T-helper types 1, 2, and 3 cytokine interactions in symptomatic manic patients

It has been reported that the balance between T-helper type 1 (Th1) cytokines and T-helper type 2 (Th2) cytokines plays a role in psychiatric disorders such as bipolar disorder. The T-helper type 3 (Th3) cytokine, which transforming growth factor beta-1 (TGF-β1), has been shown to modulate the production of Th1 and Th2 cytokines. However, the role of TGF-β1 in bipolar disorder has not yet been explored. A total of 70 manic patients with bipolar disorder and 96 normal controls was recruited. The plasma levels of IFN-γ, IL-4, and TGF-β1 were studied at the time of admission and 8 weeks after mood stabilizer treatment. The detection rate and plasma concentrations of IFN-γ and IL-4 and the IFN-γ/TGF-β1 and IL-4/TGF-β1 ratios were significantly higher in patients than in controls, while the TGF-β1 level was significantly lower. The TGF-β1 level increased significantly after treatment and the IFN-γ/TGF-β1 and IL-4/TGF-β1 ratios returned to control values. TGF-β1 may play a role in the pathophysiology of bipolar disorder through the action of TGF-β1 in modulating the IL-4/TGF-β1 ratio.