Male or female patients aged more than 18, Patients undergoing standard myelo-ablative, conditioning regimen and AGVHD ciclosporin prophylaxis for allogeneic stem cell transplantation, or Patients with acute leukaemia undergoing first induction therapy or second induction therapy after relapse, or consolidation therapy, Expected neutropenia < 0.5 giga/l for at least 2 weeks, Normal chest CT scan and/or normal X-ray of the chest at baseline, Patients with no sign or symptoms of fungal infection and no previous proven or probable IFI, Females of childbearing potential must be surgically incapable of pregnancy, or practising an acceptable method of birth control with a negative pregnancy test (blood or urine) at baseline, Understanding of the study and agreement of the patient to give written informed consent, Ability and agreement to comply with all study requirements, Patient willing to attend hospital appointments for each injection (infusions will be performed in hospital, under strict medical supervision). All patients will be hospitalised prior to, and remain in hospital for at least one day, after the first infusion.