OUTLINE: This is a double blind, supportive care study for patients on MRC-LEUK-AML11, AML12, or UKALLXII (or their successors). Patients are stratified according to proven or suspected fungal infection. Patients receive daily doses of intravenous liposomal amphotericin B based on stratification. All patients are then randomized to also receive either sargramostim (GM-CSF) (arm I) or a placebo (arm II) by subcutaneous injections (intravenous infusion over 4-6 hours is permitted if subcutaneous route is unacceptable). Treatment continues for 42 days. Some patients with localized lesions that clinically improve should be considered for surgical removal of the residual lesion. Patients may continue therapy after 42 days at the physician's discretion. Patients are assessed weekly until the end of study (particularly on day 28 and at end of study).