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P Lebon

Publications and source records attributed to P Lebon.

At least 19 recordsLinked to original sources
PubMed1999

[Severe forms of rubella encephalitis: arguments for a better vaccination policy].

BACKGROUND: Two cases of rubella encephalitis in young adults are reported. CASES REPORTS: 2 patients, 19 and 16-year-old, presented with severe encephalitis. One required mechanical ventilation. Neither were vaccinated against rubella. MRI scan of the brain was normal. The diagnosis was confirmed by serology. Good recovery was noted in both patients. DISCUSSION: Both cases of rubella encephalitis occurring in young adults illustrate the severity of this rare disease. As already shown in Finland, improvement with the French vaccination policy should lead to the prevention of rubella encephalitis.

Adolescent↗
PubMed1999

Progressive multifocal leucoencephalopathy with peripheral demyelinating neuropathy after autologous bone marrow transplantation for acute myeloblastic leukemia (FAB5).

Progressive multifocal leucoencephalopathy is an opportunistic JC virus-related pathology occurring in immunocompromised patients. We report a case of severe cellular immunodeficiency in a patient who underwent autologous bone marrow transplantation for acute myeloblastic leukemia, and who subsequently developed progressive multifocal leucoencephalopathy, an unusual pathology in this context. Progressive multifocal leucoencephalopathy was preceded by a peripheral demyelinating neuropathy. We discuss the possible link between these two neuropathies, the possible aggravation or activation from CMV infection, as well as the possible contribution of bone marrow purging in the resultant cellular immunodeficiency.

Adult↗
PubMed1999

Inhibition of interferon-inducible MxA protein expression by hepatitis B virus capsid protein.

Chronic hepatitis B treatment has been significantly improved by interferon (IFN) treatment. However, some studies have suggested that hepatitis B virus (HBV) might have a direct effect on the resistance to IFN. Defective particles, generated by spliced HBV RNA and associated with chronic hepatitis B, have been previously characterized; expression of these particles leads to cytoplasmic accumulation of the capsid protein. The aim of this study was to investigate the role of these defective genomes in IFN resistance. The global antiviral activity of IFN was studied by virus yield reduction assays, the expression of three IFN-induced antiviral proteins was analysed by Western blotting and confocal microscopy, and the regulation of MxA gene expression was studied by Northern blotting and the luciferase assay, in Huh7 cells transfected with a complete or the defective HBV genome. Results showed that the expression of the defective genome reduces the antiviral activity of IFN and that this modulation involves a selective inhibition of MxA protein induction by the HBV capsid protein. Our results also show the trans-suppressive effect of the HBV capsid on the MxA promoter, which might participate in this phenomenon. In conclusion, this study shows a direct interplay between the IFN-sensitive pathway and the capsid protein and might implicate this defective HBV genome in virus persistence.

Blotting, Northern↗
PubMed1998

Induction of interferon-alpha by glycoprotein D of herpes simplex virus: a possible role of chemokine receptors.

The induction of type I interferons by most RNA viruses is initiated by virus-derived double-stranded (ds)RNA. However, retro- and DNA-viruses, which do not synthesize dsRNA, must rely on different mechanisms of induction. For human immunodeficiency virus type 1 (HIV-1), recombinant glycoproteins 120 or 160 suffice to induce interferon (IFN)-alpha in blood-derived lymphocytes [H. Ankel, M. R. Capobianchi, C. Castilletti, and F. Dianzani (1994). Virology 205, 34-43]. Here we show that for herpes simplex virus type 1 (HSV-1) recombinant glycoprotein, gD is the major inducer, whereas gB, gC, gE, gG, gI, and the complex of gH and gL are poor inducers. The recombinant extramembrane fragment of gD was sufficient to induce IFN-alpha levels comparable to that of intact virus. Like with HIV-1, induction was inhibited by a monoclonal antibody that recognizes cerebrosides and sulfatides. Furthermore, monoclonal antibodies specific for the chemokine receptors CCR3 and CXCR4 also blocked induction. We conclude that HSV-1 induces IFN-alpha by interaction of its glycoprotein gD with appropriate receptors on IFN-producing cells. Based on the known receptor roles of galactosyl cerebrosides and chemokine receptors in HIV infection, such structures on IFN-producing cells could also participate in the induction of IFN-alpha by HSV-1.

Animals↗
PubMed1998

Characterization of the human analogue of a Scrapie-responsive gene.

