Marie-Edith Lafon

Nerves and perisinusoidal cells in human liver

Unmyelinated nerve fibres are visible in the human hepatic lobule. They extend through the Disse space, surrounded by Schwann cell processes, often close to perisinusoidal cell processes. A few bare nerve endings or varicosities are found contiguous to either hepatocytes or perisinusoidal cells. These nerve endings or varicosities contain large and small granular vesicles and small clear vesicles. This heterogeneity probably corresponds to the presence of various neurotransmitters (noradrenaline, acetylcholine, various neuropeptides...). The effect of nerves on perisinusoidal cells has not yet been elucidated. However, the location, shape, morphology and origin of perisinusoidal cells would suggest that they play a role in the hemodynamic regulation of sinusoidal blood flow. It has recently been shown how important non-parenchymal-parenchymal communication is in the action of nerves on glucose release by hepatocytes; the cell to cell communications may also apply to nerves and sinusoidal cells for the hemodynamic regulation of sinusoidal blood flow.

Long-term expansion of effector/memory Vδ2− γδ T cells is a specific blood signature of CMV infection

The ability of human gammadelta T cells to develop immunologic memory is still a matter of debate. We previously demonstrated the involvement of Vdelta2- gammadelta T lymphocytes in the response of immunosuppressed organ recipients to cytomegalovirus (CMV). Here, we demonstrate their ability to mount an adaptive immune response to CMV in immunocompetent subjects. Vdelta2- gammadelta T-cell peripheral blood numbers, repertoire restriction, and cytotoxicity against CMV-infected fibroblasts were markedly increased in CMV-seropositive, compared with CMV-seronegative, healthy persons. Whereas Vdelta2- gammadelta T cells were found as naive cells in CMV- patients, they virtually all exhibited the cytotoxic effector/memory phenotype in CMV+ patients, which is also observed in transplanted patients challenged with CMV. This long-term complete remodeling of the Vdelta2- gammadelta T-cell population by CMV predicts their ability to exhibit an adaptive anti-CMV immune response. Consistent with this, we observed that the secondary response to CMV was associated with a faster gammadelta T-cell expansion and a better resolution of infection than the primary response. In conclusion, the increased level of effector-memory Vdelta2- gammadelta T cells in the peripheral blood is a specific signature of an adaptive immune response to CMV infection of both immunocompetent and immunosuppressed patients.

Occult Hepatitis B Virus Infection in HIV-Infected Patients with Isolated Antibodies to Hepatitis B Core Antigen: Aquitaine Cohort, 2002–2003

We prospectively assessed the prevalence of occult hepatitis B virus (HBV) infection by investigating HBV replication in 160 human immunodeficiency virus (HIV)-infected patients with isolated antibodies to hepatitis B core antigen. This prevalence was 0.6% (1 case/160 patients; 95% confidence interval, 0%-3.4%). A second serum sample was collected later from 52 of the patients. HBV DNA was once again undetectable in all patients, except for the sole patient who had previously been found to be HBV DNA positive.

Detection of JC virus DNA in the peripheral blood leukocytes of HIV-infected patients.

ObjectivesTo assess whether JC virus (JCV) DNA is frequently harboured by peripheral blood leukocytes (PBL) in HIV-positive patients, before the onset of progressive multifocal leukoencephalopathy (PML). DesignThe polyomavirus JCV induces PMI in immunocompromised persons and particularly AIDS patients. Leukocytes may play a central part in the onset of PML, but their precise role in JCV latency and reactivation still remains hypothetical. The controversial presence of JCV DNA in PBL has been, until now, investigated only among small groups of patients. We therefore studied 157 HIV-positive persons and compared them with 65 HIV-negative immunocompromised patients. MethodsDNA was extracted from PBL. The presence of JCV DNA was demonstrated by the polymerase chain reaction (PCR) alone or combined with a molecular hybridization assay. ResultsThe presence of JCV DNA was ascertained by PCR and hybridization in 28.9% of 135 HIV-infected persons at all stages of HIV infection and only 16.4% of 61 HIV-negative immunocompromised patients. No correlation could be drawn between the detection of JCV DNA and the clinical or biological status of the HIV-positive patients. ConclusionsJCV DNA is detectable in the PBL of 28.9% of HIV-infected persons, even in the early stages of infection. JCV is more seldomly amplified in I HV-negative immunocompromised patients. Further work is in progress to determine the prognostic value of the presence of JCV DNA in the blood of HIV-positive patients.

HIV type 1 isolates from 200 untreated individuals in Ho Chi Minh City (Vietnam): ANRS 1257 Study. Large predominance of CRF01_AE and presence of major resistance mutations to antiretroviral drugs.

HIV-1 isolates from 200 untreated patients recruited in 2001 and 2002 in the south part of Vietnam and particularly in Ho Chi Minh City were sequenced in the RT, protease, and env genes. Out of 200 isolates 198 belonged to CRF01_AE while only one subtype B and one intersubtype (B-CRF01_AE) recombinant could be observed. Of the isolates 6.5% had major resistance mutations to antiretroviral drugs.

