Fifteen patients with prolonged neutropenia (a median of 23 days with granulocyte [PMN] < or = 500/microliters) and established fungal infections that had not responded to adequate antifungal therapy were transfused with PMN concentrates collected from 35 cytokine-primed granulocyte colony-stimulating factor (GCSF) donors. Patients received a median of six transfusions. Leukocytosis and granulocytosis were observed within 24 hours of the first GCSF injection, which yielded concentrates averaging 55 x 10(9) white blood cells and 41 x 10(9) PMN. Data analysis suggested that response might be related to the duration of neutropenia and known infection, as patients given PMN tx earlier in the infectious course tended to have a better response. No significant toxicity was observed in donors.