PubMed Health⌕ Search

Biomedical subjects

Françoise Stoll-Keller

Publications and source records attributed to Françoise Stoll-Keller.

12 recordsLinked to original sources
PubMed2006

Early decrease in circulating dendritic cells number after liver transplantation could favor hepatitis C virus recurrence.

Cirrhosis and hepatocarcinoma related to hepatitis C virus (HCV) lead to more than 30% of liver transplantations. Host- and virus-related mechanisms, involved in the recurrence of HCV infection of the liver graft, are not yet well known. A weak CD4+ T-cell response was shown to be involved in the outcome of re-infection but whether dendritic cell numbers are modified in patients transplanted for HCV-related disease has never been evaluated. Eight transplanted patients for HCV-related disease and eight non-HCV-infected transplanted controls were included. Blood plasmacytoid dendritic cells and myeloid dendritic cells were quantified before transplantation, at day 7 and 1 month after transplantation. Plasma interferon (IFN)-alpha and interleukin (IL)-12 were concomitantly measured. The results showed a significant decrease in the relative (P < 0.0001) and absolute (P = 0.0002) values of blood plasmacytoid dendritic cells at day 7 after transplantation when compared to the values obtained before transplantation, increasing again 1 month later, in both HCV-infected patients and controls. The same tendency was observed for myeloid dendritic cell relative values (P = 0.0004) and plasma IL-12 (P < 0.05). IFN-alpha appeared to be less often detectable for HCV-infected patients. These results obtained on dendritic cell numbers could explain partially the early and systematic recurrence of HCV infection on the liver graft and contribute to better adapted therapeutic strategies.

Cell Count↗
PubMed2005

Evaluation of three commercially available hepatitis C virus antibody detection assays under the conditions of a clinical virology laboratory.

BACKGROUND: Most studies evaluating antibody detection assays are conducted on samples from healthy blood donors but not on samples of hospitalized patients which can show non-specific reactions. OBJECTIVES: To compare the performance of three commercial automated assays for the detection of hepatitis C virus (HCV) antibodies, Monolisa anti-HCV Plus version 2, Axsym anti-HCV 3.0 and Vitros anti-HCV, on a population of hospitalized patients. STUDY DESIGN: The specificity of the assays was prospectively evaluated in 2020 routine serum samples. In order to assign the serostatus of each sample, those giving positive or discordant results were further tested by three immunoblots and by RT-PCR (Roche). Moreover, the sensitivity was evaluated on eight commercial HCV seroconversion panels. RESULTS: The Monolisa, Axsym and Vitros assays showed specificities of 99.64%, 99.12% and 99.33%, respectively. Concerning the sensitivity, among 49 samples, the number of positive results was 21, 24 and 24 for the Monolisa, Axsym and Vitros kits, respectively. The differences were not statistically significant at an alpha risk of 5%. CONCLUSIONS: All assays appeared to be reliable for routine screening, but there were a surprising number of indeterminate samples that could not be resolved by confirmatory tests.

Algorithms↗
PubMed2005

Monitoring low cytomegalovirus viremia in transplanted patients by a real-time PCR on plasma.

Until recently, human cytomegalovirus (hCMV) infection and anti-CMV treatment in transplanted patients have been monitored essentially by pp65 antigenemia, which is time-consuming and requires experienced operators. For the last two years, pp65 antigenemia levels have tended to be lower than previously in our laboratory, which could be due to better monitoring of CMV-related risk. Results obtained by real-time PCR with a LightCycler instrument or by pp65 antigen assay were compared on 145 serial samples from bone marrow or kidney transplant recipients under the usual conditions of our laboratory. CMV DNA was extracted from plasma and quantified by using primers and probes directed to HXFL4 gene. The plasma CMV DNA load was measured by using a standard curve constructed with a commercially available quantified CMV DNA suspension. Among the 145 samples, 139 showed a pp65 antigen which was negative or lower than 20 positively stained cells per 200,000 leukocytes. In the patients with positive pp65 antigenemia, the corresponding values of CMV DNA copy number/ml were significantly higher than those observed in patients without antigenemia (P < 0.001). CMV DNA was detected from 4 up to 52 days before pp65 antigen. Elsewhere, between two dates at which pp65 antigen was positive, intermediate PCR results could be positive while the pp65 antigen was negative. This real-time quantitative PCR assay is a rapid technique adapted to monitor plasma CMV DNA in transplant setting, even for low viremia.