JC Virus Genotypes in France: Molecular Epidemiology and Potential Significance for Progressive Multifocal Leukoencephalopathy

JC virus (JCV) induces progressive multifocal leukoencephalopathy (PML), especially in human immunodeficiency virus (HIV)-infected patients. Although JCV genotypes have primarily been associated with geographic patterns, a distinctive neuropathogenicity was recently attributed to genotype 2. A multicenter study was conducted to describe the distribution of JCV genotypes in France and to investigate correlations between genotypes and PML. Genotypes were determined by sequencing 494 bp in the VP1 capsid gene. Peripheral JCV was studied in 65 urine samples from 43 HIV-infected patients and from 22 control subjects. Genotypes 1, 4, 2, and 3 were detected in 52.3%, 30.8%, 12.3%, and 4.6% of the samples, respectively. In 56 brain or cerebrospinal fluid samples, PML-associated JCV of genotypes 1, 2, 4, and 3 was found in 66%, 19.7%, 8.9%, and 5.4%, respectively. Infection with JCV genotypes 1 or 2 was correlated with PML (odds ratio, 3.29). On the other hand, infection with JCV genotype 4 could represent a lower risk for PML.

JC Virus Remains Latent in Peripheral Blood B Lymphocytes but Replicates Actively in Urine from AIDS Patients

JC virus (JCV) is thought to reach the central nervous system by a vascular route. To determine whether JCV is conveyed in peripheral blood as latent or reactivated virus, blood leukocytes, plasma, and urine from 50 AIDS patients and plasma and B lymphocytes from 60 AIDS patients were investigated. Peripheral blood from 88 human immunodeficiency virus-negative blood donors was studied. Nested polymerase chain reaction assays allowed the identification of JCV T DNA and VP1 mRNAs. The latter indicate viral replication. Blood harbored JCV DNA in 31.8% of AIDS patients (only 2.3% of blood donors; P > .001) and urine in 56%. VP1 mRNAs were detected in blood of 1 AIDS patient. Notably, 38% of DNA-positive urine samples and 10 cerebrospinal fluid samples (CSF) from AIDS patients with progressive multifocal leukoencephalopathy contained JCV mRNAs. Thus, JCV was significantly more frequent in blood from AIDS patients than from controls, but, in most instances, it was latent, whereas active replication was detected in urine and CSF.

Qualitative and quantitative molecular detection of enteroviruses in water from bathing areas and from a sewage treatment plant.

Pathogenic enteric viruses can be introduced into the environment as a result of human activities. Enteroviruses are regularly detected in environmental waters or shellfish and can provoke potentially serious diseases. Some authors believe that enteroviruses could represent an interesting indicator of viral contamination in the environment. Since molecular approaches seem to be promising for the detection of these viruses, we developed a simple qualitative RT-PCR procedure for enteroviruses, together with a quantitative RT-PCR assay using RNA internal standard. After one-tube-RT-PCR, this standard and wild enterovirus RNA were detected by differential hybridization with specific probes and a fluorimetric reaction. The quantification of enteroviruses, conducted in a sewage treatment plant, showed a decreasing number of genomic copies from the entrance to the exit (from 3.8 x 10(5) to 5.4 x 10(4) RNA copies/mL) but indicated the presence of enterovirus RNA in the neighboring river (2.2 x 10(3) RNA copies/mL). In bathing areas, enterovirus RNA was detected in 16 out of 226 samples, with copies numbers ranging from 3.7 x 10(2) RNA copies/mL to 7 x 10(4) RNA copies/mL.

New Molecular Assays to Predict Occurrence of Cytomegalovirus Disease in Renal Transplant Recipients

Thirty renal transplant recipients, after transplantation, were tested weekly with the following assays: cytomegalovirus (CMV) antigenemia (pp65 Ag), plasma qualitative Amplicor CMV (P-AMP), plasma and peripheral blood leukocyte quantitative Amplicor CMV monitor (P- and PBL-CMM), peripheral blood leukocyte (PBL) quantitative Quantiplex bDNA CMV, version 2.0 (bDNA), and whole-blood Nuclisens pp67 CMV (pp67). Eleven patients developed symptomatic CMV disease, and 7 developed asymptomatic CMV infection. For prediction of CMV disease, the sensitivity, specificity, and positive and negative predictive values, respectively, were as follows: 100%, 63%, 61%, and 100% for pp65 Ag; 100%, 42%, 50%, and 100% for bDNA; 91%, 47%, 50%, and 90% for PBL-CMM; 55%, 74%, 55%, and 74% for P-AMP; 55%, 74%, 55%, and 74% for P-CMM; and 64%, 79%, 64%, and 79% for pp67. First positive results in PBL were obtained 9-10 days before symptoms of CMV disease, compared with 5-6 days in plasma and 0 days in whole blood. PBL assays appear to be more appropriate than plasma assays when pre-emptive therapy is required to prevent the rapid progression from the first detection of the virus to CMV disease.

PCR detection of human enteric viruses in bathing areas, waste waters and human stools in southwestern France

Detection of human pathogenic viruses by molecular techniques might be suitable for identifying viral pollution in environmental waters and for improving diagnosis in patients. Environmental samples were taken from bathing areas and sewage treatment plants in southwestern France. Small volume samples (50 microL) were tested. Five groups of enteric pathogenic viruses were studied: enteroviruses, Norwalk-like viruses (NLVs), hepatitis A virus, rotaviruses and adenoviruses. Moreover, human samples were tested for NLV. After extraction of viral nucleic acids (Booms procedure), a nested polymerase chain reaction was conducted before hybridization. Five bathing waters out of 26 were positive for one viral group, without systematic association with bacterial contamination. Eight sewage plant samples out of 13 were positive for at least one viral group. Seven patients out of 45 were NLV-positive. Molecular techniques allow efficient screening of viral contamination in environmental waters and the study of NLV molecular epidemiology.