Known hypersensitivity to amphotericin B, in particular known history of anaphylactic reaction to amphotericin B, Patients undergoing cord transplantation, Creatinine clearance < 60 ml/min, Patient with moderate or severe liver disease as defined by AST or ALT > 5 times the upper limit of normal (ULN), Patients who are unlikely to survive more than 1 month, Febrile patients (≥ 38.5°C), Patients who have received systemic antifungal therapy within 15 days prior to the inclusion, Any severe cardiovascular disease (such as arrhythmias, in particular) which may constitute a contra-indication to AmBisome® administration, Any severe disease other than the haematological diseases described in the second inclusion criteria, which in the investigator's judgement may interfere with study evaluations or affect the patient's safety, Pregnant or nursing females, Patients previously included in this study, Patients who have taken any investigational drug in the last 30 days prior to the inclusion.