[Induction of complete remission in a case of drug-resistant childhood acute megakaryoblastic leukemia by combination of G-CSF and chemotherapy].

: In a 4-year-old girl having acute megakaryoblastic leukemia, recombinant human granulocyte colony-stimulating factor (G-CSF) was used in combination with chemotherapy for remission induction after the second relapse of her leukemia. G-CSF was given intravenously at a dose of 100 micrograms/m2/day 24 hours prior to chemotherapy until the peripheral neutrophil counts fully recovered. Cytosine arabinoside (Ara-c) [100mg/m2/day] and VP-16 [100mg/m2/day] were given from day 1 through day 10. Her leukemia was resistant to chemotherapy alone after the second relapse but complete remission and hematological recovery were achieved two months after the start of this therapy. Although in vitro clonal assay did not show significant stimulation of colony formation by G-CSF on leukemia cells of this patient, and the mechanism underlying remission induction by this combination therapy remains unclear, it may be of benefit to use G-CSF in combination with chemotherapy for patients with drug-resistant leukemia.