Early autoimmunity and outcome in virus encephalitis: a retrospective study based on tissue-based assay.

To explore the autoimmune response and outcome in the central nervous system (CNS) at the onset of viral infection and correlation between autoantibodies and viruses. METHODS: A retrospective observational study was conducted in 121 patients (2016-2021) with a CNS viral infection confirmed via cerebrospinal fluid (CSF) next-generation sequencing (cohort A). Their clinical information was analysed and CSF samples were screened for autoantibodies against monkey cerebellum by tissue-based assay. In situ hybridisation was used to detect Epstein-Barr virus (EBV) in brain tissue of 8 patients with glial fibrillar acidic protein (GFAP)-IgG and nasopharyngeal carcinoma tissue of 2 patients with GFAP-IgG as control (cohort B). RESULTS: Among cohort A (male:female=79:42; median age: 42 (14-78) years old), 61 (50.4%) participants had detectable autoantibodies in CSF. Compared with other viruses, EBV increased the odds of having GFAP-IgG (OR 18.22, 95% CI 6.54 to 50.77, p<0.001). In cohort B, EBV was found in the brain tissue from two of eight (25.0%) patients with GFAP-IgG. Autoantibody-positive patients had a higher CSF protein level (median: 1126.00 (281.00-5352.00) vs 700.00 (76.70-2899.00), p<0.001), lower CSF chloride level (mean: 119.80±6.24 vs 122.84±5.26, p=0.005), lower ratios of CSF-glucose/serum-glucose (median: 0.50[0.13-0.94] vs 0.60[0.26-1.23], p=0.003), more meningitis (26/61 (42.6%) vs 12/60 (20.0%), p=0.007) and higher follow-up modified Rankin Scale scores (1 (0-6) vs 0 (0-3), p=0.037) compared with antibody-negative patients. A Kaplan-Meier analysis revealed that autoantibody-positive patients experienced significantly worse outcomes (p=0.031). CONCLUSIONS: Autoimmune responses are found at the onset of viral encephalitis. EBV in the CNS increases the risk for autoimmunity to GFAP.

Serological biomarkers in autoimmune GFAP astrocytopathy.

Autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) is a newly defined meningoencephalomyelitis. The pathogenesis of GFAP-A is not well understood. The present study measured the expression levels of 200 serological cytokines in GFAP-A patients, NMOSD patients and healthy controls (HCs). The correlations between serum cytokine levels and clinical information in GFAP-A patients were analyzed. A total of 147 serological proteins were differentially expressed in GFAP-A patients compared to HCs, and 33 of these proteins were not observed in NMOSD patients. Serum levels of EG-VEGF negatively correlated with GFAP antibody titers, MIP-3 alpha positively correlated with clinical severity in GFAP-A patients, and LIGHT positively correlated with WBC counts and protein levels in the CSF of GFAP-A patients. These results suggest that GFAP and AQP4 astrocytopathy share some common pathology related to TNF signaling. Serum MIP 3 alpha may be a biomarker to assess clinical severity and a potential target for therapy of autoimmune GFAP astrocytopathy.

Silencing the NR2B gene in rat ACC neurons by lentivirus-delivered shRNA alleviates pain-related aversion.

The N-methyl-D-aspartate (NMDA) receptor NR2B subunit on neurons in the anterior cingulate cortex (ACC) is implicated in the affective response to noxious stimuli. Selectively silencing this NR2B subunit in ACC neurons could therefore alleviate pain-related aversion. However, to date, there is no optimal approach to selectively silence the NR2B gene in ACC neurons. In the present study, we constructed lentiviral vectors and delivered shRNA (NR2B-RNAi-LV) to effectively silence the NR2B gene in ACC neurons. The use of lentivirus resulted in 95% transfection efficiency and 83% silencing of the NR2B gene in ACC neurons. Electrophysiological experiments showed that the total INMDA was similarly reduced by 48% in lentivirus-transfected ACC neurons. The biochemical and functional data demonstrated that lentiviral shRNA delivery produced a high transfection and silencing efficiency in the ACC neurons. SNI rats weighting 220-250 g were randomly divided into three groups: normal saline group (NS), lenti-siRNA/NC (LV-NC) group, and lenti-siRNA/NR2B (LV-NR2B) group, and conditioned place avoidance was conducted. The results indicated that NR2B-RNAi-LV decreased greatly the conditioning scores of F-CPA while NC-GFP-LV has no effects. NR2B mRNA expression in the NR2B-RNAi-LV group was significantly lower than that in the control group and NC-GFP-LV group. This novel approach of silencing the NR2B gene in ACC neuron could potentially be used to alleviate pain-related aversion.