title: Chronic fatigue syndrome--a controlled cross sectional study.
abstract: OBJECTIVE
  To look for signs of immunodeficiencies and/or longstanding infections underlying chronic fatigue syndrome (CFS).
  
  
  METHODS
  Twenty-one patients fulfilling the Centers for Disease Control criteria for CFS were compared to 21 age and sex matched controls. A number of viral antibodies as well as the following tests evaluating the immune system were studied: autoantibody profile, cell surface markers on isolated blood mononuclear cells, cytokine production, lymphocyte proliferative responses, natural killer cell activity and quantitation of immunoglobulin secreting cells.
  
  
  RESULTS
  Production in vitro of the predominantly T cell derived cytokines interleukin 2 and interferon gamma was significantly higher in patients with CFS compared to the control group. Furthermore, the serum concentrations of IgA and IgE were lower in patients with CFS; however, this difference was caused by a larger number with values of IgA and IgE above the upper limit of the normal range among the controls than among the patients with CFS. All other variables were similar in the 2 groups.
  
  
  CONCLUSIONS
  A pathogenically significant imbalance of the immune system in patients with CFS cannot be excluded. However, evidence of a causal link between abnormal immunity and CFS was not obtained.
authors.affiliation: Medical Department TTA M. Rigshospitalet, Copenhagen, Denmark.
authors.forename: A K
authors.initials: AK
authors.lastname: Rasmussen
authors.forename: H
authors.initials: H
authors.lastname: Nielsen
authors.forename: V
authors.initials: V
authors.lastname: Andersen
authors.forename: T
authors.initials: T
authors.lastname: Barington
authors.forename: K
authors.initials: K
authors.lastname: Bendtzen
authors.forename: M B
authors.initials: MB
authors.lastname: Hansen
authors.forename: L
authors.initials: L
authors.lastname: Nielsen
authors.forename: B K
authors.initials: BK
authors.lastname: Pedersen
authors.forename: A
authors.initials: A
authors.lastname: Wiik
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D001323:Autoantibodies / Q000097:blood; D016022:Case-Control Studies; D002648:Child; D003430:Cross-Sectional Studies; D016207:Cytokines / Q000097:blood*; D015673:Fatigue Syndrome, Chronic / Q000276:immunology*; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000097:blood*; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D017678:Sex Distribution
chemical_list: D000914:Antibodies, Viral; D001323:Autoantibodies; D016207:Cytokines; D007136:Immunoglobulins