We have recently described a novel mRNA denominated ScRG-1, the level of which is increased in the brains of Scrapie-infected mice (Dandoy-Dron, F., Guillo, F., Benboudjema, L., Deslys, J.-P., Lasmézas, C., Dormont, D., Tovey, M. G., and Dron, M. (1998) J. Biol. Chem. 273, 7691-7697). The increase in ScRG-1 mRNA in the brain follows the accumulation of PrPSc, the proteinase K-resistant form of the prion protein (PrP), and precedes the widespread neuronal death that occurs in late stage disease. In the present study, we have isolated a cDNA encoding the human counterpart of ScRG-1. Comparison of the human and mouse transcripts firmly established that both sequences encode a highly conserved protein of 98 amino acids that contains a signal peptide, suggesting that the protein may be secreted. Examination of the distribution of human ScRG-1 mRNA in adult and fetal tissues revealed that the gene was expressed primarily in the central nervous system as a 0.7-kilobase message and was under strict developmental control.

Adult↗
PubMed1998

[Procalcitonin, C-reactive protein and interleukin 6 in bacterial and viral meningitis in children].

OBJECTIVES: In young children with meningitis, blood or cerebrospinal fluid (CSF) analysis cannot differentiate all cases of viral meningitis (VM) from bacterial meningitis (BM). Empirical antibiotic therapy is often given. As new markers are needed, we compared serum proCalcitonin (PCT) with CSF analysis for C-reactive protein (CRP) and interleukin-6 (IL6). PATIENTS AND METHODS: PCT was measured with a chemoluminescent assay in the sera of 23 children (aged 3 months to 14 years) hospitalized for BM and in 51 patients with VM. RESULTS: Initial CRP (mean 143.3 mg/l, range 28-351 and mean 13.9, range 1-48), CSF proteins (mean 2.2, range 0.4-4.74 and mean 0.57, range 0.12-2.72) and white blood cell count in CSF (range 240-17500 and 20-3200) in BM and VM respectively, were not sufficiently discriminative to distinguish between BM and VM. Twenty-four of the 51 patients with VM were given antibiotics. IL6 values at admission showed an overlap zone (> 100 pg/ml in 7/19 patients with VM and < 100 pg/ml in 1/8 patients with BM. PCT was discriminative in all cases: mean PCT in BM was 61 micrograms/l (range 4.8-335) and 0.33 in VM (range 0-1.7; p < 0.001). No production of PCT was detected in CSF. After antibiotic therapy, PCT decreased and reached undetectable levels after recovery. CONCLUSION: PCT is a sensitive and specific marker for early diagnosis of viral meningitis versus bacterial meningitis in children.

Adolescent↗
PubMed1998

Aicardi-Goutières syndrome: an update and results of interferon-alpha studies.

Twenty-seven patients with familial encephalopathy with calcification of the basal ganglia and chronic cerebrospinal fluid (CSF) lymphocytosis (Aicardi-Goutières syndrome) are reviewed. In 19 children, the onset was within the first 4 months of life. Most patients had normal head circumference at birth, but 21 developed microcephaly between 3 and 12 months. Neuroimaging showed severe and progressive brain atrophy in all patients. The extent and intensity of the calcification was variable even in the same sibship. CSF lymphocytosis persisted beyond 12 months of age in 7 children. High levels of interferon-alpha were found in serum and CSF in 14 patients. The higher CSF levels suggest intrathecal synthesis. Tubuloreticular inclusions related to the presence of interferon were found in 4 additional children. The 19 patients still alive (6 older than 10 years) are profoundly disabled. However, the syndrome may present with individual variations in severity, rapidity of evolution, and imaging features. Neuropathological examination in 2 patients failed to detect significant inflammatory lesions and showed only foci of necrosis and wide-spread demyelination. This study supports an autosomal recessive inheritance for this syndrome. The high level of interferon-alpha is not explained but may play a role in the pathogenesis of the disorder.

Atrophy↗
PubMed1998

Role of anti-interferon antibodies in breakthrough occurrence during alpha 2a and 2b therapy in patients with chronic hepatitis C.

