Flow cytometric analysis of cell-surface antigen expressions on acute myeloid leukemia cell populations according to their cell-size.

Acute myeloid leukemia (AML) cells which expanded from a single leukemic cell show certain degrees of morphological and biological heterogeneity. In the present study, we determined cell-surface antigen expressions (CD13, 33, 34 and 38, and HLA-DR) on AML cells based on their cell-size (large vs small cells) by flow cytometry. We found that the cell-surface antigens were more strongly expressed on the large leukemic cells than the small cells, regardless of FAB subtypes. Furthermore, our preliminary study demonstrated that AML patients who showed a relatively small difference in antigen expression between large and small leukemic cells had longer remission durations and survival periods, compared with those with a more prominent difference in antigen expression. Thus, the heterogeneity of AML cells determined by the combination of cell-surface antigen expressions and cell-size may be associated with clinically important biological behaviors.