title: Heat shock proteins and chronic fatigue in primary Sjögren's syndrome.
abstract: Fatigue occurs frequently in patients with cancer, neurological diseases and chronic inflammatory diseases, but the biological mechanisms that lead to and regulate fatigue are largely unknown. When the innate immune system is activated, heat shock proteins (HSPs) are produced to protect cells. Some extracellular HSPs appear to recognize cellular targets in the brain, and we hypothesize that fatigue may be generated by specific HSPs signalling through neuronal or glial cells in the central nervous system. From a cohort of patients with primary Sjögren's syndrome, 20 patients with high and 20 patients with low fatigue were selected. Fatigue was evaluated with a fatigue visual analogue scale. Plasma concentrations of HSP32, HSP60, HSP72 and HSP90α were measured and analysed to determine if there were associations with the level of fatigue. Plasma concentrations of HSP90α were significantly higher in patients with high fatigue compared with those with low fatigue, and there was a tendency to higher concentrations of HSP72 in patients with high fatigue compared with patients with low fatigue. There were no differences in concentrations of HSP32 and HSP60 between the high- and low-fatigue groups. Thus, extracellular HSPs, particularly HSP90α, may signal fatigue in chronic inflammation. This supports the hypothesis that fatigue is generated by cellular defence mechanisms.
authors.affiliation: Research Department, Stavanger University Hospital, Stavanger, Norway.
authors.forename: Kjetil
authors.initials: K
authors.lastname: Bårdsen
authors.affiliation: International Research Institute of Stavanger, Stavanger, Norway.
authors.forename: Mari Mæland
authors.initials: MM
authors.lastname: Nilsen
authors.affiliation: Research Department, Stavanger University Hospital, Stavanger, Norway Department of Mathematics and Natural Sciences, University of Stavanger, Stavanger, Norway.
authors.forename: Jan Terje
authors.initials: JT
authors.lastname: Kvaløy
authors.affiliation: Clinical Immunology Unit, Department of Internal Medicine, Stavanger University, Hospital, Stavanger, Norway.
authors.forename: Katrine Brække
authors.initials: KB
authors.lastname: Norheim
authors.affiliation: Department of Medical Biochemistry, Stavanger University Hospital, Stavanger, Norway.
authors.forename: Grete
authors.initials: G
authors.lastname: Jonsson
authors.affiliation: Clinical Immunology Unit, Department of Internal Medicine, Stavanger University, Hospital, Stavanger, Norway Department of Medical Science, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway roald.omdal@sus.no.
authors.forename: Roald
authors.initials: R
authors.lastname: Omdal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology; D002908:Chronic Disease; D005221:Fatigue / Q000097:blood* / Q000209:etiology*; D005260:Female; D018841:HSP90 Heat-Shock Proteins / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000473:pathology; D012859:Sjogren's Syndrome / Q000150:complications*
chemical_list: D018841:HSP90 Heat-Shock Proteins
keywords: Chronic fatigue; Sjögren’s syndrome; autoimmune diseases; cellular stress; heat shock proteins; innate immunity