Association of Peripheral TNF-α and IFN-γ Expression With Serum Uric Acid Levels and Clinical Disease Severity in Patients With Parkinson’s Disease: A Cross-Sectional Study

Background Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by dopaminergic neuronal loss, neuroinflammation, and oxidative stress. Pro-inflammatory cytokines such as TNF-α and IFN-γ contribute to neuronal injury, whereas uric acid acts as an important endogenous antioxidant. The interaction between inflammatory cytokines and antioxidant status in PD remains incompletely understood. Methods This hospital-based cross-sectional observational study included 44 patients with clinically diagnosed PD. Disease severity was assessed using the Webster Rating Scale (WRS) and the Hoehn and Yahr (H&Y) staging system. Serum uric acid levels were estimated using the uricase-peroxidase method. Peripheral blood TNF-α and IFN-γ gene expression levels were quantified using quantitative real-time polymerase chain reaction (qRT-PCR) and analyzed using the 2^-ΔΔCt method. Correlation analysis and logistic regression were performed to evaluate associations between biomarkers and disease severity. Results The mean age of participants was 73.16 ± 8.80 years, with a male predominance of 29 (65.9%). TNF-α and IFN-γ expression levels progressively increased with advancing disease severity among patients with PD. Both cytokines demonstrated significant positive correlations with WRS and H&Y scores. In contrast, serum uric acid levels progressively declined with increasing disease severity and showed significant inverse correlations with TNF-α and IFN-γ expression. On multivariate logistic regression analysis, elevated TNF-α and IFN-γ expression remained independently associated with advanced disease severity, whereas higher serum uric acid levels demonstrated a protective association. Conclusion Higher TNF-α and IFN-γ expression, along with lower serum uric acid levels, were associated with greater disease severity. These findings suggest their potential utility as candidate biomarkers, which require validation in larger longitudinal studies.