Infected CNS Research Articles

Correlation between Severity of Lung Disease in COVID-19 Infection and Acute CNS Abnormalities

Abstract Background Sever acute respiratory syndrome corona virus 2 (SARS-COV 2) began in Wuhan,China,in December 2019 and has rapidely spread around the world to become pandemic,as COVID-19 can produce pathologic changes in chest imaging,COVID-19 related brain imaging findings are also well known. Aim of the Work The aim of this current study is to correlate retrospectively between the severity of lung affection in patients with COVID-19 infections and development of acute CNS abnormalities. Patients and Methods This study is Retrospective study, the study was conducted at Ain Shams University Hospitals over a course of six months from march 2022 to September 2022 and the main source of data for this study was the archived CT and MRI imaging of the patients referred to the department of Radiology. Our inclusion criteria were patients that diagnosed with sever acute respiratory syndrome corona virus 2 infection with acute neurologic manifestation and available chest CT and brain imaging. The 5 lobes of the lungs were individually scored on a scale 0-5 (0 correspond to no involvement and 5 > 75% involvement),A CT lung severity score was determined as the sum of lung involvement,ranging from 0 (no involvement) to 25 (maximum involvement). Results A total 55 patients met the inclusion criteria,In attempt to describe and evaluate the brain and lung imaging correlation in patients with COVID-19, Compared to 20 patients without acute abnormal findings on neuroimaging,there were 35 patients with acute abnormal findings on neuroimaging and those patients were found to have significantly higher mean CT lung severity score (p < 0.0001) and they are more likely to present with ischemic stroke (14, 40%), A threshold of CT lung severity score > 18 was found to be 97% sensitive and 90% specific for acute abnormal findings on neuroimaging, the neuroimaging hallmark of these patients were acute ischemic infarcts (40%),invasive fungal sinusitis (22.9.%), Isolated cavernous sinus thrombosis,PRES,and vasculitis (each one 8.6%),cerebral venous sinus thrombosis other than cavernous sinus (5.7%),cerebritis and abnormal white matter signal (each one 2.8%).The predominant CT chest findings were peripheral ground -glass opacities with or with out consolidation. Conclusion The CT lung severity score may be predictive of acute abnormalities on neuroimaging in patients with COVID-19 with neurologic manifestation. This can be used as predictive tool in patients management to improve clinical outcome.

Characterization and diagnosis spectrum of patients with cerebrospinal fluid pleocytosis

PurposeThere is an overlap in the cerebrospinal fluid (CSF) characteristics of patients presenting with different etiologies of CSF pleocytosis. Here, we characterized patients with CSF pleocytosis treated in a large hospital.MethodsA retrospective cohort study of 1150 patients with an elevated CSF leukocyte count > 5 cells/µl treated at a university hospital in Germany from January 2015 to December 2017 was performed. Information on clinical presentation, laboratory parameters, diagnosis and outcome was collected. Clinical and laboratory features were tested for their potential to differentiate between bacterial meningitis (BM) and other causes of CSF pleocytosis.ResultsThe most common etiologies of CSF pleocytosis were CNS infections (34%: 20% with detected pathogen, 14% without), autoimmune (21%) and neoplastic diseases (16%). CSF cell count was higher in CNS infections with detected pathogen (median 82 cells/µl) compared to autoimmune (11 cells/µl, p = 0.001), neoplastic diseases (19 cells/µl, p = 0.01) and other causes (11 cells/µl, p < 0.001). The CHANCE score was developed to differentiate BM from other causes of CSF pleocytosis: Multivariate regression revealed that CSF cell count > 100 cells/µl, CSF protein > 100 mg/dl, CRP > 5 mg/dl, elevated white blood cell count, abnormal mental status and nuchal rigidity are important indicators. The CHANCE score identified patients with BM with high sensitivity (92.1%) and specificity (90.9%) (derivation cohort: AUC: 0.955, validation cohort: AUC: 0.956).ConclusionOverall, the most common causes for CSF pleocytosis include infectious, neoplastic or autoimmune CNS diseases in ~ 70% of patients. The CHANCE score could be of help to identify patients with high likelihood of BM and support clinical decision making.

Intracellular Iron Accumulation Induces Inflammatory and Oxidative Status of the Host After Japanese Encephalitis Viral Infection.

