CD8A and Parkinson disease: This aligns with recent studies illustrating the clonal expansion of CD8+ T cells in the CSF and PBMCs in neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease,35,36 as well as in PBMCs of individuals with familial ALS.13 These findings collectively imply that an enhanced intrathecal adaptive immune response is a shared characteristic of neurodegenerative disorders.