FLOW CYTOMETRIC ANALYSIS OF CELL-SURFACE ANTIGEN EXPRESSIONS ON ACUTEMYELOID-LEUKEMIA CELL-POPULATIONS ACCORDING TO THEIR CELL-SIZE

Acute myeloid leukemia (AML) cells which expanded from a single leukem ic cell show certain degrees of morphological and biological heterogen eity. in the present study, we determined cell-surface antigen express ions (CD13, 33, 34 and 38, and HLA-DR) on AML cells based on their cel l-size (large vs small cells) by flow cytometry. We found that the cel l-surface antigens were more strongly expressed on the large leukemic cells than the small cells, regardless of FAB subtypes. Furthermore, o ur preliminary study demonstrated that AML patients who showed a relat ively small difference in antigen expression between large and small l eukemic cells had longer remission durations and survival periods, com pared with those with a more prominent difference in antigen expressio n. Thus, the heterogeneity of AML cells determined by the combination of cell-surface antigen expressions and cell-size may be associated wi th clinically important biological behaviors.