Recombinant yeast-derived granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered to 10 patients after autologous bone marrow transplantation for Hodgkin's disease given as a 24-h continuous intravenous infusion from the day of marrow infusion until the patient had obtained an absolute neutrophil count of 1.5 x 10(9)/L for 2 consecutive days or until day 30, whichever occurred first. Results were compared with results from 18 historical control patients who did not receive GM-CSF but were otherwise treated in a similar fashion. The infusion of GM-CSF led to a significantly faster neutrophil and monocyte recovery compared to the patients in the historical control group. The median days to achieve an absolute neutrophil count for the GM-CSF group and the control group were 0.5 x 10(9)/L; 9.5 and 14 days; 1.0 x 10(9)/L: 10 and 18 days; 1.5 x 10(9)/L: 11 and 29 days. No significant difference was found with respect to platelet engraftment and red cell transfusion requirements. GM-CSF therapy was discontinued at a median of 12 days. Hospitalization was also shorter for the GM-CSF group (22.5 vs. 26.5 days) and no patient in the GM-CSF group had to be readmitted after initial discharge. The incidence of documented infections was similar among both patient groups and no difference was noted in terms of antimicrobial usage. Some side effects occurred with the continuous infusion of GM-CSF, particularly fluid retention, dyspnea, fever, diarrhea, and bone pain leading to early discontinuation of GM-CSF in 2 patients. The data suggest that a continuous 24-h infusion of GM-CSF significantly accelerates myeloid engraftment, leading to earlier discharge from the hospital.