GCA+ immune cells, a group of myeloid cells with pro‐inflammatory and pro‐aging properties, accumulate in the bone marrow of aged mice and induce bone aging.[11] Here, we found that GCA was highly expressed in the peripheral macrophages of AD patients and mice, and transplantation of GCA+ immune cells or intracerebral injection of recombinant GCA protein directly aggravated cognitive and memory impairments, whereas deletion of the Gca gene in the hematopoietic cells improved cognitive and memory function. The gene discussed is GCA; the disease is Alzheimer disease.