Keywords: آزمون ایمونوفلورسانس; CNS; Central nervous system; CSF; Cerebrospinal fluid; EBV; Epstein-Barr virus; HLH; Hemophagocytic lymphohistiocytosis; IFT; Immunofluorescence test; L-AmB; Liposomal amphotericin B; NK; Natural killer; PCR; Polymerase chain reaction;