Whole-Exome Sequencing of Patients With Recurrent HSV-2 Lymphocytic Mollaret Meningitis.

Recurrent lymphocytic meningitis, also referred to as Mollaret meningitis, is a rare neurological disease characterized mainly by reactivation of herpes simplex virus 2 (HSV-2) from sensory ganglia. However, the underlying host immune determinants and viral factors rendering some individuals unable to maintain HSV-2 latency are largely unknown. We collected a cohort of 15 patients diagnosed with Mollaret meningitis. By whole-exome sequencing we identified rare host genetic variants predicted to be deleterious in molecules involved in (1) ubiquitin-proteasome pathways, (2) the autophagy machinery, and (3) cell proliferation/apoptosis. Moreover, infection of patient cells with HSV-2 or stimulation by virus-derived double-stranded DNA ligands revealed reduced antiviral interferon responses in most patients. These findings may contribute to a better understanding of disease pathogenesis and protective immunity to HSV in the central nervous system, and may ultimately be of importance for identification of targets for development of improved prophylaxis and treatment of this disease.

Annexin A1 Attenuates Neutrophil Migration and IL-6 Expression through Fpr2 in a Mouse Model of Streptococcus suis-Induced Meningitis.

Streptococcus suis serotype 2 is a crucial pathogenic cause of bacterial meningitis, a life-threatening disease with neurological sequelae and high rates of mortality. Inflammation triggered by S. suis infection must be precisely regulated to prevent further tissue damage. As a glucocorticoid anti-inflammatory mediator, annexin A1 (AnxA1) mainly acts through formyl peptide receptor 2 (Fpr2) to alleviate inflammation in the peripheral system. In this study, we evaluated the roles of AnxA1 and Fpr2 in a mouse model of S. suis meningitis created via intracisternal infection in Fpr2-deficient (Fpr2-/-) and wild-type (WT) mice. We revealed that Fpr2-/- mice were highly susceptible to S. suis meningitis, displaying increased inflammatory cytokine levels, bacterial dissemination, and neutrophil migration compared with WT mice. Additionally, AnxA1 exerted anti-inflammatory effects through Fpr2, such as attenuation of leukocyte infiltration, inflammatory mediator production, and astrocyte or microglial activation in the brain. Importantly, we found that the antimigratory function of AnxA1 decreases neutrophil adherence to the endothelium through Fpr2. Finally, an in vitro study revealed that AnxA1 potentially suppresses interleukin-6 (IL-6) expression through the Fpr2/p38/COX-2 pathway. These data demonstrated that Fpr2 is an anti-inflammatory receptor that regulates neutrophil migration in mice with S. suis meningitis and identified AnxA1 as a potential therapeutic option.

[Cerebrospinal fluid TP53 gene mutation in patients with lung cancer associated meningitis and its clinical implications].

Objective: To observe the role of cerebrospinal fluid (CSF) TP53 gene mutation in lung cancer associated meningitis. Methods: A retrospective analysis was performed on 35 patients diagnosed with lung cancer associated meningitis at the Second Hospital of Hebei Medical University from December 2015 to December 2018.All patients underwent the next-generation sequencing of CSF, and TP53 gene was found to be mutant or wild type, including 23 patients with TP53 mutant type and 12 patients with TP53 wild type. The clinical characteristics, CSF leukocyte, protein, glucose, chloride, Karnofsky performance (KPS) and overall survival were observed. Results: Headache, nausea and vomiting were the main clinical manifestations in both groups.There were no significant differences in CSF pressure, leukocyte, biochemical indicators and KPS between the two groups. The average time from diagnosis of lung cancer to diagnosis of lung cancer associated meningitis in the TP53 mutant group was significantly shorter than that in the TP53 wild type group (5.79 months vs 25.5 months).The median survival time of patients in the TP53 mutant group from lung cancer diagnosis to the observation endpoint was 19.77 months, while it was 88.73 months in the TP53 wild type group, and the difference was statistically significant (P=0.043). Conclusions: Mutation in the tumor suppressor gene TP53 can be detected in the CSF of patients with lung cancer associated meningitis. Patients with such mutation have earlier meningeal metastasis and shorter median survival time.

