The hub genes (BHLHE40, CASP4, PKM, SERPINB1, TLR2, VEGFA) were correlated with a variety of invading immune cells, suggesting the involvement of numerous immune cells, including CD56dim natural killer cells, central memory CD4+ T cells, activated B cells, type 1 T helper cells, and natural killer T cells, in the development of AD. Here, CASP4 is linked to Alzheimer disease.