Association of peripheral immune activation with amyotrophic lateral sclerosis and Parkinson's disease: A systematic review and meta-analysis.

Background: Recent studies have revealed the link between immune activation and neurodegenerative diseases.

Methods: By employing meta-analysis, we estimated the standardized mean difference (SMD) and their corresponding 95% confidence intervals (CIs) between the groups.

Results: According to the pre-set criteria, a total of 21 published articles including 2377 ALS patients and 1244 HCs, as well as 60 articles including 5111 PD patients and 4237 HCs, were identified. This study provided evidence of peripheral immune activation in the pathogenesis of ALS and PD.

Conclusion: Our results suggested monitoring changes in peripheral blood immune cell populations, particularly lymphocyte subsets, will benefit understanding the developments and exploring reliable and specific biomarkers of these two diseases.