Clonally expanded TEMRA CD8+ T cells originating from the circulation have been reported in the CNS of Setx knock-in (KI) mice developing ALS4-like disease, as well as in ALS4 patients, who typically have mutations on senataxin (SETX) gene (18) (Figure 2). Here, SETX is linked to amyotrophic lateral sclerosis type 4.