IL34 and neurodegenerative disease: Despite the microglial population was not affected after systemic administration of anti-IL-34 antibodies, due to their low brain penetrance, we observed a local reduction of microglia proliferation after the intracerebral injection of anti-IL-34 antibodies in mice infected with prion disease, showing that IL-34 is a key driver of microglial proliferation in the context of neurodegenerative disease (Obst et al., 2020).