Peripheral Immune-Inflammatory Parameters in Parkinson's Disease. Dependence on the Stage of Progression

According to the modern concepts, neuroinflammation and peripheral immune dysfunction play key roles in the onset and progression of Parkinson's disease (PD), one of the most common and severe neurodegenerative diseases. However, changes in the cellular and molecular immune parameters during the development of PD are still poorly understood. This work is devoted to analysis of the immune cell populations (monocytes, T- and B-cells and their subtypes), expression of Toll-like receptors (TLR), and spontaneous and mitogen-induced production of pro- and anti-inflammatory cytokines in the peripheral blood of the patients at different stages of idiopathic PD and healthy individuals. It was shown that the stage II of PD is characterized by the decrease in amount of the CD3⁺ T-cells, increase in the TLR2 expression on CD4⁺CD25⁺ Tregs, as well as increase in the spontaneous production of proinflammatory cytokines IFNγ and IL-17A. The stage III of PD is associated with the decrease in production of mitogen-induced IFNγ. Relative number of the CD19⁺CD25⁺ Breg cells in the patients with PD increased regardless of the disease stage. Thus, the obtained results indicate differences in the cellular and molecular immune parameters in the patients with PD and in the healthy individuals, which are dependent on the stage of the disease. These data are important for understanding molecular basis of PD development and prognosis of its course, and may be useful in identifying biomarkers of the disease severity and developing new treatment approaches depending on the stage of the disease.