The factors mitigating the microglia/macrophage activation and inflammatory damage in Japanese encephalitis (JE)virus infected CNS are still being ascertained. We aim to characterize the changes in iron transporter and iron storage proteins along with inflammatory and oxidative stress-mediated signaling during the JE viral infection. Cortical tissue samples from mice with JE viral infection were processed for biochemical, histological, and molecular analysis. Iron storage protein, i.e., ferritin, was found significantly increased post-JE viral infection, and iron accumulation was noted in cortical tissue. Key proinflammatory associated markers, such as TNF-α, IL-6, and its regulator TLR4, were found tobe increased, while SOCS1 (anti-inflammatory regulator) transcription decreased with increased levels of oxidative stress markers NOX2-mediated NF-ΚB/p65 and protein carbonyl. Furthermore, it is noted that hepcidin level increased and ferroportin level decreased, and iron transporter gene expression got imbalanced after JE viral infection. This observation was further confirmed by deferoxamine (DFO) treatment to JE viral infection mice model, where the decline in hepcidin transcription level and iron load in cortical tissue of JEviralinfected animals was noted. However, no change was found in the ferroportin level compared to JEviralinfected animals. Together, these findings suggest that iron overload and hepcidin-ferroportin regulation are involved in JE viral infection disease pathologies and associated with the inflammatory and oxidative status of the host during infection.

A rare case of AIDS co-infected with COVID-19 presenting with disseminated Herpes zoster complicated with CMV and Varicella zoster virus meningoencephalitis.

During the COVID-19 pandemic, numerous co-infections have been reported, with some studies indicating that patients with HIV/AIDS have worse outcomes when co-infected with COVID-19. Here, we present the case of a young adult male who presented with disseminated Varicella and was simultaneously diagnosed with AIDS and COVID-19 virus with several infection-related complications. A 25-year-old African-American male presented to the Emergency Department with vesicular, blistering rashes in multiple dermatomes including his eyelids. The screening test in the ED was positive for COVID-19. Given his high-risk sexual history, he was tested for HIV which returned positive with a CD4 count of zero. He was started on IV antivirals for disseminated varicella with zoster ophthalmicus. The patient was intubated for worsening respiratory failure and required intensive care. During the hospital course, he developed worsening encephalopathy and CSF analysis was positive for CMV and VZV. The patient has a prolonged hospital stay and exhibited evidence of infectious CNS vasculitis and HIV myelopathy. Anti-retroviral therapy was started after the acute period and the patient showed slow but definite clinical improvement. To the best of our knowledge, this is the first case report of a patient with AIDS with COVID-19 and disseminated VZV and with multiple complex infection-related complications.

Time dependency of CSF cell count, lactate and blood-CSF barrier dysfunction after epileptic seizures and status epilepticus

BackgroundThis retrospective observational study was conducted to examine the temporal relationship between increased cell count, lactate concentration in cerebrospinal fluid (CSF) and blood-CSF barrier dysfunction and the onset of a seizure event. MethodsPatients with a seizure event who underwent lumbar puncture for CSF analysis during diagnostic work-up (interindividual analysis) and those with at least one follow-up CSF analysis (intraindividual analysis) were studied. Pathologically altered parameters, such as cell count, lactate concentration, and blood-CSF barrier dysfunction as indicated by the albumin quotient (QAlb=CSF albumin/serum albumin), were examined with regard to the changes over time after seizure onset. ResultsAn increased CSF cell count (>4/µl) was shown in 3% of our patients, whereas pathological lactate concentrations were found in 24% after single seizures and 28% after status epilepticus (SE)/recurring seizures. However, lactate levels showed a marked decrease with increasing time after an isolated seizure (p<0.0001) but not after SE/recurring seizures. Lactate levels were most frequently and significantly elevated within the first six hours after a single seizure (p<0.0001). Blood-CSF barrier dysfunction was detected in 34% after isolated seizures and in 47% after SE/recurrent seizures. Blood-CSF barrier dysfunction showed no association with latency between seizure onset and time of CSF collection. ConclusionsChanges in lactate and CSF protein concentrations are common after epileptic seizures. In contrast, CSF pleocytosis is uncommon and should prompt careful investigation for the presence of intrathecal infection or autoimmune CNS disease. Elevated lactate levels more than 6 h after the seizure event may indicate ongoing epileptic activity.

