No abstract

Background The pathogenesis of PD has not been fully elucidated, but recent studies have shown that the adaptive immune system may play a role in the pathology of PD. However, there is a lack of longitudinal studies exploring the relationship between peripheral adaptive immune indicators and the rate of disease progression in PD. Methods We included early PD patients with disease duration < 3 years and assessed the severity of clinical symptoms and peripheral adaptive immune system indicators (CD3 + , CD4 + , CD8 + T lymphocyte subsets, CD4 + :CD8 + ratio, IgG, IgM, IgA, C3, C4) at baseline. Clinical symptoms were followed up every year. We used the Unified Parkinson's Disease Rating Scale (UPDRS) to assess the disease severity and the Montreal Cognitive Assessment (MoCA) to assess global cognitive function. Result A total of 152 PD patients were eventually included. The linear mixed model showed no significant association between baseline peripheral blood adaptive immune indicators and baseline MoCA scores or UPDRS part III scores. A higher baseline CD3 + lymphocyte percentage was associated with a slower rate of decline in MoCA scores. Baseline immune indicators were not associated with the rate of change of the UPDRS part III scores. Conclusion The subset of peripheral T lymphocytes was related to the rate of cognitive decline in early PD patients, suggesting that the peripheral adaptive immune system may be involved in the process of cognitive decline in early PD. Supplementary Information The online version contains supplementary material available at 10.1007/s00415-023-11790-3.