BACKGROUND/AIMS: Alpha interferon induces aminotransferase normalization in about 50% of patients with chronic viral hepatitis C. However, some patients who initially respond experience a relapse during the treatment period (breakthrough phenomenon). The aim of this study was to evaluate the prevalence of breakthrough and its relationship with the emergence of neutralizing anti-interferon antibodies. METHODS: We studied 172 patients with histologically proven chronic hepatitis C, treated with interferon alpha 2a or 2b 3 mega units three times a week for 6 months. For each patient, HCV RNA level (polymerase chain reaction and bDNA) and anti-interferon antibodies dosage were determined during therapy. RESULTS: Among 84 patients with initial response, 13 (15.5%) experienced breakthrough. The kinetics of alanine aminotransferase and HCV RNA levels were strongly correlated, suggesting that breakthrough is not due to a random alanine aminotransferase fluctuation during treatment, but to the reappearance of viral replication. Neutralizing anti-interferon antibodies emergence was observed in 38.5% in patients with breakthrough, as compared to 9.0% and 2.8% of non-responder and complete-responder patients, respectively (p<0.0005). By multivariate analysis, the only factor predictive of breakthrough was the emergence of neutralizing anti-interferon antibodies 3 months after the onset of therapy. CONCLUSION: Our results suggest that the emergence of neutralizing anti-interferon antibodies during treatment may explain breakthrough in about one third of cases. Other causes may also be responsible for this phenomenon and they remain to be determined.

Adult↗
PubMed1998

Aicardi-Goutières syndrome: an expanding phenotype.

The Aicardi-Goutières syndrome (AGS) is an autosomal recessive progressive encephalopathy associated with basal ganglia calcification, white-matter abnormality, cerebro-spinal fluid (CSF) pleocytosis and elevated CSF interferon alpha (IFN alpha). Two brothers of consanguineous parents who presented in the first year with developmental delay are reported. The first boy is normocephalic with spastic diplegia and normal I.Q. Tests in the second year of life showed punctate calcification of the basal ganglia and subcortical white matter and CSF pleocytosis. At 9 years clinical and imaging features are unchanged and CSF including IFN alpha is normal. The second boy at 21 months has dystonic cerebral palsy, slight fall-off in head growth and cognitive delay. Imaging abnormalities are more severe than those in the brother, CSF examination reveals pleocytosis and marked increase in IFN alpha. Detailed metabolic and viral studies were negative in both cases. Although the clinical course is not progressive, it is suggested that the brothers have AGS and represent the mild end of the spectrum of the disorder. CSF examination (including IFN alpha), should be performed early in children with an apparently static encephalopathy and brain calcification, as typical abnormalities decrease or disappear with age.

Basal Ganglia Diseases↗
PubMed1998

Multicenter evaluation of the Amplicor Enterovirus PCR test with cerebrospinal fluid from patients with aseptic meningitis. The European Union Concerted Action on Viral Meningitis and Encephalitis.

The Amplicor Enterovirus PCR test was compared with viral culture for the detection of enteroviruses in cerebrospinal fluid (CSF) specimens. In a multicenter study in which nine laboratories participated, a total of 476 CSF specimens were collected from patients with suspected aseptic meningitis. Sixty-eight samples were positive by PCR (14.4%), whereas 49 samples were positive by culture (10.4%), demonstrating that the Amplicor Enterovirus PCR test was significantly more sensitive than culture (P < 0.001). After discrepancy analysis the sensitivity and specificity of the Amplicor Enterovirus PCR test obtained by using viral culture as the "gold standard" were 85.7 and 93.9%, respectively. Our results with the CSF specimens collected in different countries demonstrate that the Amplicor test is capable of detecting a large variety of enterovirus serotypes and epidemiologically unrelated isolates in CSF specimens from patients with aseptic meningitis. The Amplicor Enterovirus PCR test is a rapid assay which can be routinely performed with CSF samples and is an important improvement for the rapid diagnosis of enteroviral meningitis.

Cerebrospinal Fluid↗
PubMed1998

Variations of HSV-1 glycoprotein B in human herpes simplex encephalitis.

The factors which cause herpes simplex encephalitis (HSE) to occur among herpes simplex virus type 1 (HSV-1) infected humans are not understood. In experimental models, HSV-1 neuroinvasiveness is influenced by amino acid changes in HSV glycoproteins D (gD) or B (gB), which are essential to the virus infectivity and to the induction of host immune responses. To test the possible involvement of these glycoproteins in human HSE, we compared CSF-derived sequences of these genes with those obtained from peripheral HSV-1 isolates. We have previously shown the conservation of gD in 10 HSE samples. Here, we show that the functional domains of gB involved in cell penetration and cell fusion, and the major antigenic domains D2a, D2b and Dd5a were highly conserved. In the gB amino-terminal domain, we distinguished several alleles that were common to HSE and peripheral isolates, and identified in only three out of fifteen HSE cases, a variation that was not encountered in 20 control strains. Overall, there were no striking differences between peripheral and HSE gBs. These results suggest that gB alone may not be responsible for neuroinvasiveness nor human neuropathogenicity.

Adolescent↗
PubMed1997

Etiology and response to antibiotic therapy of community-acquired pneumonia in French children.