Adult↗
PubMed2004

Expertise of French laboratories in detection, genotyping, and quantification of hepatitis C virus RNA in serum.

Before initiating new large-scale therapeutic trials for hepatitis C virus (HCV)-infected patients, the French Health Authorities for HCV research decided to organize an evaluation of the expertise of laboratories that could be engaged to undertake molecular biology assays in such trials; 21 experienced laboratories participated in this national evaluation of laboratory expertise, which was performed in two successive rounds. The first round evaluated the laboratories for their abilities to detect HCV RNA in serum, determine genotypes, and quantify HCV RNA loads. The results observed by qualitative assays for HCV RNA detection were 100% sensitivity and 100% specificity for all laboratories. The genotyping results were 100% concordant for 9 laboratories and greater than 90% for 10 laboratories. By contrast, large coefficients of variation were observed for quantitative determination of HCV RNA loads, leading to a second round with standardized quantitative assays only. The dispersion of the results was larger by the AMPLICOR HCV Monitor assay than by the branched-DNA assay (mean coefficients of variation, 57.4 and 16.9%, respectively). In the majority of cases, discrepancies between the results of the two tests were found for samples with high viral loads. These results indicate the usefulness of validating, by controlling for expertise, both the reliabilities of laboratories involved in multicenter work and the standardized assays chosen for use in the evaluation of the biological impacts of new therapies.

Analysis of Variance↗
PubMed2003

A study of susceptibility of primary human Kupffer cells to hepatitis C virus.

BACKGROUND/AIMS: Histological examination of a liver-biopsy from a patient with chronic hepatitis C shows activated Kupffer cells. In vitro infection of human Kupffer cells (KC) was performed to study their interaction with hepatitis C virus (HCV). METHODS: KC, isolated by collagenase perfusion and centrifugal elutriation, were infected with various HCV positive sera. The presence of the viral genome was followed, at different times, quantitatively by a branched-DNA assay and qualitatively by reverse transcriptase-nested polymerase chain reaction. A strand-specific assay performed with the thermostable enzyme rTth was used to detect the synthesis of a negative replicative intermediate. Cytopathic effect was examined by electron microscopy. Production of cytokines and inducible nitric oxide synthase was evaluated in the supernatants. RESULTS: Quantification of HCV-RNA showed that the level of viral RNA associated with KC after adsorption decreased rapidly. Genomic viral RNA disappeared within 5 days of infection. Negative-strand RNA was never detected in any of these experiments. No cytopathic effects could be detected at any time. KC did not produce inflammatory nor antiviral cytokines. CONCLUSIONS: Our results strongly suggest that primary cultures of KC are not permissive for HCV in vitro.

Disease Susceptibility↗
PubMed2003

Assisted reproduction techniques for HIV serodiscordant couples: 18 months of experience.

BACKGROUND: Assisted reproduction techniques can minimize the risk of infection and treat possible sterility associated with serodiscordant couples. METHODS: We assessed the efficacy of these techniques in 57 couples in which at least one partner had human immunodeficiency virus (HIV-1) infection that was currently under control (47 men and 10 women). The semen of seropositive men was prepared and tested for viruses. Assisted reproduction techniques included intrauterine insemination (IUI), IVF and especially ICSI, with ovarian stimulation that used a long agonist protocol and recombinant FSH. Embryos were transferred on day 3 after oocyte retrieval. RESULTS: For couples with seropositive men, five IUI and 49 IVF or ICSI attempts were perfomed, whilst for seropositive women these numbers were three IUI and 12 IVF or ICSI. No pregnancy occurred following the eight IUI trials. Seroconversion was not observed in any partners of seropositive men. Efficacy of treatment for these couples with ICSI was good, the clinical pregnancy rate per embryo transfer was 48.8%. The results for seropositive women were disappointing, with a clinical pregnancy rate per embryo transfer of 9.1%. Fourteen babies from 47 treated couples have so far been born and no pregnancies from IUI. CONCLUSIONS: Assisted reproduction techniques and particularly ICSI provide HIV-1-seropositive men with a safe and highly effective means of fathering children. These techniques may be less effective for seropositive women.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Persistent multiple pulmonary nodules in a nonimmunocompromised woman after varicella-related myelitis treated with acyclovir.

