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) α, 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-α, 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-α and IL-6 concentrations but decreased IL-18 concentrations than controls. TNF-α 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-α, IL-6, and IL-18 activities may contribute to the pathophysiology of depressive disorder.