title: A systematic review and critical evaluation of the immunology of chronic fatigue syndrome.
abstract: OBJECTIVE
  Immune dysfunction in patients with chronic fatigue syndrome (CFS) has been widely but inconsistently reported. Traditional reviews of the literature have produced a variety of conclusions. We present the results of the first systematic review of the subject.
  
  
  METHODS
  EMBASE, MEDLINE and PSYCHINFO databases were searched, and leading researchers in the field were contacted. Inclusion criteria were applied, and studies were then divided into groups based on the quality of their methodology. Study results were collated and described.
  
  
  RESULTS
  Studies ranged widely in quality. There was an inverse association between study quality and finding low levels of natural killer cells, suggesting that the association may be related to study methodology. On the other hand, reports of abnormalities in T cells and cytokine levels were not related to study quality.
  
  
  CONCLUSIONS
  The conclusions of this systematic review differ from a recent traditional narrative review of the immunology of CFS. No consistent pattern of immunological abnormalities is identified.
authors.affiliation: Department of Psychological Medicine, Guy's, King's and St. Thomas' School of Medicine, 103 Denmark Hill, London SE5 8AZ, UK.
authors.forename: Marc
authors.initials: M
authors.lastname: Lyall
authors.forename: Mark
authors.initials: M
authors.lastname: Peakman
authors.forename: Simon
authors.initials: S
authors.lastname: Wessely
mesh_terms: D016207:Cytokines / Q000494:pharmacology*; D015673:Fatigue Syndrome, Chronic / Q000276:immunology* / Q000503:physiopathology; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology*
chemical_list: D016207:Cytokines