HHV-6 is reported to be a causative agent of exanthema subitum [20] and has been associated with a broad spectrum of diseases, including febrile convulsions [11] , encephalopathy [9, 18] , hepatitis [6] , and lymphoproliferative disorders [15] . An active HHV-6 infection can cause fatal disease in an immunocompromised host, including patients after stem cell transplantations (SCTs), but fatal outcome in immunocompetent persons due to HHV-6 infection is extremely rare [14, 16] .