Peripheral immune cell traits and Parkinson's disease: A Mendelian randomization study

Area of Science:

• Immunology
• Neuroscience
• Genetics

Background:

• Peripheral immune system alterations are observed in Parkinson's disease (PD), but their causal role is debated.
• Investigating the link between immune system features and PD is crucial for understanding disease mechanisms.

Purpose of the Study:

• To investigate the causal relationship between peripheral immune system features and Parkinson's disease (PD).
• To utilize a two-sample Mendelian randomization (MR) approach for robust causal inference.

Main Methods:

• Employed a two-sample Mendelian randomization (MR) design using genome-wide association study (GWAS) data for peripheral immune traits and PD.
• Utilized inverse-variance weighted (IVW), MR-Egger, and weighted median methods to assess causal associations.
• Conducted sensitivity analyses using MR-Egger and MR-PRESSO to detect and correct for horizontal pleiotropy.

Main Results:

• Analyzed 731 immune traits for association with PD.
• Identified four peripheral immunological features associated with PD after FDR adjustment.
• Observed that CX3CR1 expression on monocytes (OR: 0.85, 95% CI: 0.81-0.91) and CD14+CD16+ monocytes (OR: 0.87, 95% CI: 0.82-0.93) were associated with reduced PD risk.

Conclusions:

• Monocytes play a significant role in the pathophysiology of Parkinson's disease.
• CX3CR1 expression on monocytes is associated with a decreased risk of developing PD.