title: Clinical parameters and HHV-6 active replication in relapsing-remitting multiple sclerosis patients.
abstract: BACKGROUND
  Although the etiology of multiple sclerosis (MS) remains uncertain, clinical, epidemiological, and laboratory findings suggest that environmental factors may be involved in the disease.
  
  
  OBJECTIVE
  This study was undertaken in order to investigate the possible relation of human herpesvirus-6 (HHV-6) in relapsing-remitting MS (RRMS).
  
  
  METHODS
  A one-year follow-up study was performed analyzing serum samples of 63 patients with RRMS and 63 healthy blood donors (HBD) by a quantitative real time PCR, to measure HHV-6 prevalence and viral load. Clinical data (starting age and EDSS increase) were collected.
  
  
  RESULTS
  (i) We found 25.4% of RRMS patients with at least one positive serum sample along the one year follow-up. (ii) 19.1% of RRMS samples in relapse had HHV-6 active infection vs. 7.9% of RRMS samples in remission. (iii) We only found variant A. (iv) RRMS patients with HHV-6 active replication initiated the disease 1.9 years earlier, and they had a higher EDSS increase.
  
  
  CONCLUSIONS
  A higher HHV-6A frequency of active infection seems to be related with the exacerbations in a subset of RRMS patients. Regarding the relationship between HHV-6A active infection and the clinical data in RRMS patients, further investigations are needed.
authors.affiliation: Servicio de Neurología, Hospital Clínico San Carlos, Madrid, 28040, Spain. labesmul@hcsc.es
authors.forename: Roberto
authors.initials: R
authors.lastname: Alvarez-Lafuente
authors.forename: Marta
authors.initials: M
authors.lastname: García-Montojo
authors.forename: Virginia
authors.initials: V
authors.lastname: De las Heras
authors.forename: Manuel
authors.initials: M
authors.lastname: Bartolomé
authors.forename: Rafael
authors.initials: R
authors.lastname: Arroyo
mesh_terms: D000293:Adolescent; D000328:Adult; D004279:DNA, Viral / Q000097:blood; D005260:Female; D015654:Herpesvirus 6, Human / Q000302:isolation & purification / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000503:physiopathology* / Q000821:virology*; D016133:Polymerase Chain Reaction; D019349:Roseolovirus Infections / Q000821:virology*; D019562:Viral Load; D014779:Virus Replication
chemical_list: D004279:DNA, Viral