INFLUENCE OF RHGM-CSF ON ARA-C SENSITIVITY OF PATIENTS WITH ACUTE MYELOID-LEUKEMIA IN RELAPSE - A FLOW-CYTOMETRY STUDY

Twenty-three patients with acute myelogenous leukemia (AML) in first r elapse were treated with high-dose cytosine-arabinoside (Ara-C) and am sacrine or idarubicin. To prime the cells, the patients were given rhG M-CSF. We studied the influence of 48-h infusion of rhGM-CSF on prolif eration and Ara-C sensitivity of leukemic cells both ex vivo and in vi tro. We found that a 48-h infusion of rhGM-CSF increased both white bl ond cell counts and peripheral blood blast cell percentages. Using a B romodeoxyuridine/DNA (BrdUrd/DNA) staining in flow cytometry, we found an non-constant increase in cells in the S-phase, Ex vivo 48-h cultur e of leukemic cells with or without rhGM-CSF, with or without other he matopoietic growth factors (HGFs), showed a greater increase of the ce lls in the S-phase with GF but no correlation with the ex vivo results . We used a method of quantitation of the DNA synthesis previously des cribed (Lacombe F., et al. (1992) Cytometry 13, 730) to monitor the Ar a-C sensitivity of the cells in S-phase before and after 48-h infusion with rhGM-CSF. We observed a great variation in the Ara-C sensitivity of the leukemic cells before and after infusion with rhGM-CSF from on e patient to another. The BrdUrd/DNA method seems a convenient method to study the influence of HGFs on Ara-C sensitivity of the patients. C opyright (C) 1996 Elsevier Science Ltd.