Th1, Th2 and Th3 cytokine alteration in schizophrenia

Prog Neuropsychopharmacol Biol Psychiatry. 2004 Nov;28(7):1129-34. doi: 10.1016/j.pnpbp.2004.05.047.


Background: Several studies have shown that there is an imbalance between T helper 1 (Th1) cytokines and T helper 2 (Th2) cytokines in patients with schizophrenia. The T helper 3 (Th3) cytokine, transforming growth factor beta-1 (TGF-beta1), has been shown to suppress the production of Th1 cytokines. Therefore it is hypothesized that it may play a role in schizophrenia by suppressing overactive Th1 system.

Methods: We recruited 88 schizophrenic patients and 88 matched controls. The basal plasma concentrations of IFN-gamma (Th1), IL-4 (Th2) and TGF-beta1 (Th3) were studied at the time the patients were admitted to the hospital and following 8 weeks of treatment with antipsychotics.

Results: The detection rate of plasma IFN-gamma and basal plasma TGF-beta1 level were significantly higher in schizophrenic patients than in controls whereas detection rate of plasma IL-4 was lower in patients. The ratio of Th1/Th2 cytokines (IFN-gamma/IL-4) was higher in schizophrenic patients. Following the neuroleptic treatment, the IFNgamma and TGF-beta1 levels returned to control values, and IL-4 concentration rose above the control value.

Conclusion: Schizophrenic patients showed higher Th1/Th2 ratio which is attenuated by effective neuroleptic treatment. It is possible that TGF-beta1 plays a role in reducing the activity of Th1 cytokine.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antipsychotic Agents / therapeutic use
  • Cytokines / metabolism*
  • Female
  • Humans
  • Interferon-gamma / blood
  • Interleukin-4 / metabolism
  • Male
  • Middle Aged
  • Psychiatric Status Rating Scales
  • Schizophrenia / drug therapy
  • Schizophrenia / metabolism*
  • Th1 Cells / metabolism*
  • Th2 Cells / metabolism*
  • Transforming Growth Factor beta / metabolism*
  • Transforming Growth Factor beta1


  • Antipsychotic Agents
  • Cytokines
  • TGFB1 protein, human
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • Interleukin-4
  • Interferon-gamma