FCGR1A and dementia: Among participants without dementia, the significant relationships observed between microglia and Alzheimer’s neuropathology were mainly negative, except for diffuse plaques which were positively related with four of the five microglial markers (Iba1, CD68, HLA-DR, CD64: P < 0.001) and Iba1 with neuritic plaques (P = 0.003) (Table 6A).