Long-term sequelae after viral meningitis and meningoencephalitis are frequent, even in mildly affected patients, a prospective observational study.

Introduction: An increasing number of studies demonstrate that viral meningitis and meningoencephalitis, even those with a mild course of meningitis, can result in residual sequelae. Methods: We aimed to investigate the long-term outcome in both viral meningitis and meningoencephalitis/encephalitis patients and impact of long-term sequelae on patients' social and professional daily lives in a prospective observational study with a follow-up period of 20 months. Results: A total of 50 patients (12% encephalitis, 58% meningoencephalitis and 30% meningitis) and 21 control persons participated in the study. The most common cause was the tick-borne encephalitis (TBE) virus. The most important persistent signs and symptoms after 2 years were subjective cognitive impairment (36%), fatigue and/or excessive daytime sleepiness (31%), disturbed nighttime sleep (31%) and headaches (13%), as well as feeling more rapidly exhausted after cognitive effort (53%). Independent of disease severity in the acute phase, almost one third of patients still reported mildly impaired social and/or professional life due to the long-term sequelae, with scores in the health status assessment still significantly lower compared to healthy controls. Discussion: Regardless of the severity of the acute illness and despite constant improvement within 2 years, 67% of patients still had persistent signs and symptoms, but these were only relevant to everyday social or professional life in about 30% of these patients.

[Dengue encephalitis in Argentina]. / Encefalitis por dengue en Argentina.

Dengue virus is an endemic virus in Argentina that, although it was initially considered to be non-neurotropic, it is currently recognized to be neuroinvasive; thus conditioning a prevalence of neurological manifestations of up to 15% among patients. Even being considered severe symptoms, there is underdiagnoses of dengue encephalitis due to its varied clinical presentation. Neurological manifestations of dengue encephalitis can range from fever and headache to altered levels of consciousness and seizures. Although the cerebrospinal fluid may be normal in up to a third of cases, it usually presents increased protein concentration and pleocytosis. Regarding neuroimaging methods, the findings are usually varied and nonspecific, and can even be normal in up to 40-50% of cases. We present three cases of dengue encephalitis diagnosed in a university hospital in Buenos Aires, Argentina, where the clinical presentation varied from temporal-spatial disorientation to refractory convulsive status with different presentations in the cerebrospinal fluid but all with positive PCR for dengue in it and with normal neuroimaging.

El virus dengue es un virus endémico en Argentina que, si bien inicialmente se consideró que no era neurotrópico, actualmente se reconoce que tiene neuroinvasión, condicionando así una prevalencia de manifestaciones neurológicas de hasta el 15% entre los enfermos. Aun siendo considerados síntomas de gravedad, existe subdiagnóstico de encefalitis por dengue debido a su variada forma de presentación clínica. Las manifestaciones neurológicas de la encefalitis por dengue pueden abarcar desde fiebre y cefalea hasta alteraciones del nivel de conciencia y convulsiones. Si bien el líquido cefalorraquídeo (LCR) puede hallarse normal en hasta un tercio de los casos, lo habitual es que presente aumento de concentración de proteínas y pleocitosis. En cuanto a los métodos de neuroimagen, los hallazgos suelen ser variados e inespecíficos, e incluso pueden ser normales hasta en 40-50% de los casos. Se presentan 3 casos de encefalitis por dengue diagnosticados en un hospital universitario de Buenos Aires, Argentina, en donde la presentación clínica varió desde desorientación témporo-espacial hasta estatus convulsivo refractario con diferentes presentaciones en el LCR pero todos con PCR positivo para dengue y con neuroimágenes sin alteraciones.

Clinical features and prognostic model for viral encephalitis after allogeneic haematopoietic stem cell transplantation.

