title: The inflammatory response system and the availability of plasma tryptophan in patients with primary sleep disorders and major depression.
abstract: BACKGROUND
  It is now well established that major depression is accompanied by an immune-inflammatory system response and that indicators of the latter are inversely correlated with lower availability of plasma tryptophan in depression. Inflammation and infection can alter sleep architecture, whereas sleep disturbances can impair immune functions.
  
  
  OBJECTIVE
  The aims of the present study were to examine: (i) immune-inflammatory markers, i.e. serum interleukin-6 (IL-6), IL-8, IL-6 receptor (IL-6R), IL-1R antagonist (IL-1RA), gp130, and prostaglandin E2 (PGE2) production by mitogen-stimulated whole blood and the availability of plasma tryptophan in patients with primary sleep disorders, major depression and healthy volunteers; and (ii) the relationships between the availability of tryptophan and indicators of the immune-inflammatory response system.
  
  
  RESULTS
  Mitogen-stimulated release of PGE2, and serum IL-6 and IL-8, were significantly increased in both depressed and sleep disordered patients compared to normal controls. Serum IL-1RA was significantly higher in depressed patients than in normal controls. Patients with depression and sleep disorders had a significantly lower availability of tryptophan than normal controls. There were significant and inverse relationships between the availability of plasma tryptophan and serum IL-1RA, IL-6 and IL-8.
  
  
  CONCLUSIONS
  The results suggest that (i) there is an activation of the immune-inflammatory response system in primary sleep disorders and depression; and (ii) the decreased availability of plasma tryptophan may be related to the inflammatory system response.
authors.affiliation: Clinical Research Center for Mental Health, University Department of Psychiatry, Antwerp, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Song
authors.forename: A
authors.initials: A
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Bonaccorso
authors.forename: C
authors.initials: C
authors.lastname: Heide
authors.forename: R
authors.initials: R
authors.lastname: Verkerk
authors.forename: G
authors.initials: G
authors.lastname: Kenis
authors.forename: E
authors.initials: E
authors.lastname: Bosmans
authors.forename: S
authors.initials: S
authors.lastname: Scharpe
authors.forename: A
authors.initials: A
authors.lastname: Whelan
authors.forename: P
authors.initials: P
authors.lastname: Cosyns
authors.forename: R
authors.initials: R
authors.lastname: de Jongh
authors.forename: M
authors.initials: M
authors.lastname: Maes
mesh_terms: D000328:Adult; D016207:Cytokines / Q000097:blood; D003866:Depressive Disorder / Q000276:immunology* / Q000503:physiopathology; D015232:Dinoprostone / Q000097:blood; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D007249:Inflammation; D008297:Male; D008875:Middle Aged; D008934:Mitogens / Q000494:pharmacology; D012893:Sleep Wake Disorders / Q000276:immunology* / Q000503:physiopathology; D014364:Tryptophan / Q000097:blood* / Q000378:metabolism
chemical_list: D016207:Cytokines; D008934:Mitogens; D014364:Tryptophan; D015232:Dinoprostone