MAPT and Alzheimer disease: There were more phospho‐tau (pT231)‐positive neurons in both the neocortex and hippocampus in AD mice underwent splenectomy than in sham mice (t = 3.74, p = 0.0025 for the neocortex; t = 2.73, p = 0.017 for the hippocampus; Figure 5c).