MAPT and Alzheimer disease: Overall, we did not observe overt microglial activation in FTLD-tau, which may have different neuroinflammatory characteristics than other chronic neurodegenerative diseases associated with tau deposition such as Alzheimer’s disease.23,59 We cannot exclude that at the time of the examination, earlier activation might have resolved, or become impaired or exhausted.23 Nevertheless, interactions between microglia and pTau emphasize a link between them, with FTLD-MAPT potentially having a differential microglial reactivity pattern.