A number of previously identified microglial-specific markers, such as TMEM119, show reduced immunoreactivity in disease [103,104] and are expressed by peripheral-derived cells that enter the brain under pathological conditions such as ischemic stroke, EAE, MS, 6-OHDA [105,106,107], which we further demonstrated in our own work following focal traumatic cortical impact injury [108]. Here, TMEM119 is linked to myeloid sarcoma.