Characterization of peripheral hematopoietic stem cells and monocytes in Parkinson's disease

Background Emerging evidence has highlighted the pivotal role of the immune system in neurodegenerative diseases. This study investigated the impact of progressive neurodegeneration on the differentiation and development of hematopoietic stem cells in the peripheral blood of Parkinson's patients. Methods: A colony‐forming cell assay was established to study hematopoietic stem cells from venous blood of Parkinson's patients, and flow cytometry was used to analyze the expression of chemokine receptors on monocytes. Results We demonstrate that there is strong upregulation in the percentage of monocyte precursors in the peripheral blood of Parkinson's patients and asymptomatic high‐risk individuals. We identify the receptor CCR2 as undergoing strong upregulation on the surface of classical monocytes in Parkinson's patients. Conclusions The association between blood cell development and progressive cell death in the brain of Parkinson's patients should be further investigated as a potential dynamic biomarker and indicator of disease progression. © 2013 Movement Disorder Society