Hospital-diagnosed infections before age 20 and risk of a subsequent multiple sclerosis diagnosis

The involvement of specific viral and bacterial infections as risk factors for multiple sclerosis has been studied extensively. However, whether this extends to infections in a broader sense is less clear and little is known about whether risk of a multiple sclerosis diagnosis is associated with other types and sites of infections, such as of the CNS. This study aims to assess if hospital-diagnosed infections by type and site before age 20 years are associated with risk of a subsequent multiple sclerosis diagnosis and whether this association is explained entirely by infectious mononucleosis, pneumonia, and CNS infections. Individuals born in Sweden between 1970-1994 were identified using the Swedish Total Population Register (n = 2,422,969). Multiple sclerosis diagnoses from age 20 years and hospital-diagnosed infections before age 20 years were identified using the Swedish National Patient Register. Risk of a multiple sclerosis diagnosis associated with various infections in adolescence (11-19 years) and earlier childhood (birth-10 years) was estimated using Cox regression, with adjustment for sex, parental socioeconomic position, and infection type. None of the infections by age 10 years were associated with risk of a multiple sclerosis diagnosis. Any infection in adolescence increased the risk of a multiple sclerosis diagnosis (hazard ratio 1.33, 95% confidence interval 1.21-1.46) and remained statistically significant after exclusion of infectious mononucleosis, pneumonia, and CNS infection (hazard ratio 1.17, 95% confidence interval 1.06-1.30). CNS infection in adolescence (excluding encephalomyelitis to avoid including acute disseminated encephalitis) increased the risk of a multiple sclerosis diagnosis (hazard ratio 1.85, 95% confidence interval 1.11-3.07). The increased risk of a multiple sclerosis diagnosis associated with viral infection in adolescence was largely explained by infectious mononucleosis. Bacterial infections in adolescence increased risk of a multiple sclerosis diagnosis, but the magnitude of risk reduced after excluding infectious mononucleosis, pneumonia and CNS infection (hazard ratio 1.31, 95% confidence interval 1.13-1.51). Respiratory infection in adolescence also increased risk of a multiple sclerosis diagnosis (hazard ratio 1.51, 95% confidence interval 1.30-1.75), but was not statistically significant after excluding infectious mononucleosis and pneumonia. These findings suggest that a variety of serious infections in adolescence, including novel evidence for CNS infections, are risk factors for a subsequent multiple sclerosis diagnosis, further demonstrating adolescence is a critical period of susceptibility to environmental exposures that raise the risk of a multiple sclerosis diagnosis. Importantly, this increased risk cannot be entirely explained by infectious mononucleosis, pneumonia, or CNS infections.

Metagenomic Next-Generation Sequencing for Diagnosis of Infectious Encephalitis and Meningitis: A Large, Prospective Case Series of 213 Patients.

Purpose: We assessed the performance of metagenomic next-generation sequencing (mNGS) in the diagnosis of infectious encephalitis and meningitis.Methods: This was a prospective multicenter study. Cerebrospinal fluid samples from patients with viral encephalitis and/or meningitis, tuberculous meningitis, bacterial meningitis, fungal meningitis, and non-central nervous system (CNS) infections were subjected to mNGS.Results: In total, 213 patients with infectious and non-infectious CNS diseases were finally enrolled from November 2016 to May 2019; the mNGS-positive detection rate of definite CNS infections was 57.0%. At a species-specific read number (SSRN) ≥2, mNGS performance in the diagnosis of definite viral encephalitis and/or meningitis was optimal (area under the curve [AUC] = 0.659, 95% confidence interval [CI] = 0.566–0.751); the positivity rate was 42.6%. At a genus-specific read number ≥1, mNGS performance in the diagnosis of tuberculous meningitis (definite or probable) was optimal (AUC=0.619, 95% CI=0.516–0.721); the positivity rate was 27.3%. At SSRNs ≥5 or 10, the diagnostic performance was optimal for definite bacterial meningitis (AUC=0.846, 95% CI = 0.711–0.981); the sensitivity was 73.3%. The sensitivities of mNGS (at SSRN ≥2) in the diagnosis of cryptococcal meningitis and cerebral aspergillosis were 76.92 and 80%, respectively.Conclusion: mNGS of cerebrospinal fluid effectively identifies pathogens causing infectious CNS diseases. mNGS should be used in conjunction with conventional microbiological testing.Trial Registration: Chinese Clinical Trial Registry, ChiCTR1800020442.

Amphotericin B Penetrates into the Central Nervous System Through Focal Disruption of the Blood Brain Barrier in Experimental Hematogenous Candida Meningoencephalitis.

