Direct and mononuclear cell mediated effects on interleukin 6 production by glioma cells in infection with herpes simplex virus type 1

Steroids for the treatment of viral encephalitis: a systematic literature review and meta-analysis

BACKGROUND

Specific antiviral treatment is only available for a small subset of viral encephalitis (VE). Adjunctive steroids are used, but there is scant evidence evaluating its utility. We present a systematic review and meta-analysis on the outcome of steroid use in VE.

METHODS

We conducted a systematic literature review and reported it according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. Two observational studies from unpublished or partially published data were added. For the meta-analysis, we employed the metaphor package of the statistical software R-4.3.1.

RESULTS

We screened 378 studies and included 50. 155 patients were added from the Houston and Linz cohorts. Individual data were available for 281 persons, 120 (43%) of whom received steroids. The most common pathogens were herpes simplex virus 1, West Nile virus, and measles. Study designs and patient outcomes were heterogeneous. Only three of the trials report an advantage of steroid therapy. Steroid-induced side effects were scarce. Ten cohorts were included into the meta-analysis. For the pooled data, the null hypothesis could not be rejected (p = 0.245) using a random effects model, i.e., a benefit of steroid treatment on survival in VE could not be shown.

CONCLUSIONS

Steroids as potent anti-inflammatory agents may act through a reduction of secondary inflammation-mediated damage. Our data do not support the use of steroids in VE. However, multiple shortcomings apply. Standardized controlled trials are needed to investigate optimal dosing and timing of steroid administration and to explore potential subgroups that could benefit.

Clinical use of steroids in viral central nervous system (CNS) infections: three challenging cases

The role of adjunctive corticosteroids in reducing morbidity and mortality of viral CNS infections remains poorly defined. Clinicians are often left in a quagmire regarding steroid use in complex and rapidly evolving viral CNS infections. Limited studies have explored the underlying mechanisms behind the potential benefit of steroids. Here, we describe steroid use in three cases of viral CNS disease: varicella zoster virus (VZV), Powassan virus, and influenza A-associated acute necrotizing encephalopathy.

Binding between Prion Protein and Aβ Oligomers Contributes to the Pathogenesis of Alzheimer's Disease

A plethora of evidence suggests that protein misfolding and aggregation are underlying mechanisms of various neurodegenerative diseases, such as prion diseases and Alzheimer's disease (AD). Like prion diseases, AD has been considered as an infectious disease in the past decades as it shows strain specificity and transmission potential. Although it remains elusive how protein aggregation leads to AD, it is becoming clear that cellular prion protein (PrP^C) plays an important role in AD pathogenesis. Here, we briefly reviewed AD pathogenesis and focused on recent progresses how PrP^C contributed to AD development. In addition, we proposed a potential mechanism to explain why infectious agents, such as viruses, conduce AD pathogenesis. Microbe infections cause Aβ deposition and upregulation of PrP^C, which lead to high affinity binding between Aβ oligomers and PrP^C. The interaction between PrP^C and Aβ oligomers in turn activates the Fyn signaling cascade, resulting in neuron death in the central nervous system (CNS). Thus, silencing PrP^C expression may turn out be an effective treatment for PrP^C dependent AD.

Herpes simplex virus-1 infection of colonic explants as a model of viral-induced activation of Crohn's disease

