Fig. 5

Daratumumab does not impair colony production by thawed or fresh mobilized CD34+ progenitor cells or cause apoptosis of CD34+ cells in vitro. a Cryopreserved thawed unselected mobilized human blood progenitor cells were plated at a concentration of 5 × 10⁴ cells/mL of semisolid medium with daratumumab or isotype control at 500 and 1000 ng/mL, and colonies were counted on day 14 (mean ± SD). There was no decrease in CFU-GM or BFU-E with daratumumab. b Fresh unselected mobilized peripheral blood progenitor cells were plated in semisolid medium containing daratumumab or isotype control (100 ng/mL) at 5 × 10⁴ cells/mL and no difference was seen in colony counts (mean ± SD). c CD34-selected cells were incubated in complement-rich human serum with no antibody, daratumumab or isotype control at 500 ng/mL for 1 h and then plated directly in semisolid medium at 500 cells/mL. There were no significant decreases in colonies with daratumumab compared to isotype control (mean ± SD). d CD34-selected cells were incubated in complement-rich human serum with no antibody, daratumumab or isotype control in increasing amounts and then assessed for evidence of caspase 3/7 activity (RLU, relative light units) (n = 6) (mean ± SD). There was no evidence of caspase 3/7 activity at any concentration of daratumumab used