The objective of this study was to identify independent prognostic factors of viral encephalitis (VE) after allogeneic haematopoietic stem cell transplantation (allo-HSCT) and establish a prognostic model to identify post-transplant VE patients with a greater likelihood of mortality. Among 5380 patients in our centre from 2014 to 2022, 211 patients who developed VE after allo-HSCT were reviewed in this retrospective study. Prognostic factors were selected, and a prognostic model was constructed using Cox regression analysis. The model was subsequently validated and estimated using the area under the receiver operating characteristic curve (AUC), a calibration plot and decision curve analysis (DCA). Glasgow Coma Scale score <9, lesions >3 lobes on magnetic resonance imaging and severe thrombocytopenia were identified as independent prognostic risk factors for VE patients who underwent allo-HSCT. The prognostic model GTM (GTM is an abbreviation for a model composed of three risk factors: GCS score <9, severe thrombocytopenia [platelet count <20 000 per microliter], and lesions >3 lobes on MRI) was established according to the regression coefficients. The validated internal AUC was 0.862 (95% confidence interval [CI], 0.773-0.950), and the external AUC was 0.815 (95% CI, 0.708-0.922), indicating strong discriminatory ability. Furthermore, we constructed calibration plots that demonstrated good consistency between the predicted outcomes and the observed outcomes. DCA exhibited high accuracy in this system, leading to potential benefits for patients.

Type 2 herpes simplex virus-induced anti-N-methyl-D-aspartate receptor encephalitis responsive to immunoglobulin monotherapy.

Herpes simplex virus-2 encephalitis (HSV2E) in immunocompetent adults is exceptionally rare, and the subsequent onset of autoimmune encephalitis after HSV2E is even less common. This report presents the inaugural Chinese case of anti-N-methyl-D-aspartate receptor encephalitis (NMDARE) induced by HSV2E, confirmed via metagenomic next-generation sequencing (mNGS). The patient demonstrated a favorable response to intravenous immunoglobulin (IVIG) monotherapy. This case emphasizes the importance of considering autoimmune encephalitis in patients exhibiting new or recurrent neurological symptoms after HSV2E recovery. Comprehensive mNGS and neuronal antibody testing are essential for timely diagnosis. Moreover, IVIG monotherapy can serve as an effective treatment for NMDARE induced by HSV2, providing a viable alternative, particularly when steroid therapy is contraindicated.

Western equine encephalitis: a pediatric case report. / Encefalitis equina del oeste: a propósito de un caso pediátrico.

Western equine encephalitis (WEE) is a zoonotic disease caused by an RNA virus of the genus Alphavirus, and humans are accidental hosts. Although most patients do not develop symptoms upon infection, children are at higher risk for neurological involvement. Here we describe the case of a previously healthy 13-year-old male patient who lived in an urban area in the province of Buenos Aires, Argentina, who was hospitalized and diagnosed with meningoencephalitis. Due to the torpid course of his condition and because none of the most frequent microorganisms were isolated, a test for IgG antibodies for WEE virus in blood and cerebrospinal fluid was requested; both samples were positive. WEE virus is often an underdiagnosed cause of encephalitis and should be taken into consideration in both rural and urban areas.

La encefalitis equina del oeste (EEO) es una zoonosis causada por un virus ARN del género Alphavirus, del cual los humanos son huéspedes accidentales. Aunque la mayoría de los pacientes no desarrollan síntomas al infectarse, los niños tienen mayor riesgo de presentar compromiso neurológico. Presentamos el caso de un paciente de sexo masculino de 13 años de edad, previamente sano, residente de un área urbana de la provincia de Buenos Aires, Argentina, quien se internó con diagnóstico de meningoencefalitis. Por presentar evolución tórpida y, al no haber obtenido rescate microbiológico para los gérmenes más frecuentes, se solicitó la detección de anticuerpos IgG para el virus de EEO en sangre y en líquido cefalorraquídeo, ambos con resultado positivo. El virus de la EEO suele ser causa subdiagnosticada de encefalitis y debe ser considerado tanto en zonas rurales como urbanas.

Evolution from viral encephalitis to autoimmune encephalitis to multiple sclerosis: a case report.

