Via ScienceDaily, more evidence that your immune system fights the onset of Alzheimer's - which lends further support to those working on vaccines and other immunotherapies: "Our results provide in vivo evidence that the brain's immune system plays a protective role in early Alzheimer's disease by mediating the clearance of amyloid-beta ... While it has been known that the immune system reacts against amyloid-beta in the brain, the relation of that response to the pathology of Alzheimer's disease has not been clear. ... The current study was designed to clarify the role of microglia in Alzheimer's and identify factors involved in the immune cells' accumulation at amyloid plaques. ... lack of a protein required for recruitment of the brain's primary immune cell led to increased amyloid-beta deposits and earlier death in a mouse model of Alzheimer's disease. ... By showing that microglia have a protective role in helping remove amyloid-beta from the brain, our findings suggest that enhancing the accumulation of these cells may be beneficial to patients with early-stage Alzheimer's disease."