Coinfection of HHV 6 and HTLV-I Causing Encephalitis After Autologous Hematopoietic Stem Cell Transplantation: A Case Report and a Systematic Review of the Literature.

Background: A 52-year-old woman with multiple myeloma and asymptomatic human T lymphotropic virus (HTLV)-I infection underwent an autologous stem cell transplantation. Eighteen days after transplantation, she developed fever, headache, ataxia, and tremors. Coinfection of human herpesvirus 6 and HTLV-I encephalitis was diagnosed.