Persistent multiple pulmonary nodules were observed on the chest X ray of a nonimmunocompromised woman 6 months after she was treated with acyclovir for a varicella-related myelitis without respiratory symptoms. Early antiviral therapy given for varicella infections might decrease the intensity of clinical symptoms without actually preventing the occurrence of varicella-zoster virus-related lesions such as the persistent pulmonary nodules reported here.

Acyclovir↗
PubMed2003

Multicenter quality control for the detection of hepatitis C virus RNA in seminal plasma specimens.

The discrepant results available in the literature about the presence of hepatitis C virus (HCV) RNA in seminal plasma of men chronically infected by this agent are related, at least in part, to the molecular techniques used and particularly to the wide range of protocols dedicated to RNA extraction. In order to evaluate these protocols and to standardize the method of detection of HCV RNA in this fluid, a panel of coded specimens was tested blindly in 12 French laboratories; it included 14 seminal plasma specimens and four water controls spiked with HCV RNA ranging from 10 to 20000 IU/ml and two HCV-negative seminal plasma specimens. The extraction step was performed according to methods using either silica beads (NucliSens [Organon Teknika S.A., Fresnes, France]; RNA viral kit [Qiagen, Courtaboeuf, France]) or guanidinium thiocyanate (Amplicor HCV assay; Roche Diagnostics, Meylan, France), preceded or not by a centrifugation of the seminal plasma. For the amplification step, all the laboratories performed the same reverse transcription-PCR technique (Amplicor HCV Cobas assay). The percentage of correct results ranged from 53.3 to 100, the poorest results being obtained when no centrifugation step preceded the Amplicor extraction protocol. The rate of correct results was significantly higher in laboratories using a preliminary centrifugation of the specimen (P = 0.034 by chi-square test). By contrast, the overall number of correct results was not correlated to the initial volume of sample used for the test. These results allowed us to validate standardized techniques adapted to the performance of this test on a routine basis, especially in men infected with HCV and involved in programs of medically assisted reproduction.

Hepacivirus↗
PubMed2003

[Immunomodulating effect of HCV during the development of chronic hepatitis C: toward new therapeutic approaches].

In France, HCV seroprevalence is estimated to be 1%. Most cases are related to illicit parenteral drug use. About 80% of patients infected by HCV will develop chronic infection with HCV RNA detectable in their serum. Factors involved in viral persistence are nor yet clearly identified. Patients who develop a chronic infection show a predominant Th2 response, but a weak Th1 response. This immune response imbalance could result from HCV interaction with dendritic cells functions. Several experimental and clinical studies support this hypothesis. New data on HCV strategy to establish chronic infection suggest that immmunomodulatory molecules could be useful to improve efficacy of therapy.

Adjuvants, Immunologic↗
PubMed2002

Dendritic cell susceptibility to hepatitis C virus genotype 1 infection.

In vitro infection of human monocyte-derived dendritic cells was carried out to study their susceptibility to hepatitis C virus (HCV) infection. Immature dendritic cells and mature dendritic cells were incubated overnight at 37 degrees C with HCV-positive (genotype 1) serum samples; the presence of the viral genome associated with the production of its replicative intermediate was used as evidence of infection. In immature dendritic cells, HCV RNA was detectable from days 1-10 post-infection (p.i.), and de novo synthesis of negative-strand HCV RNA could be demonstrated by a strand-specific rTth reverse transcription-polymerase chain reaction at day 2. In mature dendritic cells, the positive-strand form was detectable from days 1-5 p.i., while the negative-strand HCV RNA appeared at days 1 and 2 p.i. Quasispecies present in the inoculum and 6 days p.i. were analyzed by sequencing hypervariable region 1 of the E2 protein. Only two of seven HVR variants present in the inoculum were found in HCV-infected immature dendritic cells. Another two HVR variants not found in the inoculum were recovered from infected immature dendritic cells, suggesting serum minor variants selection or virus evolution during in vitro replication. Analysis by single-strand conformation polymorphism assay of 5' untranslated region of HCV sequences showed that the patterns obtained from the inoculum and infected immature dendritic cells and mature dendritic cells differed slightly. These findings indicate that both immature dendritic cells and mature dendritic cells are susceptible to HCV genotype 1 infection, supporting at least HCV RNA replication. This model should be a valuable tool for the study of modulation of dendritic cell functions in HCV infection.

Amino Acid Sequence↗