CD38 ligation induces a block in normal myeloid cell differentiation.

CD34⁺ cells were cultured for 7 days on allogeneic bone marrow stromal layers in the presence of anti-CD38 (T16) or of a control nonreactive Ig. After culture, 4 phenotypically distinct cell populations could be identified by staining with anti-CD34 PE and anti-MPO FITC (left panels). Right panel shows percent cell recovery of each of the 4 subpopulations in the presence of anti-CD38 as compared with parallel control cultures with nonreactive Ig; results are mean (± SD) of 8 experiments.