Dexamethasone Downregulates Expressions of 14-3-3ß and γ-Isoforms in Mice with Eosinophilic Meningitis Caused by Angiostrongylus cantonensis Infection.

Steroids are commonly used in patients with eosinophilic meningitis caused by A. cantonensis infections. The mechanism steroids act on eosinophilic meningitis remains unclear. In this mouse experiments, expressions of 14-3-3 isoform ß and γ proteins significantly increased in the CSF 2-3 weeks after the infection, but not increasedin the dexamethasone-treated group. Expression of 14-3-3 ß, γ, ε, and θ isoforms increased in brain meninges over the 3-week period after infection and decreased due to dexamethasone treatment. In conclusion, administration of dexamethasone in mice with eosinophilic meningitis decreased expressions of 14-3-3 isoform proteins in the CSF and in brain meninges.

Identifying genes associated with invasive disease in S. pneumoniae by applying a machine learning approach to whole genome sequence typing data.

Streptococcus pneumoniae, a normal commensal of the upper respiratory tract, is a major public health concern, responsible for substantial global morbidity and mortality due to pneumonia, meningitis and sepsis. Why some pneumococci invade the bloodstream or CSF (so-called invasive pneumococcal disease; IPD) is uncertain. In this study we identify genes associated with IPD. We transform whole genome sequence (WGS) data into a sequence typing scheme, while avoiding the caveat of using an arbitrary genome as a reference by substituting it with a constructed pangenome. We then employ a random forest machine-learning algorithm on the transformed data, and find 43 genes consistently associated with IPD across three geographically distinct WGS data sets of pneumococcal carriage isolates. Of the genes we identified as associated with IPD, we find 23 genes previously shown to be directly relevant to IPD, as well as 18 uncharacterized genes. We suggest that these uncharacterized genes identified by us are also likely to be relevant for IPD.

Comparison of Common Monogenic Defects in a Large Predominantly Antibody Deficiency Cohort.

BACKGROUND: Predominantly antibody deficiencies (PADs) are the most common primary immunodeficiencies, characterized by hypogammaglobulinemia and inability to generate effective antibody responses. OBJECTIVE: We intended to report most common monogenic PADs and to investigate how patients with PAD who were primarily diagnosed as suffering from agammaglobulinemia, hyper-IgM (HIgM) syndrome, and common variable immunodeficiency (CVID) have different clinical and immunological findings. METHODS: Stepwise next-generation sequencing and Sanger sequencing were performed for confirmation of the mutations in the patients clinically diagnosed as suffering from agammaglobulinemia, HIgM syndrome, and CVID. RESULTS: Among 550 registered patients, the predominant genetic defects associated with agammaglobulinemia (48 Bruton's tyrosine kinase [BTK] and 6 µ heavy chain deficiencies), HIgM syndrome (21 CD40 ligand and 7 activation-induced cytidine deaminase deficiencies), and CVID (17 lipopolysaccharides-responsive beige-like anchor deficiency and 12 atypical Immunodeficiency, Centromeric instability, and Facial dysmorphism syndromes) were identified. Clinical disease severity was significantly higher in patients with µ heavy chain and CD40 ligand mutations compared with patients with BTK (P = .003) and activation-induced cytidine deaminase (P = .009) mutations. Paralysis following live polio vaccination was considerably higher in patients with µ heavy chain deficiency compared with BTK deficiency (P < .001). We found a genotype-phenotype correlation among patients with BTK mutations regarding clinical manifestation of meningitis and chronic diarrhea. Surprisingly, we noticed that first presentations in most patients with Immunodeficiency, Centromeric instability, and Facial dysmorphism were respiratory complications (P = .008), whereas first presentations in patients with lipopolysaccharides-responsive beige-like anchor deficiency were nonrespiratory complications (P = .008). CONCLUSIONS: This study highlights similarities and differences in the clinical and genetic spectrum of the most common PAD-associated gene defects. This comprehensive comparison will facilitate clinical decision making, and improve prognosis and targeted treatment.

