scRNA-seq and scTCR-seq analyses of CSF cells isolated from patients with PD show clonally expanded T cells were enriched in CD27−CCR7−GZMAhiGZMBhiPRF1hiNKG7hi CD8+ T cells, and these cells also express high levels of CCL5, CST7, GZMH and GZMK [5]. Here, CD8A is linked to Parkinson disease.