Combined serum IL-6, C-reactive protein, and cortisol may distinguish patients with anhedonia in major depressive disorder

Yinghui Li; Yingying Yue; Suzhen Chen; Wenhao Jiang; Zhi Xu; Gang Chen; Zixin Zhu; Liangliang Tan; Yonggui Yuan

doi:10.3389/fnmol.2022.935031

Combined serum IL-6, C-reactive protein, and cortisol may distinguish patients with anhedonia in major depressive disorder

Front Mol Neurosci. 2022 Aug 24:15:935031. doi: 10.3389/fnmol.2022.935031. eCollection 2022.

Authors

Yinghui Li^{1

2}, Yingying Yue², Suzhen Chen², Wenhao Jiang², Zhi Xu², Gang Chen², Zixin Zhu², Liangliang Tan², Yonggui Yuan^{1

2}

Affiliations

¹ Nanjing Medical University, Nanjing, China.
² Department of Psychosomatics and Psychiatry, ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, China.

Abstract

Neuroinflammation and anhedonia in major depressive disorder (MDD) are closely connected, though the exact mechanism is unclear. This study aimed to investigate the relationships between cytokines, C-reactive protein (CRP), cortisol, and anhedonia, revealing the potential predictive value in identifying anhedonic MDD. In total, 66 patients with MDD (29 with anhedonia and 37 without anhedonia) and 66 healthy controls (HCs) were included. The severity of depression and anhedonia was evaluated using the Hamilton Rating Scale for Depression-24 (HAMD-24) and Snaith-Hamilton Pleasure Scale (SHAPS), respectively. Serum cytokines were measured using flow cytofluorometric kits, while CRP and cortisol were measured using enzyme-linked immunosorbent assay kits. We found higher serum levels of interleukin-2 (IL-2), IL-6, and cortisol in MDD than in HC where anhedonic MDD was highest. CRP and IL-6 were positively associated with anhedonia, and cortisol levels were related to both anhedonia and depression. A combination of IL-6, CRP, and cortisol had optimal predictive value for distinguishing anhedonic MDD. Anhedonic MDD has unique neuroendocrine-immune characteristics compared with those without anhedonia. The combination of IL-6, CRP, and cortisol might be an early marker to distinguish anhedonic MDD.

Keywords: C-reactive protein; anhedonia; cortisol; cytokines; depression.