Genotipos de Neisseria meningitidis aislados de pacientes con enfermedad meningocócica en Paraguay, 1996-2015 / Genotypes of Neisseria meningitidis isolates in patients with meningococcal meningitis in Paraguay, 1996-2015 / Genótipos de Neisseria meningitidis isolados de pacientes com doença meningocócica no Paraguai, 1996-2015

RESUMEN Objetivo Describir las características fenotípicas y genotípicas de cepas de Neisseria meningitidis aisladas de enfermedad meningocócica en Paraguay entre 1996 y 2015. Métodos Se estudiaron por métodos microbiológicos convencionales y técnicas moleculares 114 aislamientos de N. meningitidis y 12 muestras clínicas sin aislamiento confirmadas por reacción en cadena de la polimerasa (PCR) que fueron remitidas por los diferentes centros centinelas y centros colaboradores de Paraguay. Resultados El grupo de edad más afectado fue el de menores de 1 año (19,0%), seguido por el de 1 a 5 años (17,5%). Un mayor porcentaje de las cepas se aisló de casos de meningitis (81,7%) y el serogrupo B se encontró en 60,3% de los casos. Los fenotipos más frecuentes fueron B:4:P1.14 (16,0%), B:15:P1.5, C:NT:NST y W:NT:P1.2 (10,5%), respectivamente. Los complejos clonales prevalentes fueron ST-11/ET37 complex 29,6% (8/27) con predominio del serogrupo W (6/8), ST-35 complex 18,5% (5/27) en el serogrupo B (4/4), y ST-32/ET5 complex 14,8% (4/16) en el serogrupo B (5/5). Conclusiones En Paraguay la enfermedad meningocócica es relativamente infrecuente. Los análisis de distribución de serogrupo muestran que el más frecuente es el B y en los últimos dos años aumentaron los casos de enfermedad meningocócica por C y W. Los complejos clonales encontrados se correlacionan con los hallados en la región del Cono Sur. Debido al alto nivel de virulencia de N. meningitidis, su vigilancia debe constituir una prioridad estratégica de los sistemas de salud pública nacionales y regionales para prevenir brotes epidémicos y apoyar la toma de decisiones en salud pública.

ABSTRACT Objective Describe the phenotypical and genotypical characteristics of Neisseria meningitidis isolates from cases of meningococcal disease in Paraguay between 1996 and 2015. Methods Conventional microbiological methods and molecular techniques were used to study 114 isolates of N. meningitidis and 12 clinical samples without isolation (confirmed by polymerase chain reaction), provided by various sentinel centers and collaborating centers in Paraguay. Results The most affected age group was children under 1 year (19.0%), followed by 1-5-year-olds (17.5%). The highest percentage of strains was isolated in meningitis cases (81.7%) and serogroup B was found in 60.3% of cases. The most frequent phenotypes were B:4:p1.14 (16.0%), B:15:p1.5, C:nt:nst, and W:nt:p1.2 (10.5%), respectively. The prevalent clonal complexes were: ST-11/ET37 complex, 29.6% (8/27), predominantly serogroup W (6/8); ST-35 complex, 18.5% (5/27), in serogroup B (4/4); and ST-32/ET5 complex, 14.8% (4/16), in serogroup B (5/5). Conclusions Meningococcal meningitis is relatively uncommon in Paraguay. Distribution analysis showed that serogroup B is the most common and that the number of cases of meningococcal disease caused by serogroups C and W increased in the last two years. The identified clonal complexes were correlated with those found in the Southern Cone region. Due to the high virulence of N. meningitidis, its surveillance should be a strategic priority of national and regional public health systems to prevent epidemic outbreaks and support public health decision-making.

