IL-6 decreases the sensitivity of DLBCL SU-DHL-2 cells to naratuximab emtansine. Parental (top) and resistant (bottom) cells were exposed (72 hours) to increasing concentrations of naratuximab emtansine in the presence or absence of recombinant IL-6 (30 ng/mL), anti-IL-6 antibody tocilizumab (25 μg/mL), and IL-6 plus tocilizumab. Cell viability was determined by MTT assay. Bar plot corresponds to IC₅₀ values. ∗P < .05.