CD38 ligation inhibits in vitro growth of patient-derived leukemic myeloid cells.

AML blast cells from 2 patients (patients 3 and 4 in Table 1) were cultured for 7 days on allogeneic bone marrow stromal layers in the presence of anti-CD38 (T16) or of a control nonreactive Ig. Isometric contour plots depict the cells' light scattering (FSC, forward scatter; SSC, side scatter) after culture. In cultures with control Ig, most cells had light-scattering properties of viable myeloblasts. These cells also expressed CD13 and/or CD33 (not shown). Myeloblast cell recovery was drastically reduced in cultures with anti-CD38, where most residual viable cells had lymphoid morphology, and lacked CD13 and CD33 (not shown).