Relationship between levels of inflammatory cytokines in the peripheral blood and the severity of depression and anxiety in patients with Parkinson's disease

OBJECTIVE: The present study aims to investigate the relationship between expression of inflammatory cytokines in the peripheral blood and the severity of depression and anxiety in patients with Parkinson's disease (PD). PATIENTS AND METHODS: Between January 2012 and December 2015, 62 PD patients admitted to our institution were included in the PD group, and 62 healthy subjects seeking health check-up at our institution during the same period of time were enrolled in the control group. Levels of inflammatory cytokines, including IL-1 beta, IL-6, interferon-gamma (INF-gamma), hypersensitive C-reactive protein (hsCRP) and soluble IL-2 receptor (sIL-2R), were measured by using Enzyme-linked immunosorbent assay (ELISA). Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA) were used to assess the severity of depression and anxiety, respectively. RESULTS: A total of 124 subjects were included into PD group and control group, 62 for each. No significant differences were observed in the gender, age, body mass index (BMI), smoking history and alcohol history between two groups (p > 0.05). Levels of IL-1 beta, IL-6, TNF-alpha, hsCRP and sIL-2R were significantly higher in patients of PD group than those in the control group (p < 0.05). HAMD and HAMA scores in PD group were significantly higher than those in the control group [(22.74 +/- 6.34), (20.90 +/- 5.86) vs. (2.17 +/- 3.46), (3.79 +/- 3.55), p < 0.05]. HAMD and HAMA scores were positively correlated with the levels of TNF-alpha, hsCRP and sIL-2R in the peripheral blood of PD patients (p < 0.05). CONCLUSIONS: Expression of inflammatory cytokines are elevated in the peripheral blood of PD patients, and the severity of depression and anxiety is correlated with levels of TNF-alpha, hsCRP and sIL-2R in the peripheral blood of these patients.