RESUMO Objetivo Descrever as características fenotípicas e genotípicas de cepas de Neisseria meningitidis isoladas de casos de doença meningocócica no Paraguai entre 1996 e 2015. Métodos Foram estudados por métodos microbiológicos convencionais e técnicas moleculares 114 isolados de N. meningitidis e 12 amostras clínicas sem isolamento confirmadas por reação em cadeia da polimerase (PCR) enviados por diferentes centros-sentinela e centros colaboradores do Paraguai. Resultados A faixa etária mais afetada foi a de crianças menores de 1 ano (19,0%) e crianças de 1 a 5 anos (17,5%). Uma maior porcentagem de cepas foi isolada de casos de meningite (81,7%) e o sorogrupo B foi identificado em 60,3% dos casos. Os fenótipos mais comuns foram B:4:P1.14 (16,0%), B:15:P1.5, C:NT:NST e W:NT:P1.2 (10,5%), respectivamente. Os complexos clonais mais prevalentes foram o complexo ST-11/ET37 (29,6%, 8/27) com predomínio no sorogrupo W (6/8), complexo ST-35 (18,5%, 5/27) no sorogrupo B (4/4) e complexo ST-32/ET5 (14,8%, 4/16) no sorogrupo B (5/5). Conclusões A doença meningocócica é relativamente pouco comum no Paraguai. A análise da distribuição dos sorogrupos demonstrou que o sorogrupo B é o mais prevalente e, nos últimos dois anos, ouve um aumento nos casos de doença meningocócica pelos sorogrupos C e W. Os complexos clonais encontrados se correlacionam com os achados na região do Cone Sul. Devido à alta virulência da N. meningitidis, a vigilância deste agente deve ser uma prioridade estratégica dos sistemas de saúde pública nacionais e regionais para prevenir surtos epidêmicos e subsidiar a tomada de decisão em saúde pública.

New molecular tools for meningitis diagnostics in Ethiopia - a necessary step towards improving antimicrobial prescription.

BACKGROUND: Meningitis remains a top cause of premature death and loss of disability-adjusted life years in low-income countries. In resource-limited settings, proper laboratory diagnostics are often scarce and knowledge about national and local epidemiology is limited. Misdiagnosis, incorrect treatment and overuse of antibiotics are potential consequences, especially for viral meningitis. METHODS: A prospective study was conducted over three months in a teaching hospital in Ethiopia with limited laboratory resources. Cerebrospinal fluid (CSF) samples from patients with suspected meningitis were analysed using a multiplex PCR-based system (FilmArray, BioFire), in addition to basic routine testing with microscopy and culture. Clinical data, as well as information on treatment and outcome were collected. RESULTS: Two hundred and eighteen patients were included; 117 (54%) neonates (0-29 days), 63 (29%) paediatrics (1 month-15 years) and 38 (17%) adults (≥16 years). Of 218 CSF samples, 21 (10%) were PCR positive; 4% in neonates, 14% in paediatrics and 18% in adults. Virus was detected in 57% of the PCR positive samples, bacteria in 33% and fungi in 10%. All CSF samples that were PCR positive for a bacterial agent had a white cell count ≥75 cells/mm3 and/or turbid appearance. The majority (90%) of patients received more than one antibiotic for treatment of the meningitis episode. There was no difference in the mean number of different antibiotics received or in the cumulative number of days with antibiotic treatment between patients with a microorganism detected in CSF and those without. CONCLUSIONS: A rapid molecular diagnostic system was successfully implemented in an Ethiopian setting without previous experience of molecular diagnostics. Viral meningitis was diagnosed for the first time in routine clinical practice in Ethiopia, and viral agents were the most commonly detected microorganisms in CSF. This study illustrates the potential of rapid diagnostic tests for reducing antibiotic usage in suspected meningitis cases. However, the cost of consumables for the molecular diagnostic system used in this study limits its use in low-income countries.

Metabolic shift in the emergence of hyperinvasive pandemic meningococcal lineages.

Hyperinvasive lineages of Neisseria meningitidis, which persist despite extensive horizontal genetic exchange, are a major cause of meningitis and septicaemia worldwide. Over the past 50 years one such lineage of meningococci, known as serogroup A, clonal complex 5 (A:cc5), has caused three successive pandemics, including epidemics in sub-Saharan Africa. Although the principal antigens that invoke effective immunity have remained unchanged, distinct A:cc5 epidemic clones have nevertheless emerged. An analysis of whole genome sequence diversity among 153 A:cc5 isolates identified eleven genetic introgression events in the emergence of the epidemic clones, which primarily involved variants of core genes encoding metabolic processes. The acquired DNA was identical to that found over many years in other, unrelated, hyperinvasive meningococci, suggesting that the epidemic clones emerged by acquisition of pre-existing metabolic gene variants, rather than 'virulence' associated or antigen-encoding genes. This is consistent with mathematical models which predict the association of transmission fitness with the emergence and maintenance of virulence in recombining commensal organisms.

Variable clinical phenotypes of X-linked lymphoproliferative syndrome in China: Report of five cases with three novel mutations and review of the literature.

BACKGROUND: X-linked lymphoproliferative disease (XLP) is a rare life-threatening syndrome. Rapid recognition and definitive diagnosis are critical to improve the prognosis and survival of patients with XLP. Nowadays, little is known about patients with XLP in China. METHODS: We report the characterization of five Chinese XLP patients with three novel mutations and review the literature related to this syndrome. Male patients with fulminant infectious mononucleosis (FIM), Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (HLH) or persistent EBV viraemia were enrolled in this study. The patients' clinical features were assessed by retrieval of data from medical records. Immunological function included analysis of lymphocyte subsets and the detection of immunoglobulins G, A, M and/or E were evaluated by flow cytometry and nephelometry. Direct sequencing was used to detect SH2D1A/XIAP gene mutations. RESULTS: Twenty-two male patients with FIM, EBV-associated HLH or persistent EBV viraemia were evaluated among 421 PID patients in our centre. Four patients had SH2D1A mutations, and one patient had an XIAP mutation. The onset age of the 5 patients range from 1month to 4years which was earlier than that in the western world. The diagnosis age was between 16months and 9years with a long diagnosis lag (1-97months). Two of them had positive family history. The clinical phenotypes varied in different patients among which two patients with FHLH and hypogammaglobulinaemia, one with hypogammaglobulinaemia, lymphoma and aplastic anaemia (AA) which is the first case with AA in China, one with hypogammaglobulinaemia only and the other one with FHLH. For immunological function, three exhibited reduced CD4/CD8 ratios. Arg55stop mutations as well as splice mutation in intron 1 were most frequently found and exon 2 was the hottest exon in China. Two patients died at the time of diagnosis for severe infection or hepatic coma. Three were alive and waiting for haematopoietic stem cell transplantation (HSCT). CONCLUSION: For patients with severe EBV-associated HLH, hypogammaglobulinaemia, lymphoma and aplastic anaemia, possibility of XLP should be considered and if confirmed, HSCT should be performed as soon as possible.

Evidence for an association between infant mortality and homozygosity for the arctic variant of carnitine palmitoyltransferase 1A.

PURPOSE: Infant mortality in Alaska is highest among Alaska Native people from western/northern Alaska, a population with a high prevalence of a genetic variant (c.1436C>T; the arctic variant) of carnitine palmitoyltransferase 1A (CPT1A). METHODS: We performed an unmatched case-control study to determine the relationship between the arctic variant and infant mortality. The cases were 110 Alaska Native infant deaths from 2006 to 2010 and the controls were 395 Alaska Native births from the same time period. In addition to the overall analysis, we conducted two subanalyses, one limited to subjects from western/northern Alaska and one limited to infants heterozygous or homozygous for the arctic variant. RESULTS: Among western/northern Alaska residents, 66% of cases and 61% of controls were homozygous (adjusted odds ratio (aOR): 2.5; 95% confidence interval (CI): 1.3, 5.0). Among homozygous or heterozygous infants, 58% of cases and 44% of controls were homozygous (aOR: 2.3; 95% CI: 1.3, 4.0). Deaths associated with infection were more likely to be homozygous (OR: 2.9; 95% CI: 1.0-8.0). Homozygosity was strongly associated with a premorbid history of pneumonia, sepsis, or meningitis. CONCLUSION: Homozygosity for the arctic variant is associated with increased risk of infant mortality, which may be mediated in part by an increase in infectious disease risk. Further studies are needed to determine whether the association we report represents a causal association between the CPT1A arctic variant and infectious disease-specific mortality.Genet Med 18 9, 933-939.

Extensive Admixture and Selective Pressure Across the Sahel Belt.

Genome-wide studies of African populations have the potential to reveal powerful insights into the evolution of our species, as these diverse populations have been exposed to intense selective pressures imposed by infectious diseases, diet, and environmental factors. Within Africa, the Sahel Belt extensively overlaps the geographical center of several endemic infections such as malaria, trypanosomiasis, meningitis, and hemorrhagic fevers. We screened 2.5 million single nucleotide polymorphisms in 161 individuals from 13 Sahelian populations, which together with published data cover Western, Central, and Eastern Sahel, and include both nomadic and sedentary groups. We confirmed the role of this Belt as a main corridor for human migrations across the continent. Strong admixture was observed in both Central and Eastern Sahelian populations, with North Africans and Near Eastern/Arabians, respectively, but it was inexistent in Western Sahelian populations. Genome-wide local ancestry inference in admixed Sahelian populations revealed several candidate regions that were significantly enriched for non-autochthonous haplotypes, and many showed to be under positive selection. The DARC gene region in Arabs and Nubians was enriched for African ancestry, whereas the RAB3GAP1/LCT/MCM6 region in Oromo, the TAS2R gene family in Fulani, and the ALMS1/NAT8 in Turkana and Samburu were enriched for non-African ancestry. Signals of positive selection varied in terms of geographic amplitude. Some genomic regions were selected across the Belt, the most striking example being the malaria-related DARC gene. Others were Western-specific (oxytocin, calcium, and heart pathways), Eastern-specific (lipid pathways), or even population-restricted (TAS2R genes in Fulani, which may reflect sexual selection).

Phenotypic and genotypic characteristics of cryopyrin-associated periodic syndrome: a series of 136 patients from the Eurofever Registry.

OBJECTIVE: To evaluate genetic, demographic and clinical features in patients with cryopyrin-associated periodic syndrome (CAPS) from the Eurofever Registry, with a focus on genotype-phenotype correlations and predictive disease severity markers. METHODS: A web-based registry retrospectively collected data on patients with CAPS. Experts in the disease independently validated all cases. Patients carrying NLRP3 variants and germline-mutation-negative patients were included. RESULTS: 136 patients were analysed. The median age at disease onset was 9 months, and the median duration of follow-up was 15 years. Skin rash, musculoskeletal involvement and fever were the most prevalent features. Neurological involvement (including severe complications) was noted in 40% and 12% of the patients, respectively, with ophthalmological involvement in 71%, and neurosensory hearing loss in 42%. 133 patients carried a heterozygous, germline mutation, and 3 patients were mutation-negative (despite complete NLRP3 gene screening). Thirty-one different NLRP3 mutations were recorded; 7 accounted for 78% of the patients, whereas 24 rare variants were found in 27 cases. The latter were significantly associated with early disease onset, neurological complications (including severe complications) and severe musculoskeletal involvement. The T348M variant was associated with early disease onset, chronic course and hearing loss. Neurological involvement was less strongly associated with V198M, E311 K and A439 V alleles. Early onset was predictive of severe neurological complications and hearing loss. CONCLUSIONS: Patients carrying rare NLRP3 variants are at risk of severe CAPS; onset before the age of 6 months is associated with more severe neurological involvement and hearing loss. These findings may have an impact on treatment decisions.

Increased concentration of interferon lambda-3, interferon beta and interleukin-10 in the cerebrospinal fluid of patients with tick-borne encephalitis.