Hematogenous Candida meningoencephalitis (HCME) is a life-threatening complication of neonates and immunocompromised children. Amphotericin B (AmB) shows poor permeability and low cerebrospinal fluid (CSF) concentrations, but is effective in treatment of HCME. In order to better understand the mechanism of CNS penetration of AmB, we hypothesized that AmB may achieve focally higher concentrations in infected CNS lesions. An in vitro BBB model was serially infected with C. albicans. Liposomal AmB (LAMB) or deoxycholate AmB (DAMB) at 5 μg/ml were then provided, vascular and CNS compartments were sampled 4h later. For in vivo correlation, rabbits with experimental HCME received a single dose of DAMB 1 mg/kg or LAMB 5 mg/kg, and were euthanized after 1, 3, 6 and 24h. Evans blue solution (2%) 2 ml/kg administered IV one hour prior to euthanasia stained infected regions of tissue but not histologically normal areas. AmB concentrations in stained and unstained tissue regions were measured using UPLC. For selected rabbits, MRI scans performed on days 1-7 postinoculation were acquired before and after IV bolus Gd-DTPA at 15min intervals through 2h post-injection. The greatest degree of penetration of DAMB and LAMB through the in vitro BBB occurred after 24h of exposure (P=0.0022). In vivo the concentrations of LAMB and DAMB in brain abscesses were 4.35±0.59 and 3.14±0.89-times higher vs. normal tissue (P≤0.019). MRI scans demonstrated that Gd-DTPA accumulated in infected areas with disrupted BBB. Localized BBB disruption in HCME allows high concentrations of AmB within infected tissues, despite the presence of low CSF concentrations.

Microglial Phagocytosis of Neurons: Diminishing Neuronal Loss in Traumatic, Infectious, Inflammatory, and Autoimmune CNS Disorders.

Errors in neuron-microglial interaction are known to lead to microglial phagocytosis of live neurons and excessive neuronal loss, potentially yielding poorer clinical outcomes. Factors that affect neuron-microglial interaction have the potential to influence the error rate. Clinical comorbidities that unfavorably impact neuron-microglial interaction may promote a higher rate of neuronal loss, to the detriment of patient outcome. This paper proposes that many common, clinically modifiable comorbidities have a common thread, in that they all influence neuron-microglial interactions. Comorbidities like traumatic brain injury, infection, stress, neuroinflammation, loss of neuronal metabolic integrity, poor growth factor status, and other factors, all have the potential to alter communication between neurons and microglia. When this occurs, microglial phagocytosis of live neurons can increase. In addition, microglia can shift into a morphological form in which they express major histocompatibility complex II (MHC-II), allowing them to function as antigen presenting cells that present neuronal debris as antigen to invading T cells. This can increase risk for the development of CNS autoimmunity, or can exacerbate existing CNS autoimmunity. The detrimental influence of these comorbidities has the potential to contribute to the mosaic of factors that determine patient outcome in some CNS pathologies that have neuropsychiatric involvement, including TBI and CNS disorders with autoimmune components, where excessive neuronal loss can yield poorer clinical outcomes. Recognition of the impact of these comorbidities may contribute to an understanding of the common clinical observation that many seemingly disparate factors contribute to the overall picture of case management and clinical outcome in these complex disorders. In a clinical setting, knowing how these comorbidities can influence neuron-microglial interaction can help focus surveillance and care on a broader group of potential therapeutic targets. Accordingly, an interest in the mechanisms underlying the influence of these factors on neuron-microglial interactions is appropriate. Neuron-microglial interaction is reviewed, and the various mechanisms by which these potential comorbidities influence neuro-microglial interaction are described.

Dynamics of Virus-Specific Memory B Cells and Plasmablasts following Viral Infection of the Central Nervous System.

Humoral responses within the central nervous system (CNS) are common to many neurotropic viral infections, with antibody (Ab)-secreting cells (ASC) contributing to local protection. However, a role for virus-specific memory B cells (Bmem) within the CNS is poorly explored due to lack of robust phenotypic or functional identification in mice. This study takes advantage of the progeny of mice expressing tamoxifen-inducible Cre recombinase (Cre-ERT2) under the Aicda promoter crossed with Rosa26-loxP-tdTomato reporter mice (AIDCre-Rosa26tdTomato) to monitor B cells having undergone activation-induced cytidine deaminase (AID)-mediated somatic hypermutation (SHM) following neurotropic coronavirus infection. AID detection via tdTomato expression allowed tracking of virus-specific ASC and Bmem in priming and effector sites throughout infection. In draining lymph nodes, tdTomato-positive (tdTomato+) ASC were most prevalent prior to germinal center (GC) formation, but total tdTomato+ B cells only peaked with robust GC formation at day 14 p.i. Moreover, their proportion of Bmem dominated over the proportion of ASC throughout infection. In the CNS, tdTomato+ cells started emerging at day 14 p.i. While they initially comprised mainly Bmem, the proportions of ASC and Bmem became similar as tdTomato+ B cells increased throughout viral persistence. Delayed tamoxifen treatment demonstrated ongoing CNS recruitment of tdTomato+ B cells, mainly ASC, primed late during GC reactions. Overall, the data support the idea that virus-induced B cells exhibiting SHM require peripheral GC formation to emerge in the CNS. Ongoing GC reactions and regional signals further regulate dynamics within the CNS, with preferential maintenance of tdTomato+ B cells in spinal cords relative to that in brains during viral persistence.IMPORTANCE The prevalence and role of antigen-specific Bmem in the CNS during viral encephalomyelitis is largely undefined. A lack of reliable markers identifying murine Bmem has made it difficult to assess their contribution to local antiviral protection via antigen presentation or conversion to ASC. Using reporter mice infected with neurotropic coronavirus to track virus-specific Bmem and ASC, this report demonstrates that both subsets only emerge in the CNS following peripheral GC formation and subsequently prevail. While early GC reactions supported preferential Bmem accumulation in the CNS, late GC reactions favored ASC accumulation, although Bmem outnumbered ASC in draining lymph nodes throughout infection. Importantly, virus-specific B cells undergoing sustained GC selection were continually recruited to the persistently infected CNS. Elucidating the factors governing temporal events within GCs, as well as regional CNS cues during viral persistence, will aid intervention to modulate CNS humoral responses in the context of infection and associated autoimmune pathologies.

