Altered serum levels of TNF-α, IL-6, and IL-18 in depressive disorder patients

Objective: Depressive disorder is associated with abnormal changes in cytokines levels. This study aimed to assess serum concentrations of tumor necrosis factor (TNF) alpha, interleukin (IL) 6, and IL-18 in depressive patients. The correlations between these three cytokine concentrations and the patients' clinical characteristics were also assessed. Methods: Serum TNF-alpha, IL-6, and IL-18 concentrations were assessed using enzyme-linked immunosorbent assay from 64 depressive patients and 80 healthy control subjects. Depressive symptoms of patients were assessed using Hamilton Depression Scale-17. Results: Depressive patients had increased serum TNF-alpha and IL-6 concentrations but decreased IL-18 concentrations than controls. TNF-alpha and IL-6 concentrations were significantly positively associated with Hamilton Depression Scale-17 scores in depressive patients. Conclusion: These findings provided additional evidence that altered TNF-alpha, IL-6, and IL-18 activities may contribute to the pathophysiology of depressive disorder.