title: Fatigue and plasma cytokine concentrations at rest and during exercise in patients with sarcoidosis.
abstract: BACKGROUND
  Patients with sarcoidosis exhibit exercise intolerance-related fatigue and increased levels of circulating proinflammatory cytokines at rest. Exercise may result in increased plasma cytokine levels (PCLs) in healthy adults, but such a relationship has not been studied in sarcoidosis patients.
  
  
  OBJECTIVE
  To assess relationship of fatigue in sarcoidosis with PCLs at rest and with cardiopulmonary exercise testing (CPET).
  
  
  METHODS
  We assessed lung function, CPET data, multidimensional fatigue inventory, plasma tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) concentrations before, immediately after, and 4-6 h following CPET in 22 sarcoidosis patients (13 receiving immunomodulatory drugs) and 22 controls.
  
  
  RESULTS
  Patients exhibited greater fatigue, reduced cardiorespiratory function, higher Medical Research Council (MRC) scores and higher plasma TNF-α concentrations than controls at all times. Plasma IL-1β levels did not differ between cohorts. Patients exhibited a 28% increase (statistically not significant) in TNF-α level immediately post exercise. Plasma IL-β concentrations did not change among cohorts. Treated patients exhibited higher MRC and physical fatigue scores and lower breathing reserve, but no differences in cardiorespiratory function or PCLs compared to untreated patients. In treated patients, pre-exercise plasma IL-1β correlated with physical fatigue, reduced motivation and total fatigue; TNF-α levels only correlated with general fatigue score.
  
  
  CONCLUSIONS
  Treated sarcoidosis patients exhibit a relation between physical fatigue, reduced motivation and total fatigue and pre-exercise plasma IL-1β concentrations. Acute exercise does not increase PCLs. Whether the reduced MRC score and physical fatigue in treated patients is related to the therapy or to the underlying inflammatory process is difficult to determine.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. baydur@usc.edu
authors.forename: Ahmet
authors.initials: A
authors.lastname: Baydur
authors.forename: Bahram
authors.initials: B
authors.lastname: Alavy
authors.forename: Amar
authors.initials: A
authors.lastname: Nawathe
authors.forename: Shanshan
authors.initials: S
authors.lastname: Liu
authors.forename: Stan
authors.initials: S
authors.lastname: Louie
authors.forename: Om Prakash
authors.initials: OP
authors.lastname: Sharma
mesh_terms: D015331:Cohort Studies; D016207:Cytokines / Q000097:blood*; D015444:Exercise; D005080:Exercise Test; D005221:Fatigue / Q000209:etiology*; D005260:Female; D006321:Heart / Q000503:physiopathology; D006801:Humans; D007155:Immunologic Factors / Q000627:therapeutic use; D053583:Interleukin-1beta / Q000097:blood; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D011788:Quality of Life; D012119:Respiration; D012146:Rest; D012507:Sarcoidosis / Q000097:blood* / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016207:Cytokines; D007155:Immunologic Factors; D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha