Infection drives meningeal engraftment by inflammatory monocytes that impairs CNS immunity.

Tissue macrophages have an embryonic origin and can be replenished in some tissues under steady-state conditions by blood monocytes. However, little is known about the residency and properties of infiltrating monocytes after an inflammatory challenge. The meninges of the central nervous system (CNS) are populated by a dense network of macrophages that act as resident immune sentinels. Here we show that, following lymphocytic choriomeningitis virus infection, resident meningeal macrophages (MMs) acquired viral antigen and interacted directly with infiltrating cytotoxic T lymphocytes, which led to macrophage depletion. Concurrently, the meninges were infiltrated by inflammatory monocytes that engrafted the meningeal niche and remained in situ for months after viral clearance. This engraftment led to interferon-γ-dependent functional changes in the pool of MMs, including loss of bacterial and immunoregulatory sensors. Collectively, these data indicate that peripheral monocytes can engraft the meninges after an inflammatory challenge, imprinting the compartment with long-term defects in immune function.

Clinical spectrum and prognosis of neurological complications of reactivated varicella-zoster infection: the role of immunosuppression.

Immunosuppressed patients are at higher risk for developing herpes zoster (HZ), and neurological complications are frequent in them. However, the influence of immunosuppression (IS) on the severity and prognosis of neurological complications of varicella-zoster virus (VZV) reactivation is unknown. We studied retrospectively patients with neurological complications due to VZV reactivation who attended our hospital between 2004 and 2019. We aimed to assess the clinical spectrum, potential prognostic factors, and the influence of the immune status on the severity of neurological symptoms. A total of 98 patients were included (40% had IS). Fifty-five patients (56%) had cranial neuropathies which included Ramsay-Hunt syndrome (36 patients) and cranial multineuritis (23 patients). Twenty-one patients developed encephalitis (21%). Other diagnosis included radiculopathies, meningitis, vasculitis, or myelitis (15, 10, 6, and 4 patients, respectively). Mortality was low (3%). At follow-up, 24% of patients had persistent symptoms although these were usually mild. IS was associated with severity (defined as a modified Rankin scale greater than 2) (odds ratio, 4.23; 95% confidence interval, 1.74-10.27), but not with prognosis. Shorter latency between HZ and neurologic symptoms was the only factor associated with an unfavorable course (death or sequelae) (odds ratio, 0.82; 95% confidence interval, 0.71-0.95). In conclusion, the clinical spectrum of neurological complications in VZV reactivation is wide. Mortality was low and sequelae were mild. The presence of IS may play a role on the severity of neurological symptoms, and a shorter time between HZ and the onset of neurological symptoms appears to be a negative prognostic factor.

Herpes simplex virus type 2 meningitis as a manifestation of Good's syndrome.

Good's syndrome is a primary immunodeficiency phenocopy characterized for thymoma and immunodeficiency. The most frequent clinical presentation is recurrent or opportunistic infections, hematological alterations, and chronic diarrhea. We treated a 66-year-old man who consulted for 5 days of headache and diplopia with right sixth cranial nerve palsy at examination. Patient reported chronic diarrhea and prolonged febrile syndrome accompanied by weight loss of 23 kg in the last year. Exhaustive evaluation revealed Herpes simplex virus (HSV) type 2 meningitis, eosinophilic colitis, and type A thymoma. Severe antibody deficiency (hypogammaglobulinemia) associated with thymoma confirmed the diagnosis of Good's syndrome.

Assay for improved detection of antigen-specific immune cells from extrasanguinous fluids.

In this approach, pre-stained cells from extrasanguinous fluids (ESFs) are stimulated in the presence of blood from the same individual. Thus, blood-derived antigen-presenting cells enable stimulation of both ESF- and blood T cells. Pre-staining allows distinction of T cells from ESF and blood, and simultaneous analysis of antigen-specific T cells in both compartments.

Meningitis and epididymitis caused by Toscana virus infection imported to Switzerland diagnosed by metagenomic sequencing: a case report.

BACKGROUND: We report a rare case of Toscana virus infection imported into Switzerland in a 23-year old man who travelled to Imperia (Italy) 10 days before onset of symptoms. Symptoms included both meningitis and as well epididymitis. This is only the fourth case of Toscana virus reported in Switzerland. CASE PRESENTATION: The patient presented with lymphocytic meningitis and scrotal pain due to epididymitis. Meningitis was initially treated with ceftriaxone. Herpes simplex, tick-borne encephalitis, enterovirus, measles, mumps, rubella and Treponema pallidum were excluded with specific polymerase chain reaction (PCR) or serology. In support of routine diagnostic PCR and serology assays, unbiased viral metagenomic sequencing was performed of cerebrospinal fluid and serum. Toscana virus infection was identified in cerebrospinal fluid and the full coding sequence could be obtained. Specific PCR in cerebrospinal fluid and blood and serology with Immunoglobulin (Ig) M and IgG against Toscana virus confirmed our diagnosis. Neurological symptoms recovered spontaneously after 5 days. CONCLUSIONS: This case of Toscana virus infection highlights the benefits of unbiased metagenomic sequencing to support routine diagnostics in rare or unexpected viral infections. With increasing travel histories of patients, physicians should be aware of imported Toscana virus as the agent for viral meningitis and meningoencephalitis.

Eye Complications During Dupilumab Treatment for Severe Atopic Dermatitis.

Dupilumab, the first biologic approved for treatment of atopic dermatitis, has demonstrated significant clinical effect and quality of life-enhancing capacity in clinical trials. In these, dupilumab-associated conjunctivitis where reported in a minority of patients. The present case series describe 10 patients treated with dupilumab where eye complications were very common. We have described patient characteristics, including FLG mutations, atopic history and clinical effect of dupilumab. Nine of 10 developed eye-complications, most commonly conjunctivitis (in 7/10). Other adverse events were herpes simplex virus uveitis and varicella-zoster virus meningitis. Although our case series is small, we conclude that dupilumab is an effective treatment option in severe atopic dermatitis, but that the risk of adverse events from the eyes and recurrence of herpes virus infections should be kept in mind. Close collaboration with an ophthalmologist is recommended, especially among patients with severe, long-lasting atopic dermatitis and/or previous eye disease.

Balancing immunosuppression and infection: recurrent enterovirus encephalitis in SLE.

A young woman with systemic lupus erythematosus (SLE) developed recurrent enterovirus meningoencephalitis while taking prednisolone, azathioprine and rituximab. After reducing the immunosuppression, she developed a central nervous system (CNS) flare of SLE, with enterovirus still present in the cerebrospinal fluid (CSF). There are no evidence-based specific treatments for enterovirus encephalitis, but she responded well to intravenous immunoglobulin alongside pulsed methylprednisolone and rituximab. This case highlights the difficulties in managing people with co-existing infective and autoimmune conditions, especially if each affects the CNS. A viral infection and SLE flare can resemble one another clinically, although here the radiological differentiation of CNS lupus versus enterovirus encephalitis helped to guide the diagnosis.

Herpes zoster meningitis in immunocompetent children: Two case reports and a literature review.

We encountered two cases of Herpes zoster (HZ) meningitis, a rarely occurring complication of HZ, in previously healthy children. One patient treated with i.v. acyclovir (ACV, 31 mg/kg/day) did not recover. His symptoms were relieved somewhat by increased ACV dosage, but it caused transient renal dysfunction. Another patient treated with i.v. ACV (30 mg/kg/day) recovered. Treatment for HZ meningitis in immunocompetent children has not been established. In a literature review, 80% of 20 patients were treated with the usual dose of ACV 15-30 mg/kg/day. The present cases suggest that a high dosage of ACV up to 60 mg/kg/day should be considered (while monitoring for side-effects) unless symptoms improve. In the review, one of every three vaccine-strain Varicella zoster virus (VZV) cases was severe, whereas the present cases resulted from wild type. Further investigations must examine different clinical characteristics of HZ meningitis caused by wild-type and vaccine-strain VZV.

Mediators and Biomarkers of Inflammation in Meningitis: Cytokine and Peptidome Profiling of Cerebrospinal Fluid.

Differential diagnosis of bacterial and viral meningitis is an urgent problem of the modern clinical medicine. Early and accurate detection of meningitis etiology largely determines the strategy of its treatment and significantly increases the likelihood of a favorable outcome for the patient. In the present work, we analyzed the peptidome and cytokine profiles of cerebrospinal fluid (CSF) of 17 patients with meningitis of bacterial and viral etiology and of 20 neurologically healthy controls. In addition to the identified peptides (potential biomarkers), we found significant differences in the cytokine status of the CSF of the patients. We found that cut-off of 100 pg/ml of IL-1ß, TNF, and GM-CSF levels discriminates bacterial and viral meningitis with 100% specificity and selectivity. We demonstrated for the first time the reduction in the level of two cytokines, IL-13 and GM-CSF, in the CSF of patients with viral meningitis in comparison with the controls. The decrease in GM-CSF level in the CSF of patients with viral meningitis can be explained by a disproportionate increase in the levels of cytokines IL-10, IFN-γ, and IL-4, which inhibit the GM-CSF expression, whereas IL-1, IL-6, and TNF activate it. These observations suggest an additional approach for differential diagnosis of bacterial and viral meningitis based on the normalized ratio IL-10/IL-1ß and IL-10/TNF > 1, as well as on the ratio IFN-γ/IL-1ß and IFN-γ/TNF < 0.1. Our findings extend the panel of promising clinical and diagnostic biomarkers of viral and bacterial meningitis and reveal opposite changes in the cytokine expression in meningitis due to compensatory action of pro- and antiinflammatory factors.

Myelomonocytic cell recruitment causes fatal CNS vascular injury during acute viral meningitis.

Lymphocytic choriomeningitis virus infection of the mouse central nervous system (CNS) elicits fatal immunopathology through blood-brain barrier breakdown and convulsive seizures. Although lymphocytic-choriomeningitis-virus-specific cytotoxic T lymphocytes (CTLs) are essential for disease, their mechanism of action is not known. To gain insights into disease pathogenesis, we observed the dynamics of immune cells in the meninges by two-photon microscopy. Here we report visualization of motile CTLs and massive secondary recruitment of pathogenic monocytes and neutrophils that were required for vascular leakage and acute lethality. CTLs expressed multiple chemoattractants capable of recruiting myelomonocytic cells. We conclude that a CD8(+) T-cell-dependent disorder can proceed in the absence of direct T-cell effector mechanisms and rely instead on CTL-recruited myelomonocytic cells.

Neuroinvasive disease and West Nile virus infection, North Dakota, USA, 1999-2008.

To determine risk for West Nile virus (WNV) neuroinvasive disease in North Dakota, we tested plasma samples from blood donors for WNV IgG and compared infection rates with reported WNV neuroinvasive disease incidence. We estimate that 1 in 244 WNV infections leads to neuroinvasive disease; risk is substantially increased among men and older persons.

Natalizumab and HSV meningitis.

Natalizumab (Tysabri, Biogen Idec and Elan Pharmaceuticals) is a monoclonal antibody approved for use in patients with relapsing multiple sclerosis (MS) as well as moderate to severe Crohn's disease. We report the first case of a patient with a history of MS, on monthly natalizumab, who developed HSV-2 meningitis. We discuss the mechanism of action of natalizumab and review what is known about the reactivation of herpes infection in association with this medication. The question of herpes simplex virus (HSV) and varicella zoster virus (VZV) prophylaxis for patients is raised.

Acute inflammatory biomarkers in cerebrospinal fluid as indicators of blood cerebrospinal fluid barrier damage in Japanese subjects with infectious meningitis.

BACKGROUND: The blood-cerebrospinal fluid barrier (BCB) has selectivity for protein components with different molecular weights. Protein components in the cerebrospinal fluid (CSF) change when the BCB is damaged. We calculated the alpha2 macroglobulin (alpha2M) index as an indicator of BCB permeability from the point of view of molecular weight and evaluated the relationship between the alpha2M index and CSF concentrations of the inflammatory biomarkers interleukin-6 (IL-6), C-reactive protein (CRP), and serum amyloid A (SAA) in Japanese subjects with infectious meningitis, in order to determine the clinical significance of those inflammatory biomarkers in CSF. METHODS: IL-6, CRP, and SAA levels in CSF and serum were measured using various methods. The alpha2M index was calculated as the ratio of alpha2M (CSF/serum) to albumin (CSF/serum). RESULTS: CSF IL-6 levels were higher than serum IL-6 levels in 16 patients with infectious meningitis. The difference in CSF IL-6 and CRP levels between mycotic or bacterial meningitis cases and healthy controls and in CSF SAA levels between all infectious meningitis cases and healthy controls were significant. There was a significant positive correlation between CSF levels of CRP or SAA and alpha2M indices. CONCLUSIONS: Markedly increased levels of IL-6 in the CSF of patients with infectious meningitis may reflect the degree of intrathecal inflammation. On the other hand, increased CSF levels of CRP in patients with infectious meningitis, particularly mycotic or bacterial meningitis, and SAA in patients with all infectious meningitis may reflect the degree of damage to the BCB.

Meningitis Caused by the Live Varicella Vaccine Virus: Metagenomic Next Generation Sequencing, Immunology Exome Sequencing and Cytokine Multiplex Profiling.

Varicella vaccine meningitis is an uncommon delayed adverse event of vaccination. Varicella vaccine meningitis has been diagnosed in 12 children, of whom 3 were immunocompromised. We now report two additional cases of vaccine meningitis in twice-immunized immunocompetent children and we perform further testing on a prior third case. We used three methods to diagnose or investigate cases of varicella vaccine meningitis, none of which have been used previously on this disease. These include metagenomic next-generation sequencing and cytokine multiplex profiling of cerebrospinal fluid and immunology exome analysis of white blood cells. In one new case, the diagnosis was confirmed by metagenomic next-generation sequencing of cerebrospinal fluid. Both varicella vaccine virus and human herpesvirus 7 DNA were detected. We performed cytokine multiplex profiling on the cerebrospinal fluid of two cases and found ten elevated biomarkers: interferon gamma, interleukins IL-1RA, IL-6, IL-8, IL-10, IL-17F, chemokines CXCL-9, CXCL-10, CCL-2, and G-CSF. In a second new case, we performed immunology exome sequencing on a panel of 356 genes, but no errors were found. After a review of all 14 cases, we concluded that (i) there is no common explanation for this adverse event, but (ii) ingestion of an oral corticosteroid burst 3-4 weeks before onset of vaccine meningitis may be a risk factor in some cases.

Neutrophils and Neutrophil Extracellular Traps Regulate Immune Responses in Health and Disease.

Neutrophils are first responders of antimicrobial host defense and sterile inflammation, and therefore, play important roles during health and disease [...].

Varicella zoster virus meningitis with hypoglycorrhachia in the absence of rash in an immunocompetent woman.

We report varicella-zoster virus (VZV) meningitis in a healthy adult woman with no antecedent rash and with hypoglycorrhachia. Cerebrospinal fluid (CSF) examination revealed the presence of VZV DNA, anti-VZV immunoglobulin G (IgG) antibody, and intrathecal production of anti-VZV IgG antibody.

Herpes zoster and meningitis resulting from reactivation of varicella vaccine virus in an immunocompetent child.

Herpes zoster complicated by meningitis has been mainly reported in immunocompromised patients after reactivation of wild-type varicella-zoster virus. We present one of the first cases of aseptic meningitis after herpes zoster caused by reactivation of vaccine-type varicella-zoster virus in an immunocompetent child. We also highlight the increasing role of both wild-type and vaccine strains of varicella-zoster virus as a cause of viral meningoencephalitis and the use of appropriate laboratory tools to rapidly and accurately identify the virus in order to provide prompt patient care and management.

