CD4 and Cognitive impairment: At these ages animals underwent motor and cognitive assessment, followed by assessment of the peripheral immune response using flow cytometry and analysis of microglial transcriptional profiles by bulk RNA sequencing.<h4>Results</h4>Male 3KL mice exhibited earlier onset and greater severity of motor and cognitive impairments, which was linked to a pro-inflammatory peripheral immune profile marked by increased cytotoxic CD8+ T cells and IFNγ-producing CD4 Th1 cells.