Transfusion can change the labelling index in AML: association of post-transfusion LI and remission status

5-bromodeoxyuridine (BUdR) quenching of acridine orange fluorescence distinguishes cycling and non-cycling normal and malignant bone marrow cells in vitro

Suppression of the green fluorescence of acridine orange by 5-bromodeoxyuridine incorporation into cellular DNA was measured by flow cytometry. Bone marrow cells from normal volunteers and patients with chronic myelogenous leukemia acute lymphocytic leukemia acute myelogenous leukemia and multiple myeloma were incubated with BUdR in vitro. By 24 h acridine orange stained cycling cells that had synthesized DNA in the presence of BUdR were differentiated from quiescent cells as a second peak with quenched green fluorescence (DNA). After 72 h in culture 11-65% of the G0/G1 cells from normal bone marrows and bone marrows with myeloid leukemia were identified as cycling in culture by the presence of a second peak with quenched green fluorescence. A greater percentage of cells with BUdR quenched AO fluorescence was associated of acridine orange was higher in the cycling cells that had synthesized DNA in the presence of BUdR than in the non-cycling G0/G1 cells. In one patient with AML there was quenching of the DNA fluorescence of the aneuploid population but not the diploid population indicating that the aneuploid leukemia cells were proliferating. In contrast in patients with multiple myeloma, the quenched fluorescence of the diploid cell population and not the aneuploid cells, indicated that the diploid cells were proliferating. The cells from patients with untreated ALL failed to proliferation prohibiting an in vivo assessment of growth. Although measurements of proliferation obtained by this method are clearly influenced by the cell's adaptation to culture, measurement of BUdR quenching of acridine orange fluorescence is technically feasible and can identify and allow characterization of the cycling population of cells.

Treatment of acute myeloid leukaemia in children

Complete remission was achieved in 11 of 22 children with acute myeloid leukaemia using at least two courses of a 24 hour infusion of cytosine arabinoside (Ara-C) 10 mg/kg, followed by push injections of daunorubicin (DNR) 45 mg/m2, and adriamycin (ADR) 45 mg/m2. Consolidation therapy consisted of three courses of Ara-C and 6-thioguanine (Tg) and one course of cyclophosphamide (CPA) and ADR. Central nervous system prophylaxis with intrathecal Ara-C was given in all patients and cranial irradiation of five. Maintenance therapy consisted of 5 day courses of Ara-C and Tg given 4 weekly with immunotherapy (BCG) vaccine and subcutaneous leukaemic cells) between courses. Median length of first complete remission was 99+ weeks, and median survival of all patients was 44 weeks. Median survival of remitters was 195+ weeks and non-remitters, 28 weeks. Two patients developed central nervous system disease, one at presentation and the other 46 weeks from presentation. Five patients have ceased therapy and remain in remission from 32 to 142 weeks after ceasing treatment.