The aim of this study was to determine the etiologic agents associated with community-acquired pneumonia in 104 French children ages 18 months to 13 years. Potential respiratory pathogens were identified in 87 (85%) cases; these included respiratory syncytial virus in ten, other viruses in 20, Streptococcus pneumoniae in 14 and Mycoplasma pneumoniae (diagnosed by serologic procedures) in 43. Of 32 patients with Mycoplasma pneumoniae infection who were initially treated with beta-lactam antibiotics, 30 failed treatment. Recovery from mycoplasma infection occurred rapidly in patients treated with macrolide antibiotics (which included spiramycin in 31 patients, josamycin in 7, and erythromycin in 3); however, cough persisted in 12 patients for one month. The high frequency of Mycoplasma pneumoniae in children over 18 months of age must be considered when selecting an antibiotic for initial therapy.

Adolescent↗
PubMed1997

Prenatal diagnosis of fetal varicella-zoster virus infection with polymerase chain reaction of amniotic fluid in 107 cases.

OBJECTIVE: Varicella, resulting from primary infection by varicella zoster virus, carries a risk of severe congenital varicella. Prenatal diagnosis is rarely applied because methods remain to be validated. STUDY DESIGN: From 1989 to 1994, 107 women contracted clinical varicella before 24 weeks of pregnancy. Amniocentesis was performed in all cases, with simultaneous fetal blood sampling in 82 cases. Virus was detected in amniotic fluid by cell culture inoculation and polymerase chain reaction. Fetal blood was tested for anti-varicella zoster virus immunoglobulin M. RESULTS: Of the 107 amniotic fluid samples tested, nine of 107 (8.4%) were positive by polymerase chain reaction, but only two of these (1.8%) were positive in cell culture; none of the blood samples from infected fetuses were positive for specific anti-varicella zoster virus immunoglobulin M. The outcome of 99 pregnancies was fully documented. CONCLUSION: The risk of transplacental passage before 24 weeks of pregnancy was 8.4% in our series. The risk of congenital varicella is 3 in 107 (2.8%) and that of isolated postnatal varicella zoster infection is 3 in 78 (3.8%). Polymerase chain reaction is more sensitive than cell culture for the detection of varicella zoster virus in amniotic fluid.

Amniotic Fluid↗
PubMed1997

Specific diagnostic methods for herpesvirus infections of the central nervous system: a consensus review by the European Union Concerted Action on Virus Meningitis and Encephalitis.

BACKGROUND: Herpesvirus infections of the central nervous system are often severe but are fortunately rare. The incidence of these infections has however, increased in recent years as a consequence of an increase in the number of immune-compromised individuals. New diagnostic procedures have improved our ability to diagnose these infections and herpesviruses may yet be implicated as the cause of further neurological diseases with no known aetiology. Methodological standards for selection and evaluation of patient materials are essential to the provision of reliable diagnosis, yet few studies have addressed this important issue. OBJECTIVES: To describe and define methodological standards and reference methodology for diagnosis of herpesvirus infections of the CNS. STUDY DESIGN: Information gathered by literature review. RESULTS: Only for herpes simplex encephalitis is there sufficient data to allow the definition of reference methodology. Good methodological standards exist but few studies have adhered to these standards. As methods for the detection of specific intrathecal antibody synthesis are well established yet under-used in diagnostic virology, the principle of these measurements is reviewed in some detail. CONCLUSIONS: Herpesvirus infections of the CNS are of increasing importance. High quality, multi-centre studies are needed to establish the value of the new diagnostic test procedures if further improvement in the diagnostic sensitivity and specificity of these procedures is to be achieved.

Brain↗
PubMed1997

Measurement of procalcitonin levels in children with bacterial or viral meningitis.

We measured the plasma procalcitonin levels in 59 children who were admitted to the hospital because of bacterial or viral meningitis. Eighteen children with acute bacterial meningitis had elevated procalcitonin levels (mean level, 54.5 micrograms/L; range, 4.8-110 micrograms/L). The procalcitonin levels in 41 children with viral meningitis were low (mean level, 0.32 micrograms/L; range, 0-1.7 micrograms/L; P < .0001). Assay of cerebrospinal fluid (CSF) cells and proteins and serum C-reactive protein showed a zone of overlapping values between the two groups. Procalcitonin was not produced in CSF. Plasma procalcitonin levels decreased rapidly during antibiotic therapy. These data suggest that the measurement of plasma procalcitonin might be of value in the differential diagnosis of meningitis due to either bacteria or viruses.

Adolescent↗