Association between programmed death-1 pathway and major depression

Abstract

Objectives

Major depression (MD) may be associated with inflammation and immunity. PD-1 (programmed death-1), PD-L1 (programmed death-ligand 1) and PD-L2 (programmed death-ligand 2) are among the inhibitory immune mediators on the PD-1 pathway. However, previous data regarding the association between MD and PD-1 pathway were still scarce; therefore, we investigated the association of PD-1 pathway with MD.

Methods

During a period of 2 years, patients with MD and healthy controls were recruited from a medical centre in this study. The diagnosis of MD was established according to the DSM-5 criteria. The severity of MD was assessed with 17-item Hamilton Depression Rating Scale. PD-1, PD-L1 and PD-L2 were detected in peripheral blood from MD patients after 4 weeks of treatment with antidepressant drugs.

Results

A total of 54 patients with MD and 38 healthy controls were recruited. According to the analyses, there is a significantly higher PD-L2 level in MD than in healthy controls and lower PD-1 level after age and BMI adjustment. Besides, moderately positive correlation between HAM-D scores and PD-L2 level was found.

Conclusions

It was found that PD-1 pathway might play an important role in MD. We need a large sample to prove these results in the future.

Keywords:

• Immune checkpoint
• PD-1
• PD-L1
• PD-L2
• major depression

Acknowledgements

The authors express their deepest gratitude to all of the psychiatric staff for assisting in participant recruitment, and thank all of the individuals who participated in this study.

Author contributions

TH conceived and designed the study and revised it for intellectual content. TH took recruitment and management of the case. KH and TH contributed to data analysis and interpretation. KH drafted the manuscript. All authors read and approved the final manuscript.

Statement of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Additional information

Funding

This study was funded by Chang Gung Memorial Hospital, Taiwan [CMRPG8J1511 and CMRPG8L0501].