Aging gene signature of IL-7 receptor alpha low effector memory CD8 T cells is associated with neurocognitive functioning in Alzheimer's disease.

CD45RA effector memory (EM) CD8 T cell expansion was reported in Alzheimer's disease (AD). Such cells are IL-7 receptor alpha (IL-7Rα) EM CD8 T cells, which expand with age and have a unique aging gene signature (i.e., IL-7Rα aging genes). Here we investigated whether IL-7Rα aging genes and previously reported AD and memory (ADM) genes overlapped with clinical significance in AD patients. RT-qPCR analysis of 40 genes, including 29 ADM, 9 top IL-7Ra aging and 2 control genes, showed 8 differentially expressed genes between AD and cognitively normal groups; five (62.5%) of which were top IL-7Rα aging genes. Over-representation analysis revealed that these genes were highly present in molecular and biological pathways associated with AD. Distinct expression levels of these genes were associated with neuropsychological testing performance in 3 subgroups of dementia participants. Our findings support the possible implication of the IL-7Rα aging gene signature with AD.