Proteomic Analysis of Serum and Cerebrospinal Fluid in Children with Encephalopathy Associated with Human Betaherpesvirus 6B

Background Exanthem subitum (ES), a benign febrile exanthematous disease, is caused by primary human betaherpesvirus 6B (HHV-6B) infection. It may cause neurological complications, including complex febrile seizures (cFS), acute encephalopathy with biphasic seizures, and late reduced diffusion (AESD). cFS resolves spontaneously; however, AESD can pose severe sequelae. We aimed to elucidate AESD pathogenesis using a proteomic analysis. Methods Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), serum and cerebrospinal fluid (CSF) protein profiles were compared between patients with AESD and those with cFS (n = 3 or 4 per group). Metascape was used for enrichment analysis, and the selected proteins were validated using a large sample via enzyme-linked immunosorbent assay (ELISA). Results A total of 698 proteins were identified across all serum and CSF samples using LC-MS/MS. Nineteen serum proteins were differentially expressed in AESD and cFS during the acute phase. The glycolytic pathway was upregulated in AESD. Myristoylated alanine-rich C kinase substrate (MARCKS) and Golgi membrane protein 1 (GOLM1) were selected for validation using ELISA. Both proteins were upregulated during the acute phase (n = 11) compared with the convalescent phase (n = 21) in AESD (MARCKS, P =.016; GOLM1, P <.001). MARCKS during the acute phase was also upregulated in AESD compared with that in uncomplicated ES (n = 15) (P =.015). In CSF, 38 proteins were differentially expressed between AESD and cFS during the acute phase. Cholesteryl ester transfer protein in the CSF of patients with AESD was upregulated; however, this could not be validated using ELISA. Conclusions Glycolysis and MARCKS pathways might be involved in HHV-6B-associated AESD pathogenesis.