The exogenous triggers responsible for Crohn's disease (CD) relapses are not often identified. Cytomegalovirus and other members of the herpesvirus family have been implicated in precipitating relapses. However, the role of viral infections in the immunopathogenesis of CD remains poorly understood. We describe an ex-vivo model of primary viral infection of CD tissue with Herpes Simplex Virus type I (HSV-1). IL-6 and CD68 served as markers for CD inflammation, type I IFNs for viral infection. Colonic explants obtained from CD resections were infected via the luminal or the submucosal compartments with HSV-1 or mock virus solution, at varying concentrations for up to 20 h. Serial tissue sections were assayed for expression of HSV-1 specific antigens, CD-68, IL-6 and DC-SIGN. Culture supernatants were tested for IL-6 and type I IFN production. Positive immunostaining for HSV-1 specific antigens was consistently detectable using 11×10(6)PFU from 13 h onwards, mainly on cells located in the submucosa, and in the perivascular area. CD68 was up-regulated in lamina propria macrophages from mildly and non-inflamed CD tissue after HSV-1 infection. IL-6+ cells in the infected tissues were mainly submucosal DC-SIGN+ dendritic cells. IL-6 and IFN-β levels were higher in the supernatants from HSV-1-infected explants compared to controls after 20 h of culture (p<0.01). These data show increased expression of inflammatory markers during the initial stages of HSV-1 primary infection using CD colonic explants. This in vitro model appears promising to study the immunoregulatory changes induced by microbial infection in reactivation of CD.

Alzheimer's disease and infection: do infectious agents contribute to progression of Alzheimer's disease?

Infection with several important pathogens could constitute risk factors for cognitive impairment, dementia, and Alzheimer's disease (AD) in particular. This review summarizes the data related to infectious agents that appear to have a relationship with AD. Infections with herpes simplex virus type 1, picornavirus, Borna disease virus, Chlamydia pneumoniae, Helicobacter pylori, and spirochete were reported to contribute to the pathophysiology of AD or to cognitive changes. Based on these reports, it may be hypothesized that central nervous system or systemic infections may contribute to the pathogenesis or pathophysiology of AD, and chronic infection with several pathogens should be considered a risk factor for sporadic AD. If this hypothesis holds true, early intervention against infection may delay or even prevent the future development of AD.

Evaluation of combination therapy using aciclovir and corticosteroid in adult patients with herpes simplex virus encephalitis

OBJECTIVE

Herpes simplex virus encephalitis (HSVE) is associated with significant morbidity and mortality, even with appropriate antiviral therapy. In the present investigation, the first to assess efficacy of corticosteroid treatment with aciclovir therapy in HSVE, multiple logistic regression analysis was performed of predictors of outcome in adult patients with HSVE.

METHODS

A non-randomised retrospective study of 45 patients with HSVE treated with aciclovir was conducted. The patients were divided into poor and good groups based on outcome at three months after completion of aciclovir treatment. The variables evaluated were: clinical variables (sex, age, days after onset at initiation of aciclovir, Glasgow Coma Scale (GCS) at initiation of aciclovir, initial and maximum values for the cell numbers and protein concentration in the cerebrospinal fluid, and corticosteroid administration); neuroradiological variables (detection of lesions by initial cranial computed tomography and by initial magnetic resonance imaging); and one neurophysiological variable (detection of periodic lateralised epileptiform discharges on the initial electroencephalogram). Single variable logistic regression analysis was performed followed by multiple logistic regression analysis. The best set of predictors for the outcome of HSVE was estimated by stepwise logistic regression analysis.

RESULTS

A poor outcome was evident with older age, lower GCS score at initiation of aciclovir, and no administration of corticosteroid. Patient age, GCS at initiation of aciclovir, and corticosteroid administration were found to be significant independent predictors of outcome on multiple logistic regression analysis, and these three variables also formed the best set of predictors (R(2) = 0.594, p<0.0001).

CONCLUSION

Combination therapy using both aciclovir and corticosteroid represents one of the predictors of outcome in HSVE.

Consequences of CXCL10 and IL-6 induction by the murine IFN-alpha1 transgene in ocular herpes simplex virus type 1 infection

Herpes simplex virus type 1 infection of the mouse eye results in an impressive inflammatory response culminating in the death of the animal or the establishment of a "latent" infection depending on a number of ill-defined variables that include components of the innate and adaptive immune system. The application of type I interferon transgenes has been found to antagonize viral replication and spread from the eye to the nervous system. Associated with the in situ transfection of the cornea is the upregulation of two inflammatory molecules, interleukin-6 and CXCL10. In this article, we will further examine the contribution these molecules may have in the host response to ocular infection with herpes simplex virus type 1.

