CD8A and neurodegenerative disease: However, recent single-cell RNA sequencing (scRNA-seq) and single-cell T-cell receptor sequencing (scTCR-seq) analyses in conjunction with flow cytometric analysis reveal that both clonally expanded CD8+ T cells in neurodegenerative diseases [4, 5, 7] and immune suppressive CD8+ Tregs [8, 9] are terminally differentiated effector memory T cells (TEMRA) expressing high levels of cytotoxicity-associated molecules and sharing cell surface markers, raising the critical question of what role these clonally expanded CD8+ T cells play in neurodegenerative diseases.