CD33 and acute myeloid leukemia: Twenty-one of the patients had newly diagnosed AML, whereas 20 either had relapsed (n = 11) or refractory (n = 9) disease at the time of specimen collection; as summarized in Table 1, basic characteristics of the specimens from patients with newly diagnosed AML were similar to those with relapsed/refractory disease with regard to CD33 expression on myeloid blasts, amount of autologous T-cells, proportion of myeloid blasts, and culture viability.