AUTHOR=Chen Xueping , Feng Weihua , Ou Ruwei , Liu Jiao , Yang Jing , Fu Jiajia , Cao Bei , Chen Yongping , Wei Qianqian , Shang Huifang 

TITLE=Evidence for Peripheral Immune Activation in Parkinson’s Disease

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=Volume 13 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2021.617370

DOI=10.3389/fnagi.2021.617370

ISSN=1663-4365

ABSTRACT=Background: Accumulating evidence has revealed that peripheral immunity is involved in Parkinson’s disease (PD). However, the results regarding the percentage of T-cell subsets are inconsistent, and the changes of immunoglobins levels have been seldom studied in PD patients.
Methods: Serum levels of the percentage of T-cell subsets and immunoglobulins were measured in 761 PD patients and 761 age- and gender- matched healthy controls. The correlations between the variables of peripheral immune activation (PIA) and the clinical characteristics of PD were analyzed using correlation analysis.
Results: The pooled results showed that PD patients had higher proportional levels of CD3+ T and CD4+ T lymphocytes as compared to healthy controls. CD8+ T cell percentages were similar in PD patients and controls, and the CD4/CD8 ratio was significantly higher in the PD population. No significant differences in IgG, IgA, or IgM levels between these two groups were found. In addition, CD4+ T cell percentage was inversely correlated with H&Y stage and IgG level was positively correlated with disease duration and UPDRS part III. Subgroup analyses showed that these associations were existed in female patients, but not in male patients.  
Conclusions: The enhanced immune activation in the peripheral system is indicated in PD, and dynamic alterations in CD4+ T cell percentage and IgG level suggest an active role for peripheral immunity in the disease progression, especially in female PD patients.