Viral (aseptic) meningitis: A review.

Viral meningitis is an inflammation of the meninges associated with acute onset of meningeal symptoms and fever, pleocytosis of the cerebrospinal fluid, and no growth on routine bacterial culture. It is sometimes associated with viral encephalitis and meningoencephalitis. Viruses reach the central nervous system (CNS) hematogenously or in a retrograde manner from nerve endings. The viral etiology varies according to age and country. Molecular diagnostics technology has helped improve the rate of pathogen detection reducing unnecessary antibiotic use and length of hospitalization. Most of the viral infections detailed in this article have no specific treatment other than supportive care. Many of the viruses discussed are preventable by vaccination and proper skin protection against transmitting vectors.

Unbiased Metagenomic Sequencing for Pediatric Meningitis in Bangladesh Reveals Neuroinvasive Chikungunya Virus Outbreak and Other Unrealized Pathogens.

The burden of meningitis in low-and-middle-income countries remains significant, but the infectious causes remain largely unknown, impeding institution of evidence-based treatment and prevention decisions. We conducted a validation and application study of unbiased metagenomic next-generation sequencing (mNGS) to elucidate etiologies of meningitis in Bangladesh. This RNA mNGS study was performed on cerebrospinal fluid (CSF) specimens from patients admitted in the largest pediatric hospital, a World Health Organization sentinel site, with known neurologic infections (n = 36), with idiopathic meningitis (n = 25), and with no infection (n = 30), and six environmental samples, collected between 2012 and 2018. We used the IDseq bioinformatics pipeline and machine learning to identify potentially pathogenic microbes, which we then confirmed orthogonally and followed up through phone/home visits. In samples with known etiology and without infections, there was 83% concordance between mNGS and conventional testing. In idiopathic cases, mNGS identified a potential bacterial or viral etiology in 40%. There were three instances of neuroinvasive Chikungunya virus (CHIKV), whose genomes were >99% identical to each other and to a Bangladeshi strain only previously recognized to cause febrile illness in 2017. CHIKV-specific qPCR of all remaining stored CSF samples from children who presented with idiopathic meningitis in 2017 (n = 472) revealed 17 additional CHIKV meningitis cases, exposing an unrecognized meningitis outbreak. Orthogonal molecular confirmation, case-based clinical data, and patient follow-up substantiated the findings. Case-control CSF mNGS surveys can complement conventional diagnostic methods to identify etiologies of meningitis, conduct surveillance, and predict outbreaks. The improved patient- and population-level data can inform evidence-based policy decisions.IMPORTANCE Globally, there are an estimated 10.6 million cases of meningitis and 288,000 deaths every year, with the vast majority occurring in low- and middle-income countries. In addition, many survivors suffer from long-term neurological sequelae. Most laboratories assay only for common bacterial etiologies using culture and directed PCR, and the majority of meningitis cases lack microbiological diagnoses, impeding institution of evidence-based treatment and prevention strategies. We report here the results of a validation and application study of using unbiased metagenomic sequencing to determine etiologies of idiopathic (of unknown cause) cases. This included CSF from patients with known neurologic infections, with idiopathic meningitis, and without infection admitted in the largest children's hospital of Bangladesh and environmental samples. Using mNGS and machine learning, we identified and confirmed an etiology (viral or bacterial) in 40% of idiopathic cases. We detected three instances of Chikungunya virus (CHIKV) that were >99% identical to each other and to a strain previously recognized to cause systemic illness only in 2017. CHIKV qPCR of all remaining stored 472 CSF samples from children who presented with idiopathic meningitis in 2017 at the same hospital uncovered an unrecognized CHIKV meningitis outbreak. CSF mNGS can complement conventional diagnostic methods to identify etiologies of meningitis, and the improved patient- and population-level data can inform better policy decisions.