The expression of tissue factor antigen and activity on the surface of leukemic cells

Tissue factor activity of intact cell and cell lysate, and the presence of tissue factor antigen on cell surface, were examined in leukemic cells from patients with acute myelogenous leukemia (AML, M1-M5) or acute lymphoblastic leukemia (ALL-L1), and in mononuclear cells from normal donors. Leukemic cells from AML or ALL had significantly more tissue factor activity not only on intact cells but also in cell lysate than mononuclear cells from normal donors (p < 0.001). Tissue factor activities of the intact leukemic cells and lysate from AML patients with DIC were significantly higher than those without DIC (p < 0.001). The relationship between the percent of positive cells for tissue factor and the presence of DIC at the time of diagnosis of acute leukemia was observed. The patients with DIC showed the higher percentage of tissue factor-positive cells than those without (p < 0.01). The development of DIC following chemotherapy was recognized in 2 out of 7 AML-MI patients and 2 out of 4 ALL-L1 patients who had relatively high tissue factor activities of cell lysate. The release of tissue factor from cytoplasm induced by chemotherapy would be another mechanism for the development of DIC. The report suggests the possibility of the prediction for DIC by the flowcytometric assay of tissue factor antigen.