We identified a distinct cluster of terminal effector CD8+ T cells significantly clonally expanded in PD patients, which derived from central memory CD8+ T cells by TCR-dependent activation and upregulated both cell adhesion (ITGAM, ITGB1, etc.)and cell survival (PRSS23, SPON2, ZNF683) markers. The gene discussed is CD8A; the disease is Parkinson disease.