title: Prevalence of xenotropic murine leukaemia virus-related virus in patients with chronic fatigue syndrome in the Netherlands: retrospective analysis of samples from an established cohort.
abstract: OBJECTIVE
  The presence of the retrovirus xenotropic murine leukaemia virus-related virus (XMRV) has been reported in peripheral blood mononuclear cells of patients with chronic fatigue syndrome. Considering the potentially great medical and social relevance of such a discovery, we investigated whether this finding could be confirmed in an independent European cohort of patients with chronic fatigue syndrome.
  
  
  METHODS
  Analysis of a well defined cohort of patients and matched neighbourhood controls by polymerase chain reaction.
  
  
  METHODS
  Certified (ISO 15189) laboratory of clinical virology in a university hospital in the Netherlands. Population Between December 1991 and April 1992, peripheral blood mononuclear cells were isolated from 76 patients and 69 matched neighbourhood controls. In this study we tested cells from 32 patients and 43 controls from whom original cryopreserved phials were still available.
  
  
  METHODS
  Detection of XMRV in peripheral blood mononuclear cells by real time polymerase chain reaction assay targeting the XMRV integrase gene and/or a nested polymerase chain reaction assay targeting the XMRV gag gene.
  
  
  RESULTS
  We detected no XMRV sequences in any of the patients or controls in either of the assays, in which relevant positive and negative isolation controls and polymerase chain reaction controls were included. Spiking experiments showed that we were able to detect at least 10 copies of XMRV sequences per 10(5) peripheral blood mononuclear cells by real time as well as by nested polymerase chain reaction, demonstrating high sensitivity of both assays.
  
  
  CONCLUSIONS
  This study failed to show the presence of XMRV in peripheral blood mononuclear cells of patients with chronic fatigue syndrome from a Dutch cohort. These data cast doubt on the claim that XMRV is associated with chronic fatigue syndrome in the majority of patients.
authors.affiliation: Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, Netherlands. f.vankuppeveld@ncmls.ru.nl
authors.forename: Frank J M
authors.initials: FJ
authors.lastname: van Kuppeveld
authors.forename: Arjan S
authors.initials: AS
authors.lastname: de Jong
authors.forename: Kjerstin H
authors.initials: KH
authors.lastname: Lanke
authors.forename: Gerald W
authors.initials: GW
authors.lastname: Verhaegh
authors.forename: Willem J G
authors.initials: WJ
authors.lastname: Melchers
authors.forename: Caroline M A
authors.initials: CM
authors.lastname: Swanink
authors.forename: Gijs
authors.initials: G
authors.lastname: Bleijenberg
authors.forename: Mihai G
authors.initials: MG
authors.lastname: Netea
authors.forename: Jochem M D
authors.initials: JM
authors.lastname: Galama
authors.forename: Jos W M
authors.initials: JW
authors.lastname: van der Meer
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004279:DNA, Viral; D015673:Fatigue Syndrome, Chronic / Q000821:virology*; D005260:Female; D006801:Humans; D009052:Leukemia Virus, Murine / Q000302:isolation & purification*; D007963:Leukocytes, Mononuclear / Q000821:virology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D012192:Retroviridae Infections / Q000150:complications*
chemical_list: D004279:DNA, Viral