Compared with sham control mice, AD mice underwent splenectomy exhibited more astrocytes in the neocortex, more total microglia in both the neocortex and hippocampus, and more activated microglia in the neocortex (p < 0.05 for all data, Figure 5a, b), and increased levels of proinflammatory factors, including TNF‐α and IL‐6 (t = 2.98, p = 0.011 for TNF‐α; t = 2.46, p = 0.029 for IL‐6; Figure 5g). This evidence concerns the gene IL6 and Alzheimer disease.