1 Memory and Aging Center (EK, GN, GT, BLM, GDR, LTG) and Multiple Sclerosis and Neuroinflammation Center (SJP, JMG), Department of Neurology, and Department of Pathology and Laboratory Medicine (SA), University of California San Francisco; Neurological Institute of Athens (EK), Greece; and Department of Pathology (LTG), University of São Paulo Medical School, Brazil. S.A. is currently affiliated with Boston Children's Hospital, MA.