title: Risk factors of human herpesvirus 6 encephalitis/myelitis after allogeneic hematopoietic stem cell transplantation.
abstract: BACKGROUND
  Human herpesvirus 6 (HHV-6) encephalitis/myelitis is now a well-known complication after allogeneic stem cell transplantation (allo-HSCT), particularly after cord blood transplantation (CBT). In this study, we evaluated the risk factors of HHV-6 encephalitis/myelitis.
  
  
  METHODS
  We evaluated 253 patients who received allo-HSCT from 2007 to 2015 at our institute. HHV-6 encephalitis/myelitis was defined as HHV-6 DNA detection in the cerebrospinal fluid or peripheral blood by polymerase chain reaction in the presence of typical manifestations without other concurrent condition that led to the manifestations.
  
  
  RESULTS
  HHV-6 encephalitis/myelitis occurred in 11 patients (4.5%) (9 encephalitis, 3.7%; 2 myelitis, 0.8%). Multivariate analysis showed that CBT, mycophenolate mofetil (MMF) for graft-versus-host disease prophylaxis, history of allogeneic hematopoietic stem cell transplantation (allo-HSCT), and engraftment syndrome (ES) were significantly associated with incidence of HHV-6 encephalitis/myelitis (P=.025, P=.017, P=.017, and P=.014, respectively).
  
  
  CONCLUSIONS
  Although it has been shown that CBT, ES, and history of allo-HSCT are risk factors for HHV-6 encephalitis/myelitis, our study demonstrated MMF is also a risk factor for the disease.
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Miyashita
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Endo
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Onozawa
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Daigo
authors.initials: D
authors.lastname: Hashimoto
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kondo
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kahata
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Sugita
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Goto
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Matsukawa
authors.affiliation: Health Care Center, Hokkaido University, Hokkaido, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hashino
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Teshima
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D036101:Cord Blood Stem Cell Transplantation / Q000009:adverse effects*; D004279:DNA, Viral / Q000302:isolation & purification; D018792:Encephalitis, Viral / Q000453:epidemiology* / Q000821:virology; D005260:Female; D006086:Graft vs Host Disease / Q000517:prevention & control; D006402:Hematologic Diseases / Q000628:therapy*; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D015654:Herpesvirus 6, Human / Q000302:isolation & purification*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000627:therapeutic use; D009187:Myelitis / Q000453:epidemiology* / Q000821:virology; D016133:Polymerase Chain Reaction; D012307:Risk Factors; D019349:Roseolovirus Infections / Q000453:epidemiology* / Q000821:virology; D019172:Transplantation Conditioning / Q000009:adverse effects / Q000379:methods; D014184:Transplantation, Homologous / Q000009:adverse effects; D055815:Young Adult
chemical_list: D004279:DNA, Viral; D007166:Immunosuppressive Agents; D009173:Mycophenolic Acid
keywords: hematopoietic stem cell transplantation; human herpesvirus 6; mycophenolate mofetil