BACKGROUND: There are established associations between viral and autoimmune encephalitis as well as between autoimmune encephalitis and demyelinating central nervous system (CNS) diseases. Here, we report the evolution from varicella zoster virus (VZV) encephalitis to limbic autoimmune encephalitis (AIE) to multiple sclerosis (MS) in one patient. CASE REPORT: A woman in her mid-thirties presented with headache, aphasia, and a generalized tonic-clonic seizure. Cerebrospinal fluid (CSF) VZV polymerase chain reaction was positive and treatment with acyclovir was administered for VZV encephalitis. Five months later, the patient presented with cognitive deficits and MRI showed new bilateral hippocampal T2-hyperintensities. CSF analyses revealed pleocytosis and neuropil antibodies in tissue-staining. A diagnosis of limbic AIE was established and treatment with IV steroids and IV immunoglobulins initiated. One year later, the patient developed paresthesia of both legs and magnetic resonance imaging studies now showed new supratentorial and spinal demyelinating lesions. The patient was diagnosed with MS and treatment was changed to rituximab. CONCLUSIONS: This unique case report links three important neuroimmunological entities in characterizing the evolution from infectious to autoimmune encephalitis to multiple sclerosis in one patient. Identification of such rare clinical constellations is critical for correct treatment choice and provides important novel insights into the pathophysiology of neuroimmunological disorders including viral triggers and overlap manifestations of autoimmune CNS diseases.

An Interesting Case of Coronavirus NL63 Encephalitis Diagnosed in a 14-Year-Old Immunocompetent Female: A Case Report and Literature Review.

Human coronavirus NL63 (HCoV-NL63) belongs to the human coronavirus family but is distinct from other common coronaviruses such as HCoV-043, HCoV-229E, and SARS-CoV-1 and SARS-CoV-2 viruses. It causes a mild upper respiratory tract infection, affecting children and adults. The usual symptoms associated with the HCoV-NL63 infection are vomiting, a runny nose, and a sore throat. In vivo, HCoV-NL63 showed neurotropism as it can be detected in the CSF, through which it disseminates into the brain and the spinal column. Herein, we describe the case of a 14-year-old female patient who initially presented with disorientation and a drop in consciousness level and was admitted as a case of encephalitis to the pediatric intensive care unit.

Chemokine-mediated cell migration into the central nervous system in progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) has been associated with different forms of immune compromise. This study analyzes the chemokine signals and attracted immune cells in cerebrospinal fluid (CSF) during PML to define immune cell subpopulations relevant for the PML immune response. In addition to chemokines that indicate a general state of inflammation, like CCL5 and CXCL10, the CSF of PML patients specifically contains CCL2 and CCL4. Single-cell transcriptomics of CSF cells suggests an enrichment of distinct CD4+ and CD8+ T cells expressing chemokine receptors CCR2, CCR5, and CXCR3, in addition to ITGA4 and the genetic PML risk genes STXBP2 and LY9. This suggests that specific immune cell subpopulations migrate into the central nervous system to mitigate PML, and their absence might coincide with PML development. Monitoring them might hold clues for PML risk, and boosting their recruitment or function before therapeutic immune reconstitution might improve its risk-benefit ratio.

Differentiation between viral and autoimmune limbic encephalitis: a prospective cohort study with development and validation of a diagnostic model.

BACKGROUND: Distinguishing between viral encephalitis (VE) and autoimmune limbic encephalitis (ALE) presents a clinical challenge due to the overlap in symptoms. We aimed to develop and validate a diagnostic prediction model to differentiate VE and ALE. METHODS: A prospective observational multicentre cohort study, which continuously enrolled patients diagnosed with either ALE or VE from October 2011 to April 2023. The demographic data, clinical features, and laboratory test results were collected and subjected to logistic regression analyses. The model was displayed as a web-based nomogram and then modified into a scored prediction tool. Model performance was assessed in both derivation and external validation cohorts. RESULTS: A total of 2423 individuals were recruited, and 1001 (496 VE, 505 ALE) patients were included. Based on the derivation cohort (389 VE, 388 ALE), the model was developed with eight variables including age at onset, acuity, fever, headache, nausea/vomiting, psychiatric or memory complaints, status epilepticus, and CSF white blood cell count. The model showed good discrimination and calibration in both derivation (AUC 0.890; 0.868-0.913) and external validation (107 VE, 117 ALE, AUC 0.872; 0.827-0.917) cohorts. The scored prediction tool had a total point that ranged from - 4 to 10 also showing good discrimination and calibration in both derivation (AUC 0.885, 0.863-0.908) and external validation (AUC 0.868, 0.823-0.913) cohorts. CONCLUSIONS: The prediction model provides a reliable and user-friendly tool for differentiating between the VE and ALE, which would benefit early diagnosis and appropriate treatment and alleviate economic burdens on both patients and society.

