Cytokine priming of acute myeloid leukemia may produce a pulmonary syndrome when associated with a rapid increase in peripheral blood myeloblasts.

The use of granulocyte-macrophage colony-stimulating factor (GM-CSF) administered before or in combination with chemotherapy represents a new strategy in the treatment of acute myeloid leukemia (AML). This cytokine is a known growth promoter of leukemic colony-forming cells',* and can recruit quiescent cells into cycle, possibly increasing their chemosensitivity. However, in vivo GM-CSF priming for 18 to 48 hours has been associated in some patients with rapid increases in myeloblast counts in peripheral blood.*' We have examined the safety and proliferative effects of GM-CSF priming for 72 hours in 16 patients with relapsed or refractory AML. The median age was 53 years (range 20 to 72) and median duration of prior remission in the relapsed patients was 5.4 months (range 1.3 to 33 months). Previous chemotherapy in the relapsed AML patients was conventional cytosine arabinosidedaunorubicin ('7 plus 3') or the same combined with etoposide 75 mg/m2/d for 7 days. GM-CSF (synthesized in Escherichia coli; Schering-Plough, NJ) was administered at a dose of 5 pg/kg/d by subcutaneous injection6 for 3 days before commencing chemotherapy. No patients developed dyspnea with the first dose of GMCSF.6 In patients 6 and 13 this "priming period" was shortened to 2 days because the peripheral blood white cell count exceeded 30 X 109/L by the second day. GM-CSF was continued for the first 4 days of standard chemotherapy with cytosine arabinoside 100 mg/m2/d continuous intravenous (IV) infusion for 7 days plus daunorubicin 50 mg/m2/d IV on days 1 through 3. Serial bone marrows confirmed that GM-CSF priming produced