title: Human herpesvirus 6 and effectiveness of interferon β1b in multiple sclerosis patients.
abstract: BACKGROUND
  Human herpesvirus 6 (HHV-6) and Epstein-Barr virus (EBV) have been repeatedly associated with multiple sclerosis (MS) pathogenesis. Also, it has been speculated that, besides its immunomodulatory properties, the efficacy of interferon beta (IFN-beta) in treating the disease may be related to its antiviral properties. The objectives of this study were to evaluate the in vivo antiviral effect of IFN-beta-1b over HHV-6 and EBV and to analyze whether such effect could be involved in its effectiveness in MS.
  
  
  METHODS
  A total of 54 patients with MS were included in an observational, multicentric, 24-month study. HHV-6 and EBV were detected by qPCR in blood and serum samples. IFN-beta-1b effectiveness was evaluated by presence, number and severity of relapses, reduction in the relapse rate, disability progression, and response to the treatment.
  
  
  RESULTS
  Patients with HHV-6 in blood had a higher risk of severe relapses (P=0.01) and bad response (P=0.03). HHV-6 was detected more frequently during relapses than in remission in blood (P=0.024) and in serum (P=0.0002). Patients with HHV-6 in serum had more relapses (P=0.02), lesser reduction in the relapse rate (P=0.04), and a lower proportion of responders (P=0.02) than those without HHV-6 active replication. However, any association between EBV and clinical parameters could not be found.
  
  
  CONCLUSIONS
  We concluded that presence of HHV-6 in blood and serum during IFN-beta treatment could be a good marker of poor response.
authors.affiliation: Unidad de Esclerosis Múltiple, Servicio de Neurología, Hospital Clínico San Carlos, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Garcia-Montojo
authors.forename: V
authors.initials: V
authors.lastname: De Las Heras
authors.forename: M
authors.initials: M
authors.lastname: Dominguez-Mozo
authors.forename: M
authors.initials: M
authors.lastname: Bartolome
authors.forename: M A
authors.initials: MA
authors.lastname: Garcia-Martinez
authors.forename: R
authors.initials: R
authors.lastname: Arroyo
authors.forename: R
authors.initials: R
authors.lastname: Alvarez-Lafuente
mesh_terms: D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use; D005260:Female; D015654:Herpesvirus 6, Human / Q000276:immunology*; D006801:Humans; D000068576:Interferon beta-1b; D016899:Interferon-beta / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000188:drug therapy / Q000453:epidemiology / Q000821:virology; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology*; D011446:Prospective Studies; D019349:Roseolovirus Infections / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology; D055502:Secondary Prevention; D012720:Severity of Illness Index; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D000068576:Interferon beta-1b; D016899:Interferon-beta