[1] Brigham & Womens Hosp, Harvard Inst Med, Ctr Neurol Dis, Boston, MA 02115 USA
[2] Vet Affairs Med Ctr, Lab Serv, Palo Alto, CA 94304 USA
[3] Stanford Univ, Sch Med, Dept Pathol, Stanford, CA 94305 USA
[4] Harvard Univ, Sch Med, Dept Pathol, Boston, MA 02115 USA