TLR4 and Alzheimer disease: Moreover, an additional target identified in the early stage of AD is represented by Toll-Like Receptor 4 (TLR4);4,5 it is widely reported that microglia activation via TLR4 is closely associated to a number of neurodegenerative disorders including AD and ischemic stroke.6 In the senile plaques observed in the brain of AD patients, microglia is present in an activated state, and it is considered important in the pathogenesis of the disease.