CD8A and Parkinson disease: Similar to AD and PD patients, researchers discovered a clonally expanded effector memory CD8+ T- cell population in the peripheral blood and CSF of ALS patients (Campisi et al., 2022; Yazdani et al., 2022) and ALS animal models with mutations in the senataxin gene (SETX) (Carroll, 2019; Campisi et al., 2022).