title: Plasma neuropeptide Y: a biomarker for symptom severity in chronic fatigue syndrome.
abstract: BACKGROUND
  Chronic fatigue syndrome (CFS) is a complex, multi-symptom illness with a multisystem pathogenesis involving alterations in the nervous, endocrine and immune systems.Abnormalities in stress responses have been identified as potential triggers or mediators of CFS symptoms. This study focused on the stress mediator neuropeptide Y (NPY). We hypothesized that NPY would be a useful biomarker for CFS.
  
  
  METHODS
  The CFS patients (n = 93) were from the Chronic Fatigue and Related Disorders Clinic at the University of Miami and met the 1994 case definition of Fukuda and colleagues. Healthy sedentary controls (n = 100)) were from NIH or VA funded studies. Another fatiguing, multi-symptom illness, Gulf War Illness (GWI), was also compared to CFS. We measured NPY in plasma using a radioimmunoassay (RIA). Psychometric measures, available for a subset of CFS patients included: Perceived Stress Scale, Profile of Mood States, ATQ Positive & Negative Self-Talk Scores, the COPE, the Beck Depression Inventory, Fatigue Symptom Inventory, Cognitive Capacity Screening Examination, Medical Outcomes Survey Short Form-36, and the Quality of Life Scale.
  
  
  RESULTS
  Plasma NPY was elevated in CFS subjects, compared to controls (p = .000) and to GWI cases (p = .000). Receiver operating characteristics (ROC) curve analyses indicated that the predictive ability of plasma NPY to distinguish CFS patients from healthy controls and from GWI was significantly better than chance alone. In 42 patients with CFS, plasma NPY had significant correlations (<0.05) with perceived stress, depression, anger/hostility, confusion, negative thoughts, positive thoughts, general health, and cognitive status. In each case the correlation (+ or -) was in the anticipated direction.
  
  
  CONCLUSIONS
  This study is the first in the CFS literature to report that plasma NPY is elevated compared to healthy controls and to a fatigued comparison group, GWI patients. The significant correlations of NPY with stress, negative mood, general health, depression and cognitive function strongly suggest that this peptide be considered as a biomarker to distinguish subsets of CFS.
authors.affiliation: Department of Medicine, University of Miami Miller School of Medicine, 1600 NW 10th Ave, Miami, FL USA. mfletche@med.miami.edu
authors.forename: Mary A
authors.initials: MA
authors.lastname: Fletcher
authors.forename: Martin
authors.initials: M
authors.lastname: Rosenthal
authors.forename: Michael
authors.initials: M
authors.lastname: Antoni
authors.forename: Gail
authors.initials: G
authors.lastname: Ironson
authors.forename: Xiao R
authors.initials: XR
authors.lastname: Zeng
authors.forename: Zachary
authors.initials: Z
authors.lastname: Barnes
authors.forename: Jeanna M
authors.initials: JM
authors.lastname: Harvey
authors.forename: Barry
authors.initials: B
authors.lastname: Hurwitz
authors.forename: Silvina
authors.initials: S
authors.lastname: Levis
authors.forename: Gordon
authors.initials: G
authors.lastname: Broderick
authors.forename: Nancy G
authors.initials: NG
authors.lastname: Klimas
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D015673:Fatigue Syndrome, Chronic / Q000097:blood* / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009478:Neuropeptide Y / Q000096:biosynthesis / Q000097:blood*; D018923:Persian Gulf Syndrome / Q000097:blood* / Q000175:diagnosis* / Q000473:pathology; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D015415:Biomarkers; D009478:Neuropeptide Y