Autopsy case of acute myeloid leukemia with human herpesvirus-6B (HHV-6B) encephalitis following cord blood transplantation and persistent HHV-6B DNA detection in the blood

抄録

 A 29-year-old man in his second remission of acute myeloid leukemia underwent cord blood transplantation. During the course of the disease, pre-engraftment immune reaction occurred, which improved with steroid therapy; however, he developed human herpesvirus-6B (HHV-6B) encephalitis. Antiviral drugs were administered, which improved his condition; however, plasma HHV-6B DNA levels continued to increase even after treatment. Although his neurological symptoms did not worsen, antiviral drug treatment was continued because he had severe immunodeficiency. He developed acute heart failure 139 days after transplantation and eventually died, but autopsy showed no evidence of encephalitis. Patients who do not test negative for HHV-6B DNA should undergo individualized treatments based on their clinical status; however, antiviral drug therapy should have been discontinued in the present case. In cases where the polymerase chain reaction (PCR) results remain positive, plasma PCR is not a useful method to help determine the treatment duration, and the efficacy of antiviral drugs is also unknown. Hence, further studies should be conducted to understand situations like this case.