IL-17 staining using flow cytometry. (A) A representative dot plot analysis shows IL-17– and IFN-γ–expressing cells as percentage of CD4 cells in peripheral blood and BM samples from HD and myeloma (MM) patients. (B) Composite results presented as mean values with SEM for IL-17–expressing cells within CD4 population. *P < .05.