The distribution of microglia was similar in the TC and CB from AD and control brains (Table 2; Additional file 1: Figure S5). The proportion of microglia was lower than any other cell types. The Mayo dataset also includes brains from individuals with PA (Table 1); which is neuropathologically defined by amyloid-beta (Aβ) senile plaque deposits but little or no neurofibrillary tau pathology [18, 63]. We observed a significant lower relative proportion of microglia in PA brains compared to AD in both TC and CB (Additional file 1: Table S7; Additional file 1: Figure S6). Therefore, we speculated that the lack of changes in the AD microglial population was neither due to low statistical power nor the inability of our method to estimate the microglial proportions but reflected unaltered neuropathological observations in AD brains.
