Two weeks later, the child was referred to the Emergency Room for respiratory failure, persistent fever and abdominal pain. Laboratory examination showed an Hb level of 12.8g/dL, total leukocyte count (WBC) of 710/µL, absolute neutrophil count (ANC) of 90/µL, a platelet count (PLT) of 339,000/µL, and low levels of immunoglobulin (IgG = 360mg/dL, IgA = 10mg/dL, IgM = 33mg/ dL). Chest X-ray and CT scan revealed an interstitial pneumonia ( Figure 2 ). Therapy with amikacin, ceftazidime, G-CSF and voriconazole was started. Within a few hours, her clinical condition deteriorated and the patient developed Acute Respiratory Distress Syndrome (ARDS), which required immediate admission to the intensive care unit (ICU). Acceptable gas exchange was initially maintained by non-invasive continuous positive airway pressure ( Figure 3 ). Serologic tests showed a level of Aspergillus galactomannan antigen of 0.8. All tested virus and microbial antigens were negative. On day 4, concomitantly with an elevation of WBC from 400 to 10,400/µL (ANC = 4900/µL), respiratory conditions precipitated and endotracheal intubation and mechanical ventilation were started ( Figure 3) . A protective ventilatory strategy with tidal volume of 6mL/kg and positive end expiratory pressure (PEEP) of 10cmH 2 O was instituted.