CD38 and neoplasm: In addition, similar to what is observed in patients treated with daratumumab [12], treatment of mice with the anti-mCD38 antibody resulted in a significant reduction of tumor-infiltrating CD38+ Tregs (%CD4+Foxp3+: 2.5 ± 0.8% vs. 65.8 ± 10.9% in the control group, p < 0.0001) and CD38+ MDSCs (%Gr1+CD11b+: 3.7 ± 1.2% vs. 42.9 ± 2.7% in the control group, p < 0.001) (Figure 4D).