biostudies-literatureCouto BRossy FoundationCanada Foundation for InnovationOntario Research FundEdmond J. Safra Philanthropic Foundation2650-2657https://www.ebi.ac.uk/biostudies/studies/S-EPMC12316005biostudies-literatureUnknown148(8)Progressive supranuclear palsy (PSP) is a neurodegenerative disorder characterized by four-repeat (4R) tau protein deposition. The substantia nigra (SN) and midbrain tegmentum nuclei (MBT) are consistently affected. Lymphocyte infiltrates are scarce in the brains of patients with neurodegenerative diseases, although a few reports have described their presence in the α-synucleinopathy Parkinson's disease (PD). To evaluate the cytotoxic T-cell response, serial sections spanning 120 μm of the SN were immunostained consecutively for phosphorylated tau (p-tau, AT8) or α-synuclein, cytotoxic T-cell marker and microglia marker HLA-DR. Sections were analysed with stereology software in 9 patients with PSP, 10 with PD and 6 healthy controls. We semiquantitatively scored CD8-positive cells in furtheBrain : a journal of neurologyMidbrain cytotoxic T cells as a distinct neuropathological feature of progressive supranuclear palsy.PMC1231600540480Fox SHLee SLi JCouto BKnott SFearon CTartaglia MCLang AEForrest SLKovacs GGfalseMidbrain cytotoxic T cells as a distinct neuropathological feature of progressive supranuclear palsy.Progressive supranuclear palsy (PSP) is a neurodegenerative disorder characterized by four-repeat (4R) tau protein deposition. The substantia nigra (SN) and midbrain tegmentum nuclei (MBT) are consistently affected. Lymphocyte infiltrates are scarce in the brains of patients with neurodegenerative diseases, although a few reports have described their presence in the α-synucleinopathy Parkinson's disease (PD). To evaluate the cytotoxic T-cell response, serial sections spanning 120 μm of the SN were immunostained consecutively for phosphorylated tau (p-tau, AT8) or α-synuclein, cytotoxic T-cell marker and microglia marker HLA-DR. Sections were analysed with stereology software in 9 patients with PSP, 10 with PD and 6 healthy controls. We semiquantitatively scored CD8-positive cells in furthe2025-01-01T00:00:00Z2025 Aug2025-08-12T03:05:10.821Z2025-08-12T03:05:10.821ZS-EPMC123160054023318110.1093/brain/awaf135