[Expression of AC133 Antigen on Acute Leukemia Cells]

To investigate the expression of AC133 antigen on acute leukemia cells and its clinical significance, samples of 29 patients with acute lymphocytic leukemia (ALL) and 32 patients with acute myelocytic leukemia (AML) were analyzed by flow cytometric three-color direct immunofluorescence methods. It was found that 13 of 29 ALL, 6 of 8 AML-M(0)/M(1), 4 of 16 AML-M(2) and 4 of 8 AML-M(4)/M(5) expressed AC133. The mean fluoresence intensity of AC133 in each subtype of AML-M(0)/M(1), AML-M(2) and AML-M(4)/M(5) was 227.1, 143.1 and 142.5, respectively. Among 27 AC133(+) cases (44.3%), 25 cases coexpressed CD34 (92.6%) and 13 cases coex- pressed CD117 (48.1%). In contrast to other reports, our data do not support the findings that AML-M(4)/M(5) expressed very high levels of AC133. In conclusion, AC133 antigen, coexpressed with CD34 and CD117, appears more frequently and more intensely in AML-M(0)/M(1).