Abstract
Parkinson disease is the second most common neurodegenerative disease in the world, but there is currently no available cure for it. Current treatments only alleviate some of the symptoms for a few years, but they become ineffective in the long run and do not stop the disease. Therefore it is of outmost importance to develop therapeutic strategies that can prevent, stop, or cure Parkinson disease. A very promising target for these therapies is the peripheral immune system due to its probable involvement in the disease and its potential as a tool to modulate neuroinflammation. But for such strategies to be successful, we need to understand the particular state of the peripheral immune system during Parkinson disease in order to avoid its weaknesses. In this review we examine the available data regarding how dopamine regulates the peripheral immune system and how this regulation is affected in Parkinson disease; the specific cytokine profiles observed during disease progression and the alterations documented to date in patients’ peripheral blood mononuclear cells. We also review the different strategies used in Parkinson disease animal models to modulate the adaptive immune response to salvage dopaminergic neurons from cell death. After analyzing the evidence, we hypothesize the need to prime the immune system to restore natural tolerance against α-synuclein in Parkinson disease, including at the same time B and T cells, so that T cells can reprogram microglia activation to a beneficial pattern and B cell/IgG can help neurons cope with the pathological forms of α-synuclein.
Disclosure of Potential Conflicts of Interest
The authors declare that they do not have any conflicting interest.
Acknowledgments
M.vE.C. is recipient of a PhD grant from CONACyT (Mexico), V.S.G. and M.R.R. have had their work herein cited supported by the Lundbeck Foundation (VSG/MRR), the MJF Foundation (VSG/MRR), the Parkinsons Forening (MRR), and the Familie Hede Nielsens fond (VSG).
Endnotes
aThere is one single study that did not find such increase.
bIn the study in ref. Citation87 the patients were all taking amantidine and in ref. Citation85 they were under L-dopa treatment.
cCop-1 is a TCR agonist that blocks MHCII function and induces Treg.