Serum leucine-rich α2 glycoprotein as a potential biomarker for systemic inflammation in Parkinson's disease

There is ample epidemiological and animal-model evidence suggesting that intestinal inflammation is associated with the development of Parkinson's disease (PD). Leucine-rich α2 glycoprotein (LRG) is a serum inflammatory biomarker used to monitor the activity of autoimmune diseases, including inflammatory bowel diseases. In this study, we aimed to investigate whether serum LRG could be used a biomarker of systemic inflammation in PD and to help distinguish disease states. Serum LRG and C-reactive protein (CRP) levels were measured in 66 patients with PD and 31 age-matched controls. We found that serum LRG levels were statistically significantly higher in the PD group than in the control group (PD: 13.9 ± 4.2 ng/mL, control: 12.1 ± 2.7 ng/mL, p = 0.036). LRG levels were also correlated with Charlson comorbidity index (CCI) and CRP levels. LRG levels in the PD group were correlated with Hoehn and Yahr stages (Spearman's r = 0.40, p = 0.008). LRG levels were statistically significantly elevated in PD patients with dementia as compared to those without dementia (p = 0.0078). Multivariate analysis revealed a statistically significant correlation between PD and serum LRG levels after adjusting for serum CRP levels, and CCI (p = 0.019). We conclude that serum LRG levels could be considered a potential biomarker for systemic inflammation in PD.