Tick-borne encephalitis (TBE) has a wide clinical spectrum, from asymptomatic to severe encephalitis, and host-dependent factors determining the outcome remain elusive. We have measured concentrations of pro-inflammatory/Th1 interferon-γ (IFNγ), immunomodulatory/Th2 interleukin-10 (IL-10), anti-viral type I (IFNß) and type III (IFNλ3) interferons in cerebrospinal fluid (csf) and serum of 18 TBE patients, simultaneously genotyped for polymorphisms associated with the expression of genes IFNL3 (coding IFNλ3), IL10, CD209 and CCR5. IL-10, IFNß and IFNλ3 were up-regulated in csf, with IFNλ3 level higher in patients with the milder clinical presentation (meningitis) than in meningoencephalitis. There was an increased serum IFNß and a tendency for increased serum IL-10 in meningitis patients. Genotype in rs12979860 locus upstream of IFNL3 was associated with IFNλ3 expression and in rs287886 (CD209) - IL-10 expression. IL-10, IFNß and IFNλ3 are expressed and play a protective role in TBE and their expression in TBE patients is associated with genetic polymorphisms.

MicroRNA expressions associated with eosinophilic meningitis caused by Angiostrongylus cantonensis infection in a mouse model.

Angiostrongylus cantonensis (A. cantonensis) infection is the major cause of eosinophilic meningitis (EM). Severe cases or infant and child cases have poor prognosis. MicroRNAs (miRNAs) play important roles in inflammation; however, little is known about the roles in brain inflammation caused by A. cantonensis. In this study, Illumina deep sequencing and bioinformatics were used to determine the abundance and differential expression of miRNAs in the brain tissues of a mouse model. A total of 648 conserved miRNAs were identified, 157 of which were significantly differentially expressed between infected mice and normal mice. The five most fold-changed miRNAs were miR-511-5p, miR-511-3p, miR-223-3p, miR-155-5p and miR-206-3p. These expressions of miR-511, miR-223, miR-155, miR-206, miR-142 and miR-21a were validated by quantitative reverse transcription polymerase chain reaction (RT-PCR). The analysis of these miRNAs showed that miR-511-3p was more abundant than the miR-511-5p strand, and increased to a peak in 21 days after A. cantonensis infection, miR-223 might be a potential indicator of disease severity and the upregulation of miR-155-5p after stimulation with the somatic antigen of phase IV A. cantonensis implied its involvement in the central nervous system (CNS) inflammation induced by A. cantonensis infection. These observations suggest that miRNAs may play important roles in the regulation of EM caused by A. cantonensis infection.

[A case of colchicine-responsive Mollaret's meningitis with MEFV gene mutation].

A 66-year-old woman was admitted to our hospital with recurrent meningitis. She presented with 10 episodes of meningitis in 10 months. Examination of cerebrospinal fluid demonstrated pleocytosis, with neutrophils dominant at the early stage, and lymphocytes dominant at the late stage. Mollaret cells were found and the level of IL-6 was increased in cerebrospinal fluid. Several antibiotics and antiviral agents failed to prevent relapse. However, colchicine therapy successfully prevented the recurrence of meningitis. Genetic testing for familial Mediterranean fever (FMF) showed a mutation in the MEFV gene. It is difficult to diagnose the cause of Mollaret's meningitis in some patients. FMF, neuro-Behçet's disease, and neuro-Sweet disease should be included in the differential diagnosis of recurrent meningitis. In addition, colchicine therapy can prevent the relapse of meningitis in such cases.

Dexamethasone downregulated the expression of CSF 14-3-3ß protein in mice with eosinophilic meningitis caused by Angiostrongylus cantonensis infection.

Angiostrongylus cantonensis is the main causative agent of human eosinophilic meningitis in Southeast Asia and the Pacific Islands. A previous study demonstrated that the 14-3-3ß protein is a neuropathological marker in monitoring neuronal damage in meningitis. Steroids are commonly used in patients with eosinophilic meningitis caused by A. cantonensis infection. However, the mechanism by which steroids act in eosinophilic meningitis is unknown. We hypothesized that the beneficial effect of steroids on eosinophilic meningitis is partially mediated by the down-regulation of 14-3-3ß protein expression in the cerebrospinal fluid (CSF). In this animal study, we determined the dynamic changes of 14-3-3ß protein in mice with eosinophilic meningitis. The 14-3-3ß protein in serum and CSF was increased in week 2 and 3 after infections. Dexamethasone administration significantly decreased the amounts of CSF 14-3-3ß protein. By developing an in-house ELISA to measure 14-3-3ß protein, it was found that the amounts of 14-3-3ß protein in the CSF and serum increased over a three-week period after infection. There was a remarkable reduction of 14-3-3ß protein in the CSF after 2 weeks of dexamethasone treatment. In conclusion, the administration of corticosteroids in mice with eosinophilic meningitis decreased the expression of 14-3-3ß protein in the CSF.

