title: HHV-6-positivity in diseases with demyelination.
abstract: BACKGROUND
  The triggering agent of multiple sclerosis is still unknown and many viruses, including human herpesvirus-6 (HHV-6), are under suspicion. In earlier study we found patients who had HHV-6 reactive OCBs in their CSF. We wanted to investigate whether HHV-6 has an active role in diseases with demyelination.
  
  
  OBJECTIVE
  To analyze the HHV-6-reactive cases in detail and investigate the possible independent role of HHV-6 in the development of central nervous system involvements with demyelination.
  
  
  METHODS
  We studied serum and CSF samples that were collected over a period of one year, from all patients who had oligoclonal bands (OCB) in cerebrospinal fluid (CSF) and were examined in the Department of Neurology, University Central Hospital of Helsinki, Finland. Clinical evaluation was accomplished blinded of HHV-6 analysis and follow-up time was two years. All patients underwent MRI of the head and clinically indicated CSF analysis.
  
  
  RESULTS
  The 17 patients with HHV-6-reactive OCBs were significantly younger and had significantly more IgG-OCBs in comparison to patients without HHV-6-reactive OCBs. Initial diagnoses in patients with HHV-6-reactive OCBs remained the same during the follow-up time.
  
  
  CONCLUSIONS
  Patients with HHV-6-positive OCBs appear to form a separable group. In progressive neurological diseases HHV-6 may have a role in long-term infection with demyelination.
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, Finland; Department of Neurology, University of Helsinki, Finland. Electronic address: jenna.pietilainen@helsinki.fi.
authors.forename: Jenna
authors.initials: J
authors.lastname: Pietiläinen-Nicklén
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, Finland.
authors.forename: Jussi O
authors.initials: JO
authors.lastname: Virtanen
authors.affiliation: Department of Clinical Chemistry, HUSLAB Laboratory Services, Helsinki, Finland.
authors.forename: Lasse
authors.initials: L
authors.lastname: Uotila
authors.affiliation: Helsinki Medical Imaging Center, Finland.
authors.forename: Oili
authors.initials: O
authors.lastname: Salonen
authors.affiliation: Department of Neurology, University of Helsinki, Finland.
authors.forename: Markus
authors.initials: M
authors.lastname: Färkkilä
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, Finland.
authors.forename: Marjaleena
authors.initials: M
authors.lastname: Koskiniemi
mesh_terms: D000328:Adult; D001769:Blood / Q000276:immunology; D002555:Cerebrospinal Fluid / Q000276:immunology; D003711:Demyelinating Diseases / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D005260:Female; D005387:Finland; D006257:Head / Q000000981:diagnostic imaging; D015654:Herpesvirus 6, Human / Q000276:immunology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D043025:Oligoclonal Bands / Q000134:cerebrospinal fluid; D011859:Radiography; D019349:Roseolovirus Infections / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology
chemical_list: D043025:Oligoclonal Bands
keywords: Demyelinating disease; Human herpesvirus-6; Isoelectric focusing; Multiple sclerosis; Oligoclonal bands