Although not directly linked to AD, the characteristics of primed microglia in individuals with Parkinson’s disease (PD) and dementia with Lewy bodies (DLB) suggest variations in the secretion of cytokines and neurotrophins, potentially resulting in neuroprotective effects in PD and neurotoxic effects in DLB (Imamura et al., 2005). Here, BDNF is linked to Parkinson disease.