Notably, only the effector memory CD4 T cells and eosinophils showed significantly reduced infiltration in AD samples (P < 0.05), while the remaining 17 cell types, such as activated CD8 T cells, central memory CD8 T cells, and central memory CD4 T cells, exhibited increased infiltration in AD (P < 0.05), suggesting an activated immune state in AD patients (Fig. 6B). Here, CD4 is linked to Alzheimer disease.