title: Reductions in circulating levels of IL-16, IL-7 and VEGF-A in myalgic encephalomyelitis/chronic fatigue syndrome.
abstract: Recently, differences in the levels of various chemokines and cytokines were reported in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as compared with controls. Moreover, the analyte profile differed between chronic ME/CFS patients of long duration versus patients with disease of less than 3years. In the current study, we measured the plasma levels of 34 cytokines, chemokines and growth factors in 100 chronic ME/CFS patients of long duration and in 79 gender and age-matched controls. We observed highly significant reductions in the concentration of circulating interleukin (IL)-16, IL-7, and Vascular Endothelial Growth Factor A (VEGF-A) in ME/CFS patients. All three biomarkers were significantly correlated in a multivariate cluster analysis. In addition, we identified significant reductions in the concentrations of fractalkine (CX3CL1) and monokine-induced-by-IFN-γ (MIG; CXCL9) along with increases in the concentrations of eotaxin 2 (CCL24) in ME/CFS patients. Our data recapitulates previous data from another USA ME/CFS cohort in which circulating levels of IL-7 were reduced. Also, a reduced level of VEGF-A was reported previously in sera of patients with Gulf War Illness as well as in cerebral spinal fluid samples from a different cohort of USA ME/CFS patients. To our knowledge, we are the first to test for levels of IL-16 in ME/CFS patients. In combination with previous data, our work suggests that the clustered reduction of IL-7, IL-16 and VEGF-A may have physiological relevance to ME/CFS disease. This profile is ME/CFS-specific since measurement of the same analytes present in chronic infectious and autoimmune liver diseases, where persistent fatigue is also a major symptom, failed to demonstrate the same changes. Further studies of other ME/CFS and overlapping disease cohorts are warranted in future.
authors.affiliation: Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, Canada. Electronic address: landi@ualberta.ca.
authors.forename: Abdolamir
authors.initials: A
authors.lastname: Landi
authors.affiliation: Department of Medicine, Katz Group Centre for Pharmacy & Health, University of Alberta, Edmonton, AB T6G 2E1, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Broadhurst
authors.affiliation: Bateman Horne Center, 1002 E. South Temple, Suite 408, Salt Lake City, UT 84102, USA.
authors.forename: Suzanne D
authors.initials: SD
authors.lastname: Vernon
authors.affiliation: Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, Canada.
authors.forename: D Lorne J
authors.initials: DL
authors.lastname: Tyrrell
authors.affiliation: Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, Canada. Electronic address: michael.houghton@ualberta.ca.
authors.forename: Michael
authors.initials: M
authors.lastname: Houghton
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D018925:Chemokines / Q000097:blood; D015673:Fatigue Syndrome, Chronic / Q000097:blood*; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood; D019410:Interleukin-16 / Q000097:blood*; D015851:Interleukin-7 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D042461:Vascular Endothelial Growth Factor A / Q000097:blood*
chemical_list: D015415:Biomarkers; D018925:Chemokines; D036341:Intercellular Signaling Peptides and Proteins; D019410:Interleukin-16; D015851:Interleukin-7; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A
keywords: Chemokine; Chronic fatigue syndrome; Cytokine; Diagnostic; Growth factor