Type I Interferon Receptor Signaling of Neurons and Astrocytes Regulates Microglia Activation during Viral Encephalitis

SummaryIn sterile neuroinflammation, a pathological role is proposed for microglia, whereas in viral encephalitis, their function is not entirely clear. Many viruses exploit the odorant system and enter the CNS via the olfactory bulb (OB). Upon intranasal vesicular stomatitis virus instillation, we show an accumulation of activated microglia and monocytes in the OB. Depletion of microglia during encephalitis results in enhanced virus spread and increased lethality. Activation, proliferation, and accumulation of microglia are regulated by type I IFN receptor signaling of neurons and astrocytes, but not of microglia. Morphological analysis of myeloid cells shows that type I IFN receptor signaling of neurons has a stronger impact on the activation of myeloid cells than of astrocytes. Thus, in the infected CNS, the cross talk among neurons, astrocytes, and microglia is critical for full microglia activation and protection from lethal encephalitis.

Immunomodulatory Role of Complement Proteins in the Neuropathology Associated with Opiate Abuse and HIV-1 Co-Morbidity

ABSTRACTThe complement system which is a critical mediator of innate immunity plays diverse roles in the neuropathogenesis of HIV-1 infection such as clearing HIV-1 and promoting productive HIV-1 replication. In the development of HIV-1 associated neurological disorders (HAND), there may be an imbalance between complement activation and regulation, which may contribute to the neuronal damage as a consequence of HIV-1 infection. It is well recognized that opiate abuse exacerbates HIV-1 neuropathology, however, little is known about the role of complement proteins in opiate induced neuromodulation, specifically in the presence of co-morbidity such as HIV-1 infection. Complement levels are significantly increased in the HIV-1-infected brain, thus HIV-induced complement synthesis may represent an important mechanism for the pathogenesis of AIDS in the brain, but remains underexplored. Anti-HIV-1 antibodies are able to initiate complement activation in HIV-1 infected CNS cells such as microglia and astrocytes during the course of disease progression; however, this complement activation fails to clear and eradicate HIV-1 from infected cells. In addition, the antiretroviral agents used for HIV therapy cause dysregulation of lipid metabolism, endothelial, and adipocyte cell function, and activation of pro-inflammatory cytokines. We speculate that both HIV-1 and opiates trigger a cytokine-mediated pro-inflammatory stimulus that modulates the complement cascade to exacerbate the virus-induced neurological damage. We examined the expression levels of C1q, SC5b-9, C5L2, C5aR, C3aR, and C9 key members of the complement cascade both in vivo in post mortem brain frontal cortex tissue from patients with HAND who used/did not use heroin, and in vitro using human microglial cultures treated with HIV tat and/or heroin. We observed significant expression of C1q and SC5b-9 by immunofluorescence staining in both the brain cortical and hippocampal region in HAND patients who abused heroin. Additionally, we observed increased gene expression of C5aR, C3aR, and C9 in the brain tissue of both HIV-1 infected patients with HAND who abused and did not abuse heroin, as compared to HIV negative controls. Our results show a significant increase in the expression of complement proteins C9, C5L2, C5aR, and C3aR in HIV transfected microglia and an additional increase in the levels of these complement proteins in heroin-treated HIV transfected microglia. This study highlights the a) potential roles of complement proteins in the pathogenesis of HIV-1-related neurodegenerative disorders; b) the combined effect of an opiate, like heroin, and HIV viral protein like HIV tat on complement proteins in normal human microglial cells and HIV transfected microglial cells. In the context of HAND, targeting selective steps in the complement cascade could help ameliorating the HIV burden in the CNS, thus investigations of complement-related therapeutic approaches for the treatment of HAND are warranted.