Serial changes of intrathecal viral loads evaluated by chemiluminescence assay and nested PCR with aciclovir treatment in herpes simplex virus encephalitis

OBJECTIVE

We assessed the potential for estimating the effects of antiviral therapy on the clearance of intrathecal herpes simplex virus (HSV) antigens as evaluated by the chemiluminescence assay (CL) and on that of intrathecal HSV-DNA as evaluated by the nested polymerase chain reaction (PCR) in serial patients with herpes simplex virus encephalitis (HSVE).

METHODS

The materials comprised serial cerebrospinal fluid (CSF) samples from 18 patients with HSVE. All patients were diagnosed as having HSVE retrospectively based on the detection of intrathecal HSV antigens by the CL, that of HSV-DNA by the nested PCR, and also serological confirmation of intrathecal antibody production. The relationships between the days of aciclovir therapy and serial HSV viral loads as evaluated by the CL and nested PCR in the serial CSFs were assessed.

RESULTS

The serial intrathecal viral loads evaluated by the CL and nested PCR declined after the commencement of aciclovir administration in all patients. The serial alterations of the intrathecal viral load evaluated by the CL in each patient were similar to those of the intrathecal viral load evaluated by the nested PCR. The initial and maximum viral loads evaluated by the CL and nested PCR showed a wide distribution in the CSF samples taken from the patients with poor and good outcomes. Differences in the means of the viral loads in the CSF samples taken from the patients between a poor outcome and a good outcome were not evident. A transient increase of viral load as evaluated by these two methods was noted in the same 4 patients. The viral loads in these 4 patients also declined in the subsequent CSF samples. The outcome of these 4 patients was good in one patient and poor in the others.

CONCLUSION

Evaluation of intrathecal viral antigens by the CL has a potential for estimating the effects of antiviral therapy, as does evaluation of the intrathecal HSV-DNA by the nested PCR. The intrathecal viral loads evaluated by CL and nested PCR were not a predictor of outcome in HSVE.

Serum cytokine levels in Bell's palsy

OBJECTIVE

To assess the significance of the serum levels of the cytokines (interleukine (IL-6, IL-8, IL-1b, IL-2r, and tumor necrosis factor alpha (TNF - alpha)) in the patients with Bell's palsy.

STUDY DESIGN

A clinical and laboratory study in which serum cytokine levels were compared between the patients who had Bell's palsy and healthy controls.

METHODS

Twenty-three patients with Bell's palsy and 30 healthy volunteers were included in the study. The blood samples of the patients and controls were obtained, and serum IL-1b, IL-2r, IL-6, IL-8, and TNF- alpha levels determined with chemiluminescence enzyme immunometric assay on an Immulite Immunoassay. The serum of the patients was taken between 2 days and 1 month after the disease. The assay was not in vitro lymphocyte stimulation.

RESULTS

The IL-6, IL-8 and TNF- alpha levels were significantly higher in Bell's palsy than in controls (p < 0.05). The IL-1b and IL-2r levels were similar in both groups (p > 0.05). The levels of cytokine IL-6, IL-8, TNF- alpha, IL-1b, IL-2r did not correlate with the degree of recovery (p > 0.05).

CONCLUSION

An alteration in the concentration of the cytokines is expected not only in many inflammatory and infectious diseases but also in Bell's palsy. Cytokines are not stored or preformed within cells. Therefore, high cytokine levels (IL-6 and IL-8, and TNF- alpha) should represent their production in response to underlying pathology in Bell's palsy, or these cytokines may be pathogenetic factors in Bell's palsy. However, serum levels of these cytokines do not help determine the prognosis in Bell's palsy as far as the results of this study are concerned.