Nipah virus-associated neuropathology in African green monkeys during acute disease and convalescence.

BACKGROUND: Nipah virus is an emerging zoonotic virus that causes severe respiratory disease and meningoencephalitis. The pathophysiology of Nipah virus meningoencephalitis is poorly understood. METHODS: We have collected the brains of African green monkeys during multiple Nipah virus, Bangladesh studies, resulting in 14 brains with Nipah virus-associated lesions. RESULTS: The lesions seen in the brain of African green monkeys infected with Nipah virus, Bangladesh were very similar to those observed in humans with Nipah virus, Malaysia infection. We observed viral RNA and antigen within neurons and endothelial cells, within encephalitis foci and in uninflamed portions of the CNS. CD8+ T cells had a consistently high prevalence in CNS lesions. We developed a UNet model for quantifying and visualizing inflammation in the brain in a high-throughput and unbiased manner. While CD8+ T cells had a consistently high prevalence in CNS lesions, the model revealed that CD68+ cells were numerically the immune cell with the highest prevalence in the CNS of NiV-infected animals. CONCLUSION: Our study provides an in-depth analysis on Nipah virus infection in the brains of primates, and similarities between lesions in patients and the animals in our study validate this model.

Varicella-zoster virus-related neurological complications: From infection to immunomodulatory therapies.

The Varicella-zoster virus (VZV), classified as a neurotropic member of the Herpesviridae family, exhibits a characteristic pathogenicity, predominantly inducing varicella, commonly known as chickenpox, during the initial infectious phase, and triggering the reactivation of herpes zoster, more commonly recognized as shingles, following its emergence from a latent state. The pathogenesis of VZV-associated neuroinflammation involves a complex interplay between viral replication within sensory ganglia and immune-mediated responses that contribute to tissue damage and dysfunction. Upon primary infection, VZV gains access to sensory ganglia, establishing latent infection within neurons. During reactivation, the virus can spread along sensory nerves, triggering a cascade of inflammatory mediators, chemokines, and immune cell infiltration in the affected neural tissues. The role of both adaptive and innate immune reactions, including the contributions of T and B cells, macrophages, and dendritic cells, in orchestrating the immune-mediated damage in the central nervous system is elucidated. Furthermore, the aberrant activation of the natural defence mechanism, characterised by the dysregulated production of immunomodulatory proteins and chemokines, has been implicated in the pathogenesis of VZV-induced neurological disorders, such as encephalitis, myelitis, and vasculopathy. The intricate balance between protective and detrimental immune responses in the context of VZV infection emphasises the necessity for an exhaustive comprehension of the immunopathogenic mechanisms propelling neuroinflammatory processes. Despite the availability of vaccines and antiviral therapies, VZV-related neurological complications remain a significant concern, particularly in immunocompromised individuals and the elderly. Elucidating these mechanisms might facilitate the emergence of innovative immunomodulatory strategies and targeted therapies aimed at mitigating VZV-induced neuroinflammatory damage and improving clinical outcomes. This comprehensive understanding enhances our grasp of viral pathogenesis and holds promise for pioneering therapeutic strategies designed to mitigate the neurological ramifications of VZV infections.

Serum mir-142-3p release in children with viral encephalitis and its relationship with nerve injury and inflammatory response.