CD14 is a key organizer of microglial responses to CNS infection and injury.

Microglia, innate immune cells of the CNS, sense infection and damage through overlapping receptor sets. Toll-like receptor (TLR) 4 recognizes bacterial lipopolysaccharide (LPS) and multiple injury-associated factors. We show that its co-receptor CD14 serves three non-redundant functions in microglia. First, it confers an up to 100-fold higher LPS sensitivity compared to peripheral macrophages to enable efficient proinflammatory cytokine induction. Second, CD14 prevents excessive responses to massive LPS challenges via an interferon β-mediated feedback. Third, CD14 is mandatory for microglial reactions to tissue damage-associated signals. In mice, these functions are essential for balanced CNS responses to bacterial infection, traumatic and ischemic injuries, since CD14 deficiency causes either hypo- or hyperinflammation, insufficient or exaggerated immune cell recruitment or worsened stroke outcomes. While CD14 orchestrates functions of TLR4 and related immune receptors, it is itself regulated by TLR and non-TLR systems to thereby fine-tune microglial damage-sensing capacity upon infectious and non-infectious CNS challenges.

NK-92 Therapy Is Well Tolerated, Has Minimal Toxicity and Shows Efficacy in a Phase I Trial of Patients with Relapsed/Refractory Hematological Malignancies Relapsing after Autologous Stem Cell Transplantation

BackgroundAutologous NK cell adoptive immunotherapy has potential to treat a variety of malignancies, but is limited by patient-specific variations in numbers and quality of expanded cells. In contrast, allogeneic NK cell lines can overcome many of these limitations. The NK line, NK-92 can be manufactured under Good Manufacturing Practice (GMP) compliant conditions, and infused into patients, as demonstrated in two prior phase I trials for solid tumours. Here, we report the findings of a phase I trial of NK-92 with the highest cell dosing regimen tested to date, in patients with relapsed/refractory hematological malignancies.MethodsWe conducted a single-center, non-randomized, non-blinded, open-label, Phase I dose-escalation trial of irradiated NK-92 cells in adults with refractory hematological malignancies who relapsed after autologous stem cell transplantation. The objectives were to determine, safety, feasibility and evidence of activity against refractory hematological malignancies. Inclusion criteria included measurable disease, adequate organ function and ECOG performance status of < 2. Exclusion criteria were pregnancy, concurrent treatment within 28 days with other experimental therapy, known HIV, HBV or HCV infection and malignant CNS disease. Patients were treated at one of three dose levels (1x109 cells/m2, 3x109 cells/m2 and 5x109 cells/m2), given on day 1, 3 and 5 for a planned total of six monthly cycles. NK-92 cells were obtained from Conkwest, and a frozen working cell bank was established at Princess Margaret Cancer Centre and stored in liquid nitrogen. Clinical-grade NK-92 cells were then manufactured under GMP conditions by expanding a cryopreserved vial of NK-92 in Vuelife culture bags using GM1 medium. Release criteria of NK-92 for infusion included negative mycoplasma testing, day 7 culture sterility, endotoxin <0.05 EU/mL, and additionally, a negative stat gram stain and cell viability of >70%. The final NK-92 cell product was resuspended in GM2 medium (Plasma-Lyte-A medium), irradiated with 10 Gy and infused fresh intravenously over one hour.ResultsTwelve patients with hematological malignancies who relapsed after undergoing stem cell transplantation for relapsed/refractory disease were enrolled with the following diagnoses: multiple myeloma (5), diffuse large B-cell lymphoma (4), Hodgkin lymphoma (2) and mantle cell lymphoma (1). There were 9 males and 3 females and median age was 60 (range: 42-67) years. Patients had received 2-5 chemotherapy regimens before autologous stem cell transplantation and some also received additional chemotherapy after autotransplant and prior to receiving NK-92 infusions. The number of cycles of NK-92 administered ranged from 1-6, with 10 patients coming off study because of disease progression, and one patient proceeding to allogeneic stem cell transplantation. The only toxicity was infusion-related fever and chills (grade II) in one patient, and none had evidence of cytokine release syndrome. A patient with relapsed, refractory Hodgkin lymphoma had a complete response and remains in remission more than five years after NK-92 therapy. An additional three patients experienced transient responses. There were no significant alterations in hemoglobin, platelets, white cell count, creatinine or liver function tests in patients receiving NK-92 infusions. While six patients developed anti-HLA antibodies, none developed a T-cell immune response as determined by the mixed lymphocyte response of patient lymphocytes against NK-92.ConclusionNK-92 can be administered after autologous stem cell transplantation at very high doses with virtually no toxicity to patients with relapsed/refractory hematological malignancies. This is the first trial of NK-92 which includes patients with multiple myeloma. Surprisingly, most patients did not mount cellular immune responses against NK-92, despite receiving very large numbers of NK cells, up to a total of 150x109 cells. We conclude that high dose NK-92 therapy is safe and has the potential to induce long term survival in select patients. We propose that NK-92 can serve as a standardized off-the-shelf cellular treatment for malignancies and could provide a platform for gene-modified targeted cell therapy. DisclosuresKeating:Conkwest: Other: Research funding unrelated to clinical trial.

