HLA-mismatched CD34-selected stem cell transplant complicated by HHV-6 reactivation in the central nervous system

We report here a patient who suffered from PCR-confirmed human herpesvirus type 6 (HHV-6) meningoencephalitis after allogeneic purified CD34(+) cell t ransplantation from his HLA-mismatched sibling donor, even though he had be en on intense prophylaxis with i.v. ganciclovir (GCV), acyclovir (ACV) and gamma-globulin containing a specific antibody against HHV-6, Serological ev aluation disclosed that both the donor and recipient had IgG antibody again st HHV-6 before transplantation. His blood WBC count started to transiently increase on day 10, and all blood components had decreased by day 20, He t hen developed a severe headache and high blood pressure, and sporadic abnor mal neurological findings including nystagmus and delirium. An analysis of cerebrospinal fluid (CSF) revealed 8 cells/mu l, a glucose level of 130 mg/ dl and a protein level of 201 mg/dl (normal, 50 mg/dl) on day 26. At the ti me, HHV-6 was detected only in CSF by a PCR-based method and he was diagnos ed as having meningoencephalitis due to the local reactivation of HHV-6. Al though he failed to respond to high-dose therapy with ACV (60 mg/kg/day) an d gamma-globulin, the DNA of this virus disappeared from the CNS upon treat ment with GCV (30 mg/kg/day) combined with the intraventricular infusion of alpha-interferon. His clinical course was further complicated with meningo encephalitis due to staphylococcus epidermidis, and he died of tentorial he rniation on day 79 without the recovery of blood components, This experienc e may indicate that intense prophylaxis to prevent reactivation of HHV-6 in the CNS is essential for the management of such profoundly immunosuppresse d patients.