In this study, we found that compared with the ND group, the AD group had significant changes in the proportion of immune cell infiltration, including macrophage, regulatory T cell, activated CD8 T cell, memory B cell, activated dendritic cell, activated CD4 T cell, natural killer T cell, type 17 T helper cell, Neutrophil, MDSC. The gene discussed is CD4; the disease is Alzheimer disease.