CD44 and Alzheimer disease: Expression of CD44 has also been described in activated CD11b+ microglia both in vitro, upon LPS challenge [49], and in vivo, in experimental models of different neurologic diseases, such as ischemic stroke [50,51], ALS [52], optic nerve crush [53], cerebral cortex injury [53], EAE, AD, frontotemporal dementia [54], aging [38], and spinal cord injury [55].