MAPT and Parkinson disease: Although evidence of lymphocyte infiltrates in neurodegenerative diseases is scarce, previous studies have revealed a shift in CD8/CD4 ratio in blood and CSF of PSP patients.10,11 A recent report focusing on the frontal cortex showed a correlation between CD8 cells and phosphorylated-tau (p-tau) in frontotemporal-lobar degeneration (FTLD), potentially mediated by microglia and astroglial activation.12 In Parkinson's disease (PD), an α-synucleinopathy with Lewy-bodies, CD8 infiltration has been detected in the early stages of pathology.13