BACKGROUND: Viral encephalitis (VE) is a common infectious disease of the central nervous system in children. Children with severe disease may have progressive neurological damage and even lead to death. AIMS: To assess the serum miR-142-3p levels in children with VE and the correlation between miR-142-3p and the severity and prognosis of VE. Besides, its relationship with nerve injury and inflammatory response was assessed. METHODS: Children with VE were regarded as a case group and healthy children served as control. The content of serum miR-142-3p was determined using real-time quantitative PCR. The risk factors associated with severity and prognosis of cases were evaluated using logistic analysis. The discrepancy in miR-142-3p levels, nerve injury-related indicators, and inflammatory cytokines were contrasted among groups. The ROC curve was conducted to assess the diagnostic performance of serum miR-142-3p in predicting prognosis of children with VE. RESULTS: The altered expression of miR-142-3p in serum of children with VE was enhanced in contrast to healthy control. Serum nerve injury indicators MBP, ß-EP, and NSE levels and serum inflammatory cytokines IL-6, IL-18, and IFN-γ were high in children with VE in contrast to healthy control, and had positive relevance with serum miR-142-3p. Besides, serum miR-142-3p was a risk factor associated with the severity and prognosis of children with VE. Serum miR-142-3p had diagnostic performance in predicting the prognosis of children with VE. CONCLUSION: Serum miR-142-3p content is high in children with VE and maybe a diagnosis marker for predicting prognosis. The specific miR-142-3p expression may be directly related to the severity of nerve injury and inflammatory response for VE.

Phenotypic and transcriptional changes in peripheral blood mononuclear cells during alphavirus encephalitis in mice.

Sindbis virus (SINV) infection of mice provides a model system for studying the pathogenesis of alphaviruses that infect the central nervous system (CNS) to cause encephalomyelitis. While studies of human viral infections typically focus on accessible cells from the blood, this compartment is rarely evaluated in mice. To bridge this gap, single-cell RNA sequencing (scRNAseq) was combined with flow cytometry to characterize the transcriptional and phenotypic changes of peripheral blood mononuclear cells (PBMCs) from SINV-infected mice. Twenty-one clusters were identified by scRNAseq at 7 days after infection, with a unique cluster and overall increase in naive B cells for infected mice. Uninfected mice had fewer immature T cells and CCR9+ CD4 T cells and a unique immature T cell cluster. Gene expression was most altered in the Ki67+ CD8 T cell cluster, with chemotaxis and proliferation-related genes upregulated. Global analysis indicated metabolic changes in myeloid cells and increased expression of Ccl5 by NK cells. Phenotypes of PBMCs and cells infiltrating the CNS were analyzed by flow cytometry over 14 days after infection. In PBMCs, CD8 and Th1 CD4 T cells increased in representation, while B cells showed a transient decrease at day 5 in total, Ly6a+, and naive cells, and an increase in activated B cells. In the brain, CD8 T cells increased for the first 7 days, while Th1 CD4 T cells and naive and Ly6a+ B cells continued to accumulate for 14 days. Therefore, dynamic immune cell changes can be identified in the blood as well as the CNS during viral encephalomyelitis. IMPORTANCE: The outcome of viral encephalomyelitis is dependent on the host immune response, with clearance and resolution of infection mediated by the adaptive immune response. These processes are frequently studied in mouse models of infection, where infected tissues are examined to understand the mechanisms of clearance and recovery. However, studies of human infection typically focus on the analysis of cells from the blood, a compartment rarely examined in mice, rather than inaccessible tissue. To close this gap, we used single-cell RNA sequencing and flow cytometry to profile the transcriptomic and phenotypic changes of peripheral blood mononuclear cells (PBMCs) before and after central nervous system (CNS) infection in mice. Changes to T and B cell gene expression and cell composition occurred in PBMC and during entry into the CNS, with CCL5 being a differentially expressed chemokine. Therefore, dynamic changes occur in the blood as well as the CNS during the response of mice to virus infection, which will inform the analysis of human studies.

Validation of a risk score to differentiate autoimmune and viral encephalitis: a Nationwide Cohort Study in Denmark.

