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.多核巨细胞（multinucleated giant cells，MNGCs）：* 罕见多核巨细胞。 目标评分：对额叶皮层的苏木精-伊红（H&E）切片中的5个区域进行检查，以10倍放大倍率，针对脑炎、卫星现象及神经变性采用以下标准进行评分。胶质增生评分则基于5~8份脑部H&E染色切片完成。 脑炎评分：轻度：单一大脑区域出现血管周围浸润；中度：两个及以上大脑区域存在血管周围浸润，且伴罕见多核巨细胞；重度：所有大脑区域均出现血管周围浸润，且多核巨细胞频发。 胶质增生评分：轻度：单一大脑区域白质细胞密度升高；中度：2~3个大脑区域白质细胞密度升高，且偶见小胶质细胞结节；重度：所有大脑区域白质细胞密度均升高，且小胶质细胞结节频发。 卫星现象评分：神经元被3个及以上胶质细胞包绕，若仅偶尔出现则判定为轻度；频繁出现为中度；大量出现且伴神经元脱失区域出现3个及以上胶质细胞簇则为重度。 神经变性评分：轻度：偶见角形皱缩神经元；中度：频发角形皱缩神经元；重度：大量出现角形皱缩神经元，且伴神经元脱失。