Summary of clinical information and CNS histopathology based on H&E.

MNGCs: multinucleated giant cells. * rare MNGCs.Objective scoring: Five regions within the H&E section of frontal cortex were examined and scored at 10× magnification using the following criteria for encephalitis, satellitosis, and neurodegeneration. Gliosis scoring was performed on 5–8 H&E brain sections.Encephalitis scoring: Mild- perivascular infiltrated in one brain region; Moderate- perivascular infiltrates in two or more regions plus rare MNGCs; Severe-perivascular infiltrates in all regions and frequent MNGCs.Gliosis scoring: Mild- increased cellularity in white matter in one brain region; Moderate- increased cellularity in white matter in two or three regions plus occasional microglial nodules; Severe- increased cellularity in white matter in all regions with frequent microglial nodules.Satellitosis scoring: Neurons surrounded by 3 or more glial cells are characterized as mild (occasionally occurring); moderate (frequently) and severe (numerous, in addition to clusters of 3 or more glial cells at sites of neuronal drop-out).Neurodegeneration scoring: Mild- occasional angular, shrunken neurons; Moderate- frequent angular, shrunken neurons; Severe- numerous angular, shrunken neurons and neuronal drop-out.