GCA and memory impairment: 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.