title: Immune and hemorheological changes in chronic fatigue syndrome.
abstract: BACKGROUND
  Chronic Fatigue Syndrome (CFS) is a multifactorial disorder that affects various physiological systems including immune and neurological systems. The immune system has been substantially examined in CFS with equivocal results, however, little is known about the role of neutrophils and natural killer (NK) phenotypes in the pathomechanism of this disorder. Additionally the role of erythrocyte rheological characteristics in CFS has not been fully expounded. The objective of this present study was to determine deficiencies in lymphocyte function and erythrocyte rheology in CFS patients.
  
  
  METHODS
  Flow cytometric measurements were performed for neutrophil function, lymphocyte numbers, NK phenotypes (CD56(dim)CD16(+) and CD56(bright)CD16(-)) and NK cytotoxic activity. Erythrocyte aggregation, deformability and fibrinogen levels were also assessed.
  
  
  RESULTS
  CFS patients (n = 10) had significant decreases in neutrophil respiratory burst, NK cytotoxic activity and CD56(bright)CD16(-) NK phenotypes in comparison to healthy controls (n = 10). However, hemorheological characteristic, aggregation, deformability, fibrinogen, lymphocyte numbers and CD56(dim)CD16(+) NK cells were similar between the two groups.
  
  
  CONCLUSIONS
  These results indicate immune dysfunction as potential contributors to the mechanism of CFS, as indicated by decreases in neutrophil respiratory burst, NK cell activity and NK phenotypes. Thus, immune cell function and phenotypes may be important diagnostic markers for CFS. The absence of rheological changes may indicate no abnormalities in erythrocytes of CFS patients.
authors.affiliation: Faculty of Health Science and Medicine, Population Health and Neuroimmunology Unit, Bond University, Robina, Queensland, Australia. ebrenu@student.bond.edu.au
authors.forename: Ekua W
authors.initials: EW
authors.lastname: Brenu
authors.forename: Donald R
authors.initials: DR
authors.lastname: Staines
authors.forename: Oguz K
authors.initials: OK
authors.lastname: Baskurt
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Ashton
authors.forename: Sandra B
authors.initials: SB
authors.lastname: Ramos
authors.forename: Rhys M
authors.initials: RM
authors.lastname: Christy
authors.forename: Sonya M
authors.initials: SM
authors.lastname: Marshall-Gradisnik
mesh_terms: D015703:Antigens, CD / Q000276:immunology; D002460:Cell Line; D004907:Erythrocyte Deformability; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism; D015673:Fatigue Syndrome, Chronic / Q000097:blood / Q000276:immunology; D005434:Flow Cytometry / Q000379:methods; D018056:Hemorheology; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology*; D016131:Lymphocyte Subsets / Q000276:immunology; D009504:Neutrophils / Q000166:cytology / Q000276:immunology; D010641:Phenotype; D016897:Respiratory Burst / Q000276:immunology
chemical_list: D015703:Antigens, CD