BACKGROUND: A score to differentiate autoimmune (AE) and viral encephalitis (VE) early upon admission has recently been developed but needed external validation. The objective of this study was to evaluate the performance of the score in a larger and more diagnostically diverse patient cohort. METHODS: We conducted a retrospective nationwide and population-based cohort study including all adults with encephalitis of definite viral (2015-2022) or autoimmune aetiology (2009-2022) in Denmark. Variables included in the score-model were extracted from patient records and individual risk scores were assessed. The performance of the score was assessed by receiver-operating characteristics (ROC) curve analyses and calculation of the area under the curve (AUC). RESULTS: A total of 496 patients with encephalitis [AE n = 90, VE n = 287 and presumed infectious encephalitis (PIE) n = 119] were included in the study. The score was highly accurate in predicting cases of AE reaching an AUC of 0.94 (95% CI 0.92-0.97). Having a score ≥ 3 predicted AE with a PPV of 87% and an NPV of 91%. The risk score was found to perform well across aetiological subgroups and applied to the PIE cohort resulted in an AUC of 0.88 (95% CI 0.84-0.93). CONCLUSION: The excellent performance of the score as reported in the development study was confirmed in this significantly larger and more diverse cohort of patients with encephalitis in Denmark. These results should prompt further prospective testing with wider inclusion criteria.

Tenascin-C in patients with central nervous system infections.

BACKGROUND: The extracellular matrix protein tenascin-C has been discovered to be an important regulator of the response to tissue injury and repair in cerebrovascular diseases. This study investigated if tenascin-C is released in response to infections in the central nervous system (CNS). METHODS: Tenascin-C concentration in the cerebrospinal fluid (CSF) was measured in patients, (>18 years) with and without CNS infections, admitted to a department of infectious diseases in Denmark. CSF tenascin-C was measured on the Meso-scale platform. RESULTS: 174 patients were included of which 140 were diagnosed with a CNS infection and 34 where this was ruled out (control group). Median CSF tenascin-C levels were significantly higher among patients with bacterial meningitis (147 pg/mL), viral meningitis (33 mg/mL), viral encephalitis (39 pg/mL) and Lyme neuroborreliosis (45 pg/mL) when compared to controls (21 pg/mL). Correlations between tenascin-C and CSF markers of inflammation and age were only moderate. CONCLUSION: Levels of CSF tenascin-C are higher among patients with bacterial and viral neuroinfections, already on admission, but exhibit only a modest correlation with baseline indices of neuroinflammation. CSF tenascin-C is highest among patients with bacterial meningitis compared to the other CNS infections. Patients with unfavorable outcomes presented with higher median CSF tenascin-C than their counterparts.

Development of a High-throughput Sequencing Platform for Detection of Viral Encephalitis Pathogens Based on Amplicon Sequencing.

Objective: Viral encephalitis is an infectious disease severely affecting human health. It is caused by a wide variety of viral pathogens, including herpes viruses, flaviviruses, enteroviruses, and other viruses. The laboratory diagnosis of viral encephalitis is a worldwide challenge. Recently, high-throughput sequencing technology has provided new tools for diagnosing central nervous system infections. Thus, In this study, we established a multipathogen detection platform for viral encephalitis based on amplicon sequencing. Methods: We designed nine pairs of specific polymerase chain reaction (PCR) primers for the 12 viruses by reviewing the relevant literature. The detection ability of the primers was verified by software simulation and the detection of known positive samples. Amplicon sequencing was used to validate the samples, and consistency was compared with Sanger sequencing. Results: The results showed that the target sequences of various pathogens were obtained at a coverage depth level greater than 20×, and the sequence lengths were consistent with the sizes of the predicted amplicons. The sequences were verified using the National Center for Biotechnology Information BLAST, and all results were consistent with the results of Sanger sequencing. Conclusion: Amplicon-based high-throughput sequencing technology is feasible as a supplementary method for the pathogenic detection of viral encephalitis. It is also a useful tool for the high-volume screening of clinical samples.

EBV-associated CNS infection in an immunocompetent adult: A case report and literature review.

EBV infections rarely cause CNS involvement. For young adult patients with suspected CNS infection, bacterial and other common viral infections should be excluded first and treated empirically until proven otherwise. Challenges in diagnosing EBV-associated CNS infection, emphasizing the role of CSF PCR in confirming the diagnosis.

The prognostic value of the NPT test combined with amplitude integrated electroencephalogram in children with VE and its bioreliability analysis.

