title: Coemergence of insomnia and a shift in the Th1/Th2 balance toward Th2 dominance.
abstract: OBJECTIVE
  Insomnia is associated with physical and mental disorders. We examined the effect of insomnia on immune functions, focusing on the T helper 1 (Th1)/ T helper 2 (Th2) balance, by a cross-sectional design.
  
  
  METHODS
  We provided a self-administered questionnaire to evaluate sleep habits, smoking and medical disorders to 578 men without any toxic exposure (20-64 years old), and measured natural killer (NK) cell activity in 324 men and production of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) after stimulation with phytohemagglutinin in 254 men. According to the criteria of DSM-IV, in which insomnia is classified into primary and secondary insomnia, we assessed the effect of insomnia on immune functions, controlling for age and smoking in groups with and without medical disorders.
  
  
  RESULTS
  The prevalence of insomnia in the present study was 9.2%. In the absence of medical disorders, insomniac men had a significantly lower IFN-gamma and ratio of IFN-gamma to IL-4 than noninsomniac men. Men with insufficient sleep or difficulty initiating sleep (DIS) had a significantly lower IFN-gamma to IL-4 ratio than those not suffering from insufficient sleep or DIS. In the presence of medical disorders, insomniac men had significantly higher IL-4 than noninsomniac men. Men with difficulty maintaining sleep (DMS) had a significantly lower IFN-gamma to IL-4 ratio than men without DMS. NK cell activity was independent of insomnia.
  
  
  CONCLUSIONS
  The present results showed a link between insomnia unrelated to medical disorders and a shift in the Th1/Th2 balance toward Th2 dominance, indicating that the relationship between sleep quality and the etiology of immune-related diseases should be reconsidered.
authors.affiliation: Division of Psychosomatic Research, National Institute of Mental Health, Chiba, Japan.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Sakami
authors.forename: Toshio
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Norito
authors.initials: N
authors.lastname: Kawakami
authors.forename: Takashi
authors.initials: T
authors.lastname: Haratani
authors.forename: Akira
authors.initials: A
authors.lastname: Fukui
authors.forename: Fumio
authors.initials: F
authors.lastname: Kobayashi
authors.forename: Osamu
authors.initials: O
authors.lastname: Fujita
authors.forename: Shunichi
authors.initials: S
authors.lastname: Araki
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kawamura
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D015536:Down-Regulation / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000187:drug effects / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D016131:Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D015213:Neuroimmunomodulation / Q000187:drug effects / Q000276:immunology*; D010835:Phytohemagglutinins / Q000494:pharmacology; D007319:Sleep Initiation and Maintenance Disorders / Q000276:immunology* / Q000503:physiopathology; D012907:Smoking / Q000276:immunology; D011795:Surveys and Questionnaires; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology*; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology*
chemical_list: D010835:Phytohemagglutinins; D015847:Interleukin-4; D007371:Interferon-gamma