Predictive value of flow cytometric analyses of blast cells in assessing the phenotype of the leukemia colony-forming cell (L-CFC) population in acute myeloid leukemia.

Acute myeloid leukemia (AML) blast cells (BC) express antigens that are commonly found on their normal counterparts. The leukemia colony-forming cell (L-CFC) subpopulation, identified by its ability to form leukemia colonies in vitro, is thought to be the stem cell population that produces BC. To ascertain the association between myeloid antigens on the BC and the L-CFC from the same patient, we compared the expression of CD14, CD15, CD33, p124 and HLA class I from 17 cases of AML. These particular myeloid antigens were studied because they are suitable targets in purging bone marrow for autotransplantation. We found no significant difference in the expression of CD14, CD15, CD33, and HLA class I on the BC and L-CFC from the same patient, although we observed considerable heterogeneity among different AML cases. Analysis of the progenitor cell antigen p124 revealed significant within-patient differences on the BC and L-CFC (p = 0.007), with a greater tendency for expression on the L-CFC. This heterogeneity may be due to differences in maturation stage of the L-CFC and BC. This information is important when L-CFC phenotype is used to determine the appropriate selection of antibodies for purging of residual disease in the context of auto-transplantation.