Background: Viral encephalitis (VE) is one of the common diseases of children with intracranial infection, it has come on urgent, progress is fast, and the clinical features of severe cases may even lead to disability, death, and other serious adverse prognostic outcomes, so seek in early diagnosis and prognosis of efficiency of the relevant indicators to stop in time and take effective means to prevent the further development is of great significance. Neopterin (NPT), as a factor that plays an important role in the process of validation development, has been relatively rarely studied in children with VE. Methods: In this study, 127 cases of children with VE were retrieved from the TCGA database by bioinformatics, and their amplitude integrated electroencephalogram (AEEG) related information was collected at the same time. The neurodevelopmental status of VE children was evaluated according to the Gesell scale and divided into the good group (n=88) and the poor group (n=39). The differences in NPT expression and AEEG score between them were observed. In addition, the clinical data of 100 children without VE were screened from the database, and the differences in NPT expression and AEEG score between VE children and non-VE children were compared. The ROC curve was used to evaluate the clinical efficacy of NPT combined with AEEG in diagnosis and prognosis prediction. Kaplan-Meier was used to observe the effect of NPT high expression and low expression on poor prognosis of VE children.

Blood and CSF findings of cellular immunity in anti-NMDAR encephalitis.

OBJECTIVES: To investigate the immunopathogenic mechanisms of anti-N-methyl-D-aspartate receptor encephalitis (NMDAR-E) by characterizing the changes of immune cells in both peripheral blood (PB) and cerebrospinal fluid (CSF) of patients with NMDAR-E. METHODS: Cytology and flow cytometry were used to explore and compare different immunological parameters in PB and CSF of patients with NMDAR-E, viral encephalitis (VE) and healthy volunteers. Moreover, different models were established to assess the possibility of identifying NMDAR-E patients based on PB and CSF parameters. RESULTS: The neutrophil counts and monocyte-to-lymphocyte ratios (MLR) in PB are higher in NMDAR-E patients than in both VEs and controls (P < 0.001, respectively), while the percentages of CD3 + T, CD4 + T lymphocytes, and the leukocytes count in CSF were lower in NMDAR-Es than in VEs (P < 0.01, respectively). The higher percentages of CD8 + T cells in blood and CSF were both correlated with more severe NMDAR-E (P < 0.05, respectively). The poor neurological status group had significantly higher PB leukocytes but lower CSF leukocyte count (P < 0.05). Longitudinal observations in patients with NMDAR-E showed a decreasing trend of leukocyte count, neutrophils count, neutrophil-to-monocyte ratios (NMR), and neutrophil-to-lymphocyte ratios (NLR) with the gradual recovery of neurological function. CONCLUSIONS: The expression patterns of T lymphocyte subsets were different in patients with NMDAR-E and viral encephalitis. The changing trends of leukocyte and lymphocyte populations in peripheral blood and cerebrospinal fluid may provide clues for the diagnosis of different types of encephalitides, including NMDARE, and can be used as immunological markers to assess and predict the prognosis.

Acute Rift Valley fever virus infection induces inflammatory cytokines and cell death in ex vivo rat brain slice culture.

Rift Valley fever virus (RVFV) is an emerging arboviral disease with pandemic potential. While infection is often self-limiting, a subset of individuals may develop late-onset encephalitis, accounting for up to 20 % of severe cases. Importantly, individuals displaying neurologic disease have up to a 53 % case fatality rate, yet the neuropathogenesis of RVFV infection remains understudied. In this study, we evaluated whether ex vivo postnatal rat brain slice cultures (BSCs) could be used to evaluate RVFV infection in the central nervous system. BSCs mounted an inflammatory response after slicing, which resolved over time, and they were viable in culture for at least 12 days. Infection of rat BSCs with pathogenic RVFV strain ZH501 induced tissue damage and apoptosis over 48 h. Viral replication in BSCs reached up to 1×107 p.f.u. equivalents/ml, depending on inoculation dose. Confocal immunofluorescent microscopy of cleared slices confirmed direct infection of neurons as well as activation of microglia and astrocytes. Further, RVFV-infected rat BSCs produced antiviral cytokines and chemokines, including MCP-1 and GRO/KC. This study demonstrates that rat BSCs support replication of RVFV for ex vivo studies of neuropathogenesis. This allows for continued and complementary investigation into RVFV infection in an ex vivo postnatal brain slice culture format.