Antigen sequence typing of outer membrane protein (fetA) gene of Neisseria meningitidis serogroup A from Delhi & adjoining areas.

BACKGROUND & OBJECTIVES: Meningitis caused by Neisseria meningitidis is a fatal disease. Meningococcal meningitis is an endemic disease in Delhi and irregular pattern of outbreaks has been reported in India. All these outbreaks were associated with serogroup A. Detailed molecular characterization of N. meningitidis is required for the management of this fatal disease. In this study, we characterized antigenic diversity of surface exposed outer membrane protein (OMP) FetA antigen of N. meningitidis serogroup A isolates obtained from cases of invasive meningococcal meningitis in Delhi, India. METHODS: Eight isolates of N. meningitidis were collected from cerebrospinal fluid during October 2008 to May 2011 from occasional cases of meningococcal meningitis. Seven isolates were from outbreaks of meningococcal meningitis in 2005-2006 in Delhi and its adjoining areas. These were subjected to molecular typing of fetA gene, an outer membrane protein gene. RESULTS: All 15 N. meningitides isolates studied were serogroup A. This surface exposed porin is putatively under immune pressure. Hence as a part of molecular characterization, genotyping was carried out to find out the diversity in outer membrane protein (FetA) gene among the circulating isolates of N. meningitidis. All 15 isolates proved to be of the same existing allele type of FetA variable region (VR) when matched with global database. The allele found was F3-1 for all the isolates. INTERPRETATION & CONCLUSIONS: There was no diversity reported in the outer membrane protein FetA in the present study and hence this protein appeared to be a stable molecule. More studies on molecular characterization of FetA antigen are required from different serogroups circulating in different parts of the world.

Combining quantitative genetic footprinting and trait enrichment analysis to identify fitness determinants of a bacterial pathogen.

Strains of Extraintestinal Pathogenic Escherichia c oli (ExPEC) exhibit an array of virulence strategies and are a major cause of urinary tract infections, sepsis and meningitis. Efforts to understand ExPEC pathogenesis are challenged by the high degree of genetic and phenotypic variation that exists among isolates. Determining which virulence traits are widespread and which are strain-specific will greatly benefit the design of more effective therapies. Towards this goal, we utilized a quantitative genetic footprinting technique known as transposon insertion sequencing (Tn-seq) in conjunction with comparative pathogenomics to functionally dissect the genetic repertoire of a reference ExPEC isolate. Using Tn-seq and high-throughput zebrafish infection models, we tracked changes in the abundance of ExPEC variants within saturated transposon mutant libraries following selection within distinct host niches. Nine hundred and seventy bacterial genes (18% of the genome) were found to promote pathogen fitness in either a niche-dependent or independent manner. To identify genes with the highest therapeutic and diagnostic potential, a novel Trait Enrichment Analysis (TEA) algorithm was developed to ascertain the phylogenetic distribution of candidate genes. TEA revealed that a significant portion of the 970 genes identified by Tn-seq have homologues more often contained within the genomes of ExPEC and other known pathogens, which, as suggested by the first axiom of molecular Koch's postulates, is considered to be a key feature of true virulence determinants. Three of these Tn-seq-derived pathogen-associated genes--a transcriptional repressor, a putative metalloendopeptidase toxin and a hypothetical DNA binding protein--were deleted and shown to independently affect ExPEC fitness in zebrafish and mouse models of infection. Together, the approaches and observations reported herein provide a resource for future pathogenomics-based research and highlight the diversity of factors required by a single ExPEC isolate to survive within varying host environments.