CD8+ T Cells Complement Antibodies in Protecting against Yellow Fever Virus

The attenuated yellow fever (YF) vaccine (YF-17D) was developed in the 1930s, yet little is known about the protective mechanisms underlying its efficiency. In this study, we analyzed the relative contribution of cell-mediated and humoral immunity to the vaccine-induced protection in a murine model of YF-17D infection. Using different strains of knockout mice, we found that CD4(+) T cells, B cells, and Abs are required for full clinical protection of vaccinated mice, whereas CD8(+) T cells are dispensable for long-term survival after intracerebral challenge. However, by analyzing the immune response inside the infected CNS, we observed an accelerated T cell influx into the brain after intracerebral challenge of vaccinated mice, and this T cell recruitment correlated with improved virus control in the brain. Using mice deficient in B cells we found that, in the absence of Abs, YF vaccination can still induce some antiviral protection, and in vivo depletion of CD8(+) T cells from these animals revealed a pivotal role for CD8(+) T cells in controlling virus replication in the absence of a humoral response. Finally, we demonstrated that effector CD8(+) T cells also contribute to viral control in the presence of circulating YF-specific Abs. To our knowledge, this is the first time that YF-specific CD8(+) T cells have been demonstrated to possess antiviral activity in vivo.

Confirmed enterovirus encephalitis with associated steroid-responsive acute disseminated encephalomyelitis: An overlapping infection and inflammation syndrome

BackgroundInflammatory disorders of the central nervous system have generally been separated into infectious or immune-mediated aetiologies. However, there are emerging examples of confirmed infectious viral infection of the brain followed by secondary inflammation or autoimmunity that is amenable to immune suppressive therapies. MethodsWe report four children with confirmed enterovirus encephalitis (CSF enterovirus PCR positivity), who had MRI evidence of inflammatory demyelination compatible with ADEM. ResultsTwo patients had a monophasic course, whereas two had a biphasic course. Serum myelin oligodendrocyte glycoprotein antibodies were negative in two tested patients, although all patients had mirrored CSF and serum oligoclonal bands. All four patients only improved with introduction of immune therapy (corticosteroids in three, corticosteroid and intravenous immunoglobulin in one). ConclusionThese cases provide a further example of the overlap between CNS infection and immune mediated CNS disease. Randomised controlled trials investigating immune therapies in encephalitis are required.

IL-1R1 signaling regulates CXCL12-mediated T cell localization and fate within the central nervous system during West Nile Virus encephalitis.

Immune cell entry into the virally infected CNS is vital for promoting viral clearance yet may contribute to neuropathology if not rigorously regulated. We previously showed that signaling through IL-1R1 is critical for effector T cell reactivation and virologic control within the CNS during murine West Nile virus (WNV) encephalitis. WNV-infected IL-1R1(-/-) mice also display increased parenchymal penetration of CD8(+) T cells despite lack of CD4-mediated full activation, suggesting dysregulation of molecular components of CNS immune privilege. In this study, we show that IL-1 signaling regulates the CNS entry of virus-specific lymphocytes, promoting protective immune responses to CNS viral infections that limit immunopathology. Analysis of blood-brain barrier function in the WNV-infected IL-1R1(-/-) mice revealed no alterations in permeability. However, parenchymal proinflammatory chemokine expression, including CCL2, CCL5, and CXCL10, was significantly upregulated, whereas microvasculature CXCL12 expression was significantly decreased in the absence of IL-1 signaling. We show that during WNV infection, CD11b(+)CD45(hi) infiltrating cells (macrophages) are the primary producers of IL-1β within the CNS and, through the use of an in vitro blood-brain barrier model, that IL-1β promotes CXCR4-mediated T cell adhesion to brain microvasculature endothelial cells. Of interest, IFNγ(+) and CD69(+) WNV-primed T cells were able to overcome CXCL12-mediated adhesion via downregulation of CXCR4. These data indicate that infiltrating IL-1β-producing leukocytes contribute to cellular interactions at endothelial barriers that impart protective CNS inflammation by regulating the parenchymal entry of CXCR4(+) virus-specific T cells during WNV infection.

Presence of severe neuroinflammation does not intensify neurofibrillary degeneration in human brain

This study investigated the allegedly causal relationship between microglial activation and neurofibrillary degeneration (NFD) typical of Alzheimer's disease (AD) by determining if presence of extreme microglial activation coincides with intensified NFD. We performed comparative histopathological analyses of NFD and microglial reactivity in 18 primary subjects ranging from 4 to 51 years of age. Ten of these subjects (median age 34) died from infectious disease (HIV, sepsis) and CNS trauma, while eight subjects (median age 32.5) died from non-infectious conditions (controls). Second, we also examined two 52-year-old subjects with Down syndrome where one had comorbid sepsis and the other one did not. We found that all 10 subjects with infectious/traumatic diagnoses showed severe neuroinflammation, while the 8 control subjects completely lacked neuroinflammatory changes. However, all 18 primary subjects were found to show the same early-stage, pretangle neuropathology of Braak stage 1a and 1b, that is, they exhibited primarily subcortical NFD in the locus coeruleus and sporadic lesions in the transentorhinal cortex. Similarly, the two subjects with Down syndrome showed the same high levels of NFD (Braak stage VI) irrespective of the comorbid sepsis-related neuroinflammation present in one of these individuals. Collectively, our findings show that despite rampant microglial activation in all subjects with neuroinflammatory conditions the extent of NFD is at the same level as seen in non-inflamed controls. These findings demonstrate that microglial activation does not initiate or exacerbate NFD, and we conclude that CNS inflammation is unlikely to be causally involved in the development of NFD characteristic of AD dementia.

Interferon regulatory factor 8 deficiency causes phenotypic and functional changes in myeloid cells inside and outside the CNS (P4145)

Abstract We identified IRF8 as a constitutive and IFN-γ-stimulated nuclear factor in microglia of the CNS. IRF8 is a transcription factor with a key role in the cellular response to IFN-γ but is also pivotal in myeloid cell differentiation. Here we employed IRF8 KO mice to determine the role of IRF8 in microglial development and function in the healthy CNS and in the microglial response to injury (facial nerve axotomy [FNA]) or infection (West Nile Virus [WNV] encephalitis). Microglia were present in the CNS of IRF8 KO mice but showed altered morphology and significantly reduced surface area and had alterations in a number of key markers including reduced levels of Iba1, CCR2 and CCR5 but increased levels tomato lectin binding. Following FNA the microglial response was markedly delayed and attenuated in IRF8 KO mice and the wrapping of motor neuron cell bodies by microglia involved in synaptic stripping and phagocytosis was incomplete. Finally, IRF8 KO mice had increased susceptibility to WNV accompanied by a marked reduction in both microglial cell activation and leukocyte accumulation in the brain. In the periphery, ly6Cint monocytes were increased in number but exhibited defective trafficking to the infected CNS while ly6Chi monocytes were almost completely absent. In conclusion: (1) IRF8 is a major intrinsic determinant of the microglial phenotype in the healthy and the diseased CNS, and (2) IRF8 has a crucial role in the development and trafficking of inflammatory monocytes.

2615 – Status post meningitis and encephalitis? 20 years after infection, psychiatry problems

Infects of CNS are very severe disorders, if not treated can lead to death. Nowadays we still noticed presence of them. In our study we traced psychiatric problems of 30 patients age 35±5, both sex, had survived meningitis and encephalitis in their early adolescence 12 to 14. 80% meningitis, other encephalitis. In day care hospital they came because of headache, depression, panic, anxiousness, compulsive behavior, emotional instability. CT of brain were observed. Before study 80% patients got drugs. Find out are exist significance and link between infection of CNS (duration, type bacterial or viral, seizures if had happen) and psychiatric problems 20 years after? Study-Follow up 30 patients during one year treated in day care hospital. eeg controlled. Ct brain if necessary. To measure depression used Beck, Montgomery A scales. To measure panic used Pais 3 scales. 20 years after severe infection CNS noticed that just 20% visible eeg abnormalities. No seizures, but 10 % got AE. 50% dg as panic, felt better on clonazepam. 20%depression mild, recovered on escitalopram. 10% personae disorders on therapy. Evaluated study showed that duration of CNS infection and seizers in anamnesis after 20 years consequence in irritability eeg as well as behavior problems so needed drugs. Bacterial infection (pneumoccoc, enteroccoc) linked in depression. As difference, viral infection linked in anxiety, panic and personal disorders. Beck and Montgomery A scales significant improvement after therapy. Panic scales also.