The level of IL-6 was associated with sleep disturbances in patients with major depressive disorder

Abstract

Purpose: Major depression disorder (MDD) was associated with inflammatory processes, but association results of inflammatory syndrome and MDD were inconsistent. To provide more evidence, we measured the plasma levels of IL-1β, IL-6, interferon (INT)-α2, INT-γ, and tumor necrosis factor (TNF)-α in patients having MDD and explored correlations between the five proinflammatory cytokines and specific depressive symptoms.

Patients and methods: Plasma concentrations of IL-1β, IL-6, INT-α2, INT-γ, and TNF-α were measured using ELISA for 44 MDD patients and 54 healthy controls. Patients with MDD were assessed on the 17-item Hamilton Depression Rating Scale (HAMD-17), and a total score and five syndrome scores were acquired.

Results: IL-6 levels in depressed patients were significantly elevated than in healthy controls, but no significant differences were observed in the levels of INF-α2, INF-γ, IL-1β, or TNF-α. In addition, correlation analysis revealed that sleep disturbances positively correlated with IL-6. Although there was no significant difference between the two groups in the levels of INF-α2, a significant positive correlation between IFN-α2 and retardation was observed.

Conclusion: Elevated IL-6 levels were observed in MDD patients and IL-6 may correlate with sleep disturbances.

Keywords:

• major depression disorder
• inflammation
• cytokine
• interleukin-6
• sleep disturbances

Acknowledgments

This research was supported by the National Natural Science Foundation of China (Grant No.: 81671344), and the 1.3.5 Project for Disciplines of Excellence, West China Hospital of Sichuan University (Grant No.: ZY2016103 and ZY2016203).

Author contributions

MW, XM, JW, and XY designed the study. MW performed the statistical analyses and wrote the initial draft of the manuscript. All of the authors contributed to data collection and analysis, critically revised the article and gave final approval of the version to be published, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Disclosure

The authors report no conflicts of interest in this work.