All patients received PSZ AFP oral suspension;3.2% of patients (9/270) developed IFDs (seven AML, one allo-HSCT recipients, one aplastic anemia);Sub-optimal exposure to PSZ oral suspension was frequent (5/7 patients with IFDs had the first PPC < 0.5 mg/L (3/5 the first PPC < 0.3 mg/L));Proven IFDs (6/9): two candidemia (two C. glabrata), two disseminated fusariosis (two F. solani), one pulmonary mucormycosis, one IA (A. terreus);Probable IFDs (3/9): one pulmonary mucormycosis, two IA. The gene discussed is